115
FXUS63 KFGF 262333
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
633 PM CDT Sat Jul 26 2025

.KEY MESSAGES...

- There is a level 2 out of 5 risk for severe thunderstorms
  later this evening into early morning hours Sunday. The main
  hazards will be wind to 70 mph, hail to size of ping pong
  balls, isolated tornadoes, and localized flash flooding.

- There is a level 1 out of 5 risk for severe thunderstorms
  Sunday. The main hazards will be gusty winds to 70 mph, hail
  to the size of ping pong balls, and flash flooding.

- Heat related impacts are expected this afternoon and early
  evening for eastern North Dakota into Minnesota. Heat impacts
  are expected again Sunday afternoon across southeast North
  Dakota and west central Minnesota.

&&

.UPDATE...
Issued at 633 PM CDT Sat Jul 26 2025

Convection continues to develop in the SD and NE this evening.
Storms are expected to cluster into a linear complex as we move
through the evening and into the overnight hours. CAMS continue
to have a good handle on the timing of entering ND around 02-04z
and shifting through the CWA through 11-13z. Shear continues to
be weak, but once the LLJ kicks in shear will increase and
storms will be able to maintain their structure as they move
into eastern ND and NW MN overnight. We will continue to
monitor conditions through the evening and overnight. Have
multiple ways to receive alerts and warnings this evening and
especially during the overnight timeframe.

Otherwise it continues to be hot and humid across the area with
dew points in the 70s and temperatures in the 80s to lower 90s.
This has brought heat indices into the upper 90s to lower 100s
this afternoon and evening. Dew points will remain in the 70s
tomorrow afternoon and evening, with temperatures in the 80s to
lower 90s. When headed out stay hydrated!

&&

.DISCUSSION...
Issued at 348 PM CDT Sat Jul 26 2025

...Synopsis...

Southwest flow is in place over the central Rookies with westerly
flow still in place over the Northern Plains, and this pattern is
keeping periodic thunderstorm chances in the forecast through Monday
as progressive waves move through the mid levels and a surface front
gradually shifts south. Ensembles show a strong signal for amplified
ridging by the middle part of the weest to the west and northwest
flow over our region, bringing a period of relief from hotter
temperatures and severe thunderstorm chances. Late next week there
is a bit more spread in the evolution of the pattern as the
mid/upper ridge transitions east with the potential for more waves
moving around the north or western part of the ridge towards our
region. This may bring increasing temperatures and a return to
conditional severe thunderstorm chances by early next week.

...Severe risk late this evening and overnight...

The threat for severe thunderstorms this afternoon and early evening
are much lower due to strong capping, any remnant boundaries where
earlier initiation could occur remaining outside of our CWA, and a
lack of organized synoptic forcing locally.

Our focus then is on later this evening when upstream convective
activity is shown by CAMs to spread northeast towards our CWA as a
mid level shortwave rides out of central Rockies. A deep reservoir of
instability and moisture will be in place ahead of this with strong
deep layer shear due to strong mid level flow,and increasing 0-3km
shear and strongly veered low level flow in response to a
SW/orthogonally orientated 40-50kt LLJ. Upscale growth into a QLCS
type MCS may bring an increased risk for damaging winds to 75 mph,
with isolated tornadoes. Hail may be a secondary threat. CAMs have
locked onto this signal in the 10 PM to 5 AM window (southwest to
northeast progression). The MCS should show weakening trends as it
continues north and east over our CWA becoming elevated, lowering
the magnitude and coverage of impacts (more of a marginal wind
threat if severe risk lingers beyond 4 AM). There are solutions that
show the northwestern evolution of the MCS favoring a backbuilding
signature which could raise the potential for thunderstorm training
and flash flooding if that scenario plays out.

...Severe risk Sunday...

The evolution/coverage of the severe threat Sunday will greatly
depend on the final track/evolution of the weakening MCS earlier in
the morning and any remnant shower/thunderstorm activity in the
morning hours. The main frontal zone is now shown by all guidance to
have shifted to our southern and southeastern CWA, but this position
will ultimately vary. The main mid level wave will have pushed off
to the east, and the question becomes what forcing will be available
for much of our CWA beyond just destabilization near the frontal
zone. The main signal in CAMs favors this frontal zone for new
initialization during peak heating thorugh early evening as CIN
weakens. MLCAPE 2000-3000 J/KG may still be in place in the warm
sector with low level veering hodographs and deep effective
shear 30-40kt. This raises the potential for supercell
development in our east/southeast with all hazards (including
tornadoes) "if" this frontal zone is in place and we have a
period of clearing. HREF members does show some intense UH
tracks quickly moving off this frontal zone within the period of
initiation, matching this idea. However if things remain
elevated or thunderstorms tend to cluster, then impacts would
favor hail/wind and localized flash flooding.

...Heat impacts today and Sunday...

Tds have performed as expected with manly locations in the low to
middle 70s, and stations closer to active agriculture where peak ET
is occuring reporting upper 70s/near 80. Temperatures have been a
little slower to increase, but are heat indicies are approaching 100
and should reach that when highs are achieved in the next 2-3hrs.
The heat advisory continues through 8 PM this evening across our
CWA. On Sunday the frontal zone is farther south with higher
temperatures and dewpoints in southeast ND and west central MN.
Cloud cover from the morning convection and new afternoon convection
could play a role in limiting heat impacts for some locations, but
based on current trends confidence was high enough to issue a new
Heat Advisory for southeast ND and west central MN (near and ahead
of the front) from Noon to 8 PM.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 633 PM CDT Sat Jul 26 2025

Thunderstorm chances increase around 04-05z for FAR and 05-07z
for TVF, GFK, and DVL. BJI sees thunderstorms move through
around the 08-10z timeframe. Some of these storms may be strong
to severe with damaging winds, large hail, and lightning.
Visibility reductions and MVFR to IFR ceilings are expected in
and around any of the thunderstorms that move through.
Thunderstorms should move out of the region around sunrise
(12-15z timeframe). Following the thunderstorms winds will
remain light and variable and skies SCT to BKN. A secondary
round of thunderstorms are possible for GFK, TVF, FAR, and BJI
late tomorrow afternoon and into tomorrow evening.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Heat Advisory until 8 PM CDT this evening for NDZ006>008-
     014>016-024-026>030-038-039-049-052>054.
     Heat Advisory from noon to 8 PM CDT Sunday for NDZ039-049-052-
     053.
MN...Heat Advisory until 8 PM CDT this evening for MNZ001>009-
     013>017-022>024-027>032-040.
     Heat Advisory from noon to 8 PM CDT Sunday for MNZ003-029>032-
     040.

&&

$$

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