Update on another potential severe weather system on Friday

After a day like today, with a borderline moderate risk setup and Tornado Watch that ends up busting pretty bad, it would be understandable to head into the next event with a little skepticism.  However, this is what meteorologists do - mess one up, then get back up and charge full-steam into the next! So here we go!

Since most of our efforts the past few days have been concentrated on today's events, we haven't talked too much about Friday. That would be the weatherman's version of the old sports cliche about "overlooking the next opponent." With today behind us now, it's time to look ahead. Despite talking publicly mostly about today, we have also kept a close eye on Friday and models are in pretty decent agreement with the latter portion of the event - the cold frontal passage and the weather associated with it.  What they absolutely do NOT agree on is the early morning hours and we'll start there.

In the wake of today's cold front, humidity has plummeted as Gulf moisture was shoved south. However, this will be short-lived as a warm front ahead of Friday's system surges back north Thursday night, bringing that warm moist air back to the Mid-South. A couple of normally reliable models (GFS, ECMWF) indicate that rain and thunderstorms will break out in the pre-dawn hours Friday morning around this warm front, with some possibly containing hail and a threat of strong wind. The other model we use a great deal (NAM) is the one that performed the best leading up to today's system and it says "no dice" on Friday morning.  The Storm Prediction Center and NWS-Memphis go with the former theory and we'll try it  again as well! SPC places the metro in a Slight Risk for large hail and strong wind with some storms early Friday.

We'll then see a break in the precip in the wake of the retreating warm front and prior to the arrival of the cold front, which should move into the metro in the early evening hours. The break will be a chance for the atmosphere to A) energize on abundant Gulf moisture flowing north on gusty wind and B) likely destabilize with some sunshine and temps warming into the mid to upper 70s. All models indicate widespread convection firing ahead of the cold front late Friday afternoon into Friday night.  The big question is - like today - does this happen to our west (putting us in line for severe storms) or to our east (missing the metro entirely)?  It'll be close.  For now, we plan for the worst and hope for the best. A Slight Risk is also in place for Friday afternoon and evening with the primary threat being damaging wind and isolated tornadoes. I would say the highest risk is east of the metro, particularly NE MS, north AL, and middle TN ,where the tornado threat may be a little higher as well.  The MWN Storm Center has maps showing the details. The good news is that once this system moves through Friday night, we'll be left with DRY conditions (and mild) for several days, including a nice looking weekend!

Expect an update again tomorrow. The full MWN Forecast can be found here.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe weather threat for Wednesday becoming better defined

Looking over the morning computer model data, there appears to be a dual-threat for strong storms in the next 24 hours.  While neither is particularly impressive, I feel the more likely threat of strong to severe storms comes with the second.  While models still have some significant discrepancies, that is why you have MWN!

The first window of opportunity is somewhat of a broad brush and covers the early morning hours Wednesday, or roughly from 2-8am. The main threats during this time frame will be hail and possibly some high wind gusts in the strongest storms. We expect the strongest storms, and better chance of severe weather, to be to the north and west of the metro, or over northern AR and northwest TN.

Slight Risk (yellow) area for tonight, as defined by SPC

The second chance for severe weather is ahead of and along the actual cold front, which now appears to move through the metro around mid-afternoon.  Thus, we'll put this "window" at 11am-4pm.  *IF* the morning convection can lull for a few hours (or longer) before the front approaches, I actually feel like the chance of damaging wind or hail could be a little higher with a squall line during the afternoon hours.  SPC indicates that we are just west of a 30% risk area tomorrow (see below), meaning the chance of severe weather within 25 miles is nearing 30%. Contributing to the higher risk is the timing - during peak daytime heating when temps should be in the mid 70s with a few dry hours leading up to the front. If rain continues throughout the morning, it may be a bit more difficult to get severe weather in the afternoon.

Probability of severe weather on Wednesday, as defined by SPC. Red is 30%. Yellow/red areas also in Slight Risk.

Once this threat has moved out, we'll focus more on Friday's weather event, but suffice it to say, the setup on Friday is definitely more favorable for severe weather and will bear watching closely.

As you prepare for the possibility of severe weather in the upcoming 4 days or so, be sure to put MWN's StormWatch+ service in your "severe weather toolkit." Not only does it push severe weather alerts for your specific location to your smartphone, but it will wake you up at night if a watch or warning is issued! Just place it on your nightstand or dresser and leave the ringer on. An audio tone (that I have been told DOES wake you up!) will sound when an alert is issued.  Remember: sirens are NOT designed to wake you at night, unless you live right under one. A personalized weather alert service is your best defense. Learn more about StormWatch+ and download it at StormWatchPlus.com.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

March arriving like a lion? Two potential severe weather events this week

MWN has been closely monitoring the weather situation for Tuesday night into Wednesday for several days now as a cold front brings a high chance for rain and thunderstorms, and possibly a risk of severe weather. In the 24 hours since our last update, computer models are beginning to come into better agreement, though some slight differences remain, and confidence is starting to increase on our risk of severe weather with this system.

On Tuesday, a warm front to our south will lift north towards the metro area. As it does, showers are expected to break out Tuesday afternoon and continue into early Tuesday evening until the warm front lifts north of the area. The threat of severe weather is expected to be very low with this activity and even thunder may be hard to come by.

Meanwhile, showers and thunderstorms will be organizing during the evening hours across Arkansas and eastern Oklahoma along and ahead of a slow moving cold front. As this activity progresses east-northeast toward the metro, likely after 9 PM and especially during the overnight, the risk of seeing a few strong to severe storms will begin to increase. As indicated yesterday, the amount of instability that will be in place is in question, but strong wind dynamics will be present. If any strong to severe storms do occur, the most likely threat is damaging winds with a secondary threat of hail. Though the threat for a tornado is not zero, it is unlikely, and would be highly dependent on sufficient levels of instability developing. As of this morning, the Storm Prediction Center put the metro area back under a “Slight Risk” for severe weather for the Tuesday night timeframe.

Storm Prediction Center's outlook for Tuesday (focus for the metro is Tue night)

As computer models have slowed the progress of the actual cold front, it appears it will move through the metro sometime around the late morning to early afternoon Wednesday. Thunderstorms are expected to redevelop along the front sometime during this period, and if they develop early enough to affect the metro, another threat for strong to severe storms will exist. Instability levels may be greater during this round, so a more robust threat for damaging winds and large hail could be in the works. The threat for a tornado is unlikely in this round as well. The Storm Prediction Center has the metro area under a “Slight Risk” for this period too.

NAM model forecast for noon Wednesday as cold front approaches metro area.

The front will pass east of the area Wednesday afternoon, taking the threat of severe weather with it. However, the front won’t be bringing any cooler air to the area. In fact, high temperatures Thursday and Friday will remain in the 70s, which begins the setup for potentially another strong system on Friday, with yet another threat for severe weather possible. Though it’s too early to get into specifics, and shifts in model data are likely in the days ahead, Friday’s severe weather threat could be the more significant of the two.

European model forecast for Friday afternoon when another threat for severe weather may develop.

MWN is closely monitoring both severe weather threats in the week ahead and those in the area are urged to stay updated via the methods at the bottom of the post. Once again, we emphasize that now is the time to make sure you are prepared for spring severe weather season, which may be kicking off this week. Be sure to review last week’s blog posts from severe weather awareness week for preparedness tips.

