Calvin, North Dakota Weather Forecast Discussion

825
FXUS63 KFGF 082357
AFDFGF
Area Forecast Discussion
National Weather Service Grand Forks ND
657 PM CDT Mon Sep 8 2025
.KEY MESSAGES...
- There is a 1 of 5 risk for isolated severe thunderstorms
  through late evening across portions of west central
  Minnesota. Large hail, up to 1 inch, will be the primary
  hazard.
&&
.UPDATE...
Issued at 657 PM CDT Mon Sep 8 2025
Still getting showers and a few weak thunderstorms developing
over the southern Red River Valley into western MN as shortwave
moves through. Not a lot of ML CAPE to work with but elevated
CAPE is around 2500 J/kg and effective shear around 30 kts so
can`t completely rule out some cells strong enough for elevated
hail in the next few hours. Risk still looks marginal so
messaging 1 out of 5 seems reasonable. Made some minor tweaks to
POPs for timing and placement as we head into the overnight, but
no major changes to our messaging.
&&
.DISCUSSION...
Issued at 328 PM CDT Mon Sep 8 2025
...Synopsis...
Showers and thunderstorms are possible this afternoon, evening, and
early overnight hours. H5 shortwave continues southeastward along
the downstream side of an approaching ridge. This ridge is expected
to move very slowly to the east, displaying characteristics of a
standing wave or weak blocking pattern. This is due to deep, H5
troughs on either side of the ridge, with slow movement to the east.
Warmer temperatures build into the ridge today through Friday,
allowing afternoon highs to climb well into the 70s to low 80s each
afternoon. Mid 80s become possible heading into Friday and Saturday
before the ridge pushes to the east, giving way to southwest H5
flow. The oncoming flow pattern shows support for showers and
thunderstorms as early as Thursday afternoon, with additional precip
chances each day through Sunday. While it remains too early to
gather exact details, strong storms could be possible late this week
and into the weekend due to multiple shortwave passages.
...Isolated Severe Thunderstorms Possible Today...
A weak shortwave is moving across the region this afternoon and
evening. A relatively strong 850mb jet is currently moving eastward
into west central Minnesota, providing moisture ahead of the
shortwave and allowing MUCAPE to climb upwards of 2000 J/Kg. Lapse
rates this evening will be high enough to allow a mention of at
least a few stronger storms; however, this conditional threat will
be somewhat short-lived as the low level jet continues eastward. The
primary hazard this evening will be hail up to 1 inch in diameter,
with the potential for smaller hail persisting into the early
overnight period.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 657 PM CDT Mon Sep 8 2025
KTVF has MVFR ceilings right at 3000 ft but every other TAF site
currently VFR. Should see showers and possibly a few
thunderstorms for the next few hours at KFAR and KBJI as an
upper level disturbance passes through the area. Then all sites
should become dry with VFR conditions and light and variable
winds by late evening. There is some guidance that develops
LIFR stratus and brings it as far west as KGFK and KFAR tomorrow
morning. However, other model runs keep us VFR and probability
of less than 1000 ft ceilings is less than 40 percent at the Red
River airports. Will keep them out of the stratus for now, but
included some 500 ft ceilings at KBJI which has probability over
50 percent. All sites should be VFR by late morning, with winds
picking up out of the north at around 7 to 10 kts.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
DISCUSSION...Lynch
AVIATION...JR

NWS FGF Office Area Forecast Discussion