Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 222346
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
546 PM CST Tue Jan 22 2019

.UPDATE...
Issued at 543 PM CST Tue Jan 22 2019

Skies have cleared over most of eastern ND and far NW MN...with
low cloud area Baudette to Fargo and east, moving east. Question
is fog potential as short term models hinting strongly at fog
development tonight east of the Red River. Will monitor as winds
will be light.

Temps in clear area to drop likely more than fcst so will monitor
temps and likely drop them in NW MN.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 232 PM CST Tue Jan 22 2019

Light flurries resulting from weak broad scale lift associated
with the passage of an upper level wave continue to drift eastward
across the Red River Valley and northwest MN. To the west across
central ND, broad subsidence behind the wave has allowed clearing
skies that will be gradually shifting eastward through the
afternoon/evening.

Model guidance suggests a second cloud bank, currently over far
western ND, may move into the region later tonight in response to
weak mid level warm advection. A few snow flurries can`t be ruled
out under this cloud bank, but model guidance is in relative
disagreement in terms of placement and coverage of flurry
potential.

Areas that do not see much cloud cover tonight, mainly over
northwest MN, may see lows drop down into the single digits below
zero. Otherwise, overnight lows in the single digits above zero
are expected.

Winds will gradually turn to the south/southwest by Wednesday
morning and will allow temperatures to climb into the 20s for much
of eastern ND with upper teens across northwest MN. Besides the
potential for lingering flurries tomorrow morning, relatively
benign weather is expected for the first half of the day. The
arctic front (see extended discussion) will begin pushing into the
Devils Lake region late Wednesday afternoon/early evening.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 232 PM CST Tue Jan 22 2019

The main concern for the extended period will be the potential
for ground blizzard conditions late Wednesday afternoon/early
evening through Thursday morning followed closely by hazardous
wind chills. Additionally, confidence has increased slightly in
the potential for accumulating snow late Sunday and into Monday of
next week.

Wednesday night through Thursday...

Guidance continues to be in good agreement that a upper level
shortwave trough will propagate southward along the periphery of a
strong Hudson low. Afternoon water vapor imagery shows this
approaching shortwave currently across the northern territories of
Canada with surface obs showing a frigid airmass under this feature.
This low is expected to phase with strong zonal flow over the
Canadian Rockies to facilitate the development of the Canadian low
and arctic high that will induce a strong pressure gradient wind as
it pushes southward into the ND/MN region Wednesday evening and
Thursday morning.

Sustained surface winds of 25 knots are likely across much of
eastern ND with sustained winds of 30 knots possible through the Red
River Valley thanks to favorable topographic effects. Nearly dry
adiabatic lapse rates induced by strong low level cold advection
will allow vertical mixing up to 900mb per forecast soundings,
tapping in to a 35-40 knot low level jet. This will allow strong
wind gusts up to 45 mph, especially through the Valley.

These winds will likely cause blowing snow and subsequent reductions
in visibility. White out conditions will be possible in open country
beginning Wednesday evening across the Devils Lake basin and
overnight Wednesday night into Thursday morning across the Red River
Valley.

Winds, and subsequent impacts from blowing snow, are expected to
gradually die down by Thursday afternoon. As cold air moves in
behind the front, wind chill values down to -35 F will be possible.

Thursday night through Friday...

As the arctic airmass settles into place Thursday night and into
Friday, temperatures will drop down into the -15 to -25 range by
Friday morning with wind chill values in the -30 to -45 range.

Friday night through Sunday...

Following this surge of arctic air on Thursday, a baroclinic zone is
expected to establish itself across the Dakotas delineating the
colder arctic airmass over the midwest from the slightly warmer
continental air mass to the west. The combination of this baroclinic
zone and northwesterly flow aloft will be conducive for a couple
shortwave impulses to propagate through the region over the weekend.

Model guidance has come into better agreement over the past 24 hours
as to the development, timing, and placement of a strong Canadian
clipper across the region Sunday night through Monday. This system
will bring the potential for widespread snowfall amounts and some
blowing snow, though the exact details such as snow amounts,
placement, timing, and wind speeds are still uncertain at this time.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 543 PM CST Tue Jan 22 2019

Main question overnight/Wed AM will be fog/low cloud potential
east of the Red River. Short term models indicate fog forming
tonight in clear area east of the Red where winds will be light.
Also low clouds forming with the fog and lasting into Wednesday.
Unsure of this scenario, but winds are light but also not much low
level moisture. Front and strong NW winds arriving DVL/GFK by 00z
with lowered vsbys.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Storm Watch from Wednesday afternoon through Thursday
     morning for NDZ006>008-014>016-024-026>030-038-039-049-
     052>054.

MN...Winter Storm Watch from Wednesday afternoon through Thursday
     morning for MNZ001>004-007-029-030-040.

&&

$$

UPDATE...Riddle
SHORT TERM...AM
LONG TERM...AM
AVIATION...Riddle


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