New Year's Eve forecast and a chance of wintry weather Thursday night [VIDEO]

Wrapping up 2014 with a brief look at temps and precip for the past year, the discussing COLD conditions for your New Year's Eve and New Year's Day as well as an overrunning precipitation event on Thursday night that could mean a chance of wintry weather for a short period.

Bottom line

Very cold conditions expected through Thursday with Arctic high pressure in control. Wind chills in the teens are expected overnight and in the 20s all day tomorrow. New Year's Eve festivities tomorrow will require a heavy coat as temps drop back into the 20s.

Precipitation ahead of our next system breaks out Thursday late afternoon or evening as light rain, possibly mixed with a bit of sleet for a few hours until the atmosphere moistens up. All rain expected after midnight (early Friday) and continuing, periodically heavy, through Saturday with temps remaining above freezing. Thunderstorms are also possible Saturday depending on the track of low pressure.

Thanks so much to all of our followers and friends for a phenomenal 2014! We can't adequately express our gratitude through a blog, but know that your amazing support is what will keep us going into what should be a fantastic 2015!

Watch for an update to this blog on Thursday morning with the latest on possible winter weather and follow us on social media for any changes in the meantime

Erik Proseus
MWN Meteorologist

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A wet weekend leads to a dry and cold week as 2015 arrives

We hope that everyone had a great Christmas and are thankful that rain held off to make for very pleasant weather for the holiday! Rain has moved in today though as a cold front approaches and moisture surges in from the Gulf. The front will pass through early this evening and bring temps down from the tolerable mid 50's quickly into the 40's. The cold front won't stop the rain though, as it continues overnight and into Sunday morning as low pressure moves along the front, wrapping rain back into the metro. Sunday will be much cooler behind the front with temperatures fairly steady in the mid 40s, or about 10 degrees cooler than today.

What temperatures could look like tonight at 9 PM as the cold front pushes through the metro. Graphic courtesy WeatherBell Analytics.

By noon on Sunday most rain will be out of the metro, with some lingering showers left over in northern Mississippi departing toward the east as yet another low moves along the front. This will effectively end precipitation chances in the metro until after New Year's Day. Cool but dry conditions are expected for those of you heading to the Liberty Bowl to see Texas A&M take on WVU.

Simulated radar at noon Sunday, showing what's left of rain departing to our east. Graphic courtesy WeatherBell Analytics.

Temps in the meantime look to get quite cold with temps in the lower 40's for highs and the upper 20's for lows on both New Year's Eve and New Year's Day as massive Arctic high pressure moves into the western U.S., but "leaks" east across the Plains into the Mississippi Valley.

Temperatures could be more than 10 degrees below normal as we prepare to ring in the New Year. Graphic courtesy WeatherBell Analytics.

Looking ahead to Thursday night, precipitation will make its return from the south, while temperatures at the onset could be right around freezing as lingering cold air hangs around. It's too early to make a call with any certainty, but initial precipitation Thursday night into early Friday could fall as light ice or snow. However we expect precipitation to change over to rain during the day Friday as warmer temperatures stream into the region from the south. Rain could continue into the weekend for those of you with any plans for the first weekend of the 2015. 

Here's a look at the full MWN 6-Day Forecast:

We'll keep everyone updated on the latest conditions and expectations heading towards the Liberty Bowl and New Year's Eve on our social media channels listed below.

William Churchill, MWN Social Media Intern

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First look ahead to Christmas weather in the Mid-South

Everybody and his cousin  (who lives in the Memphis area) are inquiring minds and want to know: "Are we going to get a White Christmas??"  I'll answer that 2 ways. First, read this excellent blog post MWN intern Kevin put together a couple of days ago. Historically speaking, it's highly unlikely. But that's not the answer you want a week out. So here is our first "official" look at holiday weather, using actual forecast data.

We first have to get through the next several days, which bring us a couple of rounds of precipitation - the first one overnight tonight and another Friday afternoon and night. Sunday and Monday look pleasant with increasing temperatures (50 Sunday, mid 50s Monday), then the next weather system arrives Tuesday the 23rd with a good chance of rain.

Tuesday's system should clear out by Wednesday morning, so Christmas Eve looks to be  windy chilly but likely dry. Right now we're calling for temperatures in the 40s with partly sunny skies and gusty north wind. In fact, to our north, a huge low pressure system is being predicted by multiple long-term models to be over the Great Lakes region with  impacts across a wide expanse from the Northeast to the Tennessee and Mid/Upper Mississippi Valleys (see GFS model solution below). This system will be responsible for our wind and could get a few snow showers as close as middle TN on Christmas Eve.  If you have travel plans, particularly by air, north and east of Memphis on Christmas Eve, this system could cause all kinds of delays.

GFS forecast surface map and precip type late Christmas Eve. A "mega-low" over the Great Lakes region would have ea large sphere of influence over the eastern half of the country. Graphic courtesy WeatherBell Analytics.

