011
FXUS63 KFGF 190518
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1218 AM CDT Thu Jun 19 2025

.KEY MESSAGES...

- Isolated severe thunderstorms possible this afternoon and
  evening, with additional activity possible Thursday afternoon.
  There is a 1 of 5 risk both days.

- Scattered severe thunderstorms are possible Friday afternoon
  and evening. Risk level will be 2 of 5 as more widespread
  activity is expected.

- Heat index values this weekend could exceed 100 degrees in
  the southern Red River Valley and portions of west central and
  northwest Minnesota. Heat related impacts are possible.

&&

.UPDATE...
Issued at 1213 AM CDT Thu Jun 19 2025

Scattered thunderstorms still meander generally eastward
tonight. Severe weather is not anticipated, although gusty winds
to 50 mph and small, sub-severe hail may still occur before 2
AM. General decrease trend in overall coverage of thunderstorms
are forecast through tonight, with only showers and/or weak
storms by sunrise.

&&

.DISCUSSION...
Issued at 438 PM CDT Wed Jun 18 2025

...Synopsis...

An active pattern prevails through at least Sunday as several H7
shortwaves traverse an increasingly southwesterly H5 flow pattern.
With each shortwave passage, there will be a chance of
thunderstorms, with severe storms possible nearly each day.
Temperatures will be on the increase through Sunday, with widespread
90 degree highs this weekend. Heat index values have a 70 percent
chance to exceed 100 degrees on Saturday and about a 40 percent
chance for Sunday. Look for much cooler temperatures from Monday
through Wednesday, with near normal highs in the 70s.

...Isolated Severe Storms This Afternoon and Evening...

Scattered showers with isolated strong to severe thunderstorms are
expected this afternoon and evening along a weak boundary. Looking
at mostly disorganized clusters of storms, with soundings supportive
of brief downburst winds and hail up to 1 inch. Storms should be
able to become surface based, with near adiabatic lapse rates and
CAPE upwards of 2000 J/Kg, and DCAPE generally just under 1000 J/Kg.
Low level flow is rather weak; however shear in the 0-3 Km layer
does provide some support for slightly larger hail.

...Isolated Severe Storms Possible Thurs Afternoon and Evening...

For Thursday, another round of strong to severe storms are possible
during the afternoon and evening. A nearly stationary boundary
provides an axis of development in an environment where MLCAPE
values will be upwards of 3000 J/Kg. Shear will be more supportive
of organized storms, perhaps brief supercells or hybrid supercell
clusters.

...Scattered Severe Storms Possible Friday Afternoon and Evening...

The severe thunderstorm environment on Friday will be favorable for
supercell development along a theta-e gradient boundary. This will
lift northward into southern Red River Valley and into west central
and northwest Minnesota during the afternoon. Along the boundary,
modeled SBCAPE is showing up as high as 4500 J/Kg. Dew points have
been modeled a bit high thus far, which could be elevating that
number a bit; however, even in scenarios where SBCAPE is 2500
to 3500 J/Kg, supercells are still supported and will be able to
produce all hazards. Deep layer shear, as well as long
hodographs, support a mention of large hail, with low to mid
level shear supportive of damaging wind gusts and a few
tornadoes.

...Heat Impacts Possible This Weekend...

Dew points continue to increase Saturday into Sunday beneath
shortwave ridging. Temperatures during the afternoon and evening are
likely to reach at least the upper 80s, with low to mid 90s
supported for much of the southern Red River Valley. Heat index
values are expected to reach upwards of 100 degrees or slightly
higher both Saturday and Sunday afternoon. A cold front begins
pushing across the area Sunday, which will shift the higher heat
indices eastward slightly during the afternoon.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1213 AM CDT Thu Jun 19 2025

Scattered thunderstorms are still in the region through at least
07Z, with KGFK, KTVF, and KBJI holding -TSRA/VCTS in the TAF.
Thunderstorms will bring variable winds, gusting 15-25kt.
Otherwise, VFR conditions will prevail along with light and
variable winds under 5kt.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Extreme Heat Watch from Saturday afternoon through Sunday
     evening for NDZ052-053.
MN...Extreme Heat Watch from Sunday afternoon through Sunday
     evening for MNZ006-009-016-017-022>024-027-028.
     Extreme Heat Watch from Saturday afternoon through Sunday
     evening for MNZ029>032-040.

&&

$$

UPDATE...CJ/Lynch
DISCUSSION...Lynch
AVIATION...CJ