774 
FXUS63 KMPX 172340
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
540 PM CST Tue Dec 17 2019

.UPDATE...For 00Z Aviation discussion below

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 255 PM CST Tue Dec 17 2019

The brief burst of light snow is expected to depart to the east by 
the late afternoon, with areas along and northeast of I94 having 
seen a dusting at most with just a few flakes to the south. A broad 
area of low clouds coincides with this shortwave trough and will subsequently also depart rather quickly. Skies are expected to clear out and winds weaken overnight as high pressure pushes into the area.

The broad upper level wave spanning the entire CONUS places us 
squarely in northwesterly flow aloft, with a broad area of high 
pressure at the surface drifting into MN overnight. This will result 
in a brief surge of arctic air as temperatures drop into the -5 to -
15 range across central and southern MN and western WI, with some -
20 or lower temperatures in far northern MN. This pattern will 
thankfully be short lived with southwesterly return flow warming 
temperatures dramatically for Thursday compared to Wednesday. With 
our snowpack now a few days old, this surge will not be quite as 
cold as the few we have seen so far this winter season. Winds are 
also expected to be low enough such that wind chill criteria will 
not be an issue, even in the far northern fringes of our coverage 
area.

.LONG TERM...(Thursday through Tuesday)
Issued at 255 PM CST Tue Dec 17 2019

Very little change in the extended period with a gradual warm-up this 
weekend, and continuing into next week. Models have been consistent 
with this trend of changing the long wave trough across the 
central/eastern part of North America, to the western part of North 
America. There will be differences in sensible weather elements, but 
overall temperatures will average 10 to 15 degrees above normal 
starting this weekend. Although I can't rule out 40s in the extended 
period, the low sun angle combined with a snowpack, should preclude 
anything more than mid to upper 30s. I believe the main impacts will 
be the development of fog as moisture in the boundary layer will 
become very moist as melting snow starts. Depending upon the amount 
of mixing in this boundary layer, will dependent on the amount of 
fog and low stratus development. Once the melting starts, I wouldn't 
be surprised to see less sun and more cloud cover, or until the 
pattern begins to shift. 

Another aspect to the pattern change is the well established split 
flow regime and taking the bulk of the active weather well south 
across the southern tier of the nation.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 540 PM CST Tue Dec 17 2019

Mostly clear skies tonight, with a broken mid-level deck moving
across the area on Wednesday. Northwest winds become light and
variable for the overnight hours, then become south-southeasterly
on Wednesday around 10 knots, with gusts to 20 knots at western
sites (KAXN/KRWF/KMKT).

KMSP...No concerns.

/OUTLOOK FOR KMSP/
Thu...Mainly VFR. MVFR CIGS possible. Wind SE 5 kts.
Fri...MVFR. Winds SSW 5 kts. 
Sat...Mainly VFR. MVFR CIGS possible. Winds SSW 5 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...TDH
LONG TERM...JLT
AVIATION...LS