As for Christmas Day, as the large low pressure system to our north moves slowly into southeast Canada, it's influence on the Mid-South will lessen and high pressure will build in. Therefore, as of this minute, I expect an "average" Christmas Day with cool and dry conditions. Of course, things can still change rapidly between now and then and details are yet to be ironed out.

Experimental GFS modeled temps and precip for the next 10 days. This is NOT a forecast, just one possible solution. Days are listed near the bottom from left to right, temps are the red/black lines and rain amounts are the blue bars. Graphic courtesy WeatherBell Analytics.

So while we may not have the White Christmas you would like, hope is not lost! The same models showing the mega-low are showing a rapid warm-up to end Christmas week, but beginning the last weekend of the year in to early January, signs are pointing towards a general cool-down. Perhaps we can get some moisture to work its way into below average temperatures and bring some snow for early 2015! No bets on that this far out though!

We'll continue to keep you updated on our latest thinking on our social media channels below and will update the blog again as needed.

Erik Proseus
MWN Meteorologist

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A warm start to a chilly week with periods of wet weather

Yesterday was a great December day with temps in the mid 60s and lots of sunshine. Despite off and on rain, it's also a mild day today as the rain out-raced the cold front, so warm Gulf air continues to flow into the region as the cold front lingers to our west. The front will move through late this afternoon however, bringing an end to the 60s for the foreseeable future. This was just the first in a series of weather systems to affect the region this week.

Tuesday and Wednesday will be "tweener" days as high pressure briefly takes over following today's front and our next weather system affects the region Wednesday night. Colder air will filter in behind tonight's front bringing highs Tuesday back down to near normal in the 50s. Lows will drop to near freezing Wednesday morning and clouds will increase during the day, holding temperatures down in the 40s for the daytime hours.

Forecast mid-level pressure (500mb or ~18,000') Wednesday morning indicating a flat ridge over the southern U.S. Graphic courtesy WeatherBell Analytics.

The pattern shift that persists through the end of the week begins Wednesday night as moisture rides up into the area on west-southwesterly wind flow, bringing a period of light precipitation - the second weather system of the week. Right now, it appears temperatures will remain above freezing all night with lows in the mid 30s. This scenario bears watching though in case surface temps trend any colder. The most likely precipitation type if NOT rain will be light freezing rain. Again, ice is not currently in the forecast.

GFS forecast precipitation amounts from midnight through 6am Thursday as moisture and precip arrive from the west. Amounts range from 0.25-0.50". Graphic courtesy WeatherBell Analytics.

GFS forecast temps at 6am Thursday, indicating mid 30s across the metro. Graphic courtesy WeatherBell Analytics.

Very light precipitation is possible again on Thursday and Thursday night with cloudy skies and cool temperatures. The last weather system of the week arrives early Friday as low pressure develops over Texas and moves east. Odds are that this low will bring a fair amount of rain Friday into early Saturday as it travels by to our south. Amounts of 1-2" are possible. There are signs from one medium-range computer model (the European) that there could be enough cold air filtering in on the backside of the low Friday night to POSSIBLY change rain over to light snow. However, none of the other models depict this same scenario as of now. In fact, the European model became much less bullish with snow in this morning's data, so confidence increases in a relatively warmer solution (but still cold for those who will be out in the elements!).

As always, there are many factors that will affect the eventual outcome, including strength and track of the low and resultant amount of cold air that moves in and how quickly it does so. We are carrying RAIN in the forecast but continue to monitor. We're hopeful for a mainly dry, but chilly, weekend as the season officially changes from autumn to winter Sunday evening. Also, looking ahead, it currently looks dry and cool for the Autozone Liberty Bowl next Monday (40s).

Farther out (too far if it were any day but Christmas), long-range models are pointing to one more southern stream system around Tuesday/Wednesday similar to this Friday's, then a chilly Christmas Day that looks dry. We'll update again in a few days with the latest thinking and be sure to follow us on social media for any updates. Also, be looking for a blog later tonight on the history of Christmas Day weather in Memphis! Hint: it doesn't bode well climatologically for a white holiday.

Erik Proseus
MWN Meteorologist

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November 2014 Climate Data and Forecast Accuracy

November Recap

November was a cold and dry month across the Mid-South. In fact, the month tied for the 7th coldest on record. The cold also led to some of the earliest snowfall on record with two measurable events - the 4th and 7th earliest on record. Though it was a cold month, for the months of September-November (defined as meteorological fall), the average temperature was just 1.2 degrees below normal due to slightly above normal temps in September and October. Precipitation for the same three-month period was 1.25" below average at 11.31". There was no severe weather during November.

Memphis International Airport, Memphis, TN

Temperature
Average temperature: 47.4 degrees (5.8 degrees below average)
Average high temperature: 56.5 degrees
Average low temperature: 38.2 degrees
Warmest temperature: 75 degrees (4th)
Coolest temperature: 20 degrees (18th)
Records set or tied: Record warmest low temperature - 61 on the 30th
Comments: November 2014 ranked as the 7th coldest November on record (since 1875). Ten days saw temperatures fall below 32, which is 7 above normal. For the year, the average temperature at Memphis is 62.6 degrees, which is 2.1 degrees below average.

