Fortunately, my good friend Ande of Gemini Multimedia was there with his HD video camera to capture it all. Check out this amazing time-lapse footage. Awesome job Ande!
Saturday, October 31, 2009
Time-lapse of Friday morning's weather
Ahead of the impending storm system yesterday morning, there were some spectacular views of the various cloud layers, all moving asynchronously across the sky, and even a gorgeous early morning rainbow, created by the suns rays rising in the east penetrating a rain-soaked system approaching from the west.
Friday, October 30, 2009
Analysis of surface conditions during a frontal passage
The cold frontal passage on October 30 brought more than just a torrent of rain to the Mid-South. While the flooding conditions and widespread 3-6" rainfall totals over two days were certainly impressive, the cold front itself also was easily captured by watching weather parameters before and after the front crossed the region. Take the graphs below from WXLIVE! in Bartlett:
The front crossed the weather sensors at about 7:45am (or just before the second number 8 on the lower scale, x-axis, and marked by the red dotted lines).
In the upper-left, the temperature (white line) stayed above 70F all night long (it was a mild night!), peaked just prior to the frontal passage, then began a nose-dive until about 2pm when it leveled off. The dewpoint (yellow line) did nearly the same thing. Rapidly falling temperature and dewpoint (a measure of moisture in the air) are good indicators of a cold front.
In the upper-right, the barometric pressure fell prior to the frontal passage, then immediately rose a LOT (0.20" Hg in 4 hours). The pressure bottoms out as the front crosses the sensor.
In the lower-left panel, the sudden change in wind direction is also easily seen. Prior to the front, the wind was consistently out of the south to southeast. When the front hit, it switched to the west, then stayed out of the west to southwest, ushering in the cooler and drier air noted in the upper-left panel. Wind speed (lower-right) also indicates the peak wind of nearly 30 mph just ahead of the front, then a relative lull for a little more than an hour following the front before picking up again during the mid-day hours.
All of these conditions make the timing of the front pretty easy to figure out at this location. Certainly looking out the window in this case would have made the exact timing a no-brainer as well, but it's interesting to see the effects of a strong front like this on measurable parameters. In all, 3.68" of rain was recorded at WXLIVE! Thursday and Friday.
For realtime conditions from WXLIVE!, check out Rapid Fire, or for current graphs like the one above, see this page.
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The front crossed the weather sensors at about 7:45am (or just before the second number 8 on the lower scale, x-axis, and marked by the red dotted lines).In the upper-left, the temperature (white line) stayed above 70F all night long (it was a mild night!), peaked just prior to the frontal passage, then began a nose-dive until about 2pm when it leveled off. The dewpoint (yellow line) did nearly the same thing. Rapidly falling temperature and dewpoint (a measure of moisture in the air) are good indicators of a cold front.
In the upper-right, the barometric pressure fell prior to the frontal passage, then immediately rose a LOT (0.20" Hg in 4 hours). The pressure bottoms out as the front crosses the sensor.
In the lower-left panel, the sudden change in wind direction is also easily seen. Prior to the front, the wind was consistently out of the south to southeast. When the front hit, it switched to the west, then stayed out of the west to southwest, ushering in the cooler and drier air noted in the upper-left panel. Wind speed (lower-right) also indicates the peak wind of nearly 30 mph just ahead of the front, then a relative lull for a little more than an hour following the front before picking up again during the mid-day hours.
All of these conditions make the timing of the front pretty easy to figure out at this location. Certainly looking out the window in this case would have made the exact timing a no-brainer as well, but it's interesting to see the effects of a strong front like this on measurable parameters. In all, 3.68" of rain was recorded at WXLIVE! Thursday and Friday.
For realtime conditions from WXLIVE!, check out Rapid Fire, or for current graphs like the one above, see this page.
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Watch for flooding!
The Flash Flood Watch for the entire region until 7am Saturday and Flash Flood Warnings are now also posted for all counties bordering the Mississippi River as very heavy rain moves slowly into the region from east Arkansas. Doppler radar estimates rainfall totals across central and eastern AR range from 3-6" since mid-day Thursday and this rain is headed in our direction. There will also be some embedded thunderstorms, though the likelihood of severe weather is low. Temperatures are currently in the lower 70s on your way out the door this morning, but will be falling later this morning and this afternoon behind the frontal system pushing through the region now. Little Rock is about 15 degrees cooler than Memphis as of this writing, so look for temps to fall into the 50s by this afternoon.Please exercise caution on the roadways today - watch for standing water, flooded intersections and underpasses, and other hazards ,and keep your children away from swollen streams and ditches. Flooding is the #1 weather-related cause of death in the U.S.
As a side note - October 2009 has gone down in the record books as the wettest October since record keeping began in 1895. Today's precipitation will just pad that record!
MemphisWeather.net resources for you to follow today:
MWN Forecast
StormView Radar
Severe Weather Warning Map
WXLIVE!-Severe Weather (email warning notification)
WXLIVE!-Rapid Fire (realtime current conditions from Bartlett)
Rain will come to an end tonight and Saturday will mark the beginning of an extended dry streak with seasonal temperatures and plenty of sunshine!
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Wednesday, October 28, 2009
A deluge on tap - how wet will October get?
As of this morning, the driest month of the year (on average) has seen just over 7" of rainfall in 2009, more than double the average of 3.31". Unfortunately, we aren't done yet. With 3 days to go in the month and quite possibly one doozy of a storm system ahead, we will likely end up with one of the wettest Octobers on record. For the year, Memphis has received 51.28" of rain. After the next couple days, we will probably see our average annual precipitation total of 54.65" exceeded with two more months of 2009 left!
