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000
FXUS63 KUNR 090810
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
210 AM MDT Tue Apr 9 2024

.KEY MESSAGES...
203 AM MDT Tue Apr 9 2024

- Dry and warmer weather today

- Very gusty northwest winds on Wednesday with scattered rain and
  snow showers (minimal accumulations)

- Warming trend Thursday through Friday, with very mild weather
  this coming weekend (highs in the 70s with even a few lower
  80s)

&&

.DISCUSSION...(Today Through Monday)
Issued at 203 AM MDT Tue Apr 9 2024

The latest water vapor loop and 500-mb height analysis showed a
closed upper low north of MN while a strong jet was pushing a
short-wave trough across the Pacific Northwest. Inbetween was a
short-wave ridge across MT that will bring milder weather to the
CWA today. At the surface, there was a lee trough from central MT
into eastern WY, with higher pressure to the south in western NE.
This was leading to a mild west-to-southwest flow across the CWA
early this morning.

The short-wave ridge will move across the CWA today and be
associated with some increasing clouds due to midlevel WAA and a
stream of Pacific moisture. As we warm up and start mixing, the
northwest winds will get a little breezy northwestern SD, but
nothing out of the ordinary. Otherwise, increasing 850-mb temps
should lead to highs mostly in the 50s (cooler where substantial
snow cover exists).

This evening and tomorrow the short-wave trough and associated
cold front will move across the CWA with very gusty northwest
winds developing (especially northwestern into west-central SD).
HREF and NBM probabilities suggest a wind advisory will be needed,
with perhaps a few gusts near high-wind warning criteria along
the squeeze-zone on the plains just east of the BLKHLS. However,
the progged surface 3-hour pressure rises of 3-4mb support
advisory-level winds. The Q-G forcing with the wave will be
marginal, but the 700-500mb lapse rates of 7-8C/km will support
scattered showers (generally from 06z-24z). SBCAPE of 100-300 J/kg
may result in a clap of thunder, but have not included mention of
that at this time. SREF/NBM probabilities support mostly rain,
but given the steep low-level lapse rates and CAA, snow will be
the likely precip type across the BLKHLS and northeastern WY. The
wave and associated showers should be east of the CWA by or
around 00z Thursday.

A substantial warming trend then is on tap Thursday through Saturday
as 850-mb temps reach near 20C. Highs in the 70s are likely Friday-
Monday (possibly into the 80s this weekend toward south-central SD).
The ensembles agree well on another big upper low moving into the
Southwest U.S. by Monday, possibly bringing rain/snow to the CWA
on Tuesday. Even though confidence is high in this upper low
occurring, there is much uncertainty on its precise track across
the central CONUS at this time. However, it does appear this storm
will be even warmer than the most recent one.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1120 PM MDT Mon Apr 8 2024

VFR conditions can generally be expected overnight into Tuesday.
Breezy westerly winds will develop across northwest SD on Tuesday.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Bunkers
AVIATION...26