Saturday, November 17, 2018

Recap of the November 14 snow event and a look at Thanksgiving week

The first winter weather event of the 2018-2019 season occurred on Wednesday as a potent upper level low moved over the Mid-South. Snowfall totals pretty well lined up with projections, as shown by the graphic and snow totals list below. The heaviest precipitation occurred over northwest TN and northeast AR, while the immediate metro saw amounts from 1/4-3/4" of snow that melted away on Thursday. The 0.6" at Memphis International Airport was the greatest November snow total since November 7, 1991.


PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
753 AM CST THU NOV 15 2018

THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS REPRESENTING THE TOTAL
AMOUNTS AMOUNTS FOR THE STORM THAT HAS BEEN AFFECTING OUR REGION.
APPRECIATION IS EXTENDED TO COUNTY, STATE, AND LOCAL OFFICIALS,
COOPERATIVE OBSERVERS, SKYWARN SPOTTERS AND MEDIA FOR THESE REPORTS.
THIS SUMMARY ALSO IS AVAILABLE ON OUR HOME PAGE AT
WEATHER.GOV/MEMPHIS

********************STORM TOTAL SNOWFALL********************

LOCATION          STORM TOTAL     TIME/DATE   COMMENTS                   
                     SNOWFALL           OF 
                     /INCHES/   MEASUREMENT

ARKANSAS

...CRAIGHEAD COUNTY...
   JONESBORO              2.0  1100 PM 11/14  911 CALL CENTER         
   4 N JONESBORO          1.8   600 AM 11/15  CO-OP OBSERVER          
   LAKE CITY              1.5  1045 PM 11/14  SOCIAL MEDIA            

...GREENE COUNTY...
   6 W PARAGOULD          1.5   947 PM 11/14  SOCIAL MEDIA            
   2 SSE PARAGOULD        1.0   700 AM 11/15  CO-OP OBSERVER          

...POINSETT COUNTY...
   HARRISBURG             2.0   717 PM 11/14  SOCIAL MEDIA            

MISSISSIPPI

...BENTON COUNTY...
   1 NE ASHLAND           0.3   700 AM 11/15  CO-OP OBSERVER          

...COAHOMA COUNTY...
   3 SW CLARKSDALE        0.6   700 AM 11/15  COCORAHS                

TENNESSEE

...BENTON COUNTY...
   1 NNE BIG SANDY        1.5   816 PM 11/14  TRAINED SPOTTER         
   10 S CAMDEN            1.5   710 PM 11/14  SOCIAL MEDIA            
   CAMDEN                 1.3   744 PM 11/14  SOCIAL MEDIA            

...CARROLL COUNTY...
   BRUCETON               1.5   736 PM 11/14  AMATEUR RADIO           
   4 SE CLARKSBURG        1.3   800 PM 11/14  SOCIAL MEDIA            
   CEDAR GROVE            1.0   500 PM 11/14  TRAINED SPOTTER         
   ATWOOD                 1.0  1000 PM 11/14  SOCIAL MEDIA            

...CHESTER COUNTY...
   4 W HENDERSON          1.0   548 AM 11/15  CO-OP OBSERVER          

...DYER COUNTY...
   DYERSBURG              1.0   628 PM 11/14  PUBLIC                  

...FAYETTE COUNTY...
   6 NW WHITEVILLE        2.0   200 PM 11/14  SOCIAL MEDIA            
   10 N SOMERVILLE        1.1   630 AM 11/15  CO-OP OBSERVER          
   3 W CENTER POINT       0.5   655 AM 11/15  CO-OP OBSERVER          

...GIBSON COUNTY...
   MEDINA                 1.5   747 PM 11/14  SOCIAL MEDIA            
   TRENTON                0.8   819 PM 11/14  SOCIAL MEDIA            

...HARDEMAN COUNTY...
   WHITEVILLE             0.8   411 PM 11/14  TRAINED SPOTTER         

...HENRY COUNTY...
   PARIS                  1.5   745 PM 11/14  TRAINED SPOTTER         

...MADISON COUNTY...
   10 NE JACKSON          2.5   508 PM 11/14  PUBLIC                  
   5 N JACKSON            1.5   650 AM 11/15  CO-OP OBSERVER          
   6 SSE JACKSON          1.3   730 PM 11/14  COCORAHS                
   JACKSON                1.0   422 PM 11/14  BROADCAST MEDIA         
   BEMIS                  0.8   919 PM 11/14  SOCIAL MEDIA            

