629
FXUS63 KFGF 292058
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
358 PM CDT Sun Jun 29 2025

.KEY MESSAGES...

- Scattered thunderstorms are expected Monday afternoon.
  Lightning and hail to the size of nickels would be the main
  threats with stronger storms.

- Severe thunderstorm chances return Independence Day (Friday)
  into next weekend to parts of the region.

&&

.DISCUSSION...
Issued at 358 PM CDT Sun Jun 29 2025

...Synopsis...

Mid level troughing continues to move from northwest to southeast
this afternoon. Northwest flow prevails at the H5 level, with a
slightly drier airmass settling into the region. For Monday, another
chance for showers and isolated thunderstorms is possible along the
trailing side of the departing trough. There could be just enough
instability to allow a mention of small hail; however, most activity
will be on the weaker side. Ridging builds into the Northern Plains
and Upper Midwest starting late Tuesday, with the axis centered over
the area by early Thursday. This will allow at least some moisture
return into the area ahead of another mid level trough that is
expected to traverse the region over the July 4th weekend. As the
ridge flattens and the trough deepens, we could see an opportunity
for strong thunderstorms as well as the potential for heat impacts.

...Isolated Strong Storms Possible Monday Afternoon...

There is a low chance for the development of a few stronger storms
Monday afternoon as a mid level shortwave continues to work eastward
into the Upper Midwest. Low level lapse rates will be favorable for
convective activity, but lose intensity in the mid levels. MLCAPE is
showing in the range of 900-1500 J/Kg, with shear profiles only
marginally supportive of organized convection. The primary risk will
be lightning, but a few stronger cells could produce near-severe
hail during peak afternoon heating. Atmospheric support for
thunderstorm activity falls significantly as sunset approaches and
the mid levels decouple from the better lapse rates near the surface.

...Severe T-Storm Potential for Independence Day Weekend...

H5 ridging weakens late this week and into the weekend, giving way
to a more active pattern out of the west to southwest. Moisture
return increases Thursday into Friday with dew points climbing into
the upper 60s to near 70 degrees by Friday afternoon. This return
flow will be ahead of a cold front and relatively sharp theta-e
gradient. While timing is still uncertain, this setup certainly
supports the potential for severe thunderstorm development during
the afternoon and evening of July 4th and into Saturday as well.
Ensembles show an 80 percent chance for CAPE values greater than
2000 J/Kg and a 50 percent chance for CAPE values in excess of 3000
J/Kg. At this distance, confidence in thunderstorm mode is somewhat
low, with soundings suggesting support for all modes, but favoring
hybrid clusters and linear line segments.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1230 PM CDT Sun Jun 29 2025

VFR conditions prevail at all sites through the period. Look for
an increase in cloud cover with the potential for a scattered
shower or thunderstorm during the late overnight hours into
Monday morning. Better chances are in the forecast further into
Monday, primarily for KBJI, with slightly lower chances at KGFK
and KFAR. Will continue to update as confidence grows, but at
this time, projected coverage looks too inconsistent to include
in the TAFs.

&&

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

&&

$$

DISCUSSION...Lynch
AVIATION...Lynch