683
FXUS63 KABR 031716
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1216 PM CDT Wed Jul 3 2024

.KEY MESSAGES...

- There is a Marginal Risk (level 1 of 5) for severe weather this
  evening across south central South Dakota, mainly along and south
  of Interstate 90. The main threats with the stronger storms will
  be large hail and strong wind gusts.

- Rain showers, and a few thunderstorms, will occur across the area
  tonight and through the day Thursday, making for a cooler and
  soggy Fourth of July.

- The active weather pattern of showers and thunderstorms persists
  into Friday.

&&

.UPDATE...
Issued at 1215 PM CDT Wed Jul 3 2024

Update this morning mainly focuses on warm advection elevated
convection developing along the White river in the southwest CWA.
The environment is still marginal for severe weather up in central
South Dakota, with better instability and thus stronger storms
expected in the southwest of the state. That said, NAM indicates the
atmosphere across the rest of the CWA has skinny CAPE, and as such
we could see some more weak convection similar to what we
experienced yesterday, so have added some additional low POPs/cloud
cover for north central/northeast SD. No other changes of note

See below for update to the aviation discussion...

&&

.SHORT TERM /TODAY THROUGH THURSDAY AFTERNOON/...
Issued at 308 AM CDT Wed Jul 3 2024

Upper level zonal flow across the area today will give way to a
shortwave trough approaching from the west and tracking across the
Northern Plains late tonight and Thursday.

At the surface, weak high pressure will be over the region this
morning. A low pressure system will approach the area from the west,
with a warm front setting up over southern South Dakota. This front
may be the focus for thunderstorms late this afternoon and this
evening, mainly along and south of Interstate 90. This is
highlighted by a Marginal Risk (level 1 of 5) for severe weather.
The better chances will stay south of the CWA, but cannot rule out a
stray storm or two reaching Jones or Lyman counties. The cold front
associated with the low will then gradually drift eastward tonight
and Thursday, and in association with the upper level shortwave,
will be the focus for precipitation. Instability will be minimal,
but there will be some shear (35 to 45 knots) available tonight, so
may see some thunderstorm development. During the day Thursday, both
instability and shear are minimal across the CWA, so expect the
precipitation to be mainly in the form of rain showers. Current CAMS
are indicating the potential for a period of more widespread rain in
the morning, then becoming more scattered in the afternoon, but
overall looking like a cooler, soggy Fourth of July.

High temperatures today will be in the lower to mid 80s. Low
temperatures tonight will be in the upper 50s to lower 60s. Highs on
Thursday will be in the upper 60s to mid 70s.

&&

.LONG TERM /THURSDAY EVENING THROUGH TUESDAY/...
Issued at 308 AM CDT Wed Jul 3 2024

Thursday evening, the upper level low is over eastern SD and will be
moving east through the night. Friday through Saturday, we are in
north to northwest flow aloft. Sunday, another low comes down from
Canada and clips northeast SD with the trough spreading across all
of SD. We remain in a trough pattern through the end of the period.

Thursday evening, showers and non-severe thunderstorms are expected
across the region. Chances of exceeding an inch max out at 30% in
eastern SD and decrease to the west. Rain chances don`t really go
away until Monday. However, Friday and Saturday`s highest PoPs look
to be around 30 to 40%. Accumulations through Saturday morning (48
hours starting Thursday morning) have a 60% chance of exceeding half
an inch in eastern SD and a 10% chance of exceeding half an inch in
central SD. Higher chances move in Saturday evening into the
overnight hours with 50 to 65% PoPs over far northeast SD. Early
Sunday morning, these PoPs spread to cover the James River valley
and points east and then decrease into the afternoon. There are some
slight chances (up to 15%) for some sprinkles through the end of the
period but no measurable precipitation is expected.

Temperatures will be around average through the period with highs in
the 80s. Winds are still expected to be around normal through the
term.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1215 PM CDT Wed Jul 3 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions initially. Storms south of KPIR should remain south
of the terminal for most of the day, though potentially later this
afternoon/evening we could see something move towards the KPIR/KMBG
terminals. Convection will weaken but become more widespread through
the evening/overnight. Additionally, MVFR CIGS will also develop as
this low pressure system moves across the area.

&&

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

$$

UPDATE...Connelly
SHORT TERM...Parkin
LONG TERM...KK
AVIATION...Connelly