...OBION COUNTY...
   UNION CITY             1.8   837 PM 11/14  PUBLIC                  

...SHELBY COUNTY...
   3 ENE WHITEHAVEN       0.6   600 PM 11/14  OFFICIAL NWS OBS        
   3 NE BARTLETT          0.5   600 PM 11/14  NWS EMPLOYEE            
   3 N BARTLETT           0.3   512 PM 11/14  TRAINED SPOTTER         
   4 SE GERMANTOWN        0.3   502 AM 11/15  CO-OP OBSERVER          
   2 SW CORDOVA           0.3   800 PM 11/14  OFFICIAL NWS OBS        

...WEAKLEY COUNTY...
   MARTIN                 1.2   915 PM 11/14  PUBLIC                  


...PRELIMINARY SNOW AND SLEET TOTALS SORTED BY MAGNITUDE...

LOCATION                      SNOWFALL    COMMENTS                   
                               IN/S/

10 NE JACKSON TN                2.5        508 PM 11/14/2018         
HARRISBURG AR                   2.0        717 PM 11/14/2018         
JONESBORO AR                    2.0       1100 PM 11/14/2018         
6 NW WHITEVILLE TN              2.0        200 PM 11/14/2018         
4 N JONESBORO AR                1.8        600 AM 11/15/2018         
UNION CITY TN                   1.8        837 PM 11/14/2018         
BRUCETON TN                     1.5        736 PM 11/14/2018         
1 NNE BIG SANDY TN              1.5        816 PM 11/14/2018         
PARIS TN                        1.5        745 PM 11/14/2018         
LAKE CITY AR                    1.5       1045 PM 11/14/2018         
5 N JACKSON TN                  1.5        650 AM 11/15/2018         
MEDINA TN                       1.5        747 PM 11/14/2018         
10 S CAMDEN TN                  1.5        710 PM 11/14/2018         
6 W PARAGOULD AR                1.5        947 PM 11/14/2018         
CAMDEN TN                       1.3        744 PM 11/14/2018         
4 SE CLARKSBURG TN              1.3        800 PM 11/14/2018         
6 SSE JACKSON TN                1.3        730 PM 11/14/2018         
MARTIN TN                       1.2        915 PM 11/14/2018         
10 N SOMERVILLE TN              1.1        630 AM 11/15/2018         
4 W HENDERSON TN                1.0        548 AM 11/15/2018         
CEDAR GROVE TN                  1.0        500 PM 11/14/2018         
2 SSE PARAGOULD AR              1.0        700 AM 11/15/2018         
DYERSBURG TN                    1.0        628 PM 11/14/2018         
JACKSON TN                      1.0        422 PM 11/14/2018         
ATWOOD TN                       1.0       1000 PM 11/14/2018         
TRENTON TN                      0.8        819 PM 11/14/2018         
BEMIS TN                        0.8        919 PM 11/14/2018         
WHITEVILLE TN                   0.8        411 PM 11/14/2018         
3 ENE WHITEHAVEN TN             0.6        600 PM 11/14/2018         
3 SW CLARKSDALE MS              0.6        700 AM 11/15/2018         
3 W CENTER POINT TN             0.5        655 AM 11/15/2018         
3 NE BARTLETT TN                0.5        600 PM 11/14/2018         
3 N BARTLETT TN                 0.3        512 PM 11/14/2018         
4 SE GERMANTOWN TN              0.3        502 AM 11/15/2018         
2 SW CORDOVA TN                 0.3        800 PM 11/14/2018         
1 NE ASHLAND MS                 0.3        700 AM 11/15/2018         

Looking ahead to Thanksgiving week, a generally drier and more seasonal pattern takes over. The main precipitation concern is scattered showers mainly during the night on Sunday into Monday. Thanksgiving should be dry and pleasant for walking off all those calories! Black Friday shoppers won't freeze at Friday morning doorbusters, with moderate temperatures into the holiday weekend. The dry pattern could slip away though with rain projected next weekend.