Finally, we also HIGHLY encourage you to have multiple methods of receiving notification of severe weather threats, especially overnight. NOAA Weather Radio is one; outdoor warning sirens may NOT wake you up and are not intended to. The other is StormWatch+ - now available in the MemphisWeather.net smartphone apps for Android and iPhone. This mobile alerting technology will send you an audio alert (that will wake you up if your phone is not silenced and it's close by) and push notification if your location is under a watch or warning. It's personalized weather alerting in the palm of your hand! Learn more and download the app at StormWatchPlus.com.

--Kevin Terry, MemphisWeather.Net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Update on potential severe weather early this week

As we first posted yesterday, MWN is closely monitoring the weather for Tuesday night as thunderstorms, including a threat for severe weather, may develop near or over the Mid-South region. Since yesterday’s initial post, the timing of this system has changed a bit on the computer models, and that has made some impact on the threat for the metro area.

NWS forecast for Wednesday AM, with advertised cold front now likely to pass through around mid-morning.

It now appears that the low pressure area and associated cold front will be moving through a bit later than first projected, and this means that rain and thunderstorms may move into the metro area later Tuesday night, especially overnight, and could now linger into the first part of Wednesday. With the likelihood of thunderstorms being pushed back potentially several hours in the metro, the greatest threat of severe weather on Tuesday is now likely to be focused further west. For this reason, the Storm Prediction Center has moved its “Slight Risk” area mostly out of the metro area, though we do sit just outside its eastern fringe. (There will be scattered showers and perhaps some thunder during the day Tuesday as a warm front lifts north through the region, but at this time the threat for severe weather during that time period is very low.)

The Storm Prediction Center's "Slight Risk" area has shifted west with this morning's update.

Despite the focus shifting west, the threat for severe weather in the metro has not been completely eliminated. With thunderstorms still likely to impact the area overnight Tuesday into Wednesday morning, and sufficient wind dynamics in place, some storms may remain strong as they move through the area with wind gusts the most likely hazard. The largest limiting factor to more widespread severe weather locally, partly due to the system’s later timing, will be instability.

With this event still more than 48 hours out, further adjustments are possible. If more sufficient instability levels appear in later models, or if the timing continues to change, our threat of severe weather may increase again. MWN is continuing to closely monitor this situation and will keep you updated via the methods at the bottom of the post.

As also indicated yesterday, now is a great time to make sure you are prepared for severe weather this spring.  Review the blog posts from earlier this week on various severe weather types and what to do in case severe weather strikes. We also HIGHLY encourage you to have multiple methods of receiving notification of severe weather threats, especially overnight. NOAA Weather Radio is one; outdoor warning sirens may NOT wake you up and are not intended to. The other is StormWatch+ - now available in the MemphisWeather.net smartphone apps for Android and iPhone. This mobile alerting technology will send you an audio alert (that will wake you up if your phone is not silenced and it's close by) and push notification if your location is under a watch or warning. It's personalized weather alerting in the palm of your hand! Learn more and download the app at StormWatchPlus.com.

--Kevin Terry, MemphisWeather.Net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Next potential severe weather event on the horizon

Signs of spring are beginning to show up everywhere you look - trees and flowers beginning to come to life, warmer days with later sunsets, and even my seasonal allergies are letting me know without a doubt that spring is near!  In fact, the calendar shows the first day of "meteorological spring" (defined as Mar-Apr-May) as next Thursday.  Another sign of spring is stronger storm systems that typically arrive about twice a week, bringing increasing chances of severe weather.

This past Thursday evening, a potent system moved through, preceded by near-80 degree temperatures and very gusty wind and followed by a much cooler but still breezy day yesterday.  Fortunately, the ingredients for thunderstorms didn't come together in our area with that one.  That may not be the case with the next system though...  Below is a graphical view of the possible setup for Tuesday and Wednesday of next week.  The Storm Prediction Center has highlighted the Mid-South for possible severe weather overnight Tuesday night.

The Storm Prediction Center's area of focus for Tuesday night

Tuesday AM setup - warm front to our north and developing low pressure over the Rockies

By Wednesday AM, a strong cold front is just east of the metro with deep low pressure over the Upper Midwest

Forecast dewpoint map valid at midnight Tuesday night/Wednesday morning. Mid 60s dewpoints  indicate very moist air from the Gulf of Mexico - enough moisture for strong thunderstorms. Remember temps also cannot be lower than the dewpoint, so this would indicate possible upper 60s to near 70 degree temps at midnight!

Forecast wind map valid midnight Tuesday night (same as above). 10-20 mph south wind - allowing Gulf air to surge north into the region.

These graphics don't provide all the details, but for 4-5 days out it gives us reason to keep a close eye on the situation.  The timing will likely change a little (especially this far out) and these maps likely won't reflect the exact situation when it unfolds. SPC indicates that severe weather COULD include the possibility of tornadoes with this system. MWN will monitor closely however and keep you updated via the methods at the bottom of the post.

Now would be a great time to make sure you are prepared for severe weather this spring. Review the blog posts from earlier this week on various severe weather types and what to do in case severe weather strikes. We also HIGHLY encourage you to have multiple methods of receiving notification of severe weather threats, especially overnight. NOAA Weather Radio is one; outdoor warning sirens may NOT wake you up and are not intended to. The other is StormWatch+ - now available in the MemphisWeather.net smartphone apps for Android and iPhone.  This mobile alerting technology will send you an audio alert (that will wake you up if your phone is not silenced and it's close by) and push notification if your location is under a watch or warning. It's personalized weather alerting in the palm of your hand! Learn more and download the app at StormWatchPlus.com.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week: SKYWARN storm spotters

SEVERE WEATHER AWARENESS WEEK CONCLUDES WITH A LOOK AT SKYWARN.

SEVERE WEATHER CAN STRIKE DURING ANY MONTH OF THE YEAR AT ANY TIME OF THE DAY OR NIGHT. WHEN SEVERE THUNDERSTORMS THREATEN... THE NATIONAL WEATHER SERVICE CALLS SKYWARN VOLUNTEERS INTO ACTION. SKYWARN VOLUNTEERS ARE THE EYES AND EARS OF THE NATIONAL WEATHER SERVICE... PROVIDING INSTANT REPORTS OF SEVERE WEATHER... INCLUDING HAIL... HIGH WINDS... AND DANGEROUS CLOUD FORMATIONS.

SKYWARN SPOTTERS KEEP A CLOSE EYE ON THE SKY ANYTIME SEVERE  THUNDERSTORMS APPROACH. MANY COMMUNITIES DEPLOY SPOTTERS AROUND THE EDGE OF THE CITY AND USE THEIR EARLY REPORTS OF IMPENDING HAZARDOUS WEATHER TO WARN THE COMMUNITY. SOME SPOTTERS RELAY REPORTS FROM THEIR HOME OR BUSINESS WHILE OTHER MORE ADVENTUROUS VOLUNTEERS BRAVE THE ELEMENTS AND TRY TO GET AS CLOSE TO THE STORM AS POSSIBLE.

