157
FXUS63 KFGF 281132
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
632 AM CDT Sat Jun 28 2025

.KEY MESSAGES...

- There is a 2 out of 5 risk for severe thunderstorms this
  afternoon and evening in west-central Minnesota.

&&

.UPDATE...
Issued at 632AM CDT Sat Jun 28 2025

The overnight showers/thunderstorms have move out of our CWA,
while the LLJ has weakened and shifted south. The main frontal
zone is still south of our CWA and while WAA and elevated
instablity is supporting a few showers/non severe thunderstorms
to the south and west they are struggling to hold together as
the move east and north out of the more favorable air mass where
they are forming. The main focus today will still be on the late
afternoon/evening period as the frontal zone shifts northeast
and briefly stalls near our west central MN counties. No changes
to messaging planned at this time.


&&

.DISCUSSION...
Issued at 346 AM CDT Sat Jun 28 2025

...Synopsis...

Westerly flow is still in place this morning with a mid level wave
exiting to our east this morning. A more organized trough is shown
to kick east across the Canadian prairies later tonight into Sunday.
This deepens as it progresses east Sunday night into Monday with
northwest cyclonic flow eventually developing Monday night. Severe
chances remain in place mainly during the afternoon and evening
period today, though a strong/marginally severe storm has a low
chance of development early this morning. Monday in cyclonic flow
there is a good signal for diurnal showers and embedded/scattered
thunderstorms. Marginal thermodynamic profiles and weak shear lower
probs for severe, though a few strong storms may develop during
those periods in MN. Riding amplifies Tuesday through Thursday
lowering the predictability/potential for thunderstorms. There is
more spread in the evolution of the pattern between ensemble
clusters next weekend as the ridge breaks down and westerly flow
develops, which would allow for progressive waves.

...Strong storm potential early this morning...

A LLJ and axis of WAA remains in place while the main mid level
wave is progressing eastward. Low levels are decoupled, but
elevated instability (1000-1500 J/KG) remains in place with strong
effective shear. Instabilty has been on a decreasing trend and
shower/thunderstorm clusters have been trending away from the main
instability axis. However, there is still a window for a few strong
cores to develop before 8AM with hail to the size of nickels the
main threat. Consensus of latest CAMs favor a lull in activity after
the early morning showers/storms end through 18Z.

...Severe potential this afternoon and evening...

A warm frontal zone is still shown to be the main focus for
organized severe development later this afternoon and evening during
peak heating, with guidances showing this right along our southeast
CWA (uncomfortably close). This allows for a window in the 4-8pm
period for potential supercell development in our far west-central
MN counties, and we`ll want to monitor the frontal position this
afternoon for that narrow corridor in our southeast. While left
movers may be favored based on the current simulations of CAMs in
our CWA, the position of the front is too close to rule out a
tornado threat and all hazards would be possible.

Farther north of this front there will be enough instability and
effective shear to support isolated severe convection.
Coverage/location would be less certain and there is more spread in
the signal for this between CAMs run-run. Hail to 1.5" would be
the main threat before sunset.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 632 AM CDT Sat Jun 28 2025

VFR conditions should prevail across eastern ND and northwest
MN, with light southerly winds 10kt or less. The main aviation
impact will once again be from thunderstorm activity, however
coverage today is going to be more isolated to scattered in
nature (20-30% chance) at each terminal and confidence was too
low to pin down one period to highlight. Best coverage will tend
to be along a front in northeast SD and west central MN (south
of our TAF sites). Will need to monitor and amend as activity
develops and tracks through the region later today.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...DJR
AVIATION...DJR