The National Blend of Models temperature output for Memphis for the coming 10 days features generally seasonal conditions.
Erik Proseus
MWN Meteorologist

----
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Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, November 13, 2018

#Novembrrr continues - decent snow chance on Wednesday

UPDATE: 8:00pm 

Based on the latest model data, there is a low risk of a bit of mixed wintry precipitation (freezing rain, sleet, or snow) in the morning between about 7-10am. We'll be watching this closely, but be aware of this during the morning rush. Most of this mix should occur southwest in the metro in AR, but it 's worth mentioning.

Also, the light precipitation overnight Wednesday night, mainly after midnight, could also mix with light freezing drizzle. If this were to occur, even the veyr small amount that would occur could quickly slick up bridges and overpasses Thursday morning. Stay tuned!



If you are wondering if we skipped fall and went straight to winter this year, I can't blame you. 

We don't typically deal with multiple snow threats in the same week in the fall. But here we are. After a brief round this morning (most of you were sleeping and missed it, but the airport officially reported light snow for one hour between 1-2am), we're looking at a more favorable setup on Wednesday into early Thursday.

Typically cold air invading behind a front as precipitation moves out is not the optimal way to get much snow. The timing is rarely right for more than flurries.

However, a strong upper level low moving overhead with cold air in place? Now we're talking. That is the scenario for the next 48 hours or so. See the loop below as a strengthening low pressure system (the bowling ball sporting the flaming hot Cheetos livery) as it moves basically directly overhead.

An developing upper level low will move directly overhead the Mid-South on Wednesday night per all model solutions. This loop is taken from the Tuesday morning run of the GFS model. (WeatherModels.com)

So what can we expect in the Memphis metro? 

1) The cold air will stick around. Temperatures remain in the 30s (mostly the lower half) through today, tonight (lows will be near 30), and tomorrow (when temperatures should get back to just above freezing for the afternoon hours).

2) A Winter Weather Advisory has been issued for the metro. This means that expected winter weather could cause significant inconvenience, but won't rise to the level required for a warning (i.e., heavy snow, sleet, or freezing rain with widespread impacts).



2) Light snow could begin as early as mid- to late-morning Wednesday. The initial stages of the precipitation should be very light as moisture is drawn north ahead of the low. There's a possibility of some light sleet or rain mixing in initially, but I'm expecting most precipitation to be snow.

3) The steadiest snow will be mid-afternoon through evening (i.e., 3-9pm or so). As the upper low moves into the area, enhanced lift will combine with the arrival of the coldest air aloft to produce steady precipitation. This is also the best chance for any accumulation.

4) Accumulation could be around an inch, perhaps more north of the city. During that window mentioned above, we could see an inch of wet snow on grassy or bare ground and exposed surfaces in the immediate metro. Areas just north and west, in northwest TN and northeast AR, could see a few inches of snow. The best data we have available (it's sparse in the metro) suggests that pavement and sub-surface temperatures are fairly warm still: 40s to low 50s. That should keep paved surfaces from accumulating much, if at all. I would still be cautious on the elevated roadways, especially after dark.

Graphic created by NWS-Memphis early Tuesday morning. This information is subject to change.

5) Light snow or flurries will continue into the overnight hours. As the low pulls by to our north, the precipitation will move north with it, leaving behind the possibility of additional very light snow or maybe just flurries overnight. No additional overnight accumulation is anticipated at this time.

6) Subfreezing temperatures early Thursday could result in some travel headaches. Depending on how much precipitation we actually receive and the wetness of the pavement, temperatures that drop to near 30 Thursday morning could result in some slick spots. We won't know that for sure this early, but keep it in the back of your mind. By mid-morning, temperatures should be back above freezing.

7) Warmer days are ahead! Highs Saturday could reach 60°.



We'll have the latest information on our social media channels throughout the event and of course the MWN Forecast will also have the latest official forecast from us. Links are below. Plan ahead, stay safe, and I'll get back to working on patching the #SnowDome.


Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Sunday, November 11, 2018

Update on #Novembrrr cold & wintry precip chances Tuesday.... and Thursday

This is the promised follow-up to Saturday morning's blog on precipitation early Tuesday morning, as well as broaching yet another possibility from a system the models have just started picking up on in the past 24 hours or less. Let's take them one at a time... (And yes, seriously, why are we talking about multiple "potential" events in mid-November! There should be a law.)