So, as for this much-anticipated, and maybe much maligned when it is all said and done, weather system, the pattern sets up like this... a strong mid-autumn cold front will be moving very slowly out of the Rockies (where Denver is receiving a whopping October snowfall today) towards the region over the next 48 hours. Meanwhile, Gulf moisture in advance of the system will begin streaming into the region over the next day as a warm front lifts into the Mid-South by Thursday evening.
The first round of precipitation, mainly in the form of showers with a small chance of thunderstorms, heads into the area Thursday morning. We'll then see the distinct possibility of scattered storms Thursday afternoon and night as the cold front approaches and the warm front lifts to our north, placing us in the "warm sector" of the system. The setup also favors the possibility of some damaging wind gusts in the stronger storms, thus we are under a SLIGHT RISK of severe weather for Thursday afternoon and night. The first real bout of potentially flooding rain will come just ahead of and then immediately behind the cold front late Thursday night into Friday morning. The potential for a couple of inches of rain exists with this round and you can also expect windy conditions during this time period.
The front then stalls just to the east of the metro area, but low pressure will form over the north-central Gulf and move along the front to the north-northeast on Friday night into Saturday. Unfortunately, it looks like the low will be close enough to bring another round of heavy rain into the region around the back side of the low. The potential for the heaviest rain right now appears to occur Friday night and Saturday morning, when another couple of inches are possible, however scattered light to moderate rain could last well into the day on Halloween. Fortunately, it appears right now (this being still 72 hours out) that the rain may make an exit so that trick-or-treaters can put down their umbrellas and pick up their candy bags! We'll cross our fingers!
In all, the Memphis area could see as much as 6" of rain (one model indicates maximum amounts of 8") between Thursday morning and Saturday evening! Thus, the Flash Flood Watch which has been issued for the entire region from Thursday afternoon through Saturday morning.
It's a good time to remind all of my readers that flash flooding can be deadly and this threat is real! Stay away from areas where rushing water exists, don't let children play near swollen creeks or drainage areas, and don't drive where water crosses the road. One foot of moving water is enough to pick up a car and move it downstream. Turn Around; Don't Drown!
Stay with MemphisWeather.net, MWN on Twitter and Facebook, and local TV and radio outlets for the latest on this developing weather scenario.
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Flash Flood Watch for Thursday-Saturday
...A SLOW MOVING COLD FRONT WILL BRING TORRENTIAL RAINS TO PARTS OF THE MID-SOUTH LATE THIS WEEK...
.LOW PRESSURE WILL DEVELOP OVER THE PANHANDLE OF TEXAS LATE THIS AFTERNOON AND BEGIN TO TRACK NORTHEAST INTO MINNESOTA BY THURSDAY NIGHT. A TRAILING COLD FRONT WILL PUSH EAST INTO THE MISSISSIPPI RIVER VALLEY LATE THURSDAY AFTERNOON OR THURSDAY NIGHT AND STALL. THE FRONT IS EXPECTED TO REMAIN NEARLY STATIONARY THROUGH SATURDAY.
RICH MOISTURE STREAMING NORTH FROM THE GULF WILL INTERACT WITH THIS FRONTAL BOUNDARY... PRODUCING A PROLONGED PERIOD OF HEAVY SHOWERS AND THUNDERSTORMS FROM THURSDAY AFTERNOON THROUGH AT LEAST SATURDAY MORNING. EVENTUALLY THE FRONT WILL SAG SOUTH... ENDING THE HEAVY RAIN THREAT BY LATE SATURDAY. SEVERAL INCHES OF RAIN ARE LIKELY IN THE WATCH AREA... WHICH COULD LEAD TO FLASH FLOODING.
...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH SATURDAY MORNING...
* A COLD FRONT WILL APPROACH THE MID-SOUTH THURSDAY AFTERNOON OR THURSDAY NIGHT AND STALL OVER WEST TENNESSEE AND EAST ARKANSAS THROUGH AT LEAST SATURDAY MORNING. A RICH FEED OF MOISTURE FROM THE GULF WILL INTERACT WITH THIS FRONT TO PRODUCE A PROLONGED PERIOD OF HEAVY SHOWERS AND THUNDERSTORMS.
* STORM TOTAL RAINFALL AMOUNTS SHOULD RANGE FROM 4 TO 6 INCHES... WITH THE HEAVIEST AMOUNTS NEAR THE MISSISSIPPI RIVER. LOCALLY HIGHER TOTALS IN EXCESS OF 7 INCHES ARE ALSO POSSIBLE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED.
&&
$$
NWS
.LOW PRESSURE WILL DEVELOP OVER THE PANHANDLE OF TEXAS LATE THIS AFTERNOON AND BEGIN TO TRACK NORTHEAST INTO MINNESOTA BY THURSDAY NIGHT. A TRAILING COLD FRONT WILL PUSH EAST INTO THE MISSISSIPPI RIVER VALLEY LATE THURSDAY AFTERNOON OR THURSDAY NIGHT AND STALL. THE FRONT IS EXPECTED TO REMAIN NEARLY STATIONARY THROUGH SATURDAY.
