255
FXUS63 KFGF 032032
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
332 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.

&&

.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 /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 204 PM CDT Thu Jul 3 2025

VFR conditions are forecast through 18Z Friday. LLWS will
occur between 03Z and 15Z as low level jet develops tonight.
There is a chance for thunderstorms in northeast ND and
northwest MN between 05Z and 12Z. This may impact KDVL, with
VCTS in the forecast to denote most likely timeframe of
thunderstorms. These thunderstorms may be severe with strong,
erratic wind gusts exceeding 45kt.

Winds will generally be out of the southeast to south around
10kt.

Beyond the TAF period, widespread thunderstorms will develop
Friday afternoon and evening across eastern North Dakota into
Minnesota. These storms may be strong to severe as well bringing
gusty winds and hail in addition to excessive lightning. Very
heavy rainfall will also reduce visibility less than 1SM at
times within strongest thunderstorms.

&&

.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.

&&

$$

DISCUSSION...CJ
AVIATION...CJ