Monday/Monday night

First, Monday remains on track to be cold and wet. Get the waterproof winter coats out because low 40s on the thermometer, rain, and a north wind gusting to 20-25 mph is NOT going to feel great. The trend with this system the past 24 hours though, as far as the wintry precipitation is concerned, is positive (unless you want a snow day).

As discussed in yesterday's blog, models tend to move the precipitation out faster and the cold air in slower as we draw nearer to an event. Not always, but many times. That is happening this time. A general drying trend should take place, especially after midnight (early Tuesday). In addition, the "sufficiently-cold" temperatures for snow production are dragging their heels just a bit.

The morning run of the GFS model mirrors other model solutions in depicting almost no precipitation after midnight Monday night when temperatures finally fall far enough to produce snow.  Notice that the precipitation shifts to the east as the freezing line arrives from the west. Not atypical for our area, especially in November. (WxBell)

The result is that I have pulled all snow from the forecast on Monday night. There could be a few flurries in the wee hours Tuesday morning with temperatures just above freezing. You likely wouldn't even see them unless you work on the FedEx or UPS ramp overnight. Tuesday looks to be dry and very cold with highs in the 30s and wind chills in the 20s. I've also become more "negative Nelly" on sunshine Tuesday. Yuck.

Wednesday/Thursday

The negativity on Tuesday sunshine is directly influenced by another system that now looks like it might have an impact on mid-week weather. If it does, 3 T's - timing, track, and temperatures - will play major roles in its impact on our area.



As the main system Tuesday departs to our northeast, a piece of upper level energy now looks to be orphaned behind over the southern plains. Multiple models are now forecasting that energy to strengthen into a potent upper level low and move near the Mid-South. Because this feature is just now being picked up by models, the track and speed (timing) are different between the respective models. The only certainty is that the solutions will change over the coming days, so I'm not ready to get too excited by it. But apparently some of your weather crap apps are!

A loop of the atmospheric energy at about 18,000' (500 mb) from Wednesday morning through Friday morning, as depicted by the Sunday morning GFS model. That "bowling ball" of reds and purples is a strong upper level low pressure system that will bring a round of precipitation and very cold air aloft. Models still differ on track and timing, but it is worth watching. (PivotalWx)

The same model as above (Sunday morning GFS) only showing the surface precipitation amounts associated with the forecast track of the upper low. Note the colors are NOT precipitation type, but amount. The blue lines that encircle the Mid-South as it moves north are sub-freezing air at 5000' and indicate a potential for snow if surface temperatures are also cold enough. (WxBell)

We'll take the cautious approach for now, as the track, timing, and most importantly, temperatures in the mid and low levels of the atmosphere, will determine A) if we get any precipitation and B) what form it is in. These deep lows are carriers of very cold air aloft, so if temperatures near the ground are near freezing (and that depends on timing), there is another chance we could see some flakes. For now, the only flakes are those that randomly spit snow totals for Thursday. :-)

We'll keep you posted. In the meantime, here's a look at the temperatures for the week ahead, subject to change based on the ultimate fate of the mid-week system. The latest forecast can always be found in our mobile app or on the website. Links below. Stay warm!


Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Saturday, November 10, 2018

It's #Novembrrr and precip is coming! Time to talk about "S***"

** An update to this blog as of Sunday night is available here **

As recapped in our October Climate Summary blog, generally cooler than average weather has been with us since the extreme warmth of the first 10 days of October (remember when we were reaching near 90 degrees every day in early October??). With the exception of a day here or there and that short stretch of warmth around Halloween, we've only experienced six days in which the daily temperatures have been above average since October 11, and two of those were a single degree above normal.

First Arctic blast of fall 2018

But this weekend we are feeling the early signs of winter as the first Arctic blast of the year envelopes the eastern U.S. This morning's official low of 30° at Memphis International Airport (just 3° above the record low) brings the 2018 growing season to an end. That means that, although we will experience freezing temperatures again in the coming week (multiple times in fact...), no additional Freeze Warnings will be issued for the metro until spring. Regarding the freeze, although it seems winter is starting early (after a late end to summer), the average first freeze in Memphis is November 12, so we're actually right on time! The difference is a daytime high in the 40s that makes it feel more like winter, despite the sunshine.