RICH MOISTURE STREAMING NORTH FROM THE GULF WILL INTERACT WITH THIS FRONTAL BOUNDARY... PRODUCING A PROLONGED PERIOD OF HEAVY SHOWERS AND THUNDERSTORMS FROM THURSDAY AFTERNOON THROUGH AT LEAST SATURDAY MORNING. EVENTUALLY THE FRONT WILL SAG SOUTH... ENDING THE HEAVY RAIN THREAT BY LATE SATURDAY. SEVERAL INCHES OF RAIN ARE LIKELY IN THE WATCH AREA... WHICH COULD LEAD TO FLASH FLOODING.
...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH SATURDAY MORNING...
* A COLD FRONT WILL APPROACH THE MID-SOUTH THURSDAY AFTERNOON OR THURSDAY NIGHT AND STALL OVER WEST TENNESSEE AND EAST ARKANSAS THROUGH AT LEAST SATURDAY MORNING. A RICH FEED OF MOISTURE FROM THE GULF WILL INTERACT WITH THIS FRONT TO PRODUCE A PROLONGED PERIOD OF HEAVY SHOWERS AND THUNDERSTORMS.
* STORM TOTAL RAINFALL AMOUNTS SHOULD RANGE FROM 4 TO 6 INCHES... WITH THE HEAVIEST AMOUNTS NEAR THE MISSISSIPPI RIVER. LOCALLY HIGHER TOTALS IN EXCESS OF 7 INCHES ARE ALSO POSSIBLE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED.
&&
$$
NWS
Tuesday, October 27, 2009
Update on MWN service outage
Live data to MemphisWeather.net, including WXLIVE! current conditions (from Bartlett) and StormView Radar, was unavailable this morning from approximately 10:15-11:45am and again from 12:15-1:15pm. The outage was due to a service outage upstream from MemphisWeather.net and was unavoidable. We apologize for the inconvenience this may have caused, particularly on a"bad weather" day.
Monday, October 26, 2009
A fall pattern emerges
The overall weather pattern has become more progressive, and more typical of autumn, this week as fairly quick-hitting cold fronts move through every few days with generally fair weather between (take today's lower 70s for instance!). The next frontal system moves through the region tomorrow (Tuesday) as low pressure over the western Gulf moves directly over the Mid-South during the day. Scattered showers will move up from the south after midnight tonight and envelope the area Tuesday ahead of the low. Instability will be pretty weak, so thunder is not likely though it can't be totally ruled out. Rainfall totals will average 0.75"-1.00" across the metro area.
For those wondering how the weather will affect the Memphis Tigers football game Tuesday night at Liberty Bowl Memorial Stadium, showers should be moving out around kickoff, with a 30% chance of rain and temperatures in the mid to upper 50s. So while pre-game celebrations may be a little soggy, hopefully the game itself will be played in mostly dry conditions. Wind will be fairly light, though we know that it can get caught up in the bowl and swirl with any light breeze.
On Wednesday and early Thursday, we will be between systems while the next strong front winds up to our west. By Thursday afternoon, it will be tapping into Gulf moisture and ingredients will be coming together for scattered afternoon thunderstorms. I give the afternoon and evening about a 50% chance right now. By early Friday, chances increase significantly as the front nears the area. Wind will increase at the surface and aloft and temps will hold in the 60s overnight Thursday night, setting the stage for a potential line of strong to severe storms Friday.
By Saturday, the rain will be a distant memory and the weekend looks to be in fine shape with highs in the 65-70 degree range.
As an aside, you have probably noticed that the leaves on the deciduous trees in the area are just starting to change color. Here's an interesting post by my friend from CloudyandCool.com about the necessary ingredients for a splash of beautiful fall colors.
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For those wondering how the weather will affect the Memphis Tigers football game Tuesday night at Liberty Bowl Memorial Stadium, showers should be moving out around kickoff, with a 30% chance of rain and temperatures in the mid to upper 50s. So while pre-game celebrations may be a little soggy, hopefully the game itself will be played in mostly dry conditions. Wind will be fairly light, though we know that it can get caught up in the bowl and swirl with any light breeze.
On Wednesday and early Thursday, we will be between systems while the next strong front winds up to our west. By Thursday afternoon, it will be tapping into Gulf moisture and ingredients will be coming together for scattered afternoon thunderstorms. I give the afternoon and evening about a 50% chance right now. By early Friday, chances increase significantly as the front nears the area. Wind will increase at the surface and aloft and temps will hold in the 60s overnight Thursday night, setting the stage for a potential line of strong to severe storms Friday.
By Saturday, the rain will be a distant memory and the weekend looks to be in fine shape with highs in the 65-70 degree range.
As an aside, you have probably noticed that the leaves on the deciduous trees in the area are just starting to change color. Here's an interesting post by my friend from CloudyandCool.com about the necessary ingredients for a splash of beautiful fall colors.
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Wednesday, October 21, 2009
Hump day weather map
Today's weather map shows low presure developing over the central Plains, broad high pressure over the eastern U.S., and moisture (clouds) from former Hurricane Rick in the eastern Pacific streaming in from the southwest. Over the next 24 hours, the high will shift east, allowing the low to move northeast, dragging a cold front towards the area. As the front moves closer, precipitation will break out with a slight chance of thunder. Thursday looks to be a WET day with over an inch of rain possible!Severe Weather Awareness Day; 2008 hurricane video
Today marks Severe Weather Awareness Day for Tennessee, Arkansas, and Mississippi. the day is set aside to serve as a reminder to all Mid-South residents that just because the days are getting cooler, severe weather is still a possibility. In fact, the Mid-South has a "secondary severe weather season" during November and early December as strong frontal systems clash with warm moist air from the Gulf of Mexico with more regularity as the seasons change.
