Sunday, November 30, 2014

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:

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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Sunday, November 23, 2014

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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Monday, November 17, 2014

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.

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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Sunday, November 16, 2014

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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Thursday, November 13, 2014

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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Monday, November 10, 2014

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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Sunday, November 9, 2014

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

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.

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.

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 /, Bartlett, TN

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

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

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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Thursday, November 6, 2014

Cool weather expected to turn much colder next week

If you don't like cool weather, I recommend you stop reading now. OK maybe not, but this post is going to be all about below normal temperatures, so put on your gloves and earmuffs and continue on, intrepid readers!

What's average?

We'll start with where we're supposed to be, because sometimes that gets lost in the day-to-day forecasts. We get used to a certain pattern and don't realize that it's really supposed to be cooler/warmer than what we've experienced. The shock comes when it warms up/cools down to near normal and we instinctively think it's "abnormal." So, our average high on November 6 is 66 and average low is 47, resulting in a daily average of 57. Record highs are averaging the lower 80s right now and record lows are in the mid 20s.  Baseline established...

So what about this cold weather I am hearing about?

You may have already seen plenty of talk floating around on social media about typhoons resulting in Arctic outbreaks, polar vortices, and maybe even a "crap app" that had snow on its forecast for Memphis on November 15. I'm here to set the record straight.

It's all true. Kind of. (Yes, the app had it. No, it's not in my forecast!)

Former Super Typhoon Nuri in the northern Pacific is indeed making waves (massive ones in the Bering Strait, and even contributing to some in the upper atmosphere) that will result in an intrusion of cold air into the U.S., mainly east of the Rockies by next week. Before then, last night's cold front and another Saturday (which should pass through dry) will bring below average temperatures through Sunday, including upper 30s for morning lows.

By Tuesday, a much stronger push of cold air invades the central portion of the U.S., with a cold front forced southeast. We'll warm up nicely on Monday ahead of the front (upper 60s), then as the front passes through, rain chances go up Tuesday and temperatures will probably start to fall by late in the day. The airmass behind the front will have originated as Arctic air and, though modified, will likely bring our coolest weather so far this fall for the latter half of next week and into the mid-month weekend.

There is talk that this pattern of below normal temps could continue right through the end of the month... I'm not ready to go there yet, but we'll see.  Let's take a look at some graphics that will paint a picture of just how cold we're talking. (Click any image for a larger version. All graphics except the last courtesy WeatherBell Analytics.)  For our detailed MWN Forecast for the next 7 days, click here.

GEFS ensemble model forecast of departure from normal surface temps for the period Nov 7-12 (in Celsius). The Mid-South is depicted as 3-4C below normal, which would equate to about 50F vs our expected average of 55F.  Cool, but not too bad.
GEFS ensemble model forecast of departure from normal surface temps for the period Nov 12-17 (in Celsius). The Mid-South is depicted as about 7-8C below normal, which would equate to about 40F vs our expected average of 54F.  Now that's cold!

GEFS ensemble model forecast of departure from normal surface temps for  just one day, Nov 13 (in Celsius). The Mid-South is depicted as 9C below normal, which would equate to about 37F vs our expected average of 54F.  That's a daily average, meaning the low is colder than that and the high is warmer than that, but they average to 37. Whoa.

The GFS model surface forecast for next Thursday morning shows massive high pressure extending from central Canada to the Mid-South. The freezing line is the dark blue line that extends from the east coast through the Deep South into the Rockies. A HUGE portion of the U.S. would drop below freezing given this scenario with single digits (or lower) over the Northern Plains.
The GEFS ensemble model forecast highs and lows for the next 10 days shows the sharp dropoff in temps the middle of next week with a moderating trend starting the following week. These are NOT our forecast temps but provide an idea of the magnitude of cold air this model is forecasting. (BTW, our other long-range models agree fairly well.)

The official temperature outlook from NOAA for Nov. 12-16 indicates a 90% chance of below normal temperatures over a large portion of the Mississippi Valley and Upper Midwest. It's extremely rare to see 90% on these daily graphics, which speaks to the near certainty of this cold air outbreak, but not necessarily to its magnitude. Graphic courtesy NOAA.
So is this just a taste of things to come this winter or a one-shot deal? My 2014-'15 MWN Winter Outlook might provide some helpful information in that regard! I presented it to attendees of the NSA/Mid-South Winter Weather Workshop in Millington this morning and will be releasing a video blog containing the information to our MWN Insiders on Friday. The rest of you will get to view it a few days later, probably on Monday. If you want to see it early, we recommend you join our Insiders newsletter here!

Are you hoping for a cold and snowy winter or just hoping it goes by quickly and spring comes early?

Erik Proseus
MWN Meteorologist

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