307
FXUS63 KFGF 080442
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1142 PM CDT Mon Jul 7 2025

.KEY MESSAGES...

- Severe risk, level 2 out of 5 continues into this evening.
Damaging wing gusts, hail to golf ball size and an isolated
tornado are the main severe threats...

- A severe risk, level 1 out of 5 is possible Wednesday
  afternoon into Wednesday night...

- There is an 80 percent chance for thunderstorms across the
  area Thursday into Thursday night. Storms may be strong to
  severe...

&&

.UPDATE...
Issued at 1101 PM CDT Mon Jul 7 2025

Two areas of thunderstorms continue in portions of the area,
with one up in Roseau and Lake of the Woods counties. Lightning
activity has been fairly steady with this area, with moderate rainfall
rates and potential for small hail. Instability remains around
1000-1500 J/kg with little shear for further development. These
storms will track slowly toward the east over the next several
hours and should remain below severe limits. The other area is
a supercell that has had a history of producing tornadoes in
Polk and Norman counties. We continue to see a weakening trend
with the storm as it moves southeast through Mahnomen and
eventually into Hubbard and Becker counties. Environmental
conditions indicate the storm should continue to weaken over the
course of the next hour or two. We will continue to monitor and
keep an eye on it as it moves southeast. Otherwise, we are
seeing dry conditions across eastern North Dakota. We went ahead
and let the watch expire at 11pm for the remaining four
counties.

UPDATE
Issued at 635 PM CDT Mon Jul 7 2025

We continue to have strong to severe thunderstorms impacting
portions of eastern North Dakota and northwestern Minnesota this
evening. Some of these have been supercellular producing large
hail. Latest report was from the Severe Thunderstorm over
northeastern Grand Forks county moving into northwestern Polk
county of quarter size hail in the city of Manvel. Overall the
environment still remains conducive for strong to severe
thunderstorms through this evening, but we are starting to see a
downward trend in intensity of the current storms. Low and Mid
level lapse rates are slowly diminishing and CAPE is trending
downward in parts of the area. Ramsey, Cavalier, and Towner
counties have been removed from the Severe Thunderstorm Watch
and the rest of the counties in the watch remain through 10pm.

&&

.DISCUSSION...
Issued at 433 PM CDT Mon Jul 7 2025

...Synopsis...

Storms developing along and ahead of a frontal boundary moving
through the area this afternoon and evening with severe activity
already occuring and expected through the evening hours. Frontal
boundary moves east into Tuesday with high pressure building
into the region. Another weak shortwave will move through the
area mid-week bringing another round of storm chances and
potential isolated severe storms before a larger storm system
impacts the area Thursday into Friday. This system will bring
more widespread chances for storms and severe weather.

...Severe risk, level 2 out of 5 continues into this evening.
Damaging wing gusts, hail to golf ball size and an isolated
tornado are the main severe threats...

Storms continue to form along and ahead of the cold front
stretching from north to south across northeast ND. Instability
is decent, with deep layer shear in the 35-45kt range. Initially
have the chance for an isolated tornado near the boundary and
closer to the low across the northern forecast area where low
level shear is stronger and greater low level
instability/stretching, etc. A transition to more hail/wind is
expected through the evening and as the front pushes east.

Previous Discussion...
...Wednesday Severe Risk...

Wednesday late aftn/eve will see a short wave move ESE across
the area. The airmass advecting north into the area, esp central
ND, is more unstable with MUCAPES over 3500 j/kg and high temps
in central ND fcst to be low 90s. 0-6 km shear is 30kts or less
though. SPC did insert a marginal risk for eastern and central
ND due to instability being quite high and weak wave moving ESE
thru the area.


...Thursday into Thursday night....

Thursday afternoon and night has for the last several days been
highlighted as the most unstable day in the 7 days. MUCAPE
values from ensembles (EC/GEM,GFS) from 00z runs all over 3500
j/kg with likely over 4000 j/kg. But issue is placement of 500
mb system with this and placement of 500 mb jet. Model
continuity has been poor. Thus question is with all the
instability will there be enough forcing and shear aloft to
generate a higher end severe threat. That remains to be seen.
Given the conditions fcst all hazards would be possible, though
wind/hail favored vs tornado as unsure of any surface boundary
location. We also have some sfc CIN to overcome. But highs are
forecast to be low 90s and dew pts low 70s. If either one can
over achieve that will add to instability.

For Friday and Saturday forecast hangs on development of 500 mb
low and placement and track. GFS been all over the place in the
last 24 hours with ECMWF the most consistent in having upper low
in the area Saturday with persistent area of showers and
t-storms near and just east of the wave over much of the area
Friday. Slower ECMWF would keep rain chance longer into Saturday
vs NBM.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1142 PM CDT Mon Jul 7 2025

Thunderstorms have moved away from the TAF locations this
evening, with drying conditions and SCT clouds. Overnight winds
go light and variable for some locations, while others remain
light out of the north. There is a chance for some patchy fog
overnight within the Red River Valley and into lakes country as
recent rain and light winds may allow for a few patchy dense
locations. This would bring ceilings down to MVFR with potential
IFR in the dense portions of the fog. Otherwise, we expect VFR
conditions post 12z for all TAF locations.

&&

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

&&

$$

UPDATE...Spender
DISCUSSION...MJB
AVIATION...Spender