WHO ARE THESE SKYWARN VOLUNTEERS? A LARGE NUMBER OF SKYWARN STORM SPOTTERS IN THE MID-SOUTH ARE AMATEUR RADIO OPERATORS... OR HAMS. THESE PUBLIC-SERVICE MINDED INDIVIDUALS MAKE IDEAL STORM SPOTTERS SINCE THEY HAVE THE ABILITY TO COMMUNICATE THEIR REPORTS. THEY ARE WILLING TO BE TRAINED AND THEY HAVE A REAL INTEREST IN HELPING THE NATIONAL WEATHER SERVICE AND THEIR LOCAL COMMUNITIES PREPARE FOR SEVERE WEATHER. AMATEUR RADIO OPERATORS ARE ON CALL 24 HOURS A DAY... 365 DAYS A YEAR... EVEN THOUGH THEY RECEIVE NO COMPENSATION OF ANY KIND FOR THEIR HARD WORK.

MANY OTHER GROUPS PARTICIPATE IN THE SKYWARN PROGRAM... INCLUDING LAW ENFORCEMENT AGENCIES... FIRE DEPARTMENTS... UTILITY COMPANIES... RESCUE SQUADS... AND THE NEWS MEDIA. IN SOME AREAS... INDIVIDUAL CITIZENS ARE TRAINED AS SPOTTERS... AND ARE ASKED TO RELAY THEIR REPORTS TO THE NATIONAL WEATHER SERVICE. SPOTTERS ARE A VITAL LINK  IN THE WARNING PROCESS... AND IT IS IMPORTANT TO HAVE AS MANY TRAINED SPOTTERS IN EACH COUNTY AS POSSIBLE.

THE NATIONAL WEATHER SERVICE CAN HELP YOUR COMMUNITY SET UP A SKYWARN SPOTTER NETWORK. FOR MORE INFORMATION ON SKYWARN AND HOW YOU CAN HELP... CONTACT THE NATIONAL WEATHER SERVICE OFFICE IN MEMPHIS TENNESSEE.

The annual Memphis SKYWARN spotter training class, which is free and open to the public, will be taught by the National Weather Service on Monday, March 19, from 7-9pm at Agricenter International, Walnut Grove at Germantown Parkway.  The class has been revamped and now includes elements of both basic and advanced training.  All current SKYWARN volunteers should attend as a refresher, while new volunteers are strongly encouraged to attend and learn how to be a spotter, what to look for, and how to report. Hope to see you there!

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week: Warning Alert Systems

...NOAA WEATHER RADIO AND THE EMERGENCY ALERT SYSTEM...

SEVERE WEATHER AWARENESS WEEK CONTINUES. TODAY WE WILL FOCUS ON WEATHER RADIO... AND THE EMERGENCY ALERT SYSTEM.

WEATHER RADIO IS THE VOICE OF THE NATIONAL WEATHER SERVICE. IT PROVIDES CONTINUOUS WEATHER INFORMATION 24 HOURS A DAY... EVERY DAY OF THE YEAR. THE NATIONWIDE NETWORK OF WEATHER RADIO STATIONS PROVIDES THE PUBLIC WITH THE FASTEST MOST RELIABLE SOURCE OF UP-TO-DATE WEATHER INFORMATION DIRECTLY FROM THE NATIONAL WEATHER SERVICE.

YOU NEED A SPECIAL RADIO TO RECEIVE WEATHER RADIO BROADCASTS... A RADIO THAT IS CAPABLE OF RECEIVING SIGNALS IN THE VERY HIGH FREQUENCY PUBLIC SERVICE BAND.

BROADCASTS MAY VARY... BUT GENERALLY INCLUDE AREA FORECASTS... PRESENT WEATHER CONDITIONS... SHORT-TERM FORECASTS... CLIMATIC DATA... RIVER AND LAKE STAGE FORECASTS... AND OTHER SPECIALIZED INFORMATION. THE BROADCASTS ARE UPDATED CONTINUOUSLY.

WEATHER RADIO IS USEFUL ANYTIME... BUT IT IS MOST IMPORTANT WHEN SEVERE WEATHER THREATENS. DURING PERIODS OF SEVERE WEATHER... ROUTINE PROGRAMMING IS INTERRUPTED... AND THE FOCUS SHIFTED TO THE LOCAL SEVERE WEATHER THREAT. IN AN EMERGENCY... A WARNING ALARM TONE IS BROADCAST THAT ACTIVATES SPECIALLY DESIGNED RECEIVERS TO TURN ON AUTOMATICALLY... OR TO PRODUCE A VISUAL OR AUDIBLE ALARM.

A PRIMARY SOURCE OF WEATHER INFORMATION IS THE EMERGENCY ALERT SYSTEM /EAS/. EAS IS A SYSTEM OF COMMUNICATIONS LINKS THAT UTILIZE DATA IN A DIGITAL FORM. IT IS A RELIABLE MEANS OF LINKING THE NATIONAL WEATHER SERVICE... EMERGENCY MANAGEMENT AGENCIES... AND THE RADIO AND TELEVISION BROADCAST MEDIA TOGETHER. EAS HELPS PARTICIPATING RADIO AND TELEVISION STATIONS RECEIVE AND RELAY WEATHER WARNINGS... AND OTHER EMERGENCY INFORMATION IN A TIMELY MANNER.

FOR MORE INFORMATION ON WEATHER RADIO... CONTACT THE NATIONAL WEATHER SERVICE OFFICE IN MEMPHIS TENNESSEE.

MemphisWeather.net strongly encourages every home to have a NOAA Weather Radio.  These devices are as important as smoke detectors and possess the same capability to save your life in the middle of the night.  Specifically, our favorites are from Midland and include the basic desktop version (WR-100) and the newer version of this model (WR-120).  They can be picked up at retailers such as Radio Shack, Walgreens, Kroger, and other discount stores, as well as online retailers like Amazon. Learn more about NOAA Weather Radio on MWN's Weather Radio page.

One problem (if you can call it that) with Weather Radio and warnings sirens for that matter is that they alert on a COUNTY-wide basis, even if the warning issued by the National Weather Service is for only a small portion of the county. To know if YOUR LOCATION is in the warned area, we highly recommend our latest weather warning product, StormWatch+.  StormWatch+ pairs the NWS polygons (or warning boxes that are drawn irrespective of county borders) with your GPS-provided location to send push notifications in the event that YOU are in harm's way. No more alerts when the storm is 20-30 miles away and not a threat to your area! Learn more about StormWatch+ at our brand new website - StormWatchPlus.com and get personalized weather alerts in the palm of your hand!

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week: Floods & Flash Floods

...FLOOD AND FLASH FLOOD AWARENESS DAY...

SEVERE WEATHER AWARENESS WEEK CONTINUES TODAY WITH A LOOK AT FLOOD AND FLASH FLOOD SAFETY.

FLOODS AND FLASH FLOODS OCCUR EVERY YEAR IN THE MID-SOUTH. RIVER FLOODING OCCURS SEASONALLY WHEN WINTER OR SPRING RAINS OR TORRENTIAL RAINS ASSOCIATED WITH TROPICAL STORMS FILL RIVER BASINS WITH TOO MUCH WATER TOO QUICKLY. FLASH FLOODS OCCUR SUDDENLY... USUALLY OCCURRING WITHIN HOURS OF EXCESSIVE LOCALIZED RAINFALL. THESE FLASH FLOODS CAN BECOME RAGING TORRENTS WHICH RIP THROUGH RIVER BEDS URBAN STREETS OR VALLEYS SWEEPING EVERYTHING BEFORE THEM.

