Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 132334
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
634 PM CDT Wed Mar 13 2024

.KEY MESSAGES...

- Patchy dense fog within the Devils Lake Basin Thursday
  morning restricts visibility to a quarter of a mile on an
  isolated basis creating isolated travel impacts.

- There is a 10 percent chance for winter travel impacts
  between Friday night through Sunday morning due to brief heavy
  snow showers reducing visibility with light accumulations.&&

.DISCUSSION...
Issued at 158 PM CDT Wed Mar 13 2024

Weak upper level wave is propagating through Manitoba today bringing
weak synoptic forcing to the region. Upper level Jet aloft and lower
level saturation is kicking off sprinkles across eastern North
Dakota and northwestern Minnesota. Light returns are noted on radar,
but a majority of the area is not seeing any falling precipitation.
Most of the area has a dry layer near the surface and aloft helping
to keep the precipitation from reaching the ground. A few locations
(especially near the International Border) have seen deeper
saturation near the surface allowing for the sprinkles. The chance
for this continues through the early evening hours before synoptic
support is lost. Otherwise, areas near the International Border are
struggling to make it into the lower 40s this afternoon thanks to
the cloud coverage. Areas in the southern Red River Valley area
easily reaching into the lower to mid 50s as sunshine is more
plentiful.

Synoptic flow aloft is zonal, with strong troughing in the
southwestern United States. Clusters have a good handle on the
synoptic evolution through the forecast period with flow turning
toward the northwest by the weekend. This keeps our temperatures
near seasonal to just below seasonal post weekend. Before the
weekend we will continue to see warmer the average temperatures as
we continue to see zonal flow. Northwest flow aloft helps to keep
the chances for clipper systems to move out of the northwestern
portions of Canada this weekend and into next week. A more robust
system works its way through the northern plains Friday evening
through Sunday. Strong synoptic support is associated with the
system and helps drive QPF.

Low level saturation continues through the overnight period, with
dew point depressions near zero across the Devils Lake Basin. Winds
are light and variable overnight, with warmer than average low
temperatures. These ingredients increase the chances for patchy
dense fog during the later portions of overnight into Thursday
morning. Fog could become dense at times, with visibility reductions
down to a quarter of a mile on an isolated basis causing isolated
travel impacts during the morning commute. There will be another
chance for a flurry or sprinkle later tomorrow morning into the
early afternoon as a weaker wave moves across the International
Border. No impacts are expected from the precipitation and it would
be confined to the Turtle mountains and Intonational Border region
of the Devils Lake Basin. Expect continued warmer than average
temperatures tomorrow and again on Friday.

Cluster analysis is in agreement that the best forcing associated
with a shortwave dropping south out of Canada will remain over the
Great Lakes Friday night into the Saturday. The exception will be
areas near the Lake of the Woods, as a few rain showers work through
due to warm air advection Friday evening. As the cold front
propagates southward Friday evening into the overnight, winds will
rapidly increase out of the northwest. The strongest 850mb winds of
up to 50 mph pass through Friday night. However, diurnally the best
mixing does not arrive until Saturday morning into the afternoon,
which is the same time 850mb winds begin to decrease. Thus, it is
uncertain if we will be able to truly tap into the highest wind gust
potential. Winds will turn northerly Saturday afternoon which can
enhance gusts in the Red River Valley. NBM probabilities of wind
gusts in excess of 40 mph Friday night through Saturday are 90% in
the Red River Valley and the Devils lake Basin, to about 50% across
Lakes Country.

There is post frontal instability, with weak CAPE (<25 J/kg)
present. Two scenarios exist as to what happens post frontal
passage. Scenario one, which is favored (90%), keeps the area breezy
with a few snow or rain showers Saturday afternoon. In scenario two,
which has a 10% chance of occurrence, we would be able to tap into
the instability. This would allow for organized HCR development in
the afternoon. Warm temperatures complicates precipitation type, but
a mix of rain and snow would be associated with HCRs. Combined with
breezy northerly winds, wintry impacts would occur.

Another shortwave dives out of Canada on Sunday. A period of light
snow could break out over the region as it propagates through.
Weaker winds would reduce wintry impacts from blowing snow, keeping
impacts tied to any areas of falling snow. Overall, snowfall totals
will be light. There is currently a 40% chance for an inch or more
of snow Friday night through Sunday.

Northwest flow remains in place into early next week. Seasonal
temperatures are expected, with little to no precipitation.


&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 633 PM CDT Wed Mar 13 2024

VFR conditions prevail this evening, with cloud cover spread
across much of the area. Heading into the overnight period,
broken mid-level clouds are expected to remain rather
persistent everywhere except for KDVL, where we could see
stratus and/or patchy fog develop late this evening and
overnight. Stratus could extend as far as KGFK. Some lingering
LLWS persists this evening, but will gradually subside later in
the TAF period.

&&

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

&&

$$

DISCUSSION...Rafferty/Spender
AVIATION...Lynch


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