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622
FXUS63 KABR 220146 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
846 PM CDT Fri Jun 21 2024

.KEY MESSAGES...

- A Flood Watch remains in effect through tonight for Hand, Buffalo
  and Lyman county. An additional 1 to 2 inches of rain is possible
  in the watch area.

- Severe storms are possible this evening, primarily across
  eastern and southern South Dakota, with a low probability that
  severe storms cross into the CWA. Otherwise, looking at a random
  coverage of showers and storms through Saturday morning.

- The weather pattern turns mostly dry early next week as
  temperatures and humidity climb significantly with daytime
  highs in the mid 80s to mid 90s.

&&

.UPDATE...
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Issued at 836 PM CDT Fri Jun 21 2024

In the midst of a lull in precipitation over this CWA. Although,
shortwave energy approaching from the west-southwest is generating
some showers and thunderstorms out over the central/northern high
plains. This convection is expected to work into the CWA later,
closer to 05-06Z, and push across the CWA during the overnight
hours. No notable changes to the tonight period forecast planned
at this time.

UPDATE Issued at 651 PM CDT Fri Jun 21 2024

See below for an aviation forecast discussion for the 00Z TAFs.
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&&

.SHORT TERM /THIS EVENING THROUGH SATURDAY NIGHT/...
Issued at 303 PM CDT Fri Jun 21 2024

Very spotty radar returns all day today with the best shortwave
activity across North Dakota and the warm front farther south than
initially expected and still draped across Nebraska. By this
evening, the front is expected to nose up into southeast SD but
remain south of this cwa. While there is still a marginal risk (1
out of 5) for severe storms south of Hwy 212, the best chances
remain farther south near the front. Main concern for tonight
remains the threat of additional rain over areas that have already
flooded. Maintained the flood watch for Hand, Lyman and Buffalo
counties, portions of which still have ongoing creek and road
flooding with an areal flood warning in effect. This region could
see an additional 1 to 2 inches of rain through Saturday morning.
Other areas east and north of the watch are forecast to see under an
inch.

Hi-res models have not been great today with depicting precip onset.
They are having a tough time resolving timing and placement of the
warm front to the south and the shortwaves riding the upper ridge.
They are now slower with a shortwave trough on Saturday, as well, so
pops have increased Saturday morning into Saturday afternoon before
the system finally exits to the east between 18z and 21z. Northwest
flow aloft and lingering clouds for half of Saturday will keep
high temperatures around climo norms.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 303 PM CDT Fri Jun 21 2024

Sunday morning, we start the long term with northwesterly flow aloft
as a ridge starts to move in from the west. This upper level ridge
will last through the day Monday and then transition to generally
westerly flow overnight. Tuesday, a small shortwave passes through
the region bringing our first chance of rain, and another ridge
starts to build in Wednesday and will last through the end of the
period. A stronger shortwave moves across the ridge Friday morning
bringing some more chances for rain.

Starting with Monday night/Tuesday, rain chances look to be
concentrated more in eastern SD and west central MN with 15-30%
reaching as far west as the James River valley. Chance of more than
a quarter of an inch in 24 hours is around 30% in far eastern SD and
west central MN with chances decreasing to the west. For Friday,
chances are more widespread with 25 to 35% chances across the entire
CWA, highest chances east of the Missouri River. Chances for more
than a quarter of an inch are similar, around 15-35%, but spread
farther west. 30-35% chances reach the James River valley and 20 to
30% chances spread west to the Missouri River.

Temperatures are still expected to increase for the first part of
the term, peaking in the low to mid 90s on Monday or about 10 to 15
degrees above average. Following this, temperatures will come down
to about normal for the rest of the period. Winds are also still
expected to be about normal through the period.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 651 PM CDT Fri Jun 21 2024

Terminals KABR,KATY,KPIR,KMBG

Similar to the past couple of days, with all the low level
moisture that has gotten stuck in the boundary/mixing layer north
of a warm front in Nebraska sticking up into southeast South
Dakota, there is no lack of stratus clouds around the region.
Guidance says to expect more MVFR/IFR conditions (cigs mainly)
overnight and into Saturday morning before conditions improve to
VFR from west to east. Conditions are quiet (dry) right now, but
there is another area of low pressure approaching the region from
the southwest. Expecting another batch of showers/embedded
thunderstorms to work northeast across the region later tonight.
Less convinced that KMBG will see precipitation tonight; more
convinced that KPIR and KATY will see precipitation tonight into
early Saturday morning.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
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SD...Flood Watch until 7 AM CDT Saturday for SDZ037-048-051.

MN...None.
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&&

$$

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