WHEN A FLASH FLOOD WARNING IS ISSUED FOR YOUR COUNTY... OR THE MOMENT YOU FIRST REALIZE THAT A FLASH FLOOD IS IMMINENT... ACT QUICKLY TO SAVE YOURSELF. YOU MAY ONLY HAVE SECONDS.

A FLOOD WATCH MEANS IT IS POSSIBLE THAT HEAVY RAINS WILL CAUSE FLOODING IN THE SPECIFIED AREA. STAY ALERT TO THE WEATHER... AND THINK ABOUT WHAT YOU WOULD DO IF WATER BEGINS TO RISE OR IF YOU RECEIVE A WARNING. WATCH FOR DEVELOPMENT.

HERE ARE SOME FLASH FLOOD SAFETY RULES:

• GET OUT OF AREAS SUBJECT TO FLOODING. THIS INCLUDES DIPS... LOW SPOTS... VALLEYS... STREAM BANKS... AND FLOOD PLAINS.
• AVOID ALREADY FLOODED AND HIGH VELOCITY FLOW AREAS. DO NOT ATTEMPT TO CROSS A FLOWING STREAM ON FOOT WHERE WATER IS ABOVE YOUR ANKLES.
• IF DRIVING... KNOW THE DEPTH OF WATER IN A DIP BEFORE CROSSING. THE ROAD BED MAY NOT BE INTACT UNDER THE WATER. DON'T DRIVE INTO A POOL OF WATER OR WHERE WATER IS FLOWING. WATER UP TO THE BUMPER WILL LIKELY STALL A CAR.
• IF THE VEHICLE STALLS... ABANDON IT IMMEDIATELY AND SEEK HIGHER GROUND. RAPIDLY RISING WATER MAY ENGULF THE VEHICLE AND ITS OCCUPANTS AND SWEEP THEM AWAY.
• BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE FLOOD DANGERS. HEAVY RAIN EVENTS FREQUENTLY OCCUR AT NIGHT!
• DO NOT CAMP OR PARK YOUR VEHICLE ALONG STREAMS OR DRAINAGE AREAS PARTICULARLY DURING THREATENING CONDITIONS.

As you might have guessed, MemphisWeather.net has you covered with always-current information during potential and ongoing floods and flash floods!  The MWN Flood Center includes current radar and estimated precipitation totals, precipitation forecasts (amounts and timing), river levels and forecasts, and plenty of local resources.  In addition, StormWatch+, available via the MemphisWeather.net mobile apps for Android and iPhone, will alert you if you are in an area that is under a Flash Flood Watch or Warning.  Get the MemphisWeather.net app and learn more about StormWatch+ on this MWN page.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Small chance of a strong storm on Thursday

Many Mid-Southerners received an early wake-up call this morning thanks to thunderstorms, sparked by a passing upper level disturbance rolling through the region. Not only did some areas receive some significant rainfall, but a few places saw some pea-sized hail as well! With a cold front moving towards the Mid-South in the next 24 hours, another risk for rain or thunder may arrive with it.

The threat for any rain Thursday will first be preceded by a simply unseasonably warm afternoon. With mostly sunny skies and gusty south winds to 30 mph, high temperatures will skyrocket to the middle 70s, only a few degrees shy of a record 78 from 1982 (for Memphis).

Most computer models are placing the expected cold front near the Mississippi River during the early evening hours. However, moisture levels over the area will be limited as the front sweeps across, and this will prevent widespread rain and thunderstorms from developing. In fact, confidence is low that the metro area will even see any rainfall from this system. However, a small chance (about 20 to 30%) of a shower or thunderstorm will still exist from late Thursday afternoon into the evening.

NWS surface weather forecast map for early Thursday evening

Additionally, though the overall risk of rainfall is expected to be low, should a thunderstorm develop and pass through the metro area, there is a slight risk that the thunderstorm could intensify to strong or severe levels. A significant or widespread severe weather threat is NOT expected, but any storm could be capable of producing hail and/or gusty winds, with the most likely time for that activity in a narrow window between about 4 and 9 PM. The Storm Prediction Center currently has areas along and east of the Mississippi River in a Slight Risk for severe thunderstorms due to this threat (see graphic below).

Storm Prediction Center severe weather outlook for Thursday

The greater risk for thunderstorms, including severe weather, will likely develop east and south of the metro later Thursday night.  Meanwhile, once the front passes through, cooler temperatures will be arriving, and a breezy Friday – now with northwest winds! – is expected. Highs will be more seasonal, in the middle 50s and a full 20 degrees lower than Thursday’s levels.

MemphisWeather.Net will bring you updates during the day Thursday as the possibility of storms and the possible severity becomes more clear cut. Of course, you can also let us PUSH the information to you by downloading the MemphisWeather.net app with StormWatch+, now available for both Android and iPhone/iPad smartphones and tablets.  StormWatch+ will alert you (based on your chosen location) if you are under a Severe Thunderstorm or Tornado Watch or Warning.  Learn more about StormWatch+ here.

--Kevin Terry, MemphisWeather.Net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week: Tornadoes

...TORNADO AWARENESS DAY...

YOUR SAFETY DEPENDS ON BEING CONSTANTLY ALERT TO THE POSSIBILITY OF TORNADOES FROM THE THUNDERSTORMS THAT APPROACH YOU. THIS IS ESPECIALLY TRUE DURING TORNADO WATCHES. A CAREFUL LOOKOUT SHOULD BE KEPT DURING ANY PERIOD OF SEVERE WEATHER ACTIVITY. PLAN IN ADVANCE WHERE YOU WILL GO AND WHAT YOU WILL DO IF A TORNADO THREATENS YOU.

REMEMBER... A TORNADO WATCH MEANS THAT TORNADO DEVELOPMENT IS POSSIBLE... SO WATCH THE SKY FOR DEVELOPING THUNDERSTORMS AND ALL THE HAZARDS THEY BRING. STAY TUNED TO WEATHER RADIO... COMMERCIAL RADIO OR TELEVISION FOR WEATHER STATEMENTS OR WARNINGS.

A TORNADO WARNING... USUALLY ISSUED FOR 1 OR 2 COUNTIES AT A TIME... MEANS THAT A TORNADO HAS BEEN SIGHTED OR INDICATED BY WEATHER RADAR. PERSONS IN THE PATH OF THE STORM NEED TO IMMEDIATELY FIND SHELTER... PREFERABLY IN A STURDY BUILDING... BELOW GROUND IF POSSIBLE.

HERE ARE SOME TORNADO SAFETY RULES:

• IN HOMES OR SMALL BUILDINGS... GO TO THE BASEMENT OR STORM SHELTER... OR TO AN INTERIOR ROOM SUCH AS A CLOSET OR BATHROOM ON THE LOWEST LEVEL. GET UNDER SOMETHING STURDY... SUCH AS A HEAVY TABLE OR A BED.
• IN MOBILE HOMES AND VEHICLES...ABANDON THEM AND GO TO A STORM SHELTER OR STURDY STRUCTURE. IF THERE IS NO SUCH STRUCTURE NEARBY... LIE FLAT IN A DITCH RAVINE...GULLY...CULVERT...OR A LOW SPOT WITH YOUR ARMS AND HANDS SHIELDING YOUR HEAD.
• IN LARGE BUILDINGS SUCH AS SCHOOLS... FACTORIES... HOSPITALS... NURSING HOMES... AND SHOPPING CENTERS... GO TO THE PREDESIGNATED SHELTER AREA. INTERIOR HALLWAYS ON THE LOWEST FLOOR ARE USUALLY BEST. STAY AWAY FROM ROOMS THAT ARE LARGE IN AREA BECAUSE THEY HAVE WEAKLY SUPPORTED ROOFS.
• STAY AWAY FROM WINDOWS.