Perhaps the most high-profile Mid-South severe weather outbreak during this season was the Germantown tornado of 1994 that killed 3 people. Can you believe that was 15 years ago on Thanksgiving weekend?? Here is some video that was shot during the search and rescue/recovery/clean-up efforts peformed by the Germantown Fire Department and Tennessee Task Force 1. Use this day to review your severe weather plan with your family and business and know what to do if severe weather strikes. Check your weather radio, or buy one if you don't have one! Of course, MemphisWeather.net also keeps you up-to-date when severe weather strikes with the auto-updating Severe Weather Watch/Warning Map and WXLIVE!-Severe Weather e-mail notification service. Sign up to receive warnings as they are issued for your county! Another good reference is this Preparedness Guide from the National Weather Service and the Red Cross.
Also of interest, and many thanks to Paul Yeager at CloudyandCool.com for directing me to it, NOAA's Environmental Visualization Laboratory (which has some pretty cool imagery) has released a video compilation of satellite imagery for the entire 2008 Atlantic hurricane season. It is just over 4 minutes long, but is very cool to watch. I highly recommend it. Check it out here.
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Perhaps the most high-profile Mid-South severe weather outbreak during this season was the Germantown tornado of 1994 that killed 3 people. Can you believe that was 15 years ago on Thanksgiving weekend?? Here is some video that was shot during the search and rescue/recovery/clean-up efforts peformed by the Germantown Fire Department and Tennessee Task Force 1. Use this day to review your severe weather plan with your family and business and know what to do if severe weather strikes. Check your weather radio, or buy one if you don't have one! Of course, MemphisWeather.net also keeps you up-to-date when severe weather strikes with the auto-updating Severe Weather Watch/Warning Map and WXLIVE!-Severe Weather e-mail notification service. Sign up to receive warnings as they are issued for your county! Another good reference is this Preparedness Guide from the National Weather Service and the Red Cross.
Also of interest, and many thanks to Paul Yeager at CloudyandCool.com for directing me to it, NOAA's Environmental Visualization Laboratory (which has some pretty cool imagery) has released a video compilation of satellite imagery for the entire 2008 Atlantic hurricane season. It is just over 4 minutes long, but is very cool to watch. I highly recommend it. Check it out here.
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Tuesday, October 20, 2009
Severe Weather Awareness Day - Wednesday, October 21
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
1202 PM CDT TUE OCT 20 2009
...SEVERE WEATHER AWARENESS DAY THIS WEDNESDAY FOR THE MIDSOUTH...
THE NATIONAL WEATHER SERVICE IN COOPERATION WITH EMERGENCY MANAGEMENT AND THE MEDIA WILL PARTICIPATE IN SEVERE WEATHER AWARENESS DAY ACROSS TENNESSEE... ARKANSAS... AND MISSISSIPPI ON WEDNESDAY OCTOBER 21ST.
A TORNADO DRILL HAS BEEN SCHEDULED FOR WEDNESDAY... OCTOBER 21ST AT 915 AM CDT. THIS DRILL WILL REPLACE THE ROUTINE WEEKLY TEST ON NOAA WEATHER RADIO... NORMALLY SCHEDULED ON WEDNESDAY BETWEEN 11 AM AND NOON.
THE PURPOSE OF SEVERE WEATHER AWARENESS DAY IS TO FOCUS ON THE PREPAREDNESS OF THE SECONDARY SEVERE WEATHER SEASON IN THE MIDSOUTH... WHICH USUALLY OCCURS IN NOVEMBER THROUGH EARLY DECEMBER.
$$
NATIONAL WEATHER SERVICE MEMPHIS TN
1202 PM CDT TUE OCT 20 2009
...SEVERE WEATHER AWARENESS DAY THIS WEDNESDAY FOR THE MIDSOUTH...
THE NATIONAL WEATHER SERVICE IN COOPERATION WITH EMERGENCY MANAGEMENT AND THE MEDIA WILL PARTICIPATE IN SEVERE WEATHER AWARENESS DAY ACROSS TENNESSEE... ARKANSAS... AND MISSISSIPPI ON WEDNESDAY OCTOBER 21ST.
A TORNADO DRILL HAS BEEN SCHEDULED FOR WEDNESDAY... OCTOBER 21ST AT 915 AM CDT. THIS DRILL WILL REPLACE THE ROUTINE WEEKLY TEST ON NOAA WEATHER RADIO... NORMALLY SCHEDULED ON WEDNESDAY BETWEEN 11 AM AND NOON.
THE PURPOSE OF SEVERE WEATHER AWARENESS DAY IS TO FOCUS ON THE PREPAREDNESS OF THE SECONDARY SEVERE WEATHER SEASON IN THE MIDSOUTH... WHICH USUALLY OCCURS IN NOVEMBER THROUGH EARLY DECEMBER.
$$
Saturday, October 17, 2009
Frost Advisory for west TN, except Shelby County
...THE ARRIVAL OF THE COLDEST AIR OF THE SEASON WILL BRING FROST TO PORTIONS OF THE MID-SOUTH...
...FREEZE WATCH IS CANCELLED FOR SHELBY COUNTY...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS CANCELLED THE FREEZE WATCH. THE FREEZE WATCH HAS BEEN CANCELLED FOR SHELBY COUNTY AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING. HOWEVER... SOME PATCHY FROST WILL BE POSSIBLE LATE TONIGHT IN THE SUBURBS AND OUTLYING AREAS. LOW TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE TO UPPER 30S OUTSIDE THE CITY PROPER.
$$
...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM CDT SUNDAY FOR WEST TN...NORTHEAST MS...AND NORTHEAST AR...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A FROST ADVISORY... WHICH IS IN EFFECT FROM 2 AM TO 9 AM CDT SUNDAY. THE FREEZE WATCH IS NO LONGER IN EFFECT.