Precipitation
Monthly total: 2.56" (2.93" below average)
Days with measurable precipitation: 8
Wettest 24-hour period: 1.46" (4th-5th)
Total Snowfall: 0.2" (0.2" above average)
Records set or tied: None
Comments: Measurable snow fell on two days in November (0.1" each), which marked the 4th and 7th earliest measurable snowfalls on record. Only two days had precipitation above 0.50". As of the end of November, the yearly precipitation has been 55.03", which is 7.09" above (or 115% of) average.

Miscellaneous
Peak wind: South/43 mph (30th)
Average wind: 8.5 mph
Average relative humidity: 61%
Average sky cover: 50%

Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Temperature
Average temperature: 45.9 degrees
Average high temperature: 56.1 degrees
Average low temperature: 35.5 degrees
Warmest temperature: 74.6 degrees (4th)
Coolest temperature: 19.1 degrees (18th)
Comments: None

Precipitation
Monthly total: 2.81" (automated rain gauge), 2.86" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 11
Wettest date: 1.13" (5th) (via automated gauge)
Comments: None

Miscellaneous
Peak wind: Southwest/30 mph (29th)
Average relative humidity: 73%

Click here for a daily statistical recap for Bartlett, TN.

MWN Forecast Accuracy

MWN average temperature error: 2.51 degrees
MWN forecast temperatures within 2 degrees of actual: 59%
MWN average dewpoint error: 2.34 degrees
MWN forecast dewpoints within 2 degrees of actual: 65%

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours). Historical accuracy statistics can be found here.

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Ridges and troughs: signs of fluctuating temperatures this week

It was a rather pleasant early December day in the Mid-South, but don't get too comfortable as changes come quickly. It's the time of year that variations in the weather pattern can come frequently and we have a classic pattern setting up that favors quick swings in temperature as the atmosphere tries to figure out what season it is.

The Mid-South will get wedged between an upper level trough (or lower pressure) to our east and an upper level ridge (or higher pressure) to our west for most of the work week. This will result in what is called "northwest flow" for the area, in which the upper level flow of air is from northwest to southeast. This pattern is usually quite progressive, resulting in large oscillations in temperatures due to frontal passages and increased precipitation. In this case though, the pattern looks a lot drier, with a shortwave embedded in the flow only able to bring cloud cover (and perhaps a few sprinkles) to Memphis Wednesday into Wednesday night.

Upper level map showing height anomalies, indicative of ridges and troughs.
The Mid-South wedged in between the two, resulting in northwest flow.

Now, lets talk about those temperatures swings. First we'll start with a cold front that is coming through the Mid-South tonight, which is associated with a weak upper-level trough that makes its way through the area and then strengthens to our east, thus strengthening the northwest flow. This will bring cooler temps south for the next couple of days, resulting in lows near freezing Wednesday morning and highs in the mid to upper 40's for the middle part of the work week.

Surface temperature anomalies Wednesday morning showing temperatures about 8 degrees below average for the Mid-South.

These below average temps won't stick around too long though, with a building upper level ridge to our west that will slowly make its way into the Mid-South. We'll start feeling the effects of that ridge by Friday as above average temps settle in for the weekend (high temps in upper 50's and lower 60's).

Surface temperature anomalies during the day on Saturday. A drastic difference just 3 days after the previous map.

Looking into the longer range, there is fair agreement that temps will stay above average heading into next week. The Climate Prediction Center agrees, with their probability forecasts showing upwards of a 50% chance of above average temps all the way through the 3rd week in December. This does not mean that we won't see periods of cold, just that above average temperatures are more likely for the majority of the time.

The Climate Prediction Center forecasting over a 50% probability
that we see above average temps from December 14th-18th (early next week).

Below are the expected highs and lows for this week and as always, you can get the full MemphisWeather.net forecast here. Also follow us on Facebook and Twitter for daily details on the forecast.

William Churchill
Social Media Intern

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Rain and thunder to end the week then a cloudy but dry weekend

Rain is moving into the metro this morning as the first of a couple impulses moves through the area and a warm front continues lifting north. Temperatures are already climbing towards the mid 60s ahead of the rain with dewpoints rising above 60, which means a very humid airmass for early December. I'll use simulated radar graphics from one of our best high-resolution models as we talk through the day.

Simulated radar from the HRRR model valid at noon.

Rain will last throughout the afternoon hours, meaning a wet dismissal from school this afternoon mostly likely. Some rumbles of thunder are possible this afternoon as well.

Simulated radar at 3pm. Rain and some thunder possible as kids get out of school.

The initial batch of rain looks to be moving out around rush hour tonight. and, if they're lucky, the Collierville Christmas Parade at 7pm MIGHT catch a break with just scattered showers and thunderstorms around. The parade is rain or shine, but if you're planning to attend, use common sense and seek shelter if you see lightning or hear thunder. [UPDATE: This afternoon, Collierville officials decided to cancel the parade. There is no makeup date.] This relative "lull" in activity could also coincide with the arrival of 18,000 of you at FedExForum tonight. (Go Grizz!)