The state of Tennessee will conduct a statewide tornado drill at 9:30am today. The drill includes the sounding of outdoor warning sirens, but they will only sound if there is no ongoing inclement weather.

MWN has partnered with Take Cover Storm Shelters of Fayette County to keep Mid-South residents safe in the path of the storm.  We have become very familiar with Take Cover's high-quality product, as well as their outstanding customer service, and have no reservations about endorsing this fantastic company.  You can learn more about Take Cover and their in-ground shelters, which are installed in a concrete slab such as a garage floor, at their website.  Be sure to mention MemphisWeather.net when you contact Jessica!

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week 2012: Lightning

..LIGHTNING AWARENESS DAY...

Photo (c) 2011 - Brian Anderson. All Rights Reserved.

SEVERE WEATHER AWARENESS WEEK CONTINUES TODAY WITH A LOOK AT LIGHTNING SAFETY.

HERE ARE SOME LIGHTNING SAFETY RULES:

ANY LIGHTNING SAFETY PLAN SHOULD INCORPORATE THE 30/30 RULE. THE 30/30 RULE STATES PEOPLE SHOULD SEEK SHELTER IF THE FLASH TO BANG DELAY /LENGTH OF TIME IN SECONDS BETWEEN A LIGHTNING FLASH AND ITS SUBSEQUENT THUNDER/ IS 30 SECONDS OR LESS AND THAT THEY REMAIN UNDER COVER UNTIL 30 MINUTES AFTER THE FINAL CLAP OF THUNDER.

MOVE INSIDE A WELL CONSTRUCTED HOUSE... A LARGE BUILDING... OR AN ALL METAL VEHICLE. STAY AWAY FROM ELECTRICAL APPLIANCES AND DO NOT USE CORDED TELEPHONES.

IF YOU ARE IN A BOAT... GET OFF THE WATER AND INTO A SUBSTANTIAL BUILDING... OR AT LEAST INTO AN ENCLOSED AND ALL-METAL VEHICLE WITH THE WINDOWS UP. IF YOU'RE CAUGHT IN AN OPEN METAL BOAT... LIE DOWN IN THE BOAT WITH CUSHIONS BETWEEN YOU AND THE METAL SIDES AND BOTTOM.

IF YOU ARE CAUGHT OUTDOORS... GET DOWN TO AVOID BEING THE HIGHEST POINT FOR A LIGHTNING DISCHARGE. IF YOU'RE CAUGHT IN A FLAT OPEN FIELD OR IF YOU FEEL YOUR HAIR STANDING ON END... CROUCH DOWN AND COVER YOUR HEAD WITH YOUR HANDS SO THAT ONLY YOUR FEET WILL TOUCH THE GROUND.

MOVE AWAY FROM MOTORCYCLES... SCOOTERS... GOLF CARTS... BICYCLES... TRACTORS... AND OTHER METAL FARM EQUIPMENT. AVOID WIRE FENCES... CLOTHES LINES... METAL PIPES... DRAINS... RAILROAD TRACKS... AND OTHER METALLIC OBJECTS.

AVOID LONE TREES AND THE TALLEST TREES. IF CAUGHT IN THE WOODS... PICK A SMALL GROVE OF TREES AS YOUR SHELTER AND STAND AT LEAST 5 FEET FROM THE TRUNK OF THE NEAREST TREE TO AVOID FLYING BARK IF THE TREE IS STRUCK.

AVOID STANDING IN A SMALL ISOLATED SHED OR OTHER SMALL UNGROUNDED STRUCTURE IN OTHER AREAS.

IF IN A GROUP OF PEOPLE IN AN OPEN AREA... SPREAD OUT BEFORE YOU KNEEL DOWN.

ON WEDNESDAY... A TORNADO DRILL WILL BE CONDUCTED BETWEEN 9 AND 10 A.M.
IN TENNESSEE.

For the "small-time" weather consumer, lightning data is one piece of weather information that can be hard to come by (especially in realtime).  There are only a couple of providers of commercial lightning data in the U.S., which makes re-distributing the data cost-prohibitive for all but the largest commercial vendors.  That is why you won't find lightning data on MWN.

However, many times thunderstorms (which just means that a storm has lightning) can be inferred through radar data. MWN's StormView Radar is provided by one of the leading web-radar companies in the south and is, in fact, used by several TV stations for their web-based radar feed.  The colors of the returns (or echoes) on a radar map indicate the relative severity of the storm. On StormView Radar, anything colored orange, red, or higher has a fairly high likelihood of containing lightning. As we nowcast on Facebook and Twitter, we'll also be sure to let you know if a storm is electrified so that you may adjust your plans if necessary to maintain your safety.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Spring returns to the Mid-South this week!

The past couple of weeks have featured a return to reality – winter – for the most part in Mid-South weather, with colder temperatures and even a couple of minor flirtations with winter weather, though with no severe consequences.  However, the weather pattern across our region is beginning to undergo another transition, and that will mean more spring-like conditions in the week ahead.

First, a weak system will be passing through the region overnight into early Tuesday morning, which may trigger a few light showers. Moisture will be limited and the system fast-moving, so rain amounts will be minimal and many places may not see rain at all. This system will surely not bring any cooler air behind it, as southwest winds both Tuesday and Wednesday will send temperatures soaring. After reaching the 60s Tuesday, on Wednesday high temperatures are expected to reach 70 degrees, around 15 degrees above normal!

NAM model temperatures for Wednesday afternoon (3 PM)

Nevertheless, the return to spring won’t be permanent. By Wednesday night, a cold front will be approaching from the northwest, as moisture levels begin increasing from the Gulf of Mexico. As it passes through the area during the day Thursday, a chance of showers and thunderstorms will exist. As of the time of this writing, the chance of severe weather appears somewhat low, though it's not non-existent. We'll update again if it appears that the chance of severe weather is rising. The front will definitely bring a shot of cooler air behind it for the weekend though.

GFS model wind/precipitation for late Thursday afternoon (6 PM)

High temperatures will return to the 50s for Friday through Sunday, back close to the late February average, with lows into the 30s. Meanwhile, looking ahead to the beginning of next week, another storm system appears to be on the horizon, likely bringing another chance of rain about next Monday.

For the most up-to-date outlook for the Memphis metro area, check out the MWN Forecast!

--Kevin Terry, MemphisWeather.Net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week 2012: Severe Thunderstorms

...SEVERE THUNDERSTORM AWARENESS DAY...

THERE ARE APPROXIMATELY TWO THOUSAND THUNDERSTORMS IN PROGRESS AROUND THE WORLD AT ANY GIVEN TIME. MOST OF THESE STORMS ARE BENEFICIAL AND BRING NEEDED RAIN. ONLY A SMALL FRACTION... LESS THAN ONE PERCENT... ARE CLASSIFIED AS SEVERE. SEVERE THUNDERSTORMS ARE THOSE THUNDERSTORMS THAT PRODUCE HAIL ONE INCH IN DIAMETER OR LARGER AND/OR STRONG WIND GUSTS OF 58 MPH OR GREATER. HAIL THAT IS ONE INCH IN DIAMETER IS ABOUT THE SIZE OF A QUARTER.