CLEARING SKIES...NEARLY CALM WINDS AND TEMPERATURES FALLING INTO THE LOWER TO MIDDLE 30S WILL HAVE THE POTENTIAL TO PRODUCE AREAS OF FROST ACROSS THE ADVISORY AREA LATE TONIGHT INTO SUNDAY MORNING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR PLANTS MAY BE KILLED IF LEFT UNCOVERED.
&&
...FREEZE WATCH IS CANCELLED FOR SHELBY COUNTY...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS CANCELLED THE FREEZE WATCH. THE FREEZE WATCH HAS BEEN CANCELLED FOR SHELBY COUNTY AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING. HOWEVER... SOME PATCHY FROST WILL BE POSSIBLE LATE TONIGHT IN THE SUBURBS AND OUTLYING AREAS. LOW TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE TO UPPER 30S OUTSIDE THE CITY PROPER.
$$
...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM CDT SUNDAY FOR WEST TN...NORTHEAST MS...AND NORTHEAST AR...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A FROST ADVISORY... WHICH IS IN EFFECT FROM 2 AM TO 9 AM CDT SUNDAY. THE FREEZE WATCH IS NO LONGER IN EFFECT.
CLEARING SKIES...NEARLY CALM WINDS AND TEMPERATURES FALLING INTO THE LOWER TO MIDDLE 30S WILL HAVE THE POTENTIAL TO PRODUCE AREAS OF FROST ACROSS THE ADVISORY AREA LATE TONIGHT INTO SUNDAY MORNING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR PLANTS MAY BE KILLED IF LEFT UNCOVERED.
&&
NWS/MWN
Friday, October 16, 2009
Freeze Watch for west TN Saturday night
...THE ARRIVAL OF THE COLDEST AIR OF THE SEASON WILL BRING A CHANCE FOR A FREEZE SATURDAY NIGHT...
...FREEZE WATCH IN EFFECT FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A FREEZE WATCH... WHICH IS IN EFFECT FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING.
HIGH PRESSURE SINKING INTO THE MID-SOUTH SATURDAY EVENING WILL ALLOW FOR CLEARING SKIES... LIGHT WINDS... AND DRIER AIR TO MOVE INTO THE AREA. LOW TEMPERATURES SATURDAY NIGHT WILL LIKELY FALL INTO THE 30S WITH SOME TYPICALLY COOLER LOCATIONS FALLING TO THE FREEZING MARK. WIDESPREAD FROST IS ALSO ANTICIPATED...LIKELY PUTTING AN END TO THE GROWING SEASON.
WHILE THE MEMPHIS METRO AREA WILL LIKELY REMAIN ABOVE FREEZING... OUTLYING AREAS OF SHELBY COUNTY MAY FREEZE. THUS SHELBY COUNTY HAS BEEN INCLUDED IN THE WATCH.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FREEZE WATCH MEANS SUB-FREEZING TEMPERATURES ARE POSSIBLE. THESE CONDITIONS COULD KILL CROPS AND OTHER SENSITIVE VEGETATION... PUTTING AN END TO THE GROWING SEASON.
$$
NWS/MWN
...FREEZE WATCH IN EFFECT FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING...
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A FREEZE WATCH... WHICH IS IN EFFECT FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING.
HIGH PRESSURE SINKING INTO THE MID-SOUTH SATURDAY EVENING WILL ALLOW FOR CLEARING SKIES... LIGHT WINDS... AND DRIER AIR TO MOVE INTO THE AREA. LOW TEMPERATURES SATURDAY NIGHT WILL LIKELY FALL INTO THE 30S WITH SOME TYPICALLY COOLER LOCATIONS FALLING TO THE FREEZING MARK. WIDESPREAD FROST IS ALSO ANTICIPATED...LIKELY PUTTING AN END TO THE GROWING SEASON.
WHILE THE MEMPHIS METRO AREA WILL LIKELY REMAIN ABOVE FREEZING... OUTLYING AREAS OF SHELBY COUNTY MAY FREEZE. THUS SHELBY COUNTY HAS BEEN INCLUDED IN THE WATCH.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FREEZE WATCH MEANS SUB-FREEZING TEMPERATURES ARE POSSIBLE. THESE CONDITIONS COULD KILL CROPS AND OTHER SENSITIVE VEGETATION... PUTTING AN END TO THE GROWING SEASON.
$$
NWS/MWN
Thursday, October 15, 2009
2009-2010 MWN Winter Outlook
With the winter season not too far down the road and an increased interest in long-range forecasts, I have put together some thoughts on what we may expect to see weather-wise here in the Mid-South.Research
There is a plethora of data, long-range forecasts, and opinions available with regard to the upcoming winter season. I studied several that I find to be helpful, informative, or just plain interesting. Most of the information contained below comes from one of these sources. These include the NOAA/Climate Prediction Center (CPC) 90-day seasonal outlooks, the CPC's El Nino Diagnostic Discussions, NOAA's 2009-2010 Winter Outlook, Memphis International Airport climate records, recent blog posts from Cloudyand Cool.com, the Farmer's Almanac Winter Outlook, and the Old Farmer's Almanac Long-Range Outlook (did you know these are not the same thing?).
