755 
FXUS63 KFSD 071725
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1125 AM CST Mon Jan 7 2019

.SHORT TERM...(Today through Tuesday afternoon)
Issued at 224 AM CST Mon Jan 7 2019

Cool front near the James River Valley at 07Z will continue to push 
eastward today, followed by a period of post-frontal stratus/fog as 
cooler air pushes into relatively moist air mass. Subtle cooling 
behind the front not expected to last long, as good mixing in west-
northwest flow will help temperatures once again climb well above 
normal today. With snow cover dwindling in many areas and favorable 
mixing profile, will again favor warmer side of guidance spectrum, 
with highs from the mid-upper 30s in our northern counties around 
the Coteau des Prairies and Buffalo Ridge, to mid 40s near/south of 
I-90.

Fairly compact wave currently passing through the Pacific Northwest 
will be our next feature of interest, as it quickly crosses the 
northern Rockies today, and continues across the Dakotas/Minnesota 
tonight. Models indicate potential for spotty precip on the warm 
advection wing of the wave this evening, with a greater chance of 
measurable rain changing to snow as colder air dives in behind the 
wave later tonight. Due to the quick movement of the system, expect 
precip amounts to remain on the light side, with around an inch of 
snow possible east of Highway 81/north of Highway 14, in our far 
northeast counties. 

Winds behind the wave/surface front expected to be quite burly, with 
most models showing 925mb winds @ 35-40kt and 850mb winds @ 45-55kt 
spreading across the forecast area tonight and persisting through 
the day Tuesday. Would not be surprised to see a wind advisory for 
at least eastern parts of the forecast area on Tuesday, but for now 
will just highlight the strong winds in the HWO and on social media 
platforms. With the anticipated light snowfall tonight, will include 
mention of patchy blowing snow with these stronger winds, mainly in 
our far northeast where the amounts near 1 inch are expected, as the 
existing snowpack has become less prone to blowing with the recent 
warmth. Reinforcing shot of cold advection into southwest Minnesota 
Tuesday could drop cloud-layer temperatures down into the favored 
snow-growth range, and have also added a chance of flurries to this 
area, with more sunshine expected to prevail over the remainder of 
the CWA.

.LONG TERM...(Tuesday evening through Sunday)
Issued at 224 AM CST Mon Jan 7 2019

Gusty winds will persist into Tuesday night, especially in 
eastern areas, but should continue to diminish through the day 
Wednesday as surface and upper ridge work eastward into the area. 
Despite the ridging aloft, low level cold air persists thanks to 
limited mixing ahead of approaching surface ridge, so Wednesday 
likely to be the coldest day of the week with highs near to even 
below normal in the teens and 20s.

Warmth begins to build back into the region for the latter part of 
the week, though not to the extent that we have seen of late, with 
highs generally in the upper 20s and 30s for Thursday and Friday. 
Greater uncertainty in how temperatures will pan out next weekend, 
as models show considerable differences in handling of an upper 
trough which drops through the region Thursday night and Friday. 
Canadian moves the trough out of the area more quickly, allowing 
temperatures to warm further by Saturday. Meanwhile GFS/ECMWF are 
slower to kick the trough eastward, and thus temperatures remain 
more modest Saturday, with warming delayed until Sunday when upper 
ridge builds eastward. For now have favored this somewhat slower 
solution, but confidence in weekend temperatures is rather low at 
this point.

As far as precip chances in the later periods, it looks rather 
sparse for our forecast area. Aforementioned wave dropping through 
Thursday night/Friday could scrape our far northern/eastern areas 
with some very light precipitation, though better chance currently 
looks to remain farther northeast into Minnesota.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1122 AM CST Mon Jan 7 2019

IFR conditions will quickly mix out and shift east by about 20z.
Rain, mixed precipitation and snow will be possible later tonight
with the better chances in southwest MN from about 5z to 10z. 

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...JH
LONG TERM...JH
AVIATION...08