007
FXUS63 KFGF 300449
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1149 PM CDT Tue Jul 29 2025

.KEY MESSAGES...

- Prolonged period of wildfire smoke will degrade air quality
  through the majority of the week.

&&

.UPDATE...
Issued at 1146 PM CDT Tue Jul 29 2025

Widely scattered light rain showers are being observed in
eastern North Dakota, with around 30% chance these continue
until around 4 AM as they slowly migrate southward.

Smoke continues across the region, densest in northwest
Minnesota into the northern Red River Valley.

UPDATE
Issued at 739 PM CDT Tue Jul 29 2025

Lingering shower activity in northeast ND and northern Red River
Valley has since diminished. There is still a 30% chance for
additional showers in North Dakota before midnight.

Smoke continues to be the main weather story, with degraded air
quality and reduced visibility expected to linger for several
days across the region. This is expected to be a protracted
smoke event for our region.

&&

.DISCUSSION...
Issued at 739 PM CDT Tue Jul 29 2025

...Synopsis...

18z surface analysis indicates a broad surface high across
central Saskatchewan with water vapor indicating upstream
ridging pushing in to replace longwave troughing that has been
impacting us for the last several days. Flow with this ridge is
very weak so shear profiles over the next several days will be
very low. Instability will be heavily tied to diurnal
destabilization and organized activity will remain unlikely.
Thanks to large scale ridging and a lack of instability, AI and
ML products for severe storms are not cropping up for our area
through the next 6 days with a broad swath of potential cropping
up by next Tuesday, however this is more due to ridge breakdown
potential towards the end of the period and indicative of high
uncertainty in location as the swath is across the entire CONUS
east of the Rockies. As such, the probabilities for severe
weather are low at this time. With the lingering northwest flow
through the forecast period, expect periods of smoke to arise
and impact visibility at times.

...Prolonged period of degraded air quality...

Wildfire smoke has infiltrated the region as air mass over
Canada holding smoke continues to migrate southward over the
Northern Plains and Upper Midwest. Expansive and slow moving
high pressure at the surface and northwesterly flow aloft will
continue to feed and trap wildfire smoke from SK/MB within the
surface high. This feature will also serve to help bring smoke
aloft toward the surface, in addition to daytime mixing each day.
This is also being illustrated in available smoke guidance.

Given the slow movement of the surface high pressure housing
smoke, this is expected to be a protracted smoke event lasting
through at least Saturday, degrading air quality throughout its
entirety. Smoke will be dense enough to impact all populations,
although there are anticipated to be brief respite periods
intermixed within the overall event across the region,
especially the further into the future beyond available
guidance. This is due to unknowns on fire activity and resultant
smoke production as well as how diurnal cycle will influence
smoke concentrations - smoke relatively denser during early
morning versus daytime mixing perhaps thinning out smoke some.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1146 PM CDT Tue Jul 29 2025

Main impact to aviation within the region will be smoke both
aloft and near the surface. Long duration smoke event will
reduce visibility less than 6SM for most locations, perhaps as
low as 2SM (low confidence in location or occurrence of this,
however). There may be some relatively brief periods where
visibility is greater than 6SM, although not reflected in TAFs
given low confidence in location and timeframe of these
respites.

Otherwise, winds will be calm and variable overnight tonight
before increasing to around 10kt out of the northeast Wednesday.

The previously mentioned low chance for fog potentially
impacting KDVL has since lowered even further to below 10%.

&&

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

&&

$$

UPDATE...CJ
DISCUSSION...CJ/Perroux
AVIATION...CJ