Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 010859
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
259 AM CST Thu Dec 1 2016

.SHORT TERM...(Today and tonight)
Issued at 236 AM CST Thu Dec 1 2016

Forecast challenge will be potential for freezing drizzle during
the early morning hours...followed by temperatures. Current NIR
imagery and surface obs indicate a moist H925 to H850 layer
creating overcast conds for the entire CWA as well as all of
western Ontario, Manitoba and Saskatchewan. Therefore expect
cloudy conditions through the entire short term period.

06Z NIR imagery indicated the back edge of a H850 to H700 cloud
deck entering the far Red River Valley with the aforementioned
saturated low layer beneath. This mid level dry layer will
continue to sink south throughout the night and should cut off
any remaining light snow with the loss of ice in the column,
however there is a potential for patchy freezing drizzle behind
it. As of 0530Z, stratus is a bit too high and winds a bit too
strong for any widespread drizzle to occur and potential for even
patchy drizzle is dwindling. Will keep the patchy wording in
through mid morning and re-evaluate at the 7 AM update, but
confidence is decreasing for freezing drizzle. With the cloud
cover and northerly flow temperatures should remain in the low
30s.

A ridge of high pressure moves over western ND and will keep light
northerly flow and some cold advection over the area. Overnight
lows should drop into the mid to low 20s as temps over northern
Manitoba and northwest Ontario, currently in the upper teens to
low 20s, advect into the northern tier CONUS.

.LONG TERM...(Friday through Wednesday)
Issued at 236 AM CST Thu Dec 1 2016

A solid H925 to H850 moist layer will stay in tact through the
weekend and keep Friday and Saturday mostly cloudy to overcast
with little opportunity for daytime highs to rebound. The coldest
day will be Friday as the coldest air settles in over the
area...limiting daytime highs to the upper 20s. Return flow does
set up on Saturday however cloudy conditions will only allow about
a 5 degree warm up, climbing into the low to mid 30s for most of
the region. The next upper wave moves across southern Canada on
Saturday, bringing a chance for some light snow across the
north. One note of interest is that the shallow moist layer may
produce some light freezing drizzle Saturday afternoon and evening before
the column begins to saturate and change to snow. Model Skew-Ts at
Devils Lake do indicate low levels saturating by 18Z Saturday
however this is likely overdone given the cold temperatures
inhibiting any snow melt to the south, which would increase
moisture in the near surface layer. Most likely scenario is that POPs
are a bit too aggressive Saturday evening and column will saturate
by 06Z and bring some light snow showers across the north as the
wave moves across southern Manitoba.

Models in general agreement to start the period...but begin to
diverge toward the middle and latter portion of the period.

A trof of low pressure will cross the area on Sunday...but limited
moisture will result in some light snow with little accumulation
expected.

Otherwise...models consistent in indicating a more organized system
developing by late Monday.  Models differing on placement of surface
features...with GFS quicker to move system out and resultant cold
air push out of Canada.  Thus...favor more of an ECMWF/GEM blend at
this time.  As guidance suggests a cooling trend late in the
period...the question remains as to where the coldest air will
settle. For now...expect high temperatures generally in the 20s in
the eastern portion of the forecast area...with teens and even some
single digit highs in the Devils Lake basin.  Best chance of
measurable precipitation will occur with the main part of the system
on Monday night and Tuesday...with a secondary chance for
precipitation coming on Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1133 PM CST Wed Nov 30 2016

No overall changes to ongoing aviation pattern. MVFR/IFR cigs to
continue through most of the period. VSBY at this point not
expected to be an issue.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

SHORT TERM...Speicher
LONG TERM...Hopkins/Speicher
AVIATION...Voelker



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