Simulated radar at 6pm showing the initial batch of rain departing but more activity developing to the west.

By late evening into the early overnight hours, thunderstorms are looking more likely as a cold front draws closer and runs into very humid, warm air and sufficient wind aloft to allow for some storm organization. The Storm Prediction Center has placed the Mid-South in a Marginal risk for severe weather, which is category 1 of 5 and below a Slight Risk. The chance of severe weather is slim, but brief strong wind gusts are possible if strong wind aloft mixes down to the surface in thunderstorms.

Simulated radar at 10pm, projecting some thunderstorms in the area as a cold front nears.

A Marginal Risk of severe weather (category 1 of 5) exists for the Mid-South. Brief strong wind gusts are possible, but not likely, from evening into the overnight hours.

Overall, this will be a pretty good rainmaker with rainfall amounts over an inch likely to be common by Saturday morning and some spots possible seeing 2" if multiple storms move overhead.

Forecast rainfall totals from the National Weather Service through 6am Saturday.

The good news is that all of the rain should be gone by 6am Saturday with maybe just some drizzle or sprinkles Saturday morning. Temperatures in the morning will likely hover in the lower 50s during the morning with a steady north wind at 10-15 mph for the St. Jude Memphis Marathon.

For afternoon and early evening Christmas parades on Saturday, conditions should be dry but cloudy with that north wind still blowing and temperatures falling from around 50 at 3pm to the upper 40s by 7pm. A warm coat will be a good idea as the wind will be cool, but it won't be a frigid day with hand warmers, scarves and gloves probably not necessary.

No rain is in the forecast from Sunday through much of next week.  Click here to view the complete MWN Forecast and be sure to follow us on our social media feeds throughout the day and evening for the latest info (links below). Also check out our MWN mobile app for the latest metro radar, forecast, and Twitter updates, even if you don't use Twitter. We might just win you over. :-)

Erik Proseus
MWN Meteorologist

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Major Arctic front arrives Monday, but cold air doesn't last long

I cut a video forecast discussion this afternoon to talk about a big push of Arctic air into the region on Monday, chances of any freezing precipitation behind it, and an early look at St. Jude Marathon and Christmas parade weather next Saturday. Watch below for full details (about 11 minutes long), or skip ahead to get "The Bottom Line."



Can't see video above? Here's the link: http://youtu.be/dqyavOZ_JJ8

The Bottom Line

Say so long to Sunday's 70s as temperatures fall from the 60s overnight into the 30s by Monday afternoon in the wake of the front that will move through around dawn Monday. With wind factored in, temperatures tomorrow afternoon could feel up to 40 degrees colder than this afternoon! Showers are also expected off and on Monday into Monday night but no frozen precipitation is expected as lows remain in the mid 30s Tuesday morning.

Forecast temps as of 6am Monday as an Arctic fromt slices through the region. Temps near 60 will be found just ahead of the front, while the mercury plummets into the 30s not far behind it! Click for larger image.

An unsettled week ahead with moderating temperatures and rain chances, especially towards the latter half of the week. Highs will be back near 60 by Wednesday with clouds keeping lows above normal. By next weekend, a few showers are still possible Saturday morning for the marathon, but one mid-range model dries us out by then. Temperatures in the morning will likely be in the upper 40s to lower 50s with highs near 60 Saturday afternoon. No freezing temps for the first round of Christmas parades next weekend!

Click here for the complete MWN Forecast (or here for mobile users) and get the latest throughout the week via our social media channels below and the official forecast posted on the web and our mobile apps.

p.s. Speaking of mobile apps, now is a GREAT time to get StormWatch+ severe and winter weather alert capability added to your MWN mobile app! Our once a year sale is going on through 11:59pm Monday night! Get fast and precise mobile weather alerts at nearly 40% off. Click the links below for more info on MWN mobile apps and StormWatch+ and activate StormWatch+ through the Alerts tab in the app.

Erik Proseus
MWN Meteorologist

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Thanksgiving Week Weather for Memphis and the Nation

A mild weekend, and soggy Sunday, is in the books with a cold front arriving overnight to bring an end to 60+ degree temps for the time being. Besides cooler temperatures tomorrow, we'll also have a lot of wind with this system. Gusts increase to 30+ mph overnight and at least the first half of Monday, prompting a Wind Advisory through noon. A shower is possible overnight as the front moves through in the wee hours, but most areas will stay dry following 1/2"-1" of rain on Sunday.

Holiday Week Forecast for Memphis

For the upcoming holiday week, we'll be back to slightly cooler than normal temperatures as highs will be in the 50s with lows in the 30s. In addition, dry weather is expected all week locally, even though a weak cold front moves through on Wednesday. As we get closer, it's possible a slight chance of rain will be dropped into the Wednesday forecast, but for now we're going dry.

