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000
FXUS63 KFGF 161732
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1232 PM CDT Tue Apr 16 2024

.KEY MESSAGES...

- Windy conditions will develop early this morning and continue
  through the afternoon. Gusts up to 55 mph can be expected at
  times within portions of southeast North Dakota, west-central
  and northwest Minnesota. There is a 30 percent chance for
  gusts higher than 55 mph particularly under heavier showers
  and weak thunderstorms.

- There is a 50% chance for greater than one inch of rainfall
  through Wednesday morning. Highest chances are across the
  Devils Lake Basin, southeast North Dakota, and west central
  Minnesota.

&&

.DISCUSSION...
Issued at 403 AM CDT Tue Apr 16 2024

A strong mid/upper low is deepening on the lee side of the central
Rockies early this morning, with the surface low now over
western Nebraska. Deep southerly southerly flow is building into
the Northern Plains with a plume of deepening moist air northward,
while drier low levels are still in place over our northeast due to
low level easterly flow out of Ontario. A strong LLJ of 50+kt is
already in place and guidance shows further strengthening this
morning as the mid level low continues to shift northeast into the
Plains. This mid/upper low will be responsible for waves or
organized rain and embedded thunder through tonight/Wednesday
morning as it transitions east-northeast. The main period of
rainfall should be today with strong forcing and organization along
deformation and and inverted trough axis. There is a trend for these
features to favor the our western and southern CWA, maintaining
drier air and lighter QPF totals in the northeast.

Regarding Strong Winds: East-southeast flow expected as the strong
(50-60kt) LLJ transition over our southern CWA and this direction has
limited analogues for high wind events in our CWA as cross valley
momentum transfer can be limited. Still, there are local terrain
effects that support some downslope in west central MN, and
conservative mixed layers would support 45-55 mph gusts across our
southern CWA today, and I expanded the advisory into southeast ND
accordingly. Some guidance that tends to carry a bias (GFS/RAP)
shows a deeper mixed layer and would actually support better chances
for warning impact winds. Considering the lack of
analogues and unfavorable direction I am not confident enough to
issue a warning based on those model mixing heights. HREF does
reflect a a 20-40% prob for greater than 55 mph winds within the
advised area. One factor that could aid in momentum transfer would
be heavy rain showers/weak thunderstorms and we can`t rule out
warning impacts.

Wednesday night-Friday: As this initial mid/upper low transitions
east-northeast it eventually merges into a second (much colder)
mid/upper low (currently over British Columbia). CAA along with
weaker energy rotating around this upper low could result in
additional light rain/snow chances through this periods. While there
is a signal for snow, probabilities for more than a dusting are very
low, and warm ground temperatures and daytime temperatures will
tend to limit impacts.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1231 PM CDT Tue Apr 16 2024

Rain will continue across the area thorugh the night though dry
air has been eating away at some of the echos further into
central North Dakota. This will eventually spread north and east
tomorrow morning as rain clears towards tomorrow afternoon. Cigs
are a mix of VFR and MVFR with IFR in central North Dakota.
Tough forecast overall but expect winds to decrease tonight
around 23 to 02Z as gusts drop off and ceilings continue to
lower through the afternoon. A few vis reductions but mainly
above 3 miles except in heavier cores to 1-2 miles.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Advisory until 7 PM CDT this evening for NDZ038-039-049-
     052-053.
MN...Wind Advisory until 7 PM CDT this evening for MNZ002-003-015-
     016-022-023-027>031-040.

&&

$$

DISCUSSION...DJR
AVIATION...TT