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000 
FXUS63 KFGF 111536
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
936 AM CST Mon Dec 11 2017

.UPDATE...
Issued at 930 AM CST Mon Dec 11 2017

Have added western OTC and Grant County to the existing Wind 
advisory. Winds are penetrating well down into west central MN,
behind the cold front. With much colder air pouring in at the
surface now and cutting under the warmer/moister layer just
above... and we're seeing some ground based convective snow 
squalls in the RRV corridor. So brief enhanced reductions in 
visibility with those through the forenoon.

UPDATE Issued at 754 AM CST Mon Dec 11 2017

Received a report of localized areas of blowing snow just south of
Grand Forks. These conditions appear limited to west east
orientated roads in wide open areas. Coverage not enough to
warrant a winter weather advisory, but did update the forecast
with more blowing snow and issued a special weather statement. 

UPDATE Issued at 550 AM CST Mon Dec 11 2017

Winds across the northern valley counties are currently 30 mph
gusting to over 40 mph. RAP/HRRR soundings indicate mixing will
continue into the afternoon hours with 925mb winds 40-45 knots. As
such, feel that advisory criteria winds will continue for at least
the morning hours. Issued a wind advisory for the valley counties
and a portion of SE ND until RAP guidance diminishes the winds
aloft. Possible winter weather impacts (blowing snow) may occur 
across the part of northwest Minnesota that received fresh snow 
and temperatures did not climb above freezing. This is a very
limited area, but will monitor and adjust as necessary.  

&&

.SHORT TERM...(Today and tonight)
Issued at 406 AM CST Mon Dec 11 2017

Strong upper level low propagating through the region causing all
sorts of concerns. Initially, precipitation associated with the
vorticity advection across the southern parts of the region is
falling as mostly liquid, and leading to icy roads where
temperatures are below freezing. With that said, temperatures are
rising above freezing which is limiting impacts. 

Cold front is currently (10z) situated just north of the
International border, and set to quickly propagate from north to
south through the region this morning. Current radar imagery not
very impressive, and although snow showers will occur with the
fropa, visibility will likely not be limited too much. Winds will
increase, and the main question revolves around magnitude (i.e.
will a wind advisory be needed?). Strong wind indicators (pressure
rise max, cold air advection, winds aloft) would suggest sustained
30mph gusting to over 45mph, but current observations upstream do
not support these values. Most likely a situation where we see a
a brief period (less than an hour) of wind advisory speeds with 
the fropa. Winds will begin to diminish by late morning. The other
concern will be flash freeze potential with moist roads and  
temperatures above freezing before the fropa. Will monitor, but 
roads may have enough time to dry before temperatures drop below 
freezing. 

.LONG TERM...(Tuesday through Sunday)
Issued at 406 AM CST Mon Dec 11 2017

The parade of clippers out of Canada continues with the grand 
marshall leading the parade around the Wednesday timeframe. Guidance 
is still struggling with interaction between a compact but strong 
vort max rounding the western ridge near southern British Columbia 
and energy originating from more northern Canada. However it does 
seem guidances wants to keep the former further west into eastern 
Montana perhaps preventing phasing between the two once shown 
before. Regardless, light snow and elevated winds are expected 
Wednesday into Thursday.

Behind the grand marshall comes another clipper shortly after around 
late Friday into Saturday. It is advertised that there may be a bit 
more moisture to work with as the source air mass will not have as 
much time to be modified originating from the Pacific northwest as 
opposed to deeper into Canada. This is a result of flattening of the 
western ridge which could also bring warmer temperatures into the 
region.

Several pieces of energy emanate from the US Pacific northwest out 
of the barrel of a more zonal upper level jet max pointed towards 
southern British Columbia/Washington state. Interaction with a 
Pacific atmospheric river will supply moisture for these pieces of 
energy to play with towards the late weekend. Ensemble guidance is 
highlighting one piece of energy around the Sunday/Monday timeframe 
to cross the region bringing elevated precipitation chances.

Temperatures will continue to be above normal as colder air stays 
trapped in the eastern trough. Normal temperatures this time of year 
are in the lower 20s for highs to mid single digits above zero for 
lows.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Updated at 935 AM CST Mon Dec 11 2017

Widespread MVFR with areas of IFR CIGS and VSBYS in light snow 
and blowing snow are expected across the area through early 
afternoon... with strong north winds gusting to 45 kts along the 
central RRV corridor. Conditions will gradually improve through 
the afternoon/evening hours. MVFR cigs again possible Tuesday 
morning.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Advisory until 3 PM CST this afternoon for NDZ008-016-027-
     029-030-039-053.

     Wind Advisory until noon CST today for NDZ028-038-049-052.

MN...Wind Advisory until 3 PM CST this afternoon for MNZ001>004-007-
     029-030-040.

&&

$$

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