Saturday high temperatures are well below normal for most of the U.S. as shown by a temperature anomaly map. (WeatherModels.com via Ryan Maue)

The cold weather continues into Sunday with lows in the 20s, thanks mostly to much less wind, which allows low-level temperatures to cool more efficiently. Some clouds arrive Sunday, but we should get highs up closer to 50 in the afternoon. It'll feel warmer with less wind as well. While the cold continues, the dry weather is interrupted Monday by low pressure moving across the southeast U.S. This will drag precipitation north into the Mid-South by morning with a wet day in general on tap. Combined with a brisk north wind, it'll be an ugly day - wet and cold as temperatures top out in the lower to mid 40s.

Forecast precipitation totals (liquid) for Monday and Monday night. (NWS via PivotalWx)

So are we really expecting snow?

Monday night is where things get interesting, especially for mid-November. As the moisture draws northeast out of the region overnight, even cooler air drops in behind the departing precipitation with temperatures falling into the 30s after dark. Temperatures aloft (which are critical for potential winter precipitation shenanigans) also rapidly cool. In sum, we could have a short window overnight in which light snow mixes with the departing rain. There, I said it!

The Saturday morning GFS model depicts expected precipitation Monday evening with precipitation type as of midnight (green = rain, blue = snow). Also shown, the 35° temperature line (blue) and freezing line (blue). (WxBell)

Before you go crazy filling your gas tanks, buying sleds, asking about snow days, or the like, I do NOT expect much in the way of significance to this event, other than it's just not that common this early in the year. Mixed with rain and temperatures just above freezing, there should be no accumulation when the steadiest of precipitation occurs. Late in the night, after midnight, we could see what lingering moisture remains become all snow with temperatures near freezing.  However, there is likely to be little, if any, moisture left that could amount to any accumulation.



Bottom line it for me

In sum, for the Memphis metro, I do not expect accumulation, or even really any impacts. A strong north wind should help dry streets fairly quickly once precipitation departs. The only uncertainty in my mind is whether there could be some freezing spots around Tuesday morning for rush hour, as lows look to be near 30. It's too early to know that. This early in the year, despite the cold weekend, ground temperatures are still pretty warm, so that is a plus.

The same GFS model as above, showing accumulated snow through Tuesday evening. Areas along and north of I-40 may have a dusting, but with warm ground and some rain mix, there should be little if any impact. Areas to our north could see a swath of accumulation. (WxBell)

We'll continue to monitor incoming model data for any changes, but the "flip-flopping" of medium-range models the past few days is subsiding and they are getting a bit more in line. (Which is why I have, on purpose, not started talking about the "S" word until now.) We'll have additional short-range and high-resolution model data available this weekend as well that should bring the situation additional clarity. Or as clear as forecasting November snow in the Mid-South could possibly be!


Here are a few early season Memphis snow facts:

Earliest trace of snow - Oct. 19, 1989
Earliest measurable snow - Nov. 2, 1951 (0.2")
Earliest 1" snow - Nov. 14, 1976 (1.2")
Last time with 1" snow in November - Nov. 28-29, 2011


The rest of the week - moderating cold

Behind the departing system, Tuesday will see increasing clouds, but not temperatures. It could be a raw day with 30s most of the day and a biting wind. From there, we slowly start to warm back up as we head towards the weekend with no precipitation in sight for several days. However, there will be a few more mornings with below freezing temperatures. You can always get the latest details in the MWN Forecast in our app or on the web. Links are below.


Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

October 2018 Climate Data for Memphis, TN

October Climate Recap

October started with summer still firmly entrenched, with the first ten days of the month averaging 88 degrees for the high and 12 degrees above normal, the tide quickly turned with frontal passage on the 10th. Of the next 19 days, 17 were below normal, before a quick warm-up leading into Halloween. Record temperatures also reflected the huge temperature swing. The high temperature of 92 degrees on October 4th tied a record for the date, while the high of 50 degrees on the 16th was the coolest high temperature ever recorded on that date. So for the month, the temperature averaged just over 1 degree above normal. That warmth was driven less by the high temperature average (which was actually 0.2 degrees below normal) than the overnight lows, which averaged 2.7 degrees above normal).

