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000
FXUS63 KUNR 092010
AFDUNR

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

.KEY MESSAGES...
123 PM MDT Tue Apr 9 2024

- Very windy Wednesday with gusty northwest winds and 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)

- Next noteworthy chances for precipitation are late Sunday
  through Monday and Tuesday.

&&

.DISCUSSION...(This Evening Through Tuesday)
Issued at 123 PM MDT Tue Apr 9 2024

A weak shortwave ridge has lead to mostly sunny skies over the
region through much of the day. However as the ridge shifts off to
the east, a weak shortwave trough moving into the forecast area
is working with diurnal heating and moist ground to produce a
field of relatively flat CU. An isolated shower/sprinkle is
possible during the rest of this afternoon.

Tonight and on Wednesday, the next, slightly stronger, short-wave
trough and associated surface cold front will dive across the
forecast area. Low level cold advection and surface pressure rises
of 2-4mb/3hrs point to very wind conditions developing, with
northwest gusts of 45-55mph expected on the western South Dakota
plains. A Wind Advisory has been issued for Wednesday.

The Q-G forcing with the wave will be marginal, but the 700-500mb
lapse rates of 6-8C/km will support scattered showers. 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
parts of northeastern WY. Little or no snow accumulation is
expected. The wave and associated showers should be east of the
forecast area by or around 00z Thursday.

A substantial warming trend will occur for Thursday through
Saturday with 850mb temps climbing to around 20C. Highs in the 70s
are likely Friday through Monday. Some 80s are possible toward
south central SD, although max temps may be moderated some in
areas that have received substantial rain over the last few days.

The ensembles agree well on another big upper low moving into the
southwestern CONUS by Monday, possibly bringing rain/snow to the
forecast area on Tuesday. Even though confidence is high with
this upper low occurring, there remains much uncertainty on its
precise track across the central CONUS at this time. However, it
does appear this system will be warmer than the most recent one.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 1040 AM MDT Tue Apr 9 2024

VFR conditions are expected throughout the TAF period for most
places. The exception is for the northern BLKHLS after 06z as some
showers and local MVFR/IFR conditions could develop. Behind a cold
front, strong northwesterly winds will develop Wednesday morning,
especially across the western SD plains.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 10 AM MDT /11 AM CDT/ to 7 PM MDT /8 PM CDT/
     Wednesday for SDZ001-002-012>014-025-026-030>032-042>044-
     046-047-049-072-073-077-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...10
AVIATION...Pojorlie