Thanksgiving Day looks to be cool with highs near 50, while a warm-up commences for Black Friday and continues into next weekend. For early bird shoppers Friday morning, temps will be well down into the 30s. Next weekend now looks to be another warmer than normal weekend but there will be some rain chances, most likely on Sunday. Highs should be back into the 60s. Click here for the latest Memphis forecast from MWN.

Long-range temperature guidance from the GFS Ensemble models indicate cooler temps this week, then a warm-up next weekend. Graph only to be used for temperature trends, more than exact highs/lows.

Traveler's Forecast

For those traveling on Wednesday to parts near and far, national weather, with the exception of the East Coast, looks cool but decent. A few rain showers are possible across western KY, while rain could mix with light snow in the St. Louis area with light snow north of there into IA and IL.

On the East Coast, a Nor'Easter is brewing but models are still trying to latch onto the track of the storm. It does appear though that areas from the Appalachian Mts of North Carolina through Virginia, D.C. and right up the eastern seaboard to Boston need to prepare for a possible heavy snow event. Most of the system's effects move out by Thanksgiving morning, leaving just scattered snow showers behind. The Macy's Thanksgiving Day parade could be an interesting event if this plays out as forecast and  travel disruptions are likely throughout the region from Virginia to Maine. For air travelers, with many airline hubs on the east coast, the storm could have ripple effects nationwide.

Forecast model precipitation (green=rain, blue/purple=snow) on Wednesday afternoon for those traveling around the country. This will likely change some by Wednesday, but an early look for where trouble spots will be, especially in the east.

Forecast high temperatures for Wednesday afternoon for those traveling.

A look at POTENTIAL snowfall amounts through Thanksgiving morning in the Northeast. These WILL change since it's still a few days out, but provides an idea of where travel delays may result. Ripple effects are likely for air travelers nationwide on Wednesday.

Have a safe and enjoyable Thanksgiving Week! We give thanks to each and every one of you for your patronage and support!

p.s. Remember that StormWatch+ in the MWN mobile apps works nationwide, so if you're traveling, go ahead and set your destination up in the app early this week (especially if headed east) so you can get early notice of any Winter Storm Watches/Warnings issued.

Erik Proseus
MWN Meteorologist

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Dusting of snow deposited on the metro - the latest info

UPDATE - 6:45am:

Clouds are departing and precip is done. We'll see mostly sunny skies this morning then some clouds and possible flurries could move into mainly west TN portions of the area this afternoon as "backlash" moisture moves into the low levels. Temps will sit in the low-mid 30s all day with northwest wind keeping wind chills in the 20s.

Sunrise photo taken from north Bartlett at MWN. A dusting of snow and clouds breaking up.

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As of 5am, the main band of light snow is moving through the eastern metro. Light snow over northeast AR is slowly falling apart but flurries are possible for a couple more hours across the metro.

StormView Radar in winter mode at 5am. Precip is pushing quickly to the east.

Temperatures have fallen to or just below the freezing mark, which means wet bridges and overpasses could start to get slick.

5am metro temps

A Winter Weather Advisory is in effect until 8am for the purple counties below, mainly for the possibility of hazardous travel. No additional snow accumulation is expected on top of the dusting we received.

Winter Weather Advisory until 8am for the purple counties.

All school districts in Shelby County have announced their intentions and will be OPEN today. And all the school kids be like....

Take it SLOW and BE SAFE this morning. Consider alternate routes that don't have overpasses if possible and allow extra time to reach your destination. Leave plenty of space between you and the car in front of you and avoid rapid changes in speed or direction, especially on elevated surfaces. I'm done being your momma. Now go enjoy the light snow rather than stressing out. It's only mid-November and we could have a long winter ahead.

(Looking ahead: it will be unusually cold for November through Wednesday morning. Mid 30s today, upper teens tonight, mid 30s again Tuesday, 20s Tuesday night, then a warmup begins. Add wind to all of these temps and it'll feel even colder. We could be talking thunder by this weekend with temps trying to get back to normal or slightly above.)

Erik Proseus
MWN Meteorologist

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Another winter weather event tonight - this one NOT a surprise

Another Arctic cold front moves through the Mid-South overnight, dropping temperatures as precipitation moves out behind a low pressure system moving through the southeastern states. This is a familiar pattern for meteorologists. The timing of the arrival of cold air and departure of deepest available moisture always creates an interesting scenario for wintry precipitation in the Mid-South.

A Winter Weather Advisory (purple) for up to 1-2" of snow is in effect for counties just north of the metro overnight. 

In this case, it appears there will be some light precipitation as sub-freezing air moves into the region, mainly in the lowest 5,000' or so of the atmosphere. Though surface temperatures won't reach freezing until 4-5 am, we expect that the low level (above surface) temperatures will drop below freezing as early as midnight. Meanwhile, precipitation looks to linger until around 6am.

High-resolution Rapid Refresh (HRRR) modeled precipitation & type from 11pm-5am tonight. Notice the bulk of the rain is east of the metro, however a brief changeover to rain/sleet (pink) occurs around midnight, followed by light snow.

