Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 152322
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
522 PM MDT Fri Mar 15 2024

.KEY MESSAGES...
200 PM MDT Fri Mar 15 2024

- Red Flag Warning for northwest SD continues into early evening

- Dry weather expected through Wednesday with windy periods and
  elevated fire weather conditions

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 200 PM MDT Fri Mar 15 2024

The surface high is located to the south of the forecast area this
afternoon and a low pressure system is moving from northern
Manitoba toward the Great Lakes. The pressure gradient between
those features if producing dry westerly downslope winds over the
forecast area. A surface trough rotating around the low pressure
system is currently dropping southward from ND, tightening the
gradient and increasing wind gusts to 30-35kts over northwestern
SD.

While the minimum relative humidity may not be quite as low as
previously expected, will keep the Red Flag Warning in effect for
northwestern South Dakota due to the dry air and increasingly
gusty winds. The wind will decrease some this evening, however
northwest winds of 15 to 25 mph are possible through much of the
night on the western SD plains with 10 to 20 mph winds over
northeastern Wyoming. Saturday morning low temperatures will
generally range from the mid 20s to mid 30s.

For the period from Saturday through Wednesday, dry northwesterly
flow aloft will continue over the northern plains as the forecast
area remains on the eastern edge of a stationary upper ridge over
the PAC NW. A series of weak fronts backing into the forecast
area will act to tighten the pressure gradient, leading to
periods of windy conditions. Saturday high temps will be a bit
cooler than today, though still warmer than average, with
noticeably cooler temps on Sunday, especially toward central SD.
Monday through Wednesday will then return to warmer than average
conditions.

The second half of next week appears to be colder and more active
with chances for rain and snow, although moisture appears to be
limited.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 519 PM MDT Fri Mar 15 2024

VFR conditions are expected through the forecast period. Breezy
northwest winds will develop Saturday morning across the western
South Dakota plains, with gusts up to 40 mph.

&&

.FIRE WEATHER...
Issued At 200 PM MDT Fri Mar 15 2024

Low relative humidity is developing over northwest SD this
afternoon with increasingly gusty winds. A Red Flag Warning
remains in place for that area into early evening. The wind will
decrease some this evening but will remain breezy overnight.

A series of weak fronts will then bring periods of gusty winds
Saturday through Wednesday along with minimum relative humidities
dropping to 15-30%. The combination will lead to elevated fire
weather conditions.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning until 7 PM MDT this evening for SDZ327>331.
WY...&&

$$

DISCUSSION/KEY MESSAGES...10
AVIATION...13
FIRE WEATHER...10


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