Wintry Weather 12/11-12/12

[ams30721us]

From Spann pm discussion from Birmingham:'

LATE IN THE WEEK: The next impulse will bring rain back to Alabama Friday night. We will still just mention a cold rain for now, but I have fear the models are underestimating the low level thermal fields. While I really don’t expect snow flakes, the biggest problem initially could come from freezing rain, or rain that falls with surface temperatures are 32 degrees or colder. Again, we will just stick with rain for now and make changes as needed later in the week.

[Eric]

Relevant portion of OHX's latest AFD:

IN THE EXT FCST...SUBTROPICAL JET BECOMES ACTIVE ONCE AGAIN ACROSS
THE MID SOUTH. SFC HIGH OF POLAR ORIGIN WILL THEN BE EAST OF TN WITH
A SOUTHEASTERLY RETURN FLOW SETTING UP. WILL CONTINUE WITH A CHANCE
OF RAIN AND SNOW IN THE FCST. ALTHOUGH...ITS STARTING TO LOOK LIKE
THE PERIOD OF FROZEN PRECIP MAY BE SHORT LIVED ON SATURDAY MORNING

[Adam]

I went to school and the high for Friday and Saturuday was 40 degrees now it is 46 and 47 degrees how did that happen?

[Curt]

Already looking warmer with each run. Could this be a dead thread before it even happens??? Looks like areas where the CAD takes place even further south than us will see wintry mix (FZRA mostly). I say no thanks to that and hold out for snow later.

[ams30721us]

Wow never seen our chief met from channel 3 in chattanooga go this bullish away from models this far out!


Colder air will move in Wednesday afternoon  along with strong westerly winds.  Another wintry storm could develop this weekend. - Paul Barys

[Sbeagles]

From Nashvilewx:
Any winter precipitation this week?

On Wednesday, colder air pushes in with temps starting out in the mid 40s and falling through the 30s during the afternoon.  There may be a few flurries Wednesday afternoon on the Plateau.

And…there are a lot of question marks on it, but we are keeping our eye on Friday evening when we may see a wintry mix of snow and sleet that changes over to rain by Saturday.  This will be a changing situation, so we will keep you posted as the week wears on.

[snowdog]

Does anyone have a link for the para GFS? 

[Clay]

http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/18/model_m.shtml

[snowdog]

Appreciate it Clay. 

[Adam]

Whats the breakdown right now for Friday Night?

[Clay]

Adam, basically some shallow cold air may be left over when precip from a developing gulf low pushes into the Midsouth. Right now it seems the best threat will be in Southern Kentucky and far northern TN (Clarksville, Springfield, Lafayette). I don't think it's much to get hyped up about. Temps will quickly rise above freezing. However, there is going to be high pressure sitting over the NE which brings the N GA, Carolina wedge effect to mind. Areas north of ATL may be dealing some ice as well.

[Adam]

I hate systems like this ,theres too much that has to play out for us to maybe get an inch of snow .Tell me when we are gonna get a real snow. So why is NOAA still giving us a chance for snow?

[Nashville_wx]

00Z gfs is coming out now. I will break it down as the 18Z came in with about .150" of ZR before the transition to RN. Quite a hop from 12Z which was a hop from previous 00Z run.

[Adam]

I don't want freezing rain.

[Nashville_wx]

Oh boy. Now this has 850mb temps farther south with moisture father north. This has more of a SN to ZR look to it. You can see @ 96 hours the 850mb line is right into middle TN along I-40. Looking @ 102 hours we around .25 QPF which could easier fall as SN/IP. As soon as I can load bufkit I will be able to break it down. Looks good so far but could end up being a mess. Lets see how future runs look.