There is a plethora of data, long-range forecasts, and opinions available with regard to the upcoming winter season. I studied several that I find to be helpful, informative, or just plain interesting. Most of the information contained below comes from one of these sources. These include the NOAA/Climate Prediction Center (CPC) 90-day seasonal outlooks, the CPC's El Nino Diagnostic Discussions, NOAA's 2009-2010 Winter Outlook, Memphis International Airport climate records, recent blog posts from Cloudyand Cool.com, the Farmer's Almanac Winter Outlook, and the Old Farmer's Almanac Long-Range Outlook (did you know these are not the same thing?).
Overview
Current data confirms the presence of a weak El Nino event as sea-surface temperaures (SSTs)in the central and east-central equatorial Pacific Ocean regions are running approximately 0.5-1.0deg Celsius (1-2 deg F) above average (see map below). Based on trends and model forecasts, most climate scientists agree that the current El Nino will maintain itself or strengthen over the coming winter months, most likely becoming a moderate El Nino event this winter (SSTs 1.0-1.5 deg C above average). 
An El Nino pattern in the winter results in a more southerly position of the Pacific jet stream, typically making landfall over California and continuing across the southern U.S. This results in an active weather pattern for the southern tier of states (wet and cool conditions) and warmer than average conditions across the northern U.S. (see map below).
For the Mid-South, El Nino effects are less pronounced than in other areas, particuarly to our south. However, typically the fall and early winter months see above average precipitation (so far so good!) with below normal precipitation during the core of the winter. Temperatures average near normal in the fall to perhaps slightly below normal during the winter.
Climate forecasts
CPC's seasonal outlooks and the recently-released NOAA Winter Outlook validate the "typical" El Nino winter (especially since they are based on those conditions occurring) - a warm/wet October-December period and a dry and slightly cooler than average January-March. The Farmer's Almanac predicts near normal temperatures and above normal precipitation. The Old Farmer's Almanac's crystal ball shows near normal precipitation and near to slightly below normal temps.
Recent Mid-South El Nino winters
Comparing to recent El Nino winters (December-March of 2003, 2005, and 2007), the Memphis area was slightly cooler (-0.9 deg) and wetter (+1.90") than average in 2003, while warmer and drier than average conditions occurred in 2005 and 2007 (2005, +3.0 deg and -3.76" and in 2007, +3.4 deg and -3.99") according to climate records for KMEM from MWN.
Comparing to recent El Nino winters (December-March of 2003, 2005, and 2007), the Memphis area was slightly cooler (-0.9 deg) and wetter (+1.90") than average in 2003, while warmer and drier than average conditions occurred in 2005 and 2007 (2005, +3.0 deg and -3.76" and in 2007, +3.4 deg and -3.99") according to climate records for KMEM from MWN.
So...
...what do I think? First of all, I'm NOT a long-range forecaster or a expert in climate. Given that, and with all due respect to the farmers (and old farmers), the evidence is present that El Nino has begun this past summer and decades of measurements indicate that it will not wane over the winter. There is also plenty of data to support the "typical" conditions that occur during El Nino events across the United States. I expect to see the wet conditions of late trend towards generally drier conditions as we head into the winter. However, as the winter storms move along the jet stream to our south, a few will have the potential to bring soaking rains and perhaps even the possibility of severe weather to the area. Temperatures seem to be a little more tricky, but I'm hedging on slightly above normal temps overall.
Prospects for snow
Everyone always wants to know about snow prospects for the upcoming winter as well. Given the more southerly storm track, we should have some opportunities for a round or two of precipitation getting caught up in cold air near the surface and creating the potential for snow. The timing will have to be perfect (as is almost always required in this part of the country). Precipitation coming from the southwest overrunning a cold dome of air already in place behind a preceding frontal system would be the most likely setup.
Everyone always wants to know about snow prospects for the upcoming winter as well. Given the more southerly storm track, we should have some opportunities for a round or two of precipitation getting caught up in cold air near the surface and creating the potential for snow. The timing will have to be perfect (as is almost always required in this part of the country). Precipitation coming from the southwest overrunning a cold dome of air already in place behind a preceding frontal system would be the most likely setup.
Here's some interesting data for the past 11 winters for Memphis showing yearly snowfall amounts (at the airport) and the state of El Nino/La Nina for that winter (ENSO neutral means neither El Nino or La Nina conditions). It is interesting to note that the highest totals seemed to occur during La Nina years, not El Nino. However, there have also been only 3 years in the past 11 that we did not get at least a couple of inches. [NOTE: The 30-year (1970-2000) "climate average" for snowfall for Memphis is 5.7" - which we didn't actually hit once during the past decade.]
I'm guessing we'll get at least one "couple inch" snowfall again this year, though freezing rain/sleet seem to be fairly likely at some point, once again given the southerly storm track of typical El Nino years. I am NOT predicting "the big one" - many of you received that on February 28th this year and those don't occur all that often!
I'm guessing we'll get at least one "couple inch" snowfall again this year, though freezing rain/sleet seem to be fairly likely at some point, once again given the southerly storm track of typical El Nino years. I am NOT predicting "the big one" - many of you received that on February 28th this year and those don't occur all that often!
