Flooding in South Dakota, August 1 to 31, 2023

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1236 AM CDT Tue Aug 1 2023

.UPDATE...
Issued at 1233 AM CDT Tue Aug 1 2023

Aviation discussion updated below for the 06Z TAFs.

&&

.SHORT TERM...(This Evening through Tuesday Night)
Issued at 243 PM CDT Mon Jul 31 2023

SPC has a portion of forecast area (mostly west river) in the
marginal outlook for severe storms later this afternoon and
overnight. This looks very marginal at best with no real focus for
any forcing and the synoptic ridge building back in slowly. However,
there is sufficient moisture in place with dewpoints in the 60s and
weak southeast flow. A few storms should migrate in from the west
and possibly affect western portions of the forecast area this
evening, but activity will be isolated.

Expect some isolated RW/TRW overnight in west river and possible in
the far northeast corner of the forecast area. Flow is a bit strong
in the NE so any ND activity could drift into this region late.

Things get a bit more interesting on Tuesday. Temps will warm into
the 90s most locations with dewpoints pushing 70 in a lot of
locations. However, the best area for any development will be north
of the forecast area where the bulk shear and instability is
greatest with some shortwave energy. Slight risk area is just north
of us as well. Will keep in a chance of afternoon TRW for most of
the forecast area as storms can't be ruled out, but again main focus
will be north with the more favorable conditions.

The warming trend continues hot and muggy conditions Tuesday.

.LONG TERM...(Wednesday through Monday)
Issued at 243 PM CDT Mon Jul 31 2023

Looks like the overall flow pattern will begin to breakdown during
the long term period. On Wednesday we start off with a somewhat
amplified H5 height pattern over the CONUS. However, as we start the
upcoming weekend, energy over the intermountain west will eject into
the Plains, as other energy digs across south central Canada. This
will cause the mid level flow to flatten out somewhat over the
Northern Plains, and allow for a storm track closer to the forecast
area. The pattern will nearly mimic a split flow setup with the main
band of westerlies pushed off to the north, and another band of
stronger winds aloft setting up over the southern CONUS. In between
these two features there'll be some chance of rain as a couple waves
move through, especially Friday and Friday night. Severe chances
this weekend will be on the low end given the lack of deep layer
shear combined with relatively low MLCAPE values. The crashing
heights will lead to cooler temperatures for the weekend and early
next week. However, it will be hot Wed/Thu before the pattern
evolves into a cooler one.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1233 AM CDT Tue Aug 1 2023

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected for the TAF period. Do have two areas to
watch for convection. First for the overnight hours, there's
thunderstorms to the west and north of the area, but with abundant
mid level dry air, expect them to gradually dissipate as they move
towards the area. Second, diurnal heating and a weak disturbance
moving through the region could lead to thunderstorm development,
but confidence in both location and coverage is low and didn't
include any mention in the TAFs.

&&

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

UPDATE...TMT
SHORT TERM...Scarlett
LONG TERM...TDK
AVIATION...TMT/SRF

Hazardous Weather Outlook...UPDATED
National Weather Service Aberdeen SD
637 PM CDT Mon Jul 31 2023

SDZ003>005-009-015-016-033>035-045-048-011200-
Corson-Campbell-McPherson-Walworth-Dewey-Potter-Stanley-Sully-Hughes-
Jones-Lyman-
637 PM CDT Mon Jul 31 2023 /537 PM MDT Mon Jul 31 2023/

This Hazardous Weather Outlook is for central South Dakota and
north central South Dakota.

.DAY ONE...Tonight.

An isolated thunderstorm are possible after midnight tonight west of
the Missouri River. At this time, the severe potential remains low,
but the strongest storm could produce hail to quarter size and 60
mph wind gusts.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Periodic chances of showers and thunderstorms possible through the
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MNZ039-046-SDZ006>008-010-011-017>023-036-037-051-011200-
Traverse-Big Stone-Brown-Marshall-Roberts-Edmunds-Day-Faulk-Spink-
Clark-Codington-Grant-Hamlin-Deuel-Hyde-Hand-Buffalo-
637 PM CDT Mon Jul 31 2023

This Hazardous Weather Outlook is for west central Minnesota,
central South Dakota, north central South Dakota and northeast
South Dakota.

.DAY ONE...Tonight.

There is a possibility of isolated thunderstorms, however, they
are expected to be sub-severe.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Periodic chances of showers and thunderstorms possible through the
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

SRF