A SMALL FRACTION OF THESE THUNDERSTORMS PRODUCE TORNADOES. ALL THUNDERSTORMS ARE CAPABLE OF PRODUCING DEADLY LIGHTNING. THE HEAVY RAINS OR THE LIGHTNING ACTIVITY IN A THUNDERSTORM DO NOT HAVE ANYTHING TO DO WITH A THUNDERSTORM BEING CLASSIFIED AS SEVERE.

SOME OF THE SEVERE THUNDERSTORMS SAFETY RULES ARE AS FOLLOWS:

• FIND SHELTER IMMEDIATELY. GO TO A STURDY BUILDING THAT WILL WITHSTAND HIGH WINDS.
• AVOID ELECTRICAL APPLIANCES AND TELEPHONES.
• IT WOULD BE A GOOD IDEA TO BRING YOUR CAR INSIDE A GARAGE AND TO SECURE LOOSE OBJECTS.

REMEMBER... A SEVERE THUNDERSTORM WARNING MEANS THAT A SEVERE THUNDERSTORM IS OCCURRING. THE SEVERE THUNDERSTORM HAS BEEN DETECTED BY THE DOPPLER RADAR OR REPORTED TO THE NATIONAL WEATHER SERVICE BY OUR SKYWARN SPOTTER NETWORK OR THE LOCAL LAW ENFORCEMENT AGENCY IN A PARTICULAR COUNTY.

A SEVERE THUNDERSTORM WATCH MEANS THAT CONDITIONS ARE RIGHT FOR SEVERE THUNDERSTORMS TO DEVELOP BUT NONE HAS BEEN OBSERVED. FOLKS SHOULD KEEP AN EYE ON THE SKY AND LISTEN TO COMMERCIAL BROADCASTS OR WEATHER RADIO FOR ANY SUBSEQUENT WARNINGS.

WHEN A SEVERE THUNDERSTORM WARNING IS ISSUED FOR YOUR LOCATION.... TREAT IT THE SAME AS YOU WOULD A TORNADO WARNING. SEVERE THUNDERSTORMS CAN PRODUCE DAMAGING WINDS... LARGE HAIL AND DEADLY LIGHTNING.

Annual frequency of lightning globally in flashes per square kilometer. 

MemphisWeather.net's "Storm Center" is your one-stop shop for severe weather information.  The Storm Center includes Mid-South radar, a clickable watch/warning map that updates as new alerts are issued by the NWS, recent storm reports, maps outlining severe risk areas from the severe weather experts at the Storm Prediction Center, and severe weather safety tips. If you are looking for information on severe weather in the Mid-South, the MWN Storm Center is the place to start!

Also, don't forget about our newest severe weather alerting tool that capitalizes on the convenience of mobile app technology! StormWatch+ will alert you if you are in the path of the storm via mobile phone, even if you are asleep.  StormWatch+ is available within the MWN mobile app for Android and iPhone. Learn more or download the app by visiting StormWatchPlus.com on your computer or mobile device.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Severe Weather Awareness Week in Tennessee

...SEVERE WEATHER AWARENESS WEEK...

THE NATIONAL WEATHER SERVICE IN COOPERATION WITH EMERGENCY
MANAGEMENT AND THE MEDIA ARE PARTICIPATING IN SEVERE WEATHER
AWARENESS WEEK ACROSS TENNESSEE FROM SUNDAY FEBRUARY 19TH
THROUGH SATURDAY FEBRUARY 25TH.

EACH DAY DURING AWARENESS WEEK WILL FOCUS ON A DIFFERENT ASPECT OF
SEVERE WEATHER. DURING THE WEEK...THE NATIONAL WEATHER SERVICE IN
MEMPHIS WILL ISSUE SAFETY MESSAGES ON THE FOLLOWING TOPICS.

MONDAY...WE WILL FOCUS ON SEVERE THUNDERSTORMS.

TUESDAY...THE TOPIC WILL BE LIGHTNING.

WEDNESDAY IS TORNADO AWARENESS AND WILL SERVE AS TORNADO DRILL
DAY IN TENNESSEE.

THURSDAY...WE WILL LOOK AT FLOODING AND FLASH FLOODS.

FRIDAY IS WEATHER RADIO DAY AND THE EMERGENCY ALERT SYSTEM DAY.

SATURDAY WILL CONCLUDE SEVERE WEATHER AWARENESS WEEK WITH A
DISCUSSION ABOUT THE SKYWARN STORM SPOTTER PROGRAM.

THE PURPOSE OF SEVERE WEATHER AWARENESS WEEK IS TO DRAW ATTENTION
TO THE MANY ASPECTS OF SEVERE WEATHER WHICH AFFECT ALL OF US...TO
FOCUS ON SAFETY...AND TO LEARN WHAT TO DO WHEN HAZARDOUS
WEATHER THREATENS.

In addition to re-distributing information on topics above from the NWS, MWN will also include additional information on each topic that will be helpful to our fans, followers, and visitors, including highlighting parts of the MemphisWeather.net website or other services we offer that fit the topic for that day.  Be sure to follow along on the blog throughout the week as we highlight various aspects of severe weather as we strive to inform and educate Mid-Southerners!

For more information on Severe Weather Awareness Week in Tennessee, visit this NWS website or download the 11-page severe weather awareness book (PDF) for TN (front cover above).

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

"I love a rainy night"

Low pressure moving along the Gulf Coast states over the next 24 hours is bringing widespread rain to the southeastern U.S. today with some possible severe thunderstorms near the Gulf Coast. Further north, in the Mid-South, rain is expected to move in by this evening, as well as very gusty north wind due to the strength of the surface low and high pressure building in behind it. The rain will continue most of the night, ending by mid-morning Sunday. The graphic below from the precipitation experts at the Hydrometeorological Prediction Center (HPC) shows copious rainfall to our south, but also a pretty healthy amount over the Mid-South, through Sunday morning. Areas of north MS could see more than an inch of rain, while 0.5"-1.0" is likely in the metro.

Forecast total precipitation through Sunday morning, from HPC

Previously, we had expected that an upper-level disturbance moving through the area early Sunday could bring enough cold air to allow the rain to change over to snow as the system departed early in the day. The consensus of the computer models is now that the air will not get cold enough for snow in the immediate metro, outside of  perhaps a few flurries mixed with the rain between about 6-9am Sunday.  The best chances for snow have shifted to the TN-KY border region, middle TN, and points east. Though the rain will end Sunday morning, it will remain cool (in the 40s) all day as clouds depart in the afternoon.  President's Day looks pleasant with partly cloudy skies and highs back into the mid to upper 50s. Click here for the complete MWN forecast.

This graphic from HPC indicates the best chances for snowfall will be Sunday in the Mid-Atlantic

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Comments on potential winter weather for President's Day weekend

For a couple of days, we have been monitoring the potential for winter weather with our next system arriving this weekend. The setup is a fairly decent one for winter weather in the Mid-South - low pressure passing by to our south and an upper-level disturbance moving in on it's heels, just as cold air is drawn into the backside of the departing surface low.  The questions have centered on when the precipitation moves out and how cold it gets in the lowest few thousand feet of the atmosphere before that happens.

