946
FXUS63 KFGF 010423
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1123 PM CDT Mon Aug 31 2026

.KEY MESSAGES...

- Chance for thunderstorms returns mid to late this week. This
  includes potential for strong to severe storms, however,
  confidence remains low regarding details.

- Late summer heat forecast to return this weekend.

&&

.DISCUSSION...
Issued at 231 PM CDT Mon Aug 31 2026

...Synopsis...

Water vapor imagery this afternoon reveals a well defined upper
low in SK/MB, with its southern flank and dry slot over ND.
This is contributing to gusty southwest winds, including 50 mph
gusts in northeast ND this afternoon. This upper low migrates
eastward Tuesday, keeping breezy winds in the forecast Tuesday
afternoon.

Drier, post-frontal air mass behind last night`s cold front
will remain in place over our area Tuesday into Wednesday. Calm,
cool, and likely mostly clear conditions in addition to recent
rainfall will allow potential for fog Tuesday night/Wednesday
morning.

Into mid week around Wednesday, upper ridging begins to build
into the Northern Plains downstream of a longwave upper trough
digging into the Pacific Coast. This will promote moisture
return into the Northern Plains and Upper Midwest late Wednesday
and Thursday. This continues as upper ridging further builds
into the Plains in response to the digging and non-progressive
upper troughing in the West. This will several days of southwest
flow aloft over our region allowing for continued and somewhat
lengthy period of moisture and heat return through late week
into the weekend. This will bring ingredients into the Northern
Plains and Upper Midwest for potential strong to severe storms
as well as late summer heat with potential for minor heat
related impacts.

Ensemble guidance suggests the upper trough and ridge wave
packet breaks down into early next week, which typically would
signal the end of heat and severe potential. However, there are
notable difference between ensemble systems in how this
breakdown evolves - thus confidence in the extended forecast is
low.

...Gusty winds this afternoon...

A tightened surface pressure gradient collocated with
relatively deep mixing in northeast ND is allowing for southwest
wind gusts 40-50 mph. This is expected to continue through the
afternoon until around sunset when deep daytime mixing begins to
cease. Wind gusts will rapidly dwindle, although breezy winds
10-15 mph are expected to continue through the overnight. While
40-50 mph gusts are not typically impactful for northeast ND,
seasonal factors like full foliage on trees, as well as this
area not experiencing these longer duration high of gusts in
over a month or two will contribute to bring low impacts from
gusty winds. A Wind Advisory will remain in effect until 7 PM
for this area.


...Potential strong to severe storms mid to late this week...

Starting late Wednesday into Thursday, several model guidance
systems bring one or more shortwave impulses within the initial
surge of southwest flow aloft as the upper ridge brings to
build. This also houses increasing overall moisture that remains
pooled in the southern half of the CONUS along with steepening
lapse rates aloft sourced from the Central Rockies. Guidance
brings low but sufficient parameter spacing with respect to
instability and shear late Wednesday to early Thursday
timeframe. This lends some credence in strong to severe storms
being more on the lower end of severity, as well as likelihood
of storms being elevated bringing hail to the forefront of
potential hazards.

Overall, there are no glaring signals for significant severe
weather despite there being several opportunities for
ingredients for severe weather to come together mid to late this
week. This is backed by ML/AI guidance highlighting our region
late Wednesday through Saturday for severe potential.

It is worth noting this pattern could result in locally heavy
rain and potential for flash flooding given the longer duration
of moisture flow and an upper pattern that is non-progressive
potentially allowing for several shortwave impulses to traverse
through our region. Confidence in this is low, however, as there
are unknown mesoscale influences that are necessary for flash
flooding yet to be correctly resolved by modeled guidance.

...Late summer-like heat this weekend...

Ensemble guidance strongly suggests in strong upper ridging
into the Upper Midwest this weekend. This will promote
increasing temperatures aloft, as well as the migration and
pooling of moisture near the surface. This will not only allow
opportunity for 90s back into the forecast, but also high
humidity. As of now, Friday and Saturday look to be the days
where these two may align to bring heat indices well into the
90s, and perhaps into the low 100s (10 percent chance of
occurring). While Saturday looks to be hottest within the
forecast period, this could also extend into Sunday, although
confidence is low in this.

&&

.AVIATION /04Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1123 PM CDT Mon Aug 31 2026

VFR/clear skies overnight with some high clouds skirting the
SD/ND border and working east through the night. Winds 5-10kts
overnight and 10-15kts from 15-23z with gusts up to 20kts during
that midday period. Winds tomorrow night going light as high
pressure settles in overhead.

&&

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

&&

$$

DISCUSSION...CJ
AVIATION...TT