289
FXUS63 KFGF 041222
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
722 AM CDT Mon Aug 4 2025

.KEY MESSAGES...

- Scattered showers and a few thunderstorms today through
  Tuesday. Isolated severe storm possible late Tuesday afternoon
  or evening in eastern North Dakota west of the Red River
  vallely.

- Risk of strong to severe thunderstorms Thursday and Friday.

&&

.UPDATE...
Issued at 720 AM CDT Mon Aug 4 2025

Rain area from Fergus Falls to Grand Forks continues to drift
north and a bit northwest. So will maintain high pops this
corridor. Fortunately the dense fog has remained west of the
fcst area. But do have patchy or areas of fog mentioned in E ND.


&&

.DISCUSSION...
Issued at 326 AM CDT Mon Aug 4 2025

...Synopsis...

An active week ahead as several 500 mb short waves move thru the
area with main 500 mb trough over western Canada.

Scattered showers and a few t-storms today thru Tuesday...

Early this morning we have a very slow moving 500 mb shortwave
in central MN with a short wave trough and deeper moisture noted
from this wave northwest thru ND into south/western
Saskatchewan into central Alberta where main 500 mb low is
located. Little movement overall as blocking 500 mb was located
in west central Manitoba. Weak upper wave will bring continued
moisture with just enough surface instability for a few t-storms
along with scattered showers. HRRR is doing ok early this
morning and does have an area of showers moving slowly north
from Fargo toward Grand Forks thru the morning. With other
scattered showers in NW MN. Other scattered t-storm developmenet
will occur later today in NE ND and NW MN. Considerable cloud
cover today will limit heating and thus MU CAPES will struggle
to get to 500 j/kg.

Tuesday will see the 500 mb ridge in Manitoba move east into
northern Ontario and allow the weak 500 mb wave in MN to drift
north. Thus will continue low precip chances Tuesday. Late in
the day and night showers and t-storm chances increase as the
next 500 mb wave moves into Montana and lifts north into
Saskatchewan with 500 mb trough over western ND Tues aftn/eve
and over E ND/NW MN Tuesday night. Severe storm risk is there
for western half of ND Tues aftn. 850 mb jet increases to 45 kts
Tuesday night with axis of showers and t-storms moving thru. Low
risk of a few severe storms moving into DVL region in the
evening, but predominately the instability will be elevated
Tuesday night with PWATS over 1.5 inches. Thinking main threat
Tues night will be heavy rain. GFS is strongest with 850 mb
winds Tues night and would favor some risk of elevated severe
storms within the larger rain area. ECMWF a bit lower winds at
850 mb and global Canadian has main 850 Mb jet forcing lifting
into southern Manitoba.

...Risk of strong to severe thunderstorms Thursday and Friday...

A brief lull Wednesday, then next 500 mb wave enters Washington
state and northern Idaho Thursday. Ahead of this 500 mb heights
rise and south winds will transport warmer and very humid
airmass northward into the area. MUCAPES look to run well over
3000 j/kg Thursday aftn/eve. Main 500 mb jet is west, but
GFS/ECMWF/Canadian show a lead short wave moving thru 00z-06z.
Probs of sfc CAPE more than 2000 j/kg and 0-6 km bulk shear more
than 30 kts is over 70 pct in the forecast area, near 80 percent
in SE ND. Thus with sufficient shear and instability t-storm
development seems likely though will need to watch capping due
to warm 700 mb temps. Sfc temps near 90 should be able to break
the cap as forcing with short wave is sufficient. Supercells
would seem likely to form or move into the area with all
hazards. Friday aftn/eve will see the main 500 mb wave axis
moves through, with mean ensembles indicating once again 70-80
pct probs of sfc CAPES over 2000 and 0-6 km bulk shear more than
30 kts over the forecast area.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 720 AM CDT Mon Aug 4 2025

IFR ceilings or vsbys for the RRV this morning in light rain and
in DVL area in low clouds/fog. Some improvement this afternoon
with a southeast wind 10-15 kts, gusts 20 kts. TVF/BJI remaining
VFR much of the day as low level moisture will be a lot slower
to get in. TVF airport is more iffy on this vs BJI which for
once will have better weather.

&&

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

&&

$$

UPDATE...Riddle
DISCUSSION...Riddle
AVIATION...Riddle