1999 - Trace - La Nina
2000 - 5.5" - La Nina
2001 - 0.1" - weak La Nina
2002 - 4.5" - ENSO neutral
2003 - 2.9" - El Nino
2004 - 2.2" - ENSO neutral
2005 - Trace - weak El Nino
2006 - 3.5" - weak La Nina
2007 - 2.2" - weak El Nino
2008 - 5.4" - La Nina
2009 - 4.1" - weak La Nina
2000 - 5.5" - La Nina
2001 - 0.1" - weak La Nina
2002 - 4.5" - ENSO neutral
2003 - 2.9" - El Nino
2004 - 2.2" - ENSO neutral
2005 - Trace - weak El Nino
2006 - 3.5" - weak La Nina
2007 - 2.2" - weak El Nino
2008 - 5.4" - La Nina
2009 - 4.1" - weak La Nina
So what do you think? Educated opinions, uneducated opinions, wet fingers in the air, arthritic knee forecasts, I'll take 'em all! (And yes, I know Nino has a tilde over the second 'n'.)
Tuesday, October 13, 2009
National weather headlines for Tuesday; another wet day in the Mid-South
Today's national forecast map shows a couple of weather stories for the day. On the West Coast, the remnants of Super Typhoon Melor, which last week was the first typhoon to make landfall in Japan in two years, has turned into the first powerful fall Pacific storm of the season. Wind could reach 40-60 mph plus in coastal locations of California and even higher in the Sierra Nevadas, where several feet of snow is also possible. In addition, torrential rain will pummel northern and central California. Read more about this storm in Dr. Rob Carver's blog on Weather Underground.In the mountain west and northern Plains, winter weather in the form of scattered snow showers and some freezing rain (mainly in Nebraska) is possible.
For the Lower Mississippi Valley, including the Mid-South, it will be another rain-soaked day with the threat of flash flooding to the south of the metro area. For an excellent discussion of today's weather scenario, check out Eddie Holmes' forecast discussion for west TN. The map below shows the potential rainfall amounts for the next 24 hours. The Mid-South is in the 2"+ shading, so keep the umbrella handy today! You can also see the precip amounts expected along the west coast from the storm mentioned above.
As for the forecast, a couple more wet days are expected this week before drying takes place by this weekend. Significantly cooler air is also expected this weekend. If you have yet to crank up the heat this fall, this weekend may be your chance! The MWN Forecast will have the latest.----
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Friday, October 9, 2009
Plethora of watches/warnings
Weather watches and warnings of many types blanket the Mid-South as a strong cold front moves through bringing flash flooding and urban flooding, severe thunderstorms with damaging wind, and isolated tornadoes. The map above is current as of 11:25am.Slight risk of severe weather Friday
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ACROSS MUCH OF THE MID-SOUTH TODAY. THE MAIN HAZARD FOR THE METRO AREA WILL BE ISOLATED DAMAGING WIND GUSTS OF 60 MPH BETWEEN THE HOURS OF 9AM AND 3PM. STAY WITH MEMPHISWEATHER.NET FOR THE LATEST ON THE SEVERE WEATHER THREAT.
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Flash Flood Watch until 7pm tonight
FLOOD WATCH
NATIONAL WEATHER SERVICE MEMPHIS TN
325 AM CDT FRI OCT 9 2009
...HEAVY RAIN EXPECTED TO BRING AREAS OF FLASH FLOODING TODAY TO
MUCH OF THE MIDSOUTH...
.AN UNSEASONABLY WARM AND MOIST UNSTABLE AIRMASS WILL COMBINE WITH A
SLOW MOVING COLD FRONT TO PRODUCE SHOWERS AND THUNDERSTORMS...SOME
OF WHICH HAVE THE POTENTIAL TO PRODUCE EXCESSIVE RAINFALL ACROSS
EAST ARKANSAS...MISSOURI BOOTHEEL...WEST TENNESSEE...AND PARTS OF
NORTH MISSISSIPPI TODAY. A PROLONGED PERIOD OF HEAVY RAIN IS
LIKELY ACROSS THE WATCH AREA TODAY...BEFORE THE FRONT PUSHES EAST
AND ENDS THE FLASH FLOODING THREAT THIS EVENING.
THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS EXPANDED THE
* FLASH FLOOD WATCH TO INCLUDE PORTIONS OF EAST ARKANSAS AND
WEST TENNESSEE...INCLUDING THE FOLLOWING AREAS...IN EAST
ARKANSAS...CRITTENDEN...CROSS...LEE AND ST. FRANCIS. IN WEST
TENNESSEE...FAYETTE...HAYWOOD...MADISON...SHELBY AND TIPTON.
* THROUGH THIS EVENING
* HEAVY RAIN AND THUNDERSTORMS ALONG A SLOW MOVING COLD FRONT MAY
CAUSE FLASH FLOODING. TOTAL RAINFALL AMOUNTS OF 1 TO 3 INCHES
CAN BE EXPECTED BY THIS EVENING.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
Thursday, October 8, 2009
Severe weather outlook for Thursday/Friday
The Storm Prediction Center has increased the possibility of severe weather for the metro area for Friday, while inching the SLIGHT RISK area closer to the city overnight tonight. The graphics above show the overnight threat across all of NE AR and NW TN, generally north of I-40, while the entire region is under a SLIGHT RISK for Friday, mainly in the mid-morning to mid-afternoon hours.
For tonight, the main threats for the areas north of the metro region are damaging wind gusts and possible tornadoes as thunderstorms are expected to form and/or move into NE Arkansas this evening and continue overnight. For the metro area Friday, the cold front will likely be preceded and accompanied by line(s) of thunderstorms, with damaging wind gusts being the main threat. Hail is not expected to be a significant factor. As the storms move through, they will be moving at 40-50 mph to the northeast while the area of weather moves east to southeast.
Read my previous post for a complete discussion of this weather event and stay with MemphisWeather.net for the latest weather information. You can also follow MWN on Twitter (memphisweather1) to receive all watches/warnings as they are issued.
