702
FXUS63 KABR 011526 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1026 AM CDT Tue Sep 1 2026

.KEY MESSAGES...

- Showers move through the area today and tonight. The
  probability of 1" of moisture is about 30% across central
  South Dakota, with about a 30-40% chance for 1/4" for
  northeast South Dakota. The least amount of moisture is
  expected across north central South Dakota.

- There is a marginal (1 of 5) and slight risk (2 of 5) in place
  along and south of Highway 212 from Pierre east. The main
  threats are high winds (60 to 75 mph) and large hail (around
  golf-ball sized) in the highlighted area.

- Above normal temperatures (+5 to +10 degrees) continue through
  the week, peaking at 10 to 20 degrees above normal
  Friday/Saturday.

&&

.UPDATE...
Issued at 1019 AM CDT Tue Sep 1 2026

Current temps remain cool ranging in the upper 60s to the lower
70s and dewpoints in the 50s to around 60. Mid to high clouds
currently reside over the CWA as the negative tilted upper level
shortwave is currently over CO/WY, extending northeastward
through KY/SD per water vapor imagery/RAP model. Radar indicates
a northwest to southeast oriented band of rain extending from
south central through southeastern SD tracking northeastward per
this mid level moisture. Through the afternoon and into this
evening, additional development of showers and thunderstorms are
expected over the CWA with the potential for severe weather
over portions of south central through east central SD this
afternoon and evening. Besides updating current pops, the
forecast remains on track.

&&

.DISCUSSION...
Issued at 156 AM CDT Tue Sep 1 2026

Negatively tilted trough coming up from the south brings in a plume
of moisture from the Intermountain West. BUFKIT profiles are mainly
moist adiabatic, with the GEFS/EC PWATS right at about or a little
shy of 2 standard deviations above climo.  Best forcing is centered
around 600mb in an east-west axis that lifts north across the area
during the day. After that, a north-south oriented wave embedded
within southwest flow aloft provides additional forcing. CAMS
highlight this area for stronger convection with this wave. There is
an axis of instability but the GFS/NAM both have this axis
south of the CWA with limited elevated instability over us (NAM
peaks at about 500j/kg MUCAPE). It comes down to the very high
shear within this environment. 0-6km shear is about 50kts with
REFS paintballs for 2-5km helicity and 10m wind speeds
highlighted in the latest SPC risk area. Thus, a high shear low
CAPE setup.

In the wake of the system, with high pressure overhead and to
the northeast, light northeasterly flow and recent moisture
means the potential for fog. CAMS are highlighting the upslope
areas of the Sisseton hills.

We remain in a southwest flow regime in the wake of this system.
There is another southwest flow wave, albeit much weaker, for
Wednesday night. With such a weak system, NBM is only carrying about
a 20-40% chance for weather.  NAM BUFKIT profiles show skinny CAPE
but another favorable shear dynamic across the northeast.

An upper trough over the Pacific Northwest sits and deepens for the
rest of the week and into the weekend, building/intensifying the
ridge aloft. 700mb temperatures are running at about a standard
deviation above climo for the latter half of week and through the
weekend. The GFS/EC do bring a backdoor front/cooler low level
airmass down into the region early next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 636 AM CDT Tue Sep 1 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. KPIR has the greatest
chance for seeing storms, slightly less so for KATY and with the
lowest probability being KMBG. Winds should be easterly, so once
we get some moisture and clear out, there could be some fog for
KATY at around 12Z/end of the TAF period.

&&

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

&&

$$

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