Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
442 am MST Wednesday Jan 28 2015

Short term...today through Thursday night
issued at 216 am MST Wednesday Jan 28 2015

Water vapor shows upper ridge axis over the northern plains...with a
strong wave flattening the ridge over the northern rockies. Another
wave is noted over southwestern Wyoming. At the surface...Lee trough has advanced
through the western Dakotas...with cold front pushing into northern Montana.

Today...cold front over northern Montana will move quickly southeastward and cross the
County warning forecast area during the afternoon hours. Winds will increase by late morning as
850mb winds of 40-45kts attempt to mix towards the surface...with
winds increasing further this afternoon behind the cold front as lapse rates
steepen. Current Wind Advisory looks good. Could be a few -shra
from northestern Wyoming through the Black Hills into southwestern South Dakota as wave currently
over southwestern Wyoming moves eastward...but moisture is limited. Temperatures will be
quite mild again today...but still about 10-15f degrees cooler
than yesterdays record breaking warmth.

Tonight...winds will decrease during the evening with surface high
settling into the western zones by morning.

Thursday...plenty of insolation expected with surface high covering
the northern plains. It will be noticeably cooler with temperatures in the middle
30s to middle 40s.

Long term...Friday through Tuesday
issued at 216 am MST Wednesday Jan 28 2015

One more above average day is expected on Friday...with
highs in the 40s to around 50 degrees. Medium range models are in
better agreement on a stronger cooldown for this weekend and early
next week...though GFS ensemble still shows a fairly large spread of
possible temperatures through the period. Northwest flow will bring a
Canadian cold front across the area early on Saturday. Shortwave
energy behind the front will bring a chance for snow Saturday into
Saturday night. Any accumulations look to be light across the area.
Northwest flow aloft will continue to bring weak disturbances across
the area through the rest of the extended...with considerable cloud
cover and at least some low chances for probability of precipitation across portions of the
area...mostly far northeast Wyoming...the Black Hills...and far northwest
South Dakota. High temperatures will be near average on Saturday...then generally
below average from Sunday through Tuesday.

&&

Aviation...for the 12z tafs through 12z Thursday morning
issued at 442 am MST Wednesday Jan 28 2015

VFR conditions will generally continue through the forecast
period. Low level wind shear can be expected at krap early this
morning...ahead of an approaching cold front. After the front
passes...gusty northwest winds of 15 to 30 kts and gusts to 40 kts
will develop late this morning and afternoon...strongest winds
over the western South Dakota plains. There will also be a chance for light
rain showers across northeast Wyoming and southwest South Dakota during the day.

&&

Unr watches/warnings/advisories...
South Dakota...Wind Advisory from 11 am this morning to 7 PM MST this evening
for sdz001-002-012>014-025-026-031-032-072-073.

Wyoming...none.
&&

$$

Short term...Johnson
long term...26
aviation...26

National Weather Service Glossary of Abbreviations