Computer models have been insistent - in their own ways and with each new run of that model - on the solution.  The problem was that they didn't agree among themselves.  It was an "agree to disagree" situation that made the meteorologist the mediator. That changed this morning.

The bullish NAM model, whose stance had called for a good 2-4"+ of snow Saturday night for the metro for several "runs" (the models generally produce a forecast run four times a day), abruptly changed course with it's morning run.  Usually you'll hear me say that I don't get too excited about extremes when models flip-flop like a pandering politician.  In this case though, the NAM flipped over to come more in line with the other models.  The result is now that the NAM, GFS, and European models all are pretty much in line with the big picture, with only subtle difference in the details (including that the NAM is still slightly stronger with the upper-level disturbance and perhaps a tiny bit colder).

12Z NAM model indicates precip lingering over the metro at 6am Sunday as cold air  filters in on north wind behind the departing low pressure system over eastern Georgia.

The model consensus now appears to be a wet (rain) period from Saturday afternoon until well after midnight Sunday morning, followed by cooling temperatures in the early hours Sunday morning that could cause some of the rain to change to, or mix with, light snow.  The most likely time for any snow would be from about 4-9am Sunday if the morning models are correct. With warm temperatures ahead of the system and temperatures remaining above freezing throughout the period of potential snow, I don't expect any problems on local roadways Sunday and only minor accumulation (if any) on grassy or elevated surfaces that would quickly melt as snow ended.  Areas to the north and east - northwest and middle TN, western and northern KY - have the potential for more accumulation.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Winter Weather Advisory issued for this afternoon/evening

From the National Weather Service in Memphis:

UPDATED AT 10AM MONDAY (note: start times in graphic above have been adjusted 1 hr earlier and are not reflected in the graphic)

...WINTRY PRECIPITATION BEARING DOWN ON THE MID-SOUTH...

.INCREASING MID LEVEL MOISTURE WILL OVERSPREAD THE MID-SOUTH THIS
MORNING WITH VERY DRY AIR REMAINING IN PLACE NEAR THE SURFACE. AS
THE ATMOSPHERE CONTINUES TO MOISTEN THIS AFTERNOON...PRECIPITATION
WILL WORK ITS WAY DOWN TO THE SURFACE...GRADUALLY OVERCOMING THE
DRY AIR. AS IT DOES SO...TEMPERATURES WILL COOL AND SUPPORT SNOW
AND SLEET BY THE AFTERNOON.

WARMER MID LEVEL AIR WILL THEN BEGIN TO WORK NORTH THIS EVENING
WITH A TRANSITION TO LIGHT RAIN OR DRIZZLE BY 9 OR 10 PM.

DESOTO-MARSHALL-TUNICA-TATE-TIPTON-SHELBY-FAYETTE-
...WINTER WEATHER ADVISORY NOW IN EFFECT FROM 3 PM THIS AFTERNOON
TO 9 PM CST THIS EVENING...

* SNOW/SLEET ACCUMULATIONS...1 TO 2 INCHES NORTH OF I-40 AND UP
TO AN INCH SOUTH OF I-40.

* TIMING...SNOW AND SLEET WILL BEGIN EARLY THIS AFTERNOON AND
CONTINUE THROUGH EARLY THIS EVENING. PRECIPITATION WILL THEN
TRANSITION TO DRIZZLE AROUND 9 PM.

* IMPACTS...TRAVEL CONDITIONS WILL BE HAZARDOUS THIS EVENING AS
ROADWAYS BECOME SNOW COVERED AND SLICK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...OR
FREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE
DRIVING.

CRITTENDEN-
...WINTER WEATHER ADVISORY NOW IN EFFECT FROM NOON UNTIL 9 PM CST
THIS EVENING...

* SNOW/SLEET ACCUMULATIONS...1 TO 2 INCHES.

* TIMING...SNOW AND SLEET WILL BEGIN EARLY THIS AFTERNOON AND
CONTINUE THROUGH EARLY THIS EVENING. PRECIPITATION WILL THEN
TRANSITION TO DRIZZLE AROUND 9 PM.

* IMPACTS...TRAVEL CONDITIONS WILL BE HAZARDOUS THIS AFTERNOON
AND EVENING AS ROADWAYS BECOME SNOW COVERED AND SLICK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...OR
FREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE
DRIVING.

For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Sunday afternoon update on tomorrow's winter weather scenario

For those who have followed along with our blog posts the past couple of days, thank you!  If you have read them, you know the models had been fairly consistent up to this point with tomorrow's potential winter weather scenario, with a couple of exceptions in the details.  Today, I bring you good news (for some) and bad news (for probably many others).  This morning's models are taking a turn towards a warmer scenario, especially in the 3-7,000 foot level or so.  What does that mean?  IF they are trending in the right direction, it means the metro could see less snow than previously thought, and more rain - if not perhaps some ice as well.

I'll use the atmospheric sounding profile below to explain.  If you want "just the facts," skip down below the graphic for today's bottom line.  As mentioned in previous blog posts, the atmosphere has some recovering to do with very dry air in place behind Friday night's Arctic front.  That will delay the onset of precip until after lunch, and maybe mid-afternoon, on Monday.  The changes in the models have to do with the temps in the lower (non-surface) levels of the atmosphere.  The graphic below shows the GFS model's interpretation of the temperature and moisture profiles at 6pm Monday.  This is after precipitation has been falling for a couple of hours.

Quick orientation of the graphic: this is a slice of the atmosphere at Memphis with the top of the picture at 17,000' and the bottom at the surface.  The red plot is temperature, green plot is dewpoint, and dotted pink line is freezing.  Where red/green are right next to each other, the humidity is very high (near 100%).

From this image, we see that the temperature between 3,000-8,000' is above freezing (red line right of the dotted pink line), while from the surface to 3,000' it is below freezing.  Actually at the surface in this image, it is right at 32.  The max temperature in the warm layer is about 37 degrees, while the minimum temperature in the cold layer near the surface is about 28 degrees. As precipitation falls from above (as snow), most of it will melt between 3-8,000', then some of it will re-freeze below 3,000'.  Hence IF this model is correct, we will see sleet, possibly mixed with a little snow, and rain.  And if the surface temperature is indeed 32 or less, the rain will freeze on contact - freezing rain.  It's complicated... I know!  While not shown, the other model we typically look at, the NAM, is warmer than this interpretation and depicts more rain/sleet with above freezing temperatures at the surface.  It's our job to figure out which we think is right - or perhaps a combination of them - and make the forecast.  So, onto the bottom line (jump below):

GFS model sounding valid 6pm Monday showing a setup for mixed precipitation types

Bottom line forecast for the immediate metro area (as of mid-afternoon Sunday, remember things can change):


Timing & temperatures: Both have changed very little.  Precipitation is expected to start after lunchtime Monday, perhaps as late as 3pm, and continue through the evening, with most ending (except for light rain/drizzle) around 9pm or so. At onset, temperatures will likely get to near 40, then fall as precipitation starts, reaching the lower 30s (perhaps freezing) by rush hour.  They will then recover slightly to the mid 30s overnight Monday night.


