781
FXUS63 KFGF 040439
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1139 PM CDT Thu Jul 3 2025

.KEY MESSAGES...

- There is a level 2 out of 5 risk for severe storms tonight
  into early Friday morning for northeast North Dakota into
  northwest Minnesota. The main hazard with these storms will be
  winds to 70 mph.

- There is a level 1 out of 5 risk for severe storms in the
  afternoon and evening Friday, Independence Day. Main hazards
  will be flash flooding, wind gusts to 60 mph, and hail to the
  size of quarters. A few tornadoes will be possible early to
  mid afternoon.

- Heat-related impacts Friday, Independence Day, due to high
  humidity and heat.

&&

.UPDATE...
Issued at 1139 PM CDT Thu Jul 3 2025

Starting to get some convection developing in our far
northwestern counties as the low level jet strengthens.
Thunderstorm complex in southwestern Manitoba also continues to
slowly ooze southeastward in our direction. Lightning activity
with the newly developed storms in Cavalier county indicate a
strengthening trend. Severe threat is not over, and could still
see the potential for some damaging wind threats across our
northern tier as we head into the overnight hours.

UPDATE
Issued at 949 PM CDT Thu Jul 3 2025

Convection in western ND is starting to sustain itself a bit
more and slowly move east. Also a supercell along the
Saskatchewan/Manitoba border that has been building southeast so
will have to watch as it gets closer to Towner county. So far,
seems on track for most of our convective activity to be after
midnight. Made some minor tweaks for the POPs overnight, but see
little reason to change any of the messaging we have going.

UPDATE
Issued at 644 PM CDT Thu Jul 3 2025

A few sprinkles over west central MN as a weakening MCV moves
through, but otherwise a waiting game as robust convection is
starting to develop near the MT border. Still looking like most
of our activity will be later tonight into the overnight period
as western convection moves our direction and the low level jet
ramps up.

&&

.DISCUSSION...
Issued at 204 PM CDT Thu Jul 3 2025

...Synopsis...

Upper ridge continues to center itself over the Northern Plains
before shifting eastward into the Upper Midwest and western
Great Lakes by Saturday. Several smaller mid level waves will
move through the flow aloft, providing intermittent periods of
forcing for ascent. In the lower levels, southerly flow
continues to advect rich moisture into the region from the
south. This beneath steeper lapse rates will contribute to
increasing instability. A surface trough/frontal boundary will
move eastward, draped across eastern ND into northwest MN by the
afternoon Friday, Independence Day. This will serve as focus for
numerous thunderstorms to develop upon. Eventual movement toward
the east through the afternoon into early evening is expected.
The increasing instability, moisture, and sufficient shear will
introduce potential for strong to severe thunderstorms, as well
as potential for flash flooding. Additionally, heat-related
impacts will occur in portions of eastern ND into MN Friday,
Independence Day.

By Saturday, the frontal boundary pushes east of our area, along
with the rich moisture and instability. Upper flow becomes more
zonal to northwesterly, lessening chance for widespread severe
thunderstorms and heat-related impacts through Sunday. There is
potential for strong to severe storms Monday as sufficient
instability may move into ND and MN as a relatively stout mid
level wave moves through.

Further into next week, ensembles suggest the flow aloft remains
zonal to northwesterly. This promotes near average temperatures
and average to slightly below average precipitation chances.
There are no signals for widespread severe weather mid to late
next week at this time.

Ahead (east) of the boundary, temperatures into the 90s and very
high humidity will contribute to heat indices around 100F.
Sunshine and relatively light winds will also contribute further
for potential heat-related impacts, leading to Extreme values in
the Wet-Bulb Globe Temperature categories.


... Severe storm potential tonight/Independence Day ...

This afternoon, a small scale system (known as a mesoscale
convective vortex / MCV) is making its way eastward along the
I-94 corridor. This will persist east into Minnesota as the
afternoon continues. Moderate instability exists within and
ahead of this MCV exists, presenting a low confidence chance for
potential thunderstorm development in west-central MN this
afternoon. Should thunderstorms develop, they will have a chance
to become severe bringing gusty winds to 70 mph, hail, and
perhaps a tornado. Again, confidence is low on this potential,
but does bare watching as MCV are notorious for sparking
thunderstorms in spite of modeled guidance suggesting
otherwise, while also increasing shear to organize
thunderstorms.

Later tonight, modeled guidance continues to suggest potential
for thunderstorms that develop in western ND to move east-
northeast tonight into northeast ND as well as potentially
northwest MN. The most likely scenario depicts a complex of
thunderstorms to move into northeast ND starting around
midnight, moving through the Devils Lake basin and into the
northern Red River Valley before pushing into north-central MN
or ON by sunrise Friday. These thunderstorms may be strong to
severe bringing gusty winds as high as 70 mph. Should storms
move through a bit more discrete, there will be potential for
hail in addition to gusty winds.

For Friday, Independence Day, high instability will develop
along and ahead (east) of the boundary given such rich low
level moisture and increasing temperatures. While shear will be
low, it is sufficient for some thunderstorm organization to
introduce potential for hail to the size of quarters. Steep
lapse rates in the low levels will also allow for increased
DCAPE, introducing potential for gusty winds to 60 mph.

Probably more in the forefront of potential impacts will be the
flash flooding threat. Rich moisture, high instability, and
boundary-parallel flow introduces the likelihood of efficient
rain producing thunderstorms as well as training of
thunderstorms. This will contribute to high rain rates,
potentially as high as 2-3 inches per hour. Widespread coverage
of thunderstorms will also bring the flash flood potential over
a large portion of eastern ND into MN. General amounts of 1-3
inches can be expected, with locally highest amounts to around 6
inches (20% chance of occurring). Urban areas will be most
susceptible to flash flooding.

Timing of severe storms and flooding potential could start as
early as 2 PM, lasting through most of the afternoon,
potentially into the early afternoon, while gradually pushing to
the east into central MN.

... Heat-related impacts Independence Day ...

Ahead (east) of the boundary, temperatures into the 90s and very
high humidity (dew points in the mid to upper 70s) will
contribute to heat indices around 100F. Sunshine and relatively
light winds will also contribute further for potential heat-
related impacts, leading to Extreme values in the Wet-Bulb Globe
Temperature categories.

Potential for heat-related impacts maximizes early afternoon
before thunderstorms either move over locations and/or cast
their shadows to mitigate compounding-impact of heat from
sunshine. However, due to such high humidity, potential for
impacts will start in the morning.

With many of the population likely spending time outside for
Independence Day activities, there is potential for above
average impact potential compared to a non-holiday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1139 PM CDT Thu Jul 3 2025

Convection so far has stayed north and west of the TAF sites,
although still a chance that KDVL area could see some
development or storms moving in after 06Z. That airport has the
best chances for seeing storms as well as low level wind shear
as the jet strengthens over the area. A bit of a break during
the morning hours, then thunderstorms redevelop during the
afternoon and evening, this time over a wider part of our
forecast area. Have VCTS at most sites by the end of the period,
perhaps weakening to VCSH after 00Z. Winds will shift
southwestward and then to the northwest as a cold front starts
to drop down into the Red River Valley.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Heat Advisory from 11 AM to 7 PM CDT Friday for NDZ027-029-030-
     038-039-049-052-053.
MN...Heat Advisory from 11 AM to 7 PM CDT Friday for MNZ001>003-
     005>009-013>017-022>024-027>032-040.

&&

$$

UPDATE...JR
DISCUSSION...CJ
AVIATION...JR