-- Discussion containing changed information from previous version are highlighted. --
458
FXUS63 KABR 162006
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
306 PM CDT Mon Sep 16 2024

.KEY MESSAGES...

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- Thunderstorm chances (around 20 percent) exist tonight in
  eastern South Dakota/western Minnesota. No severe weather is
  expected.

- A Marginal Risk of severe weather (level 1 of 5) has been
  highlighted along and west of the Missouri River Tuesday evening.
  The main threat will be strong wind gusts.

- Warm temperatures will continue through Thursday before cooler
  air returns late in the week.

- Multiple chances for precipitation will persist through most of
  this week. Highest chances will arrive Tuesday night and
  continue through midday Wednesday with a 40 to 80 percent chance
  for showers and storms.
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&&

.SHORT TERM /THIS EVENING THROUGH TUESDAY NIGHT/...
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Issued at 305 PM CDT Mon Sep 16 2024

The region will be between upper level ridging to the east and a
trough over the western United States tonight and Tuesday. The
trough to the west will begin to swing northward on Tuesday,
becoming centered over Montana/Wyoming Tuesday night, with an area
of energy ahead of it sliding across western and central South
Dakota.

At the surface, a low pressure system currently over Wyoming will
slide a bit northward to eastern Montana tonight, with a boundary
extending from it northeastward to eastern North Dakota. There may
be a few showers or thunderstorms ahead of it over northeastern
South Dakota, but the better dynamics will remain north of the CWA,
and that is where more widespread convection is expected. The
daytime hours on Tuesday look quiet as the low to the west works its
way to the western Dakotas. Will see a tightening pressure gradient,
which will aid in windy conditions, with some gusts in excess of 35
mph possible. As the low swings northeastward Tuesday night, will
see a decent chance (35 to 85 percent) for showers and
thunderstorms. Instability is pretty minimal during this time, but
bulk shear values of 45 to 60 knots should be enough to support a
few strong to possibly severe storms. The region along and west of
the Missouri River has been highlighted by a Marginal Risk for
severe storms, mainly Tuesday evening. The CAMs do indicate this as
well, but indicate that convection in Nebraska may cut off the
needed moisture for storms. The main threat with any thunderstorms
that develop looks to be strong wind gusts.

Low temperatures tonight will be in the lower to mid 60s. High
temperatures on Tuesday will be in the mid 80s to mid 90s. Lows
Tuesday night will be in the 60s.
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&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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Issued at 305 PM CDT Mon Sep 16 2024

Wednesday morning starts the long term with a low pressure system
just off to our west over northeastern WY and western SD. This will
continue to move to the north and into Canada through the day. As we
have been talking about through the last several days, the cold
front from this low will sweep across our region during the day
Wednesday. Ensembles are starting to come into more agreement for
the Friday/Saturday/Sunday time frame with a low over NE/KS. This is
farther south than previous iterations.

Showers are expected to be coming to an end Wednesday morning with
20-30% PoPs around and east of the James River valley. Rain chances
Saturday and Sunday remain the same at around 30-40% even with the
low moving a bit farther south. Across the region there is generally
a 30-40% chance of more than 0.25" in 24 hours both on Saturday and
Sunday.

Temperatures through the period will be decreasing. Wednesday starts
us out with highs in the upper 70s to mid 80s. By Monday, highs will
have decreased to more fall-like temps of mid 60s to low 70s. On the
wind side of things, Wednesday afternoon is looking to be a bit
windier than previously expected. Some 30-35 mph wind gusts will be
possible across much of northeastern SD. These stronger winds are
expected to start decreasing into the evening. Otherwise, winds
during the period should be below 25 mph.
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&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1226 PM CDT Mon Sep 16 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area through the the TAF
period. South to southeast winds will gust to near 30 knots this
afternoon, then again Tuesday morning.


&&

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

$$

SHORT TERM...Parkin
LONG TERM...KK
AVIATION...Parkin