972
FXUS63 KFGF 301725
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1225 PM CDT Mon Jun 30 2025

.KEY MESSAGES...

- Scattered thunderstorms are expected this afternoon. Lightning
  and hail to the size of pennies would be the main threats with
  stronger storms. Scattered storms possible near Manitoba
  border Tuesday evening.

- Severe thunderstorm chances return Independence Day (Friday)
  late afternoon and night.

&&

.UPDATE...
Issued at 1225 PM CDT Mon Jun 30 2025

Convective showers have developed mainly east of the Red River
this afternoon. Lightning activity thus far has been minimal,
but will likely increase as diurnal heating continues. Scattered
showers with isolated storms will continue through around
sunset before ending this evening. The forecast remains on
track this afternoon.

UPDATE
Issued at 654 AM CDT Mon Jun 30 2025

Initial area of showers that moved down from Manitoba weakening
to sprinkles as they approach Grand Forks. Other showers south
of Winnipeg to Pembina weakening too. As core of 500 mb trough
and cooler temps move thru the RRV and NW MN midday and aftn
scattered showers and t-storms will develop.

&&

.DISCUSSION...
Issued at 338 AM CDT Mon Jun 30 2025

...Synopsis...

This upcoming week will feature a progressive 500 mb pattern
with 500 mb troughs and ridges moving thru the northern tier of
the US and Canada. This will lead to several thunderstorm
chances today and again late Tuesday and late this week.

...Scattered t-storms today...

Well defined 500 mb trough progressing southeast into northeast
and central ND at 08z with a well defined moisture area and an
area of scattered showers/t-storms. T-storms still occurring in
SW MB despite loss of sfc heating. So enough dynamics and cold
pool at 500 mb (-14C) with this to generate showers/t-storms. As
the center of the trough and colder air aloft settles in NW MN
and mid and northern RRV 18z-22z period do expect a decent
coverage of scattered t-storms esp east of DVL-FAR-Wadena line.
0-6 km bulk shear is quite weak 20-25 kts, so organized updrafts
not anticipated with cells more pulsy and updrafts short lived.
MU CAPE in the 800-1100 j/kg range and steep enough lapse rates
to 500 mb to bring the potential for hail to 0.75 inch in a few
storms.

..Chance of t-storms late Tuesday...

Next 500 mb feature is more of a short wave vs trough and will
move into Alberta later today and produce some storms in between
Calgary and Edmonton. This wave is forecast to move into SW MB
around 00z Wed and 0-6km bulk shear with this is 35-40 kts and
MUCAPE again in the 1500 j/kg range in SW Manitoba into far
northeast ND. Thus t-storms should develop and knowing its
northwest flow aloft and with higher instability and shear, a
few storms possible. 00z GFS is most aggressive with this
feature while ECMWF/Canadian a bit tamer and more north toward
Winnipeg. So spread low pops a tad farther south than NBM into
NE ND/NW MN.

...Late week chance of storms...

500 mb ridging builds into the area Thursday-Friday ahead of
next stronger short wave that will move in from California into
the high plains as flow at 500 mb becomes southwest temporarily.
Riding aloft and thermal 850 mb ridge over the area will bring
much warmer temps with highs into the 80s and low 90s Friday the
4th with dew pts likely into the 70s in many areas. NBM
probably a bit low. MUCAPE values could exceed 3000 j/kg (35 pct
chance), but within the 500 mb ridge will be a warm nose at 700
mb with temps 13C. Models disagree with timing of short wave
and associated sfc front/trough moving thru. GFS a tad faster
with system and has more development 18z-21z vs ECMWF has
development farther west in west ND 18z-21z but then develops a
cluster of storms and moves thru 00z-06z. Basic severe weather
parameters would along with machine learning guidance (mostly
from yesterdays models as 00z guidance that far out not in yet)
that severe weather is possible. This would depend though on a
likely the CAP breaking, which is not guaranteed.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1225 PM CDT Mon Jun 30 2025

MVFR conditions prevail at KBJI and KTVF this afternoon with
KFAR going between VFR and MVFR. Look for a continuation of this
pattern through the remainder of the afternoon, with a few
thunderstorms starting to develop through around sunset.
Confidence in any one location or time is somewhat low, but
there should be enough coverage to allow a mention of VCTS for
sites in the Red River Valley as well as northwest Minnesota.

&&

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

&&

$$

UPDATE...Lynch/Riddle
DISCUSSION...Riddle
AVIATION...Lynch