756
FXUS63 KFGF 292010
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
310 PM CDT Fri Aug 29 2025

.KEY MESSAGES...

- Showers and a few thunderstorms will bring lightning and brief
  downpours this afternoon and evening, mostly along and south
  of I-94.

&&

.DISCUSSION...
Issued at 311 PM CDT Fri Aug 29 2025

...Synopsis...

Currently, troughing resides over the eastern third of CONUS, while
two cutoff areas of low pressure are out in the Pacific Ocean,
pushing the main jet/flow well to the north of much of the
western/central CONUS into an omega block like pattern. This
leaves our FA in an area of both weaker flow and forcing
through the holiday weekend. Beyond diurnally driven
showers/storms along any weak boundaries or subtle waves,
impacts will remain limited to fog. With light winds tonight,
fog may develop just about anywhere in the FA, but favoring
locations along and south of Highway 2 where thunderstorms this
afternoon will leave more residual boundary layer moisture.

As we enter next week, a 500 mb jet digs down from the Northwest
Territories, bringing a trough and associated cold front
through the region on Tuesday. When looking at the latest
cluster analysis, every cluster has sped up the timing of the
cold front from the previous few days. This would limit diurnal
heating on Tuesday, resulting in much slimmer chances for
thunderstorm development, as the front may be nearly clear of
our FA by early to mid afternoon. Machine learning has backed
off on the idea of strong to severe thunderstorms as well.
Still, it is several days out, so it is worth monitoring to see
if models fall back to a slower timing of the front and thus a
higher chance of thunderstorms.

The bigger story next week then any thunderstorm potential is the
much cooler weather that will filter down starting Tuesday. By
Wednesday, high temperatures will be in the upper 50s to mid
60s. Thursday morning, NBM 25th percentile temperatures drop
into the upper 30s across a good portion of our northern FA. EFI
highlights the core of the coldest weather Wednesday and
Thursday well, along with a return to breezy/windy conditions as
cold air advection overspreads the region. Temperatures will
moderate towards next weekend.

...Thunderstorm chances Today...

This afternoon, the best forcing resides in SD, but a few storms
have managed to from early this afternoon. Environmentally,
shear is weak (< 20 knots), and MLCAPE is on the order of about
1000 J/Kg. Therefore, severe weather is not expected. Instead,
scattered thunderstorms will continue to develop through
sunset, with the main hazard being lightning. With the weak
shear profiles in place today, there is a brief, conditional
funnel threat. As young updrafts go up, surface vorticity will
be stretched, leading to the chance for brief, small funnels to
form. Impacts from these would be very minor. The greatest risk
for this resides in southeastern ND.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1219 PM CDT Fri Aug 29 2025

VFR conditions are expected during the TAF period, with the
exception being if we can get fog to form during the morning
hours of Saturday, much as we saw this morning. In order to try
to indicate when fog is most likely, I put in a 6SM group from
after midnight through early to mid morning Saturday at most
sites. If fog does form and become dense, this is the period
visibility would be reduced, potentially as low as a quarter
mile. Any fog that forms will burn off mid morning Saturday. As
for ceilings and winds, no impacts are anticipated.

&&

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

&&

$$

DISCUSSION...Rafferty
AVIATION...Rafferty