Precipitation was about average in October (0.39" shy of normal). There was no precipitation during the early month heat. However, starting with the front on the 10th, there were 10 days of the next 21 that recorded rainfall, landing that period (October 10-31) in the top 20% wettest on record despite only one day nearing an inch (Halloween - 0.99"). There was no severe weather in the metro in October. The only Severe Thunderstorm or Tornado Warning issued by the National Weather Service in Memphis for the month was a Tornado Warning on Halloween evening for the Jackson, TN area.

Memphis International Airport, Memphis, TN


Temperature
Average temperature: 65.3 degrees (1.2 degrees above average)
Average high temperature: 74.2 degrees (0.2 degrees below average)
Average low temperature: 56.5 degrees (2.7 degrees above average)
Warmest temperature: 92 degrees (4th)
Coolest temperature: 39 degrees (22nd)
Heating Degrees Days: 139 (19 above average)
Cooling Degree Days: 157 (65 above average)
Records set or tied: Record high - 92 degrees (4th). Record cool high (or low maximum) - 50 degrees (16th).
Comments: Four days recorded high temperatures at or above 90 degrees. Typically a 90-degree day is encountered in October once every 3.3 years.

Precipitation
Monthly total: 3.59" (0.39" below average)
Days with measurable precipitation: 10 (2.5 days above average)
Wettest 24-hour period: 0.99" (31st)
Snowfall: 0.0"
Records set or tied: None
Comments: Three days recorded more than 0.5" of rain.

Miscellaneous
Peak wind: South/40 mph (31st)
Average wind: 7.5 mph
Average relative humidity: 73%
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: 63.3 degrees
Average high temperature: 74.9 degrees
Average low temperature: 53.3 degrees
Warmest temperature: 92.5 degrees (5th)
Coolest temperature: 34.3 degrees (22nd)
Comments: None.

Precipitation
Monthly total: 3.82" (automated rain gauge), 4.63" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 10
Wettest date: 1.04" (31st) (via automated gauge)
Snowfall: None
Comments: None

Miscellaneous
Peak wind: South/19 mph (30th)
Average relative humidity: 81%
Average barometric pressure: 30.08 in. Hg

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

MWN Forecast Accuracy

MWN average temperature error: 2.05 degrees
MWN forecast temperatures within 2 degrees of actual: NA
MWN average dewpoint error: NA
MWN forecast dewpoints within 2 degrees of actual: NA

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

Climate Outlook - November

The November climate outlook for the United State from the Climate Prediction Center is shown below. Temperatures are forecast to be below normal for much of the Mississippi and Missouri River Valleys into the southern plains. For Memphis, odds of below normal temperatures in November are 40%, near normal 33% and above normal 27%. Memphis typically averages just over 53° degrees for the month of November.


A wet November is forecast for much of the United States east of the Rocky Mountains. For Memphis, odds of above normal precipitation in November are 54%, near normal 33% and below normal just 13%. November averages about 5.5" of rain in Memphis.


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Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Wednesday, November 7, 2018

Dreary today and tomorrow; cold blast on the horizon!

We are about halfway through a big pattern shift as we reach the midpoint of the week.


So what will this pattern shift entail? Today our temperatures have begun to drop after a cold front pushed through the area Monday night and was reinforced earlier today, ushering in these cool, dreary conditions. Unfortunately these conditions will continue to hang around today and tomorrow, but an end to the dreary pattern is in sight. Into this weekend, skies will begin to clear out welcoming back in plenty of sunshine. Even though sunshine will return, our temperatures will remain well below average through the period. We will even begin to see early winter-like temperatures in the extended forecast, but more on this later. 



Today

While we shouldn't see anymore rain today, it will still look and feel rather dreary. Temps are expected to rise only a few more degrees this afternoon, with highs reaching the mid 50s. A cool, northeasterly wind will help to keep things feeling even chillier today into tonight as winds will remain between 10 to 15 mph. Tonight, skies should begin to clear a little bit leaving behind partly cloudy conditions. Overnight lows will dip down into the mid 40s, so be sure to bring out the extra blanket before heading to bed. 


