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309
FXUS63 KABR 232327
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
627 PM CDT Sun Jun 23 2024

.KEY MESSAGES...

- Increasing heat and humidity on Monday, with temperatures in
  the 90s and dewpoints approaching 70. Heat index values could
  top out around 100 degrees in the afternoon, mainly across the
  James River Valley.

- A few showers and storms will be possible late Monday, otherwise
  expect dry weather until later in the work week when a more
  organized storm system moves into the Northern Plains.

&&

.UPDATE...
-- Changed Discussion --
Issued at 626 PM CDT Sun Jun 23 2024

Heat Advisory remains posted for 1 PM to 7 PM CDT Monday for
portions of eastern SD. We will be monitoring for the potential
for a few clouds and even a few showers overnight over mainly
north central SD, with chances remaining below 20 percent at this
time with the higher chances remaining across ND.
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&&

.SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/...
Issued at 309 PM CDT Sun Jun 23 2024

Upper level ridging will be dominant over the region tonight into
Monday morning, before flattening out to become more zonal Monday
afternoon. Will then see a slight shift to northwesterly flow on
Monday night, with some weak shortwave energy tracking across
central South Dakota.

At the surface, the region will be between high pressure to the east
and low pressure to the west tonight, with the low to the west
making it to the western Dakotas by Monday morning. The boundary
will track across the CWA on Monday, with southerly flow ahead of it
ushering very warm air into the region. Will see temperatures in the
90s, along with dew points well into the 60s (maybe even low 70s in
a few spots across the east). This will result in an incredible
amount of instability (4000+ J/kg of MUCAPE). However, this heat
will occur aloft as well, with H7 temps of +14C to +16C. This would
make it pretty difficult for convective development to occur during
the daytime hours. There may be a better chance across the far
eastern part of the area during the evening hours as the cap weakens
some, but confidence is low at this time. Should any storms be able
to get going, large hail and strong wind gusts would be the main
threats. The deterministic models and some of the CAMs are hinting
that there could be some precipitation development during the
overnight hours across central South Dakota ahead of approaching
high pressure and in association with the aforementioned upper
shortwave, so will keep some small POPs in during that time period.

The other concern on Monday will be high heat indices due the warm
temperatures and high dew points. The current indications are that
the locations that were previously put into a Heat Advisory for
Monday afternoon (Spink, Faulk, Hand, Hyde and Buffalo counties) are
still the most likely to see heat indices in excess of 100 degrees.
Therefore, will not make any changes to the Heat Advisory coverage.

Low temperatures tonight will be in the mid to upper 60s. High
temperatures on Monday will be in the upper 80s to mid 90s. Lows
Monday night will be in the upper 50s to mid 60s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 309 PM CDT Sun Jun 23 2024

Tuesday, we are in westerly flow aloft with some shortwave energy
which will bring some chances for rain. A ridge starts to build in
Wednesday. A shortwave will move along the ridge Thursday starting a
string of a couple days with rain chances as a cold front and low
move across the area Friday and Saturday. Another ridge builds in
Sunday.

Highest chances for rain on Tuesday will be during the daylight
hours and mainly concentrated west of the James River at 25 to 35%.
The chance of more than a quarter of an inch is around 15%. 30 to
35% PoPs move in from the west Thursday morning and continue to move
east through the day. Friday, ahead of the cold front, PoPs along
the ND/SD border will increase to around 55 to 65%. These higher
chances move east through the day, replaced by 15 to 30% PoPs in the
evening. Saturday morning we get more 30 to 35% PoPs spread across
the area. NBM is showing around a 15% chance for more than an inch
of accumulation from Thursday to Saturday. Temperatures during the
long term will be around average for the most part. Highs could be 5
to 10 degrees below average on Saturday and then return to normal on
Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
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Issued at 626 PM CDT Sun Jun 23 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected over the next 24 hours. Shifting winds
are expected through the day Monday from out of the southeast to
out of the northwest as an area of low pressure slides across SD
through the daytime hours Monday.
-- End Changed Discussion --

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from 1 PM to 7 PM CDT Monday for SDZ017-018-036-
     037-051.

MN...None.
&&

$$

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