215
FXUS63 KABR 011511 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1011 AM CDT Sat Jun 1 2024

.KEY MESSAGES...

- There is around a 30% chance of showers and storms this
  afternoon and evening across south central South Dakota. While
  an isolated severe storm is possible, 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 cold front sweeps
  across the area. All severe weather hazards are possible,
  including large hail, damaging winds, and tornadoes.

- Temperatures are forecast to rise above normal this weekend and
  return to normal for the work week.

&&

.UPDATE...
Issued at 1010 AM CDT Sat Jun 1 2024

The forecast remains on track this morning. No major changes are
planned.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 336 AM CDT Sat Jun 1 2024

The current surface weather map shows a broad ridge of high pressure
stretching from MT through SD and southern MN. While satellite
imagery indicates lower clouds and fog over far southeastern SD
early this morning, our forecast area has been cloud free. This will
change through the day today as the surface ridge slowly focuses on
eastern SD by 18Z and shifts across MN this evening in response to
an elongated area of low pressure beginning to organize to our west.

Showers and a few thunderstorms mainly this afternoon will reside
over south central SD. The SPC Convective outlook is marginal for
that area (or at a level 1 of 5). At this point, it looks like much
of the thunderstorm activity will remain south of our forecast area
until this evening. Still, a few showers or storms will remain
possible over our southwestern counties/closer to the nearing
surface trough as MLCAPE values rise above 400 J/kg and 0-3km bulk
shear magnitude values briefly increase to 35-45 kts. There is less
confidence on if the storms will remain through the overnight hours,
but the moderate low level jet of 30-35kts should help.

The surface low looks to move into far western SD after 12Z Sunday,
and reside over western SD through 18Z, allowing warm and moist air
to advect across the forecast area. Dewpoints will rise into the low
to mid 60s as temperatures rise into the 80s for much of the area.
We`ll be monitoring the eastward progression of the surface low and
associated cold front that will be the focus for strong to severe
storms during the afternoon and evening hours. MLCAPE values near
this boundary will rise above 2500 J/kg and 0-3 and 0-6km Bulk Shear
magnitude values of 25-35kts. LCL heights generally stay below 1km
through the period. We`ll be monitoring for the potential for all
severe weather hazards, including damaging winds, large hail, and
tornadoes (along with frequent lightning and heavy rain). The main
time of concern remains highest between 22Z Sunday to 04Z Monday and
east of the Missouri River. A slight risk of severe weather remains
in place for Sunday (level 2 on a scale of 5).

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 336 AM CDT Sat Jun 1 2024

Sunday evening we are still expecting some storms in the area. These
should start to diminish within a few hours of sunset. Monday, the
upper level flow pattern is generally from the west southwest and
becomes more southwesterly through the day. By Tuesday morning the
downwind side of the low is over the region with its deep moisture
layer bringing the next chance for rain. Deterministic models seem
to be a bit more in agreement this run with very similar tracks and
timing across all 3 major models. The Canadian model does show a
slightly weaker low and with that, the shortwave energy doesn`t
reach as far back as the EC or GFS. Once the low moves off, the
models start to differ. The EC shows a second low coming in on the
trough of the first, moving southeast to miss us, but pushing the
trough south and bringing a wave of shortwave energy north to south
across the area. The GFS and Canadian show us staying either on the
downwind side of a trough or in northwest flow through the end of
the period.

As mentioned above, storms are still possible into Sunday evening,
probably ending before 10 PM. These storms have a chance to be
strong/severe with large hail and strong winds being the main
threats. The next chance for rain/storms looks to be Tuesday as the
low starts to move into the region. Areas east of the Missouri River
will be the most likely area for storms to form as the cold front
moves west to east across SD. Lapse rates are around 6.5 to 7.25
C/km and MLCAPE values are around 1500 to 2000 J/kg especially
around and east of the James River valley. With lapse rates a little
on the low side, confidence is low on severe potential. The rest of
the period looks to be dry.

Monday looks to be as much as 10 degrees above average with highs in
the low to mid 80s possible mainly west river. Overnight temps are
also expected to be around 10 degrees above average with lows only
getting down into the low 60s. Starting Tuesday, high and low
temperatures will be around average through the period. We have some
strong CAA moving through the region Wednesday that will cause some
strong wind gusts particularly west river where gusts could exceed
40 mph. Gusts of 30-35 mph are possible east of the Missouri.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 634 AM CDT Sat Jun 1 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions remain at all TAF locations. There is a 10-20%
chance of showers and potentially thunderstorms at PIR after 19Z
today, and at the remainder of the TAF sites after 06Z Sunday.
Given the low potential, no mention was included at this time.


&&

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

$$

UPDATE...Wise
SHORT TERM...KF
LONG TERM...KK
AVIATION...KF