121
FXUS63 KFGF 220300
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1000 PM CDT Thu Aug 21 2025

.KEY MESSAGES...

- Isolated thunderstorms may continue through midnight over
  parts of north central MN with small hail and lightning the
  main threats.

- Breezy to windy conditions are expected over parts of the
  region Friday afternoon, with a 50% chance for wind gusts
  greater than 45 mph over the northern Red River Valley.

&&

.UPDATE...
Issued at 1000 PM CDT Thu Aug 21 2025

Surface cold front has continued to push east, and sunset
leading to low level decoupling has helped close the window on
more organized convection. There is just enough elevated
instability in our east to support a few showers or non severe
thunderstorms. Looking ahead to Friday ECMWF EFI shows values
over 0.8, NBM QMD probs, and model mixed layer gusts in the
35-44kt range raises the potential for advisory type wind gusts
in the northern Red River Valley with increasing CAA. No major
changes made to grids this point, but this will be monitored for
trends tonight and Friday.

UPDATE
Issued at 705 PM CDT Thu Aug 21 2025

Several frontal zones are moving through our CWA; one cold
front in northeast ND and far northwest ND and a per frontal
trough in west central MN. A narrow axis of ML CAPE 2000-4000
J/KG is still in place immediately ahead of the cold front where
MLCIN has weakened. Mid level flow is strong is and effective
shear has increased to 30-55 kt. A limiting factor continues to
be the amount of dry air that has been advecting in front the
west and the narrow/less organized nature of synoptic forcing.
We are still in a window for the next hour or two for potential
isolated severe thunderstorm development as the front pushes
east-southeast.

&&

.DISCUSSION...
Issued at 235 PM CDT Thu Aug 21 2025

...Synopsis...

Ridging continues to retreat southwest this afternoon, with H5
troughing extending southward from an upper low, situated over
Saskatchewan and Manitoba. Scattered showers and thunderstorms are
expected to continue through the afternoon and early evening, with
severe thunderstorms possible. A cold front traverses the area
tonight into Friday morning, with much cooler and drier weather
expected as we head into Friday afternoon and into the weekend. Look
for highs in the 70s on Friday, with breezy west winds, then in the
60s for Saturday and Sunday with breezy northwest to north winds.
Lows could fall into the low 40s Sunday night, with cooler spots
possibly seeing upper 30s. Slightly warmer temperatures return on
Tuesday as highs climb into the lower to middle 70s.


...Severe Thunderstorms this Afternoon and Evening...

There is a conditional chance for scattered severe thunderstorms
this afternoon and evening. Dew points have climbed into the upper
60s to near 70 degrees following a prefrontal trough. West of this
feature, instability is expected to climb upwards of 3500 J/Kg,
along with deep layer shear ranging from 30-40 knots. Low level flow
remains weak; however, near storm influences could allow low level
shear to be locally supportive of hybrid supercells and clusters.
Forcing is somewhat weak due to the lack of H5/H7 shortwave support
and most of the initiation is likely to occur just ahead of the cold
front, where the steepest theta-e gradients exist. Soundings
continue to support upscale growth, with line segments potentially
leading to damaging wind gusts as the afternoon progresses. DCAPE
values are in the range of 1100 to 1300 J/Kg, along with PW values
ranging from 1.3 to 1.7 inches. This should allow for moderate
precip loading into any updraft that is able to initiate. Wind gusts
of 75 mph are possible with today`s strongest storms, along with
hail up to the size of golf balls. Tornado risk continues to be
present but overall generally low. Storm scale influences will play
the biggest role for tornado risk as hybrid clusters could show more
supercell characteristics in the presence of increased low level
shear from nearby outflow boundaries.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 705 PM CDT Thu Aug 21 2025

Isolated showers/thunderstorms continue mainly from southeast
ND and across northwest MN, with chances diminishing after
sunset this evening. Due to lower coverage of thunderstorms I
kept mention out of TAFs. Trend should be towards VFR conditions
through the TAF period with increasing northwest then west
winds. Strongest winds are expected during the daytime
period/peak mixing Friday when gusts 25-35kt will be possible
(strongest in northeast ND).

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...Lynch
AVIATION...DJR