12/21-22 Arctic Blast (Single Digits Possible)

[Thundersnow]

Decided to go ahead and create a separate thread for the system this weekend, which should be a rainmaker for Saturday, followed by much colder air moving in for Sunday and Monday.  The NWS in Nashville is currently forecasting the chance of snow showers on Saturday night and Sunday.

Current forecast for Nashville for Saturday through Monday:

Saturday: Showers likely, mainly after noon. Cloudy, with a high near 58. East southeast wind 5 to 15 mph becoming south southwest. Winds could gust as high as 20 mph. Chance of precipitation is 70%.

Saturday Night: Rain showers likely before midnight, then rain and snow showers likely. Cloudy, with a low around 32. South southwest wind around 15 mph becoming west northwest. Winds could gust as high as 25 mph. Chance of precipitation is 70%.

Sunday: Scattered snow showers. Mostly cloudy, with a high near 35. West northwest wind between 15 and 20 mph, with gusts as high as 30 mph. Chance of precipitation is 30%.

Sunday Night: Partly cloudy, with a low around 22. Northwest wind 15 to 20 mph decreasing to between 5 and 10 mph. Winds could gust as high as 30 mph.

Monday: Mostly sunny, with a high near 32. North northwest wind between 5 and 10 mph.

Monday Night: Mostly cloudy, with a low around 19.

Perhaps, some snow flakes flying on Sunday... with temperatures not making it above freezing on Monday.  Lows in the teens possible on Monday night/Tuesday morning.

AFD snippet:

00Z MODELS ARE QUICKER WITH SFC PATTERN CHANGE WITH FROPA SAT
NIGHT. MUCH COLDER AIR WITH SNOW SHOWER POTENTIAL AFTER MIDNIGHT.
MOISTURE TOO THIN FOR SNOW ACCUMS AT THIS TIME. MUCH COLDER SUN
WITH SCATTERED SNOW SHOWERS IN THE FORECAST. COLD AND DRY SUN
NIGHT-MON NIGHT.

12Z GFS for this system's passage and subsequent cold air mass:

[Snowman]

I like the snow chances that pop up within 3 days. 

[Thundersnow]

I like the snow chances that pop up within 3 days. 

That's the only kind, my friend.   

[ST1]

I'm exited. I can't wait to see what this thing does.

[Nashville_wx]

Hmmmm..... I need to get in the car and drive to my cousins house in Chicago.....Hmmmmm.... Snow here next week..... Stop watching the models for 2 days....Hmmmm...,Come back and we will feel alot better. Someone please pass me the hot chocolate.

[Yazoo63]

Nashville just changed the forecast for Saturday night to 100 % chance of snow/sleet  ...

Aren't they usually ultra conservative with their winter weather outlooks ?

Hmmmmmm   

Anxiously awaiting the 00z run tonight !!!       

[Nashville_wx]

Interesting. From the looks of things, the cold air is quick on the heels of precip most likely changing over. Accumulations....Not likely.

[Charles Loring]

Yep, my forecast for Sat. night is now at 100% chance of Snow/Sleet with a low of 28ºF. I was surprised they mentioned the possibility this early, now they are actually issuing it in the forecast.  . Everyone get ready for a snowstorm Sat. night since they are mentioning it this early.

[Kevin]

Its not a 100% chance of winter precipitation Saturday night. The 100% is for rain in the evening. The actual grids indicate just a 30-40% chance of precipitation after Midnight when it would be wintry. The point/click system is reading it wrong...

[Snowman]

Another little aspect of this storm system this weekend. Flooding.

000
FGUS74 KOHX 182143
ESFOHX
TNZ005>011-022>034-056>066-075-077>080-093>095-191000-

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
343 PM CST THU DEC 18 2008

...FLOODING POSSIBLE FROM RAINFALL THIS WEEKEND...

AN AREA OF LOW PRESSURE IS EXPECTED TO MOVE THROUGH THE MID SOUTH
REGION SATURDAY AND SATURDAY NIGHT...BRINGING ADDITIONAL HEAVY
RAINFALL TO AN ALREADY SOGGY MIDDLE TENNESSEE.

TOTAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE BY LATE
SATURDAY NIGHT...CAUSING FURTHER RISES ON AREA RIVERS AND STREAMS
WHICH REMAIN HIGH FROM PREVIOUS HEAVY RAINFALL.

RESIDENTS NEAR RIVERS SHOULD WATCH FOR FUTURE STATEMENTS AND
FORECASTS FROM THE NATIONAL WEATHER SERVICE ON THIS POTENTIAL
FLOOD EVENT. FOR ADDITIONAL INFORMATION...MONITOR NOAA WEATHER
RADIO...OR VISIT US ON THE WEB AT WWW.WEATHER.GOV/NASHVILLE.

$$

LAROSA

[Eric]

Latest run of the GFS show zilch-o for TN...moisture is already "84 and out the door" when the cold air pushes in.  Could things change?  Sure, but not likely.

[Charles Loring]

  Look at what report NOAA has for Kansas City, MO; currently.

Thunderstorm Light Freezing Rain Freezing Fog

31°F
(-1°C)

[Nashville_wx]

Yawn....

[Thundersnow]

2M (Surface) Temps for Monday morning (I believe):



Below -10C for much of Middle TN.  Low teens?

[Thundersnow]

So, to sum it up over the next week, we have bookend gully washers with some really cold air in the middle.  But, the systems manage to safely avoid the cold air for the most part.   

I suppose we're still playing catchup on the last couple of dry years.