Precip type: At onset (early afternoon), I expect a mix of snow, sleet, and possibly rain. That should fairly quickly (by late afternoon) change to a rain/sleet mix with some flakes possible as well. By early evening (6-7pm), it'll probably be mostly rain.  The heaviest precipitation should be between 3-7pm, when the predominant precip type will likely be rain/sleet.  I also cannot rule out some freezing rain during this period if the surface temperature gets down to 32 (some bridges and overpasses could get to 32 even if the air temp is 33-34. Watch for slick streets during the afternoon commute home! Overnight, temperatures should stay above freezing in most locations, though outlying areas could see 32 degrees. Roads should be in decent shape overnight into Tuesday morning, though drizzle/light rain will be possible until dawn Tuesday.

Accumulation: In the immediate metro, the most likely scenario brings up to a half-inch of snow/sleet by rush hour, perhaps a light coating of freezing rain, topped off by light rain and rising temps that will likely melt anything that falls during the night.  To the north (Tipton Co and points north), higher amounts of snow/sleet are more likely with a slightly higher chance of freezing rain in the evening. Over north Mississippi, it's possible that sleet/rain will be the predominant precip type, with little accumulation, washed off in the evening by rain.

Much of the finer details may not become known until the event begins.  Be prepared for anything mentioned above, anywhere from mostly rain to some minor ice accumulations, to snow/ice mix with rain on top of that.

We'll continue to monitor the situation very closely and bring you updates via the MWN Forecast and on our social media feeds, including  Facebook and Twitter . In addition, our mobile apps for Android and iPhone include StormView Radar with precipitation type (which shows you rain/snow/ice), the forecast, current conditions, and our Twitter feed (without having to sign up for Twitter). Finally, within the apps, you can upgrade to StormWatch+ which will push you notifications of any Winter Storm Watches, Warnings, or Advisories as soon as they are issued by the NWS.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Mid-day Saturday look at Monday's winter weather scenario

As advertised, an Arctic blast arrived overnight, bringing us what will likely be the coldest day of the winter so far with temperatures topping out in the mid 30s.  Combining a north wind gusting up to 25+ mph with those temperatures and wind chills are staying in the teens to lower 20s all day!  Many Mid-Southerners even saw periodic snowflakes this morning as the last remnants of moisture were squeezed out of the lower atmosphere by very cold air moving overhead. Tonight, as wind relaxes and high pressure moves nearly overhead, temperatures will plummet into the teens area-wide, resulting in the coldest overnight low of the winter as well.

All of this cold and dry air sets us up for a likely winter weather scenario on Monday as the next upper air disturbance moves by to our south. Not a lot has changed since yesterday's first look at the setup with respect to the computer model data. Monday morning will start off cold (lows in the 20s) with clouds streaming overhead and very dry air in place below those clouds. These two things (clouds and dry air) are important factors in the forecast. The clouds will keep temperatures from climbing as much as if there were sun Monday morning. The dry air will have to be "moistened" by falling precipitation before that precip can reach the ground.  This will likely create virga (precip that evaporates as it falls from the clouds) for a few hours before the precipitation reaches the ground, further hindering the warming process of the air as well.  While I believe the models are biased warm during the morning hours (they are forecasting temps in the 40s Monday morning), I think their timing of the precipitation is probably not far off, commencing early Monday afternoon.

Bottom line: My current thinking is we'll see temperatures reach the upper 30s by noon, then as precipitation begins to reach the ground, temps should fall back to near freezing.  With a little warm air aloft, precipitation type will most likely be a mixture of snow and sleet beginning between 1-3pm. The heaviest precip looks to fall from mid-afternoon through early evening, including the Monday rush hour, mainly as snow/sleet.  Warmer air actually moves in Monday evening (especially aloft), which should change precipitation over to a a mix of rain/snow, then ultimately light rain, as temperatures hover just above freezing.  Snow/sleet totals are currently looking like they could be in the 2"+ range north of the metro, to less than an inch in north MS, leaving most of the metro with around an inch of snow or perhaps a little more.  Forecasting amounts is the hardest part of winter systems that introduce varying precipitation types, as mixing with sleet or rain could drastically affect the amount of accumulation (more on precipitation types).  This is an educated best guess based on recent model data and 17 winters of Mid-South forecasting experience!  Lingering light rain/drizzle Monday night could freeze as temperatures drop to the lower 30s and possibly create a freezing drizzle/black ice scenario Tuesday morning.

I'll have another blog update Sunday afternoon and will continue to monitor the situation very closely and bring you updates via the MWN Forecast and on our social media feeds, including  Facebook and Twitter. In addition, our mobile apps for Android and iPhone include StormView Radar with precipitation type (which shows you rain/snow/ice), the forecast, current conditions, and our Twitter feed (without having to sign up for Twitter). Finally, within the apps, you can upgrade toStormWatch+ which will push you notifications of any Winter Storm Watches, Warnings, or Advisories as soon as they are issued by the NWS.
Erik Proseus
Meteorologist, MemphisWeather.net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

First look at potential winter storm on Monday

In Memphis, as in many other "southern" cities, the word snow can cause all sort of reactions - from jubilation to trepidation.  I believe we'll hear them all this weekend as the word is spreading that we could finally see some winter in the Mid-South (well, at least the first "winter" since early December when 1-3" of snow fell across the area).

Winter-like conditions, in the form of brutally cold air, will actually arrive tomorrow, which sets the table for Monday's weather. After getting used to temperatures in the 50s/60s the past month or so, the cold air behind an Arctic front that arrives tonight will be a shock to many Mid-Southerners systems! By the time you go out to get the morning paper tomorrow, temperatures will be in the mid 20s with wind chill values in the teens - and it really doesn't improve any from there. Despite the sunshine, highs will barely crawl above freezing tomorrow afternoon. By Sunday morning lows will be in the teens for the entire region, including the city proper, with some outlying areas possibly nearing 10 degrees! Sunday's highs will only be in the upper 30s.

Saturday mid-day temperature forecast

Sunday morning temperature forecast

The cold and dry air will linger into Monday as our next weather system moves in.  Based on current computer guidance (which at 72+ hours out could, and likely will, change), precipitation looks to arrive in the metro during the afternoon hours. Temperatures will probably be in the 30s, but well above freezing. Combined with dry air in the low levels, we will likely see a mix of precipitation types, especially for the first few hours, and maybe longer.  I would expect a sleet/snow/rain mix given these conditions.  If most of it is snow, the potential exists for 1-2" by dusk, but mixing with rain or sleet, it could be on the lower end of that, with some ice mixed in as well.  Below is a POSSIBLE scenario from a decent mid-range computer model, the European, or ECMWF, regarding snowfall during the 3-6pm timeframe.  Remember that this is a model forecast, not necessarily what is going to happen!

Potential snowfall Monday afternoon (3-6pm) from the European model

The threat of freezing rain or an ice storm doesn't appear likely right now, however a couple of degrees difference in temperatures could make a huge difference in the ultimate mix of precipitation.  By evening, it looks like temperatures will actually be rising just a bit and it's conceivable that the mix turns to rain with temps in the upper 30s.

We'll continue to monitor the situation very closely and bring you updates via the MWN Forecast and on our social media feeds, including Facebook, Twitter, and this blog (links below).  In addition, our mobile apps for Android and iPhone include StormView Radar with precipitation type (which shows you rain/snow/ice), the forecast, current conditions, and our Twitter feed (without having to sign up for Twitter).  Finally, within the apps, you can upgrade to StormWatch+ which will push you notifications of any Winter Storm Watches, Warnings, or Advisories as soon as they are issued by the NWS.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.