11-30, 12-1 Wintry Weather System

[Snowman]

With two NWS offices hinting at this event, I felt it was time for its own thread. Hopefully we can get something going. Please continue this storm discussions here.

Nashville AFD:

LONG TERM...
LO POPS CONTINUED FRI WITH A LITTLE HIER E. HI PRES FRI NITE AND
SAT. WEATHER SYSTEM TRACKS WILL BE TO OUR S THRU EARLY NEXT
WEEK...BUT A FRONTAL PUSH OF COLDER AIR WILL PROMPT LO POPS FOR
MOSTLY WRAP- AROUND LITE PRECIP SUN NITE INTO MON NITE...WITH SOME
SNOW POSSIBLE. ALL IN ALL A CONTINUED COLD PATTERN WITH NOT MUCH
CHANCE FOR PRECIP.

Huntsville AFD:

AS THE SYSTEM CONTINUES EASTWARD...IT CARVES OUT A LONGWAVE TROUGH
OVER THE EASTERN CONUS. WITH UPPER LEVEL NORTHWEST FLOW/TROUGHING
ACROSS THE CWFA FOR THE LATTER PART OF THE WEEKEND INTO THE START OF
DECEMBER...A SERIES OF DISTURBANCES WILL MOVE THROUGH THE AREA.
WHILE TIMING EACH OF THESE COLD FRONTS IS DIFFICULT AT THIS
POINT...COLDER WEATHER IS CERTAINLY IN STORE FOR THE TENNESSEE
VALLEY AS THE 540DM LINE PLUNGES INTO THE GULF OF MEXICO BY MONDAY.
IF THESE FRONTS PAN OUT AS CURRENTLY PROGGED BY THE ECMWF...WILL
NEED TO KEEP AN EYE ON P-TYPE OVER THE HIGHER TERRAIN BY SUNDAY
NIGHT INTO MONDAY.

[Thundersnow]

Thought about going for a system-specific thread earlier.

Monitoring the ole 0Z OP GFS output now.   

[Snowman]

Same here. We have time for this system to build. Lets hope things head in the right direction.

[Snowman]

00Z operational is bringing that 540 thickness pretty far south throughtout the weekend into early next week. We will see what the ensembles say though.

[Curt]

Can you say "squashed"? Precip will be scarce in that air mass by the time it dries out. Cold though, -12 850 temps centered in WTN.

[Thundersnow]

I just have this feeling that the model doesn't have a good handle on what's going to happen much past three or four days.

It's a pattern in flux.

The run does resume toward the cold pattern, unlike that warm fluke from this morning's 12Z op.  The general theme seems to be ridge in the west and trough in the east.

[Cameron K.]

We'll see, maybe we squeeze a few flurries out this. At least it'll be nice to end and start a month on a cold note.

[Thundersnow]

Well, I take that back... past 300 hours, it warms up again, like the 12Z OP did. 

But, IMO, 300 200+ hours on these runs is all but worthless.

[Snowman]

Six days out, a lot can happen. I am just glad to see the cold did not disappear from the models when we began thinking this would happen weeks ago. If the cold is in place, the moisture will eventually come. I hope. 

[Curt]

Well, I take that back... past 300 hours, it warms up again, like the 12Z OP did. 

But, IMO, 300 200+ hours on these runs is all but worthless.

I dont trust most of what the models say for specifics more than 4 days out. Altho, they do pick up on general patterns in the mid range. For instance, GFS ops really caught on to the idea of our March snow event 6-7 days out, then flucuated some, only to bring it back with a vengence on day 4...which eventually panned out. So....for 240 hrs plus..its a crapshoot.

[Thundersnow]

TWC map for Sunday:

[Cameron K.]

12z GFS is coming out and it's looking very optimistic(were gonna hate that word by the end of the season) for something on the 30th-1st.

[Thundersnow]

Somewhat interesting to see this at 96 hours:



Surface temps may be too warm anyway though... unless you get some sort of cold core dynamic cooling thingy with that low.

[Curt]

Very interesting for West and Mid TN. Looks sorta like March 7, '08 low track, exccept not as strong. Temps would start borderline, with it would apear to be numerous snow showers behind the front for 24 hrs.

[StormNine]

nws Louisville said upper atmosphere may be cold enough to suppurt snow showers.  dynamic cooling would help in this case