433
FXUS63 KABR 141121 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
621 AM CDT Mon Jul 14 2025

.KEY MESSAGES...

- Near record heat around 100 degrees expected from Pierre south
this afternoon.

- There is a Marginal Risk (level 1 out of 5) of severe weather for
the afternoon and evening hours Monday and Tuesday. On Tuesday,
there is a Slight Risk (level 2 out of 5) for severe storms south of
Hwy 212. Main threats include hail up to the size of quarters and 60
mph wind gusts.

- Heavy rain is possible along and east of the James River into west
central MN Tuesday through Wednesday.

- There will be a noticeable cool-down midweek with highs
potentially 15 to 20 degrees below normal Wednesday and 10 to 15
degrees below normal Thursday.

&&

.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 431 AM CDT Mon Jul 14 2025

Hot and dry conditions are expected through this afternoon with
temperatures near Pierre and south topping out around the century
mark. Winds and dewpoints in the 50s should keep apparent Ts right
around, or just under, 100 degrees, ie. advisory criteria.

Hi-res CAMs and global models develop weak low pressure across
southwest SD this afternoon. A boundary extends northeast off the
low into central SD after 22z. This boundary should be the focus
point for convection along with some shortwaves that will move
through in the evening. There is a marginal risk for severe
thunderstorms northwest of a line from Victor to Vivian this
evening. Main threats will be strong winds and quarter sized hail.
Bulk shear of 30 to 40 kts with highest values across north central
SD along with CAPE of 2000 to 4000 J/kg will help support storms.
Lapse rates of 7.5 to 8.5 C/km may lead to microbursts. H7 temps of
+13 to +14C across central SD provide a moderate cap, but the very
warm temperatures should help convection to break through the cap.

Low pressure shifts into central SD for Tuesday with a frontal
boundary extending northeast into west central MN. Models have
continued to waffle a little on this boundary placement and where
the best moisture convergence sets up. However, anywhere north of
the boundary, training and slow moving storms, especially when
amplified by shortwave activity, may produce some heavy rain. PWATs
over 1.5 inches are supportive of localized rainfall of 4+ inches,
especially from Brown county east into the Sisseton hills. To the
south, with the boundary, there is a slight risk for severe
thunderstorms that creeps into the southern tier of the cwa with all
threats possible. Strong winds and quarter sized hail remain
possible north of the boundary, as well.

&&

.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 431 AM CDT Mon Jul 14 2025

Showers and thunderstorms (60-85%) will be ongoing Tuesday evening
into early Wednesday morning as the CWA is forecasted to be just
behind the cold front by then, associated with its surface low in
MN, and shortwave aloft over ID/MT. This shortwave will push
eastward across the Northern CONUS and weakening along the way as
the cold front continues its path southeast. With help from this
shortwave and surface troughing over the area behind the front,
showers and thunderstorms are forecasted to continue Wednesday into
Wednesday night before diminishing northwest to southeast over the
CWA early Thursday. GEFS is the quickest on the departure of the
precip with GEPS being the slowest. High pressure moves in behind
the system and will be centered over the Northern Plains Thursday
before shifting eastward on Friday. Zonal flow or slight northwest
flow (depending on cluster ensemble) continues aloft through the
weekend with precip possibly returning to the area Friday through
the weekend as a couple of surface systems (and weak shortwaves
aloft) pass over the region.

The main concern continues to be the heavy rain potential Tuesday
evening and Wednesday, especially with any slow moving and/or
training of storms. NAEFS still indicates PWATS about 1 standard
deviation above climo with values of 1.50" over the eastern half of
the CWA between 00Z Wed-18Z Wed. Probability of 24 hr precip>0.50",
per grand ensemble ending 00Z Thursday, is 45-55% James River Valley
and eastward with a 15-20% chance of 1" or more for this same area.
Deterministic NBM runs about 50-65% for 0.50" or more and 35-45% for
an inch or more James River and eastward. However locally higher
amounts are possible with any stronger storms or slow
moving/training storms as mentioned. NBM 90th percentile QPF would
be close to 2" to potentially 2.50" along and east of the Coteau
into west central MN. EC EFI highlights QPF values of 0.5 to 0.7
east of the Mo River from 00Z Wed to 00Z Thursday with the highest
values (and shift of tails of zero) James River and eastward which
matches up with where the grand ensemble/NBM highest probabilities
are. Lastly, there is a marginal risk for severe storms continuing
through Monday evening, however, HREF indicates most of the severe
threat should be to the south/southeast of the CWA by then with the
front. Any slow down of the front would allow for an isolated severe
threat in our area, mainly over south central to east central SD.

By the middle of the week, it will feel more like fall as temp will
run about 15 to 20 degrees below average on Wednesday and 10 to 15
degrees below average Thursday as cooler air sinks southward with
the high. Forecasted highs look to range in the 60s to the lower to
mid 70s Wednesday and upper 60s to mid 70s Thursday. 850mb temps
will be about 1 standard deviation below climo ranging from 10 to
13C. EC EFI has values for TMAX of -0.6 to -0.9 over central SD on
Wednesday and values of -0.8 to -0.9 over the entire CWA on Thursday
with a shift of tails of zero for both days. Temps will warm back up
Friday and the weekend in the 70s/80s to even around 90 over south
central SD on Sunday.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 620 AM CDT Mon Jul 14 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to prevail through the period.
Thunderstorms will move into central SD after 23z and may affect
KPIR/KMBG/KABR this evening.

&&

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

$$

SHORT TERM...20
LONG TERM...MMM
AVIATION...20