919
FXUS63 KABR 020515
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1215 AM CDT Sun Jun 2 2024

.KEY MESSAGES...

- There is a 20-30% chance of showers and storms early this
  morning. While an isolated severe storm is possible south of
  Pierre, the threat is low (marginal risk for severe weather, or
  1 on a scale of 5).

- A slight risk of severe weather (level 2 on a scale of 5) will
  develop Sunday afternoon and evening as a cold front sweeps
  across the area. All severe weather hazards are possible,
  including large hail, damaging winds, and tornadoes.

- There is a 30-75% chance of showers and thunderstorms Monday night
  through Tuesday. Some storms could become strong to severe.

&&

.UPDATE...
Issued at 907 PM CDT Sat Jun 1 2024

Still expecting an increase of the low-level jet as the night
progresses, with surface south-southeasterly flow ramping up as
well. CAMs continue to show potential for isolated/widely
scattered shower/storm activity tonight with the increase in the
low-level jet, as well as HREF ensemble mean MUCAPE values nearing
1000 J/KG over central SD. Adjusted PoPs to better align with
newest NBM/ECAM data, which did bring an introduction of 20-30%
chances further north and east compared to previous forecast.

&&

.SHORT TERM /THIS EVENING THROUGH SUNDAY NIGHT/...
Issued at 312 PM CDT Sat Jun 1 2024

Zonal upper level flow and sfc high pressure has kept the region dry
today. Shortwave perturbations begin to affect far southern South
Dakota this evening. Late tonight, however, a llj sets up and,
combined with those shortwaves, could generate a strong to severe
storm south of Pierre. As the shower and thunderstorm activity
spreads north and east Sunday morning as its pushed ahead of an
approaching sfc low, the question becomes how strong of a cap will
form. If the precip Sunday morning is widespread rather than
isolated, high temps may be suppressed and limit potential afternoon
instability. SPC has kept a slight risk (2 out of 5) for severe
storms Sunday afternoon through Sunday evening over most of the
forecast area with all threats remaining in play. However, hi-res
CAMS and even some of the global model solutions have backed off on
storms west of the James valley with the trough/trailing front
position farther east by 21z. The extra time for heating would be
necessary to help break the cap, and best progs are for a line to
develop just ahead of the front. The challenge is whether all of the
ingredients come together in SD for severe weather or whether it all
holds off on gelling until the line is closer to the Minnesota
border.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 312 PM CDT Sat Jun 1 2024

The long term portion of the forecast begins on Monday with a
surface low pressure over Wyoming with a trough further west.
Southerly winds will bring increasing LLM and warm temperatures into
the area, with highs reaching the 80s. As of the surface low moves
northeast into North Dakota, the trailing cold front may produce
showers and thunderstorms across the forecast area, mainly Monday
night through Tuesday morning. Depending on model used, the front
may push east into MN during the mid afternoon hours, with dry
conditions possible. Other models suggest the front stalls some over
eastern SD where additional convection may be possible. A few storms
on Tuesday may become strong to severe with hail and damaging winds
the main threats.

The weather pattern for the rest of the period will feature
northwesterly flow aloft with mainly dry conditions. A large upper
level trough over the Great Lakes Region may keep temperatures at or
slightly below average with highs mainly in the 70s, to the low 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1214 AM CDT Sun Jun 2 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Will be watching
potential for TSRA/+TSRA across the KABR KATY region between about
00Z and 05Z Monday. If a heavier TSRA moves over a terminal,
MVFR/IFR VSBY and CIGs are possible, along with GR (hail) and strong
surface wind gusts.

&&

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

$$

UPDATE...TMT
SHORT TERM...Wise
LONG TERM...SD
AVIATION...TMT