001
FXUS63 KFGF 300438
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1138 PM CDT Sun Sep 29 2024

.KEY MESSAGES...

- Wind Advisory for gusts over 45 mph in eastern North Dakota and
northwest Minnesota tonight.

- Fire Weather Watch for southeast ND and west-central MN for
  conducive conditions for rapid spread of wildfires.

- First widespread frost chances Thursday night into Friday.

&&

.UPDATE...
Issued at 1002 PM CDT Sun Sep 29 2024

Strong LLJ is developing across central/eastern ND, and gusts
near 40 mph have been reported in northeast ND since sunset.
There is still a deeper inversion projected by guidance tonight,
so how much momentum transfer will occur before the front
arrives in the morning is hard to say (after 09Z near Devils
Lake), so advisory impacts may be delayed for some areas until
sunrise Monday. There hasn`t been a change in confidence
regarding any warning impacts from wind in the Devils Lake Basin
per day shift discussion, so we will just need to monitor
upstream trends through the night. Minor adjustments were made
to near term trends and sky cover into Monday, otherwise
forecast remains on track.

UPDATE Issued at 659 PM CDT Sun Sep 29 2024

The main update for the forecast is the issuance of a Fire
Weather Watch across southeastern North Dakota and west-central
Minnesota. While conditions with relative humidity remain fairly
marginal within the official forecast, given the wind shift
expected as a front comes through and high confidence in very
gusty winds, concerns were enough to warrant the issuance of a
watch.


&&

.DISCUSSION...
Issued at 231 PM CDT Sun Sep 29 2024

...Synopsis...

The remnants of what was hurricane Helene have since merged with a
cut off low in the upper Ohio Valley. This continues to prevent
ridging from building east while also keeping the well above average
temperatures in place for the northern plains today. A big change in
the synoptic pattern does come tonight into Monday as a mid level
low deepens in Saskatchewan and Manitoba with and associated cold
front ushering in strong winds and cooler temperatures. Averages for
the coming week would be upper 30s for lows and lower 60s for highs.
Still looking to remain on the warmer end of these values but at
least not the 15-20 degrees above average of last week.

- Today

Of interest or potential impact are the strong south to southeast
winds across the region this afternoon with widespread gusts over 30
mph in central North Dakota and even a few in the far northern
valley. In combination with relative humidity below 30 percent and
near critical fire weather is place for eastern North Dakota with a
red flag warning in effect areas extending from McHenry south to
McIntosh counties and points west in central North Dakota. Not
expecting to quite reach red flag criteria in our area today but
still recommend caution if planning to burn today based on
conditions.

- Tonight

As the low deepens to our north in Canada weak mid level height
falls ahead of the main cold front may aid in the development of
some showers aloft but an impervious layer of dry air below will
prevent anything from reaching the surface tonight into tomorrow and
will more likely just manifest as a broken to overcast layer of
stratus. The associated low level mass response will greatly
strengthen the low level jet with a >80% chance for the southwesterly
850mb jet to exceed 55kts. It remains uncertain just how effectively
this wind would make it to the surface but between the increasing
pressure gradient, existence of this low level wind maxima, and any
advective component its seems a high probability that wind gusts
exceeding 45 mph will be realized overnight despite the typical
formation of a nocturnal inversion. Despite the general understanding
of the "why" to some degree have still gone ahead with the wind
advisory from 7pm to 8am for much of eastern North Dakota north of I-
94 and adjacent portions of Minnesota up to Roseau. On top of the
wind advisory there does remain the much lower potential for gusts
over 58 mph from 10pm to 3am leading a 20% chance for the need for a
high wind warning though the time and location would likely limit
some of the impacts being the threat location is confined to the
western edge of the the Red River Valley.

- Fire weather

Besides the strong winds noted above there is also the concern for
RH tomorrow to dip below 30 percent in areas through fuels remain
marginal and the combination of winds and RH both being borderline
in areas where the overlap have decide to wait and see and allow the
mid shift to potentially pull the trigger on any necessary headlines.

Things do eventually calm down after Monday with winds letting up
and temps falling. Highs in the 60s and 70s the remainder of the
week with a chance for frost Thursday night into Friday as high
pressure slides back over the area leading to ideal radiational
cooling conditions. Best frost chances lie north of HWY 200 through
could see isolated pockets south of this.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1138 PM CDT Sun Sep 29 2024

VFR conditions should prevail through the TAF period across
eastern ND and northwest MN. The main aviation concerns will be
gusty winds that will shift form the south-southeast to the
west-northwest through the TAF period as a front moves through
the region, along with a period of low level wind shear as
50-60kt low level jet progresses east ahead of this front. There
may be a brief lull in the strongest winds near the front but
this should be short lived. Gusts 35-40kt can be expected at
times ahead of and behind the front in eastern ND and
potentially as far east as KTVF. A few stronger gusts greater
than 40kt may occur at KDVL, but confidence isn`t as high at
this time.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Advisory until 10 AM CDT Monday for NDZ006>008-014>016-
     024-026>030-038-039-049-054.
     Fire Weather Watch from 7 AM CDT Monday through Monday evening
     for NDZ039-049-052-053.
MN...Wind Advisory until 10 AM CDT Monday for MNZ001>005-007-008-
     013>015-022.
     Fire Weather Watch from 7 AM CDT Monday through Monday evening
     for MNZ003-024-027>032-040.

&&

$$

UPDATE...Perroux/DJR
DISCUSSION...TT
AVIATION...DJR