494
FXUS63 KABR 111729 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1229 PM CDT Mon Aug 11 2025

.KEY MESSAGES...

- Smoke (aloft and near-surface) from Canadian wildfires will
gradually migrate out of the forecast area during the morning.

- Storms (20-40%) will line up along a fast moving front this
afternoon and evening, mainly across the northern tier of the state.
Could be some small hail and gusty winds associated with this
convection.

- Shower and thunderstorm chances, along with severe thunderstorm
potential look to increase Wednesday.

- Heat and humidity return for Thursday with heat index values
approaching 100 degrees in central SD.

&&

.UPDATE...
Issued at 1222 PM CDT Mon Aug 11 2025

Updated discussion for the 18Z TAFs below.

UPDATE Issued at 1018 AM CDT Mon Aug 11 2025

Satellite indicates smoke continuing over the CWA with the
thickest smoke along and east of the Missouri River. Latest obs
indicate near surface smoke over the area with visibilities
ranging from 3 to 5 miles. HRRR near surface smoke continues to
indicate this smoke pushing eastward through the day with most of
it out of our area by this evening. Otherwise, showers and
thunderstorms are still possible late this afternoon through this
evening (mainly north of highway 212) as a surface cold front
will push northwest to southeast over the CWA. Other than slight
tweaks to the sky grids, the forecast remains on track.

&&

.DISCUSSION...
Issued at 236 AM CDT Mon Aug 11 2025

Smoke this morning, with visibilities between three and five miles
along with low dew point depression so potentially some fog mixing
in. HRRR and RAP models depict this pocket of smoke slowly migrating
NE through the course of the morning hours, and mainly out of the
CWA by midday to mid afternoon. That is ahead of a front that will
provide the focus for showers and storms. nam bufkit profiles depict
storms with bases AOA 8000 feet with deep dry layers and skinny cape
along with unidirectional mid level flow. Could be a marginal wind
threat as DCAPE values in the nam top out around 1800 joules per
kilogram.

As for temperatures today, favorable mixing winds (southwesterly)
ahead of the front and warming mid level air, Would expect to
overachieve in comparison to nbm, however we`ll still need to
contend with smoke potentially negating that favorable mixing.

A cooler air mass returns for Tuesday, but this time the RAP/HRRR
send most of the smoke through North Dakota into Minnesota bypassing
much of the CWA.

The upper trough moves east with a wave moving in from the west
Wednesday. Strong mid level warm advection accompanies that feature
and then sticks around through the rest of the week/weekend with 700
temperatures as warm as +16C. This initial mid level warm advection
push will provide the impetus for showers and storms early Wednesday
with a 40kt low level jet pointed into central SD, but also for
surface based storms later in the day as a weak low develops in
central SD. Potential convection continues east as the low level
jet reorganizes Wednesday night.

The core of warmest air in the extended, and thus forecast
temperatures is Thursday at which point we`ll also be seeing dew
points well into the 60s to around 70 for the James River valley and
Point east. Heat index values in the NBM approach 100 in central SD.

The rest of the extended, while there remains warm air aloft (NAEFS
700mb temps > 1 standard deviation), deterministic models hint at
undercutting that warm air. Given uncertainty with the depth of the
cool air and timing of any backdoor fronts will stick with NBM
temperatures, though the caveat here is that there is a 10F spread
between the 25/75 box & whiskers ranges.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1222 PM CDT Mon Aug 11 2025

Terminals KABR,KATY,KPIR,KMBG

MVFR VISBY with smoke/haze continues over the James River Valley
and eastward before the smoke will move out of the region by late
this afternoon or evening. A front will lead to the chance of
weak showers and thunderstorms this afternoon and evening,
therefore, added a PROB30 for KABR/KATY for this potential as the
front pushes southeast through the area.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...MMM
DISCUSSION...07
AVIATION...MMM