Bottom line forecast

Short term models are in good agreement with this system. Light rain showers, drizzle, and mist continue this evening with temperatures well above freezing. One last round of steadier (though still light) precipitation will arrive by 10pm-midnight, changing from light rain to a rain/sleet mix for a couple of hours before becoming all snow (still very light). By the start of rush hour, almost all light snow will be east of the metro with flurries lingering through rush hour. Winter precipitation amounts will be under 0.10" total.

Impacts Expected

Even though all precip ends around rush hour, temperatures will fall below freezing by 4-5am, reaching the upper 20s by 7-8am for the morning low. Given the issues that occurred Thursday morning with about 0.04" of sleet/snow, I would expect you'll need to take potential icing of bridges and overpasses into effect in the morning. Check your favorite traffic source before heading out (I highly recommend the traffic layer on Google Maps that color codes roadways based on traffic speed and plots all known accidents). Give yourself PLENTY of extra time and drive carefully! Quick stops, starts, or land changes on elevated surfaces is a recipe for disaster. By mid to late morning, things should improve rapidly due to gusty wind (an evaporation aid), some sunshine, and tire heat on the roads.

Extended outlook

Temperatures will only top out in the mid 30s Monday with wind chills in the 20s all day. The coldest air of the night arrives Monday night with lows in the teens metro-wide and wind chills at the bus stop Tuesday morning near 10. Mid 30s highs are expected again on Tuesday before a warming trend commences Wednesday with a high near 50. Click here for the complete MWN Forecast.

Erik Proseus
MWN Meteorologist

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Lessons learned from the first snow of the season and their application to the next event (this weekend)

A surprise snow to start the season

Weather and traffic folks had their hands full early this morning when "surprise" snow showers passed over the metro around dawn. I quote "surprise" because there were clues last evening that some precipitation could occur this morning. In fact, I updated the official MWN Forecast shortly after 10pm last night to add the mention of flurries and a 10% chance of precipitation. In other words, the evidence wasn't particularly convincing, but it was there.

The MWN Forecast following an update at 10:15pm Wednesday

Lessons Learned

My biggest surprise, and it shouldn't have been, was the impact. Most every weather event presents learning experience(s) for meteorologists if we're paying attention. This one was no exception. Here's what I learned:

• Sometimes you have to ignore the calendar. Today's 0.1" of snow was the earliest on record at the Agricenter (records date back to 1987) and only 11 days past the earliest snow on record at Memphis International. But the atmosphere doesn't care what the calendar says. It was cold enough to snow, so when precipitation fell, that's what it did.
• Be wary of the "first of the season." Whether it's winter weather in the fall, severe storms in the spring, or 100 degree temps in the summer, forecasters tend to underestimate the first of those events in a particular season. We need to not be shy about forecasting what we expect just because it's the first one of the season. So what if it hasn't snowed yet this year? That doesn't mean the first time it does it'll be nuisance flurries.
• At the risk of crying wolf, winter weather impacts in the south cannot be underestimated. After all, we don't handle winter weather well in this part of the country. The clues I personally missed that should have resulted in a more strongly worded advisory included: roads not pre-treated, temps at or just below freezing, a hint from high-res models last night that precipitation could be more than just flurries, and the fact that it was the first event of the year. These points, taken together, resulted in bridges shut down, a plethora of accidents, and overall a pretty awful commute if you had to leave secondary roadways.

So, this event was a learning experience for all of us. I believe that if this exact event were to happen again sometime soon, I would handle it much better and be able to better forecast the impacts (because that is what really matters). Overall, those impacts would likely be reduced as well because now everyone won't think it can't happen because it's "too early" and be better prepared. I'm just glad that, in the end, we got to "re-learn" winter weather with a relatively weak event. (UPDATE: After posting this, I read that a young man passed away in a single car accident on Highway 385 after sliding on ice and rolling his vehicle. The previous statement was not intended to diminish the impacts to those who were most directly affected by the conditions. Our condolences to the young man's family.)

A second chance?

So about that next opportunity! We may not have long to try out our new-found knowledge! We're carefully watching this weekend's weather pattern. Model data has been hinting at frozen precipitation of some sort Saturday night into Sunday morning and perhaps again Sunday night. A low pressure system will move along the Gulf coast with precipitation spreading to its north, falling into cold air over the Mid-South. The latest is presented below in the form of a couple of those model solutions. Right now we favor the GFS/European solution over the NAM, but their solutions are starting to converge fairly closely.

GFS forecast total precipitation through Sunday afternoon. It forecasts most precipitation to remain south of the metro with very light amounts along and south of I-40.

GFS forecast low temperatures Sunday morning. Lows in the mid 30s are borderline for snowfall, In fact, where most precipitation is forecast to fall, lows are in the upper 30s. There is a slight chance we could see light snow or sleet in this scenario. 

NAM forecast precipitation through Sunday evening. There is a bit more very light precip in the metro, but the 0.10" (green) amounts are in almost exactly the same place in north MS as the GFS.

