843
FXUS63 KFGF 050904
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
404 AM CDT Fri Sep 5 2025

.KEY MESSAGES...

- Widespread frost potential Saturday late night into early
  Sunday.

&&

.DISCUSSION...
Issued at 347 AM CDT Fri Sep 5 2025

...Synopsis...


Large 500 mb over northern Ontario north of Lake Superior will
be the main factor in our weather today and Saturday. Clouds
will rotate around the upper low thru today into Saturday, aided
by another 500 mb vort max that will move south thru the RRV
Saturday daytime. Enough moisture in the 900-700 mb layer and
enough cool air aloft to generate a few showers, esp this
afternoon and again Saturday with the short wave, with higher
chances being in NW Minnesota. Based on current obs showing
sprinkles, brief light showers currently collab with neighboring
offices yielded a slight chc of showers anytime today (Friday),
though bit higher chance up toward Lake of the Woods closer to
upper low. I did introduce some slight chance shower chances
Saturday, mainly afternoon back into the northern and central
RRV and thru NW MN. While NBM isnt picking up on it well, most
models, esp the ECMWF and some CAMS indicate spotty showers
Satuday with short wave dropping south. Seems reasonable. Breezy
thru the period, but well below any advisory levels.

Highs today in the mid to upper 50s, with these temperatures in
some cases near the coldest max temps for Sept 5th. Forecast
highs for Grand Forks and Fargo suggest about 1-2 degrees above
the record though. A couple degrees warmer Saturday.


...Frost Potential...

For late tonight/early Sat AM excpectation is clouds will be
around many areas. There will be clear bands though with some
risk of low temps near 35 in parts of NW MN in that region from
Roseau to Park Rapids, if that area can clear out. Otherwise
position of high to our west will bring coldest readings to
western ND.

For late Saturday night/early Sunday AM, high pressure ridge
will be from southwest Manitoba into eastern South Dakota. Thus
the highest chance for a clear sky and light winds will be
eastern ND into west central MN. But also 925 mb temps Sat night
will be 2-3 degrees warmer than those on Wed night/Thu AM. So it
will be pure radiational cooling to get temps down into frost
levels. Chances for more widespread 34-36 degree low temps are
higher based on what should be more widespread clearing. But
warmer temps in the boundary layer says cooling may be limited
to some degree with below 32F temps 10 pct or less of a chance.


Looking ahead into next week...warming up but will wait til
Tuesday and beyond as upper ridge builds into central Canada and
the central U.S. Trough develops in western US. Increasing
warmth and generally extended period of southerly flow will
provide additional period of showers and thunderstorms, becoming
relatively more likely late next week after established
southerly flow has given enough time for sufficiently increasing
moisture content. At this time, there are no signals for severe
weather within the predictability horizon into late next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1120 PM CDT Thu Sep 4 2025

Recent observations and latest model guidance has become a bit
more optimistic in ceilings through Friday morning. Maintained
MVFR for all sites through at least early morning, but VFR
should return mid to late morning at all sites. The lone
exception is KBJI, where MVFR will persist into the afternoon.
Winds have really calmed down, and should remain under 10 knots
until Friday morning, when gusts back up to about 25 knots will
again occur, persisting through the afternoon. Gusts will wane
by the end of the TAF period, with ceilings breaking up into a
VFR SCT deck.

&&

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

&&

$$

DISCUSSION...DJR
AVIATION...Rafferty