277
FXUS63 KFGF 090420
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1120 PM CDT Tue Oct 8 2024

.KEY MESSAGES...

- Near critical fire weather is possible Wednesday afternoon, with
  slightly better chances on Thursday.

- Increasing chances of Widespread frost/freezes this weekend
  and beyond

&&

UPDATE
Issued at 1010 PM CDT Tue Oct 8 2024

Clear skies continue with light southeast winds, but WAA and
just enough wind is helping keep temperatures mild into the
late evening (50s to near 60). Minor adjustments were made to
reflect those trends, otherwise the forecast is on track.

UPDATE
Issued at 636 PM CDT Tue Oct 8 2024

Deep drying and subsidence is in place with ridging over the
Northern Plains, resulting in clear skies, while any flow aloft
that may carry even high clouds in the region is well east or
northwest of our region. WAA is underway aloft (850MB), so
while radiational conditions should be good, temperatures are
expected to remain "milder" compared to last night due to the
changing air mass. Forecast remains on track, and only minor
near term adjustments were necessary to reflect current trends.

&&

.DISCUSSION...
Issued at 249 PM CDT Tue Oct 8 2024

...Synopsis...

Water vapor imagery currently depicts mid-level ridging building out
of the intermountain west which will shift east through the next two
days along with a building thermal ridge across the northern plains.
This will result in temperatures soaring back into the 80s and
approaching daily record highs on Thursday. Beyond just warm temps
deep mixing will see enhanced fire weather the next two days with
the building ridging and a swift cold front on the back of the ridge
Thursday afternoon into Friday as a short wave passes to the north
increasing winds to a concerning level when paired with already low
afternoon relative humidities. Ensembles then display high
confidence in a shortwave moving south thorugh the upper midwest
this weekend bringing our first measurable rain chances in, check
notes, over two weeks.

- Fire weather

Minimum RH in the 25-30 percent range wednesday and 20-25 range
Thursday will even without wind will provide an environment worthy
out cautionary practices when burning. While Wednesday may approach
near critical fire weather with southerly winds up the Minnesota
side of the valley gusting near 20 mph, some nudging factors towards
more elevated caution  include the already primed fuels from a lack
any recent rains (0.00" in the last 2 weeks) and the associated High
fire danger rating from the DNR. Thursday may however near red flag
as there only a 40% chance for Min RH > 30 percent on Thursday
across southern North Dakota. Enhanced mechanical mixing ahead of
the nearing front in the afternoon will promote sustained winds in
the upper teens and gusts as high as 30 mph. Still a bit of
uncertainty as to how much overlap there is between winds and RH
both spatially and temporally but the chance for a near critical or
critical fire weather certainly appear likely given HDWI
probabilities exceed the 90th percentile for much of eastern North
Dakota Thursday.

THe cold front then sweeps late in the day Thursday with reduced
temperatures in the 50s and 60s for the weekend and beyond into
easily next week. As far as rain chances go with the weekend
shortwave but PWATs only in the 0.50 to 0.60 range will certainly
not promote a soaking rain especially given the weak synoptic
forcing associated with the wave. Overall looking at around a 60%
chance for > 0.05", not a lot by any means but we`ll take it after
the ongoing lack of anything measurable.

- Frost/Freeze

As we are now past the average first freeze for the region (Sept 21-
30 for most) and entering the 90th percentile for latest first 32
degree freeze dates entering the middle October this weekend these
cooler temps should not come as a shock to anyone. The current
forecast does call for lows in the lower 30s to upper 20s Monday and
Tuesday mornings next week which if true could near the latest first
fall freeze on record for some places in the forecast area. Just goes
to show how above average  we have truly been this fall.

Record High Temperatures Thursday:

October 10:
KGFK: 86/1934
KFAR: 86/2003
KPKD: 80/2010

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1120 PM CDT Tue Oct 8 2024

VFR conditions are expected through the TAF period across
eastern ND and northwest MN, with a very dry/stable air mass in
place. Light southeast winds continue early in the TAF period
with more sheltered locations in northwest MN variable or calm.
Surface gradient and mixing increases some during the day
Wednesday, and sustained winds are shown to increase to the
10-12kt range, gusting as high as 20kt at times during daytime
heating Wednesday. This should follow the standard diurnal
trend, with winds decreasing again at sunset Wednesday evening
when daytime heating/mixing ends.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...TT
AVIATION...DJR