Tomorrow

Dreary and even cooler temperatures look to be in store for tomorrow as our mostly cloudy skies will hang around throughout the day. Highs will reach the low 50s, but the constant cloud coverage and continued northeast wind will likely make it feel a bit cooler than that. 

Rain chances will begin to increase as we move through the day into tomorrow evening. A scattered, afternoon shower cannot be ruled out, but the majority of showers will begin to move in towards the evening into the overnight hours. Lows will dip down into the low 40s tomorrow night.

The NAM3 model shows scattered showers developing in the afternoon to early evening hours tomorrow with showers becoming more widespread into the overnight hours. (Tropical Tidbits)

Friday into this weekend

After some early morning, scattered showers on Friday, things look to finally clear out for the rest of the weekend.

The NAM3 model shows showers continuing into the early morning hours on Friday but clearing during the day. (Tropical Tidbits)
Even cooler temps will begin to move in behind these showers on Friday, leaving us with highs in the mid 40s to near 50 throughout the weekend. Luckily, sunny skies on Saturday and Sunday will help things to feel a tad bit warmer than that. But for those heading out for the Memphis football game, tailgating will be downright cold as morning temperatures will be in the 30s. Even the mid 40s during the afternoon hours with sunshine will require a coat. Also, you'll want to take precautions for any outdoor vegetation that you don't want to lose - morning lows Saturday and Sunday will be near or below freezing!

Next week

Well folks, it looks like we will continue to get a decent taste of early winter into next week as well. After another cold front passes through next Monday, even cooler temperatures will be arriving to much of the eastern half of the U.S.
If you haven't already, it may be a good idea to dig out those winter jackets and plenty of blankets. Overnight lows next week will dip to near or below freezing with daytime highs in the 40s to low 50s.

The Climate Prediction Center (CPC) has a 90% probability that temperatures will be well below average next week. Much of the eastern half of the U.S. will be below average as well. (CPC via Pivotal Weather)
CPC keeps the Mid-South slightly below average to near average in terms of precipitation through next week. (CPC via Pivotal Weather)
Next week is certainly going to be a chilly one - the coolest we have seen since last spring!


Caroline MacDonald
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Sunday, November 4, 2018

Election Eve severe weather potential

We have officially entered secondary severe weather season. The Halloween storms provided a highly-visible reminder by messing with people's outdoor plans - some in a big way. Fortunately, though stormy, the damage was limited in the metro. Less than a week later, on the eve of  Election Tuesday, we find ourselves in a bit more concerning scenario.


Above you will find our Sunday afternoon severe weather impact graphic. It has most of the high-level need-to-know information covered. Look it over for a basic understanding and the answers to the 4 W's: what, where, why, and when. The blog format allows us to dive into the details, so here we go.

First, if you have been following us on social media the past 24 hours or so, the first thing you notice about the graphic is the reduction in the severe weather threat west of the metro. That doesn't affect us. Yes, the threat has been "refined" and east AR's risk has dropped a bit. It's a natural progression - as we get closer in time, the scenario becomes a little more clear and the forecast details are updated. The metro remains in an ENHANCED risk of severe weather - that's a level 3 out of 5. It grabs my attention and it should yours too. Don't worry about how close we are to another risk zone.

What and Why

A cold front will move into and through the area Monday evening. The kicker (or kickers) are a developing low pressure area that will move by to our northwest, from AR into the Ohio Valley, and a strong jet stream overspreading the region. The front and low provide lift for developing storms, the low also draws up a ton of moisture from the Gulf of Mexico on gusty southerly wind, and the jet stream provides a means of exhausting this unstable air into the upper reaches of the atmosphere. Combined, we have moisture, unstable air, wind shear, and a lifting mechanism - all ingredients for severe weather.

The NWS surface forecast map valid at 6pm Monday. Notice the warm front to our north, meaning we are in the "warm sector" where moisture, wind, and unstable air combine. The cold front to the west will sweep quickly across AR during the evening. The strong jet stream is annotated blowing from NE Colorado across the Plains into northern AR. (WPC/MWN)


Where and When

The placement of the above features, and their timing, defines the where and when, as well as the "how bad?" That strong southerly wind from the developing low will bring unstable air into the entire region by late afternoon, rising from MS into TN. You may wake up tomorrow morning, step outside, and say "this doesn't feel like a severe weather day." DON'T write it off! The state of the atmosphere will change quickly by afternoon as a warm front lifts north.