Forecast low temperatures Sunday morning from the NAM model are nearly the same as the GFS, perhaps a degree or two warmer in fact. The NAM presents a similar outcome to the GFS.

Bottom line on the weekend

So, for now, we are forecasting a chance of a wintry mix of cold rain, sleet, or snow early Sunday morning, becoming rain showers during the day. Sunday night may end up dry, but if precipitation lingers, it could change back into light snow before ending as temperatures fall. The parameters that are favorable compared to this morning include slightly warmer near-surface temperatures, drier air ahead of this system (reducing precip amounts), and a bit more "forecast-able" event since we have a track record of many model runs worth of data to spot trends in.

We'll be sure to let you know what we expect as the event draws closer, achieving a balance between under- and over-forecasting and stating the knowns and unknowns as best as we are able. For now, don't change any plans! What we do expect is very cold air to remain in place over the area into early next week at least. A hard freeze is expected tonight and tomorrow night, so take any precautions necessary to protect pipes, plants, and pets and click here for the complete MWN Forecast.


Erik Proseus,
MWN Meteorologist

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MWN 2014-2015 Winter Outlook

Winter appears to be starting a bit early this year, as Arctic air is poised to ooze south of the Mason-Dixon by mid-late week. But is that a foreshadow of things to come or just an anomalous event in what would be a reversal of last year's cold winter?

This year's MWN Winter Outlook is presented below in video format and includes some background on processes such as ENSO that ultimately affect our seasonal climate, methodology behind the outlook, as well as our official forecast. I hope you'll take 25 minutes to watch the entire presentation, but if you just want the bottom line, jump ahead to about 21 minutes into the video or see below for the bullet points.

MWN Outlook Methodology:

• Based on 10 analog years with weak El Nino conditions (1952, 1953, 1954, 1959, 1970, 1977, 1978, 1988, 2005, 2007)
• Recent research by NWS-Memphis on El Nino impacts in the Mid-South
• Research and winter outlooks by WeatherBell, WeatherTrends360, and NOAA

MWN Winter Outlook:

• Temps slightly below to below average (possibly as cold as last year)
• Precipitation near average
• Snowfall near to above average (average is about 4")
• Periods of large temperature swings and possible severe weather

Of course, my typical caveats on long-range outlooks apply. I typically don't look beyond 7-10 days when forecasting and spend a great deal of effort focusing on the upcoming 36-48 hours. As a meteorologist and not climatologist, I have no formal training in long-range forecasting, but I do follow and learn from those that do. And if I got paid for accurate long-range outlooks, my family would be hungry!

The goal of producing these outlooks is as much to encourage preparation and education with regards to winter weather as it is for accuracy (though I would certainly rather be right than wrong!). Last winter was a cold and long one with some areas (especially the northern metro) experiencing multiple icing events and extended power outages. Plan ahead for how you will handle extended periods of cold weather and potential snow and ice.

Winter weather is extremely difficult to forecast, even sometimes on the day of the event (see March 2, 2014). Slight variations in temperatures (surface or lower levels of the atmosphere), available moisture, and previous or ongoing precipitation can all directly affect the type and amount of precipitation that occurs. These differences can also vary widely in a small geographic area. Once again, refer to last winter for obvious examples.

Have a safe winter and stay tuned to MWN for the latest information ahead of potential winter weather events!

Erik Proseus
MWN Meteorologist

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Arctic intrusions could be the norm for the second half of November

As you've no doubt heard, the first major Arctic outbreak of the "winter" is closing in on the Mid-South (and please don't call it the polar vortex or I'll have to sic Guido on you!). Enjoy the next 36 hours or so because we won't see temperatures this warm again for some time. Model data is very consistent in the general pattern indicating cold air will move in by mid-week and stick around a while.

Very cold air has moved into the northern plains this afternoon and will continue to move south over the next 3 days or so. By week's end, freezing temps will be found nearly to the Gulf Coast. Temps near 70 in the central Plains will be long gone by tomorrow.

In fact, multiple rounds of cold air could move over the area, reinforcing the general pattern of well-below normal temperatures for several days. Right now, there is evidence to indicate that cold air (of varying magnitude) could possibly last up to 2 weeks, or right up until around Thanksgiving!

Below are the temperature anomalies (departure from normal) for 5-day windows through 2 weeks from now. Shown are two versions of the same model - the Global Forecast System (left) and GFS Ensemble (right). The European model supports this general cold idea as well through at least 10 days. You'll see that the models are similar in the days 1-5 and 6-10 periods while the GFS stays colder longer (into the day 11-15 period).

Departure from normal temperatures from the GFS and GEFS models for 5-day periods starting today. Description of these graphics is provided in the blog text, but suffice it to say, very cold temperatures will move in and hang around for more than just a couple of days. The GEFS model data indicates a slow retreat of the cold air after Nov 19, while the GFS reinforces it. Graphics courtesy WeatherBell.

