448
FXUS63 KFGF 021130
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
630 AM CDT Sat Aug 2 2025

.KEY MESSAGES...

- Air quality impacts will continue through Sunday due to
  lingering  wildfire smoke.

- Scattered showers and isolated thunderstorms develop this
  evening and overnight across southeast North Dakota and
  northwest Minnesota, with locally heavy rain and lightning the
  main threats.

- Strong to severe thunderstorm chances return to the region
  next week, especially from Tuesday into the next weekend.

&&

.UPDATE...
Issued at 630 AM CDT Sat Aug 2 2025

Besides smoke aloft, skies remain cloud-free over much of the
region, with mid level clouds increasing in south central ND.
Light fog has contributed to additional vis reductions (3-6sm)
in addition to the smoke, however these are only an aviation
concern at this point. Smoke models continue to indicate some
clearing trends as southerly flow increases in ND, though
impacts may continue to linger in MN closer to the surface high.
Minor adjustments were made to near term trends, otherwise
forecast is on track.
                       &&

.DISCUSSION...
Issued at 322 AM CDT Sat Aug 2 2025

...Synopsis...

Split flow is in place aloft, while surface high pressure
continues to linger over much of our region. The strengthening
of the monsoonal ridge in the southwest US eventually helps
lead to a more organized west to southwest zonal pattern in the
Northern Plains, increasing return flow/instability over our
region and allowing for more energetic mid/upper waves to pass.
There will be daily shower and thunderstorm chances, however the
periods of interest for more impactful weather will be during
the second half of next week.

...Lingering smoke and air quality impacts...

Weaker flow in a less favorable direction is keeping the main
areas of smoke north of our region. However, previous areas of
smoke remain trapped due to the surface high pressure lingering
in place with ongoing air quality impacts. This may continue to
be the case until later Sunday afternoon when surface gradient
finally begins to increase along with south-southeast BL flow.

...Showers and isolated thunderstorms tonight...

A mid level low effectively cutoff over central SD is shown by
guidance to drift east-northeast through the afternoon and
overnight, with CAMs supporting scattered showers and the potential
for a few thunderstorms.  Instability isn`t going to be very high
(MUCAPE 500 J/KG or less) through this evening, though with
southeast flow finally increase Sunday morning it does increase
more towards southeast ND (1000-1500 J/KG) with skinny profiles
supportive of efficient rain processes, but weak shear (less
than 20kt) lowering the probability for severe convection. Due
to the moist air mass associated with this mid level wave and
the low motion of showers locally heavy rainfall may occur with
HREF PMM showing a signal for 1-3" rainfall, though actual point
probabilities for 1"+ are much lower indicating the
isolated/localized nature of the heavy rain threat.

...Strong to severe thunderstorm risk next week...

As a result of increasing flow aloft from the west-southwest,
southerly return flow should increase at the surface with better
instability and deeper moisture pooling over our region next week.
As has been the case, machine learning based systems start to show a
more consistent signal for severe risk during those periods, though
most periods do not show good ensemble consensus on the timing of
progressive mid level waves. Friday into Saturday may be of
particular interest, with increasing ensemble consensus on a
stronger mid/upper trough moving towards the region, though even
with that system there is spread in evolution between clusters
impacting strength/timing. As usual, even with a shift in pattern
supportive of severe risk, actual details at this range
(impacts/severe coverage) carry much lower predictability in this
progressive pattern. It still bares watching, especially the wave
during the late week period.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 630 AM CDT Sat Aug 2 2025

Smoke is lingering over parts of the region, with light fog also
contributing to visibility reductions in the 3-6sm range early
in the TAF period. Fog should clear with daytime mixing, but
smoke may continue to cause similar visibility reductions at
times through the afternoon and possibly longer in MN. Surface
level smoke is most likely to decrease in concentrations enough
for prevailing VFR in ND based on smoke models. South to
southeast winds increase during the day today with highest winds
(15-20kt) in ND during the afternoon, decreasing again near
sunset.

A low pressure system moving out of SD later this afternoon
could bring scattered showers and an isolated thunderstorm to
parts of southeast ND and west central MN late this afternoon
through the overnight period. Best chances at KFAR for VCSH are
currently during the late evening hours. As low level moisture
increases late tonight in response to this low pressure, MVFR
stratus may develop towards KDVL and KFAR, though confidence is
low in impacts before the end of the current TAF period Sunday
morning.

&&

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

&&

$$

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