607
FXUS63 KABR 191137 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
637 AM CDT Fri Jul 19 2024

.KEY MESSAGES...

- Increasing chances (20-50%) for showers and thunderstorms today
  and Saturday. Some thunderstorms could be strong to severe this
  afternoon, especially across central South Dakota, where
  there is a Marginal Risk (level 1 of 5) for severe weather.

- Additional chances of precipitation (20 to 40 percent) Saturday
  night through Tuesday (mainly afternoon and evening activity).

- Confidence is increasing for hot temperatures returning by Friday.

&&

.UPDATE...
Issued at 632 AM CDT Fri Jul 19 2024

Aviation discussion updated below for the 12Z TAFs.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 431 AM CDT Fri Jul 19 2024

The main focus in this period will be precipitation chances as a
disturbance enters the region today to deliver the first round in a
series of chances for showers and storms that will linger into the
start of the weekend. Starting off early this morning, we`re already
seeing some scattered convection breaking out across north central
SD in an ACCAS field that has developed in association with some mid
level energy shifting into the western Dakotas ahead of the main
shortwave trough. Guidance does prog this activity will continue
drifting south-southeastward through the remainder of the pre-dawn
to mid morning hours.

The aforementioned upper level trough is progged to shift southeast
across our region later today. At the sfc, a trough of low pressure
will be splayed out across portions of the central and western
Dakotas which should act in part as a focus for more convective
development this afternoon. Daytime heating this afternoon will
combine with sfc dew points in the low to mid 60s underneath
steepening mid level lapse rates of 7-8 C/km. This will lead to
increasing instability with MUCAPE values of 3000-4000 J/kg in
northwesterly deep layer shear of 35-40 kts. The best of these
ingredients look to set up across central SD in our forecast area.
Most of the convection should mainly set up west of the James Valley
this afternoon, but even some of our eastern zones could see a few
storms late this afternoon. SPC has hoisted a Marginal Risk(level 1
of 5) for severe weather across from basically Mobridge to Miller
and points west and south for this afternoon into this evening. The
strongest storms will be capable of producing large hail and
damaging winds.

That activity is expected to fade by late evening tonight. A warm
and humid air mass will remain present across the region on
Saturday. Another dose of daytime heating in the afternoon will lead
to scattered convection once again. Ingredients for strong to severe
storms looks lacking however as deep layer shear will be rather
unimpressive. Temperatures will be seasonal today and Saturday with
daytime highs in the low to mid 80s and overnight lows tonight will
be in the low to mid 60s.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 431 AM CDT Fri Jul 19 2024

Upper level pattern will feature overall troughing across the Great
Lakes southwest into the Central Plains. Beginning of the extended
period stays active, with chances for precipitation (20-40%) from
Saturday night all the way through Tuesday. Cool temps aloft should
promote heat-of-the-day shower and thunderstorm activity during the
afternoon and early evening hours, but likely a limited threat for
severe storms. Grand Ensemble probabilities for measurable are
fairly high (40-50% or higher) for various locations across the CWA
through Tuesday, highest during the 6-hr blocks ending at 1pm/7pm,
further suggesting higher chances for daytime development.

By the end of the week Friday, models indicate upper level ridging
trying to move back into the Northern Plains, which would mean hot
temperatures returning. 850mb temps off the Grand Ensemble (00Z) run
reach and exceed +20C again by Friday. Probabilities for 90 degrees
or higher at 00Z Saturday (next Friday at 7pm) show generally 40% or
higher from the James River westward, and as high as 60%+ over
central SD. Inherited NBM highs for next Friday are around 90-95
degrees from the James River west.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 632 AM CDT Fri Jul 19 2024

Terminals KABR,KATY,KPIR,KMBG

TSRA are moving southeast across the region this morning, most
likely affecting KMBG around 12Z. Although, KPIR/KABR may also see
some of this activity and have included a VC (vicinity) mention.
Brief MVFR VSBY is possible under any heavier storms. Scattered
TSRA expected this afternoon as well, with activity diminishing
after sunset.

&&

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

$$

UPDATE...TMT
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...TMT