The GFS model averages about 5 degrees C below normal in the metro from Nov 9-14 (top left panel), even considering that one of those days - tomorrow - will be above average. The GFS then cools even more to about 8-9 degrees C below average from Nov 14-19 (middle left panel) and about 11 degrees C below average between Nov 19-24 (bottom left panel).  What do those departures translate to in temperatures we experience?

Nov 9-14 daily avg temp: 54 F - dept from normal: -9 F = GFS forecast avg temp: 45 F
Nov 14-19 daily avg temp: 52 F - dept from normal: -15 F = GFS forecast avg temp: 37 F

Nov 19-24 daily avg temp: 50 F -dept from normal: -20 F = GFS forecast avg temp: 30 F

Wow! Remember that the daily average temperature is the average of the high and the low temps. If that daily average of 30F were to occur, it means that the low temps would be well down into the 20s with highs likely only in the 30s to near 40! Below are the forecast highs and lows from the GEFS model shown above (right hand panels) for the next 2 weeks. Note that these temps tend to run 2-4 degrees cooler than actual and are useful only for trend analysis once you get beyond the first week or so, NOT for actual temperature forecasting. It just gives us an idea of what to expect.

GEFS forecast highs and lows for the next 2 weeks at Memphis. After the first 5-7 days, this information is only useful for trend analysis, not actual temperature forecasting.

As far as precipitation, when it stays this cold for this long, with average daily temps in the 30s, any system with precipitation that gets close will have to be monitored carefully for the possibility of some type of freezing. The first one to watch will be next weekend. It's still way too early to know exactly what to expect and when, but it bears monitoring, which we'll be doing all week long. We will keep you updated!

One thing is for certain - if you haven't gotten out the cold weather clothes or fired up the heater yet, this week will be when you need them! Tomorrow, we'll release our 2014-2015 Winter Outlook which may provide an idea if this is a trend for the upcoming winter or not. Stay tuned!

Erik Proseus,
MWN Meteorologist

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October 2014 Weather Recap and MWN Forecast Accuracy

October Recap

After a ten month streak of below normal temperatures was broken in August, October continued a new streak of above normal temperatures, now at three months, averaging 1.4 degrees above normal. Rainfall totaled 4.00 inches for the month, which is almost exactly average, but for the year precipitation is still 124% of normal, or 10.02" above normal. There was no severe weather during the month.

There were a couple of rounds of strong to severe thunderstorms during the month. The first was  the afternoon and evening of October 2 as a squall line moved through the area. Hail and damaging wind was reported as the line moved through. Memphis International Airport recorded 61 mph wind gusts. A Tornado Warning was issued late in the evening for the eastern metro, though no damage was reported.

October 2nd late afternoon radar and storm reports in the metro. Wind and hail was reported in multiple metro counties.

The next event was the morning of October 7 when thunderstorms in a northwest flow regime dropped hail up to 1" in diameter in central Shelby County.

October 7th morning radar as a cluster of storms dropped hail in central Shelby Co.

The last event was October 13 when yet another line of storms moved through during the afternoon. This event carried a pretty serious damaging wind threat leading up to the event, but the strong wind never made it to the surface and reports in the metro were few and far between.

October 13th early afternoon radar shows a squall line with limited severe weather. Storms intensified east of the metro later in the afternoon.

Memphis International Airport, Memphis, TN

Temperature
Average temperature: 65.5 degrees (1.4 degrees above average)
Average high temperature: 75.7 degrees
Average low temperature: 55.3 degrees
Warmest temperature: 90 degrees (2nd)
Coolest temperature: 40 degrees (31st)
Records set or tied: None
Comments: For the year, the average temperature at Memphis is 64.2 degrees, which is 1.7 degrees below average.

Precipitation
Monthly total: 4.00" (0.02" above average)
Days with measurable precipitation: 10
Wettest 24-hour period: 1.71" (12th-13th)
Records set or tied: None
Comments: As of the end of October, the yearly precipitation has been 42.45", which is 10.02" above (or 124% of) average.

Miscellaneous
Peak wind: South/61 mph (2nd)
Average wind: 6.8 mph
Average relative humidity: 68%
Average sky cover: 50%

Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN

Temperature
Average temperature: 62.8 degrees
Average high temperature: 75.5 degrees
Average low temperature: 52.1 degrees
Warmest temperature: 89.3 degrees (1st)
Coolest temperature: 38.0 degrees (30th)
Comments: None

Precipitation
Monthly total: 4.84" (automated rain gauge), 5.02" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 11
Wettest date: 1.18" (18th) (via automated gauge)
Comments: None

Miscellaneous
Peak wind: Southwest/27 mph (2nd)
Average relative humidity: 82%

Click here for a daily statistical recap for Bartlett, TN.

MWN Forecast Accuracy

MWN average temperature error: 1.66 degrees
MWN forecast temperatures within 2 degrees of actual: 77%
MWN average dewpoint error: 2.89 degrees
MWN forecast dewpoints within 2 degrees of actual: 58%

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours). Historical accuracy statistics can be found here.

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