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Short-term complications, but long-term improvement
Today is "setup" day for the Mid-South ahead of the next major weather ststem to affect the area. We started off fairly pleasant this morning (temps in the lower 60s, some cloud cover, and generally dry conditions), but it will become very warm, quite breezy, and muggy by this afternoon, with a small chance of rain or thunderstorms. This courtesy of a warm front that will be moving north through the region today. The dewpoint, a measure of the amount of humidity in the air, will increase from near 60 this morning to the lower 70s by this evening, while the wind will pick up out of the south and become gusty in the 20-30 mph range. Some breaks in the clouds will help temps climb above normal for the first time in 10 days with highs in the mid 80s expected.
The weather-maker that is headed our way will stay mainly to the west overnight tonight, keeping rain chances low, but with a gusty wind continuing and humidity remaining high in the warm sector of the approaching system, we will see temps only fall into the 70s tonight.
Friday will be the big weather day as the cold front moves across the metro area during the afternoon hours. Rain and t'storms are expected by mid-morning with rain, potentially heavy at times, continuing even after the front passes. Temperatures will likely peak in the morning hours in the upper 70s before falling into the 60s during the afternoon as the front passes and wind switches around to the northwest. Flash Flood Watches are in effect for northern west TN and northeast AR for the potential of 2-3" of rain. The threat of severe weather, though low, is not non-existent as some storms may contain large hail or damaging wind ahead of and along the cold front as it passes through during the day Friday. See the NWS Hazardous Weather Outlook for details.
The front will stall out or move only slowly Saturday, so clouds may hang tough over the metro area with a slight chance of a morning shower. It will be significantly cooler with highs 20 degrees cooler than today - in the mid 60s. Conditions improve by Sunday and a reinforcing fall cold front comes through late in the weekend, bringing dry and cool autumn weather for the first half of next week.
For updated information, check out the MWN Forecast, MWN StormView Radar, and WXLIVE! current conditions. Monitor severe weather watches and warnings on the live Severe Weather map.
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Saturday, October 3, 2009
September climate stats and forecast accuracy
After a cool August, September ended up being slightly warmer than average, though precipitation was well above normal. Following are climate summaries for Memphis and Bartlett, TN.
Memphis International Airport, Memphis, TN
At the airport, the average temperature was 75.7 degrees, which was 0.9 degrees above normal. The highest temperature for the month was 93 degrees set on the 8th and the lowest was 53 on the 30th. A total of 4 September days saw highs at or above 90 degrees. No temperature records were set in September.
Though September is typically a dry month, this was not the case for September 2009. The airport recorded 8.59" of rain for the month, which was over 5" above normal. There were 16 days with measurable rainfall (9 above normal), 3 days with over 1" of rain recorded, and one day with more than 2" of rain (2.14" on the 18th). The peak wind gust was 37 mph, recorded on the 5th. Click here for the NWS climate recap for September.
Bartlett, TN
WXLIVE! also recorded a wet month with near normal temperatures. The average temperature for September was 73.4 degrees, with a max of 92.1 on the 8th (the only day above 90 for the month) and a min of 46.5 degrees on the 29th, one of 6 days for the month that dropped below 60 and one of two days below 50 to close the month. Not as much rain was recorded in Bartlett as at the airport, totaling 5.00" for the month at the automated WXLIVE! gauge, while a co-located manual gauge used for the CoCoRaHS program measured 6.16". The peak wind gust was 24 mph on the 6th. Click here for the MWN recap.
MWN Forecast Accuracy
The MWN Forecast once again produced a lower average temperature error than any of the computer models or the National Weather Service by more than 0.30 of a degree at 2.06 degrees for all forecasts. In addition, the number of forecasts produced for the month (50) was the highest in a decade, since September 1999. So, not only was the quantity of forecasts well above average, but the quality continues as well. Accuracy statistics can be found here.
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Memphis International Airport, Memphis, TN
At the airport, the average temperature was 75.7 degrees, which was 0.9 degrees above normal. The highest temperature for the month was 93 degrees set on the 8th and the lowest was 53 on the 30th. A total of 4 September days saw highs at or above 90 degrees. No temperature records were set in September.
Though September is typically a dry month, this was not the case for September 2009. The airport recorded 8.59" of rain for the month, which was over 5" above normal. There were 16 days with measurable rainfall (9 above normal), 3 days with over 1" of rain recorded, and one day with more than 2" of rain (2.14" on the 18th). The peak wind gust was 37 mph, recorded on the 5th. Click here for the NWS climate recap for September.
Bartlett, TN
WXLIVE! also recorded a wet month with near normal temperatures. The average temperature for September was 73.4 degrees, with a max of 92.1 on the 8th (the only day above 90 for the month) and a min of 46.5 degrees on the 29th, one of 6 days for the month that dropped below 60 and one of two days below 50 to close the month. Not as much rain was recorded in Bartlett as at the airport, totaling 5.00" for the month at the automated WXLIVE! gauge, while a co-located manual gauge used for the CoCoRaHS program measured 6.16". The peak wind gust was 24 mph on the 6th. Click here for the MWN recap.
MWN Forecast Accuracy
The MWN Forecast once again produced a lower average temperature error than any of the computer models or the National Weather Service by more than 0.30 of a degree at 2.06 degrees for all forecasts. In addition, the number of forecasts produced for the month (50) was the highest in a decade, since September 1999. So, not only was the quantity of forecasts well above average, but the quality continues as well. Accuracy statistics can be found here.
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