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FXUS63 KFGF 072109

Area Forecast Discussion
National Weather Service Grand Forks ND
309 PM CST Sat Dec 7 2019

.SHORT TERM...(This evening through Sunday night)
Issued at 251 PM CST Sat Dec 7 2019

The main feature of the short term forecast period will be a
clipper system that will bring winter weather impacts to the
southern half of the CWA. Generally three to five inches of snow
are possible south of the Highway 200 corridor in the 00Z to 18Z 
Monday timeframe, with winter weather impacts possible for the 
Monday morning commute in larger cities such as Valley City, 
Fargo, Fergus Falls and Wahpeton.

For tonight, breezy southerly winds will inhibit fog formation
despite some areas once again seeing above freezing temperatures.
There will be a break in precipitation for tonight into late
Sunday breaks in sky cover are evident on satellite
across eastern Montana and western North Dakota.

Sunday and Sunday night...increasing synoptic lift evident from
modeled Q-vector convergence increase chances for snowfall across
the region beginning around noontime tomorrow. The area of forcing
will transit the CWA from roughly 21Z Sun through 15Z Mon...with
deterministic models indicating stronger frontogentic forcing late
Sunday evening. WPC indicating a 50 per cent or greater
probability of exceeding four inches of snow...dropping to around
20 per cent at the six inch threshold. These higher amounts line
up with strongest FG forcing. Overall looking for three to five
inches of accumulation by the end of the Monday morning commute
south of Highway 200...with the highest confidence along and 
south of the Interstate 94, US Highway 10 and MN Highway 34 
corridor. No plans for advisory attm as further model runs narrow
down the track of the surface low.

.LONG TERM...(Monday through Saturday)
Issued at 251 PM CST Sat Dec 7 2019

The main concern for the period continues to be the well advertised 
shot of arctic air to impact the region for the first half of the 
work week. Relatively warmer conditions and the return to a more 
active pattern will be on tap for the second half of the period.

Northwest flow aloft will be accompanied by areas of high pressure 
passing through the area during the Monday through Wednesday time 
frame. Although the coldest air should remain north and east of the 
area, plenty of cold air advection will help bring down some of the 
850 mb temperatures reaching into the -20 to -25 C degree range. 
While Monday should still see high temperatures above the zero mark 
(albeit maybe just barely), Tuesday and Wednesday look to bring 
temperatures struggling to reach the zero mark, even during the day. 
Both daytime and nighttime temperatures a good 25-30 F degrees below 
normal will likely be enough to allow for an extended period of wind 
chills solidly into advisory criteria even without a push of 
stronger winds.

More zonal flow returns for the second half of the period with the 
potential for periodic light snow chances. Confidence is low on any 
high impact events with ensemble data not indicating much in the way 
of QPF at this time. However, even light snow events occurring at 
the right time (i.e, rush hour) could bring some level of 
transportation impacts at times towards the end of the work week and 
beginning of the weekend.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1143 AM CST Sat Dec 7 2019

Significant improvement in IFR cigs and most sites have turned to
VFR...with quite a few clear holes especially in w cntrl MN. Much
more optimistic outlook for afternoon flying...with worse impacts
now northeast of TVF where mixed precipitation is occuring. South
winds with skies becoming MVFR again later tonight is the main
message for remainder of the day.



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