As the low moves northeast, a screaming jet stream (approaching 150 mph) approaches, and dewpoints soar into the 60s with the warm front, ingredients come together to set off scattered thunderstorms, likely starting in AR and perhaps the MS delta during the afternoon hours and progressing quickly to the northeast. By 2-4pm, I expect we could see storms in the immediate metro. These initial storms likely won't be severe initially. However as the low moves northeast, additional scattered storms have a better chance of tapping into more unstable air and stand a better chance of  becoming severe during the evening. As the front gets pulled towards us, and eventually across the metro by late evening (we'll say 10pm-midnight), the storms should be coalescing (i.e., merging into) a squall line. That line may bring the highest risk of damaging wind, but also an abrupt end to the day's threats.

The Sunday mid-day run of the high-resolution NAM forecast model shows "simulated radar" from noon to midnight Monday. Scattered storms in the afternoon become more numerous in the evening, finally resulting in a line of storms as it moves through and to our east by midnight. (WeatherModels.com)


The latest model data suggests that the necessary ingredients for the strongest of storms (supercells) and potential tornadoes will be south of I-40, and primarily in north MS, during the evening hours prior to frontal passage. However, the atmosphere doesn't respect state or interstate boundaries (even though you should respect the polygon) so these are provided as a general guide.

The Supercell Composite Parameter (SCP) is an index used by meteorologists to gauge the amount of instability, wind shear, and wind strength in the  atmosphere, in support of severe storms. Values above 2 are supportive of supercells, and the higher the number, the more support there is for stronger severe storms. The map above shows SCP at 10pm Monday, in effect the peak values prior to frontal passage. The most concerning area is north MS and west TN near the TN River. (WxBell)


So, specifically for the metro, here's what I think, as of 2pm Sunday:

What/when: scattered storms after ~4pm, increasing severe weather into the evening, squall line 10pm-midnight
Threats: scattered damaging wind gusts area-wide and isolated tornadoes (more likely in MS)

How to Prepare

Reading stuff like this is the first step - know your threat and understand it, and stay updated. Don't write it off because you don't believe it or just don't "feel" it. Weather this time of year can change in a heartbeat.

Know where you will be during the evening hours in particular, and where you will go and what you will do if a warning is issued. Is there a safe place close by? If not, should I even be there?

How will I get warnings, especially if the threat lingers past bedtime? We recommend the multiple method approach. Any single one could fail - have a backup. Local TV/radio, NOAA Weather Radio, smartphone apps like ours (MWN with StormWatch+) are all good ways. Outdoor sirens are not (unless you are outdoors of course, and you shouldn't be if storms are nearby). Wind/storm noise, power failures, and modern soundproofing on homes render them nearly useless indoors.

Secure anything outdoors that might blow away (and which you would like to keep). If the blow-up pumpkin in the yard was headed for the trash anyway, well...

Have your safe place ready to use (interior windowless room on the lowest floor). Keep pertinent electronics charged (phones, kids distraction devices, etc.). Have fresh batteries and flashlights ready - power outages are the most common impact from wind storms.

During the event, keep your shoes on or nearby, ID on your person, and helmets nearby for the kids (and even adults) in case you have to shelter quickly. And have a plan for those pets too! We'd rather you be prepared and be inconvenienced a bit, then to not be and wish your had been.


The forecast details could and just might change. We're still more than 24 hours away from the event and the amounts of new data available to analyze in that period is ridiculous. We won't knee-jerk the forecast, but will provide updates as trends are established, mainly on Twitter and Facebook. Always seek out the latest information, as details can change with time.

Be prepared, not scared, and thank you for trusting MWN as one of your local sources of weather information!

p.s. Election Day weather looks great. High pressure takes over (maybe briefly) and the severe threat shifts to the eastern U.S.  Click here for the full forecast, which includes another chance of storms later this week.

Erik Proseus
MWN Meteorologist

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