Tornado Warning 9, NWS Aberdeen, SD

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
632 PM CDT Wed Aug 28 2024

.KEY MESSAGES...

- There is an Enhanced Risk (level 3 out of 5) for severe
  thunderstorms this evening over primarily south central ND into
  north central SD. The main threats will be hail of 2" or more in
  diameter and winds gusting over 60 mph. A tornado or two will
  be possible initially late this afternoon/early this evening
  over central/north central SD.

- Wind gusts of 30 to around 40 mph are expected over north central
  South Dakota Thursday afternoon.

&&

.UPDATE...
Issued at 626 PM CDT Wed Aug 28 2024

See updated aviation discussion below.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 328 PM CDT Wed Aug 28 2024

The heat and humidity have returned this afternoon as 60s/low 70s
dewpoints stream northward into the CWA, while actual air
temperatures have reached the mid 80s to low 90s for many locations
along and west of the James River. Strongest instability (3000 J/KG
or greater) resides across central SD this afternoon, and is
forecast to generally remain over central SD over the next several
hours. Adequate shear and favorable mid-level lapse rates, along
with the approach of stronger mid-level southwesterlies associated
with the advancing upper trough, should all be enough to support
convection in the next couple hours across southern ND into portions
of north central SD, although southern extent and areal coverage of
storms in our CWA is in question. Latest HREF ensemble paintball
reflectivity (>40 dBZ) output continues to reveal most solutions
show the highest coverage across ND, but certainly seeing some
degree of activity (to a lesser extent) across north central or
central SD. Surface cold front is analyzed across western SD and
convection will likely be closely tied to the forcing from this
feature.

As the entire upper trough and surface front move east overnight
into Thursday, continued chances for showers and thunderstorms will
exist for eastern portions of the CWA, but with limited severe
potential. An examination of parameters would suggest perhaps the
far eastern CWA, but more likely into MN is where we'd expect strong
to severe storms on Thursday. Will maintain fairly high PoPs (40-60%
chances) across the eastern CWA from mid morning to early afternoon
as CAMs continue to show scattered activity potential along and east
of the James River.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 328 PM CDT Wed Aug 28 2024

There is agreement in the clusters and deterministic models about a
ridge moving east and affecting eastern and central SD with
northwest flow aloft through most of the forecast period. Tuesday
evening, the models show a shortwave move north of SD as the ridge
starts to work its way in. However, there is some discrepancies
between the timing and strength in the models. The upper levels stay
mostly dry during the forecast period except when some moisture
moves in Sunday afternoon/evening over northern central and eastern
SD. The upper levels also have larger swaths of CAA moving over
Saturday evening, and then WAA moves in Monday morning. There are
also some more organized pockets of vorticity traveling across the
state Wednesday morning. While there is very little moisture in the
upper levels Wednesday morning, there are some upper level forcings
which could help with the develop of precipitation Wednesday morning
into the evening along the surface frontal boundary. The rest of the
forecast period shows no precipitation forming in SD. Max
temperatures warm up to the low 90s by Saturday, but then cool down,
in some affect because of the CAA, Sunday to the upper 60/70s into
Monday. Then it starts to warm up again into the low 90s by Tuesday
and Wednesday. The GFS shows strong winds at 0.5km and fairly large
lapse rates on Monday afternoon over central SD into Monday evening
over central and eastern SD. This, in addition to the strong
pressure gradient between the low to the east of the Rockies and the
departing high, could help to bring stronger winds to the surface,
which is what the ensembles show occurring in central SD, along
with higher values in the ECMWF EFI table.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 626 PM CDT Wed Aug 28 2024

Terminals KABR,KATY,KPIR,KMBG

Thunderstorms are possible this evening across central South
Dakota, some of which may be severe. Large hail and tornados will
be possible with any of the thunderstorms through the late evening
hours. Additional showers and thunderstorms will be possible east
of the Missouri River Thursday morning through the afternoon
hours, but no severe weather is anticipated during that time
frame. Periods of MVFR vsbys will be possible with any
thunderstorms. Outside of the thunderstorms, VFR conditions will
prevail tonight and through the day Thursday.

&&

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

SHORT TERM...TMT
LONG TERM...Vernon
AVIATION...Parkin

Hazardous Weather Outlook
National Weather Service Aberdeen SD
609 AM CDT Wed Aug 28 2024

SDZ003>011-015>020-022-036-037-051-291115-
Corson-Campbell-McPherson-Brown-Marshall-Roberts-Walworth-Edmunds-
Day-Dewey-Potter-Faulk-Spink-Clark-Codington-Hamlin-Hyde-Hand-
Buffalo-
609 AM CDT Wed Aug 28 2024 /509 AM MDT Wed Aug 28 2024/

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

.DAY ONE...Today and tonight.

There is a slight risk, or level 2 out of 5, of severe weather late
this afternoon through tonight. The main threats with the strongest
storms will be hail of 2" or more in diameter and winds gusting over
60 mph. A tornado or two will be possible initially late this
afternoon into early this evening over central South Dakota.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed late this afternoon and
tonight. Weather spotters are encouraged to submit reports to the
National Weather Service in Aberdeen. The public can submit reports
on our web page, Facebook page, or our X feed.

SDZ033>035-045-048-291115-
Stanley-Sully-Hughes-Jones-Lyman-
609 AM CDT Wed Aug 28 2024 /509 AM MDT Wed Aug 28 2024/

This Hazardous Weather Outlook is for central South Dakota.

.DAY ONE...Today and tonight.

Temperatures will rise into the 90s over central SD, with heat index
values nearing 100 degrees over portions of south central South
Dakota this afternoon.

There is a slight risk, or level 2 out of 5, of severe weather late
this afternoon through tonight. The main threats with the strongest
storms will be hail of 2" or more in diameter and winds gusting over
60 mph. A tornado or two will be possible initially late this
afternoon into early this evening over central South Dakota.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed late this afternoon and
tonight. Weather spotters are encouraged to submit reports to the
National Weather Service in Aberdeen. The public can submit reports
on our web page, Facebook page, or our X feed.

MNZ039-046-SDZ021-023-291115-
Traverse-Big Stone-Grant-Deuel-
609 AM CDT Wed Aug 28 2024

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

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

There is a marginal risk, or level 1 out of 5, of severe weather
Thursday afternoon. The main threats with the strongest
storms will be hail of around 1" or winds gusting over 60 mph.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

KF