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
515 PM MDT sun Mar 29 2015

Short term...this evening through Monday night
issued at 226 PM MDT sun Mar 29 2015

20z surface analysis had northwesterly winds over the County Warning Area with weak
ridge over Colorado. Some cumulus popping up in well-mixed boundary layer.
Breezy winds continue...but have been slowly declining throughout
the day.

Tonight through Monday night...upper ridge over The Rockies
amplifies and shifts into the northern plains. Warm air advection
expected throughout the period with some middle/high clouds. Deep
mixing will promote breezy/windy spots Monday afternoon.
Temperatures will quite mild and near guidance.

Long term...Tuesday through Sunday
issued at 226 PM MDT sun Mar 29 2015

Upper level ridge crosses the northern plains on Tuesday...with
dry conditions and well above average temperatures expected.
Models continue to trend warmer...and so some record highs may be
broken on Tuesday. A strong shortwave trough will approach the
northern plains Tuesday night...with some showers and
thunderstorms possible across parts of northeast Wyoming...the Black
Hills...and far northwestern South Dakota. A cold front will accompany this
upper disturbance...bringing slightly cooler temperatures and
gusty northwest winds to the area for Wednesday.

Still looks like a secondary trough will cross the central states
towards the end of the week. GFS and Gem still showing a band of
rain/snow across southern portions of the County Warning Area...although both have
brought it farther south. 12z ecm solution is disorganized. Trended
southward with probability of precipitation Thursday night and broad-brushed probability of precipitation for
Friday. Highs for the end of the week will be in the 50s...warmer
and drier for next weekend.


Aviation...for the 00z tafs through 00z Monday evening
issued at 515 PM MDT sun Mar 29 2015

VFR conditions will continue tonight through Monday.


Fire weather...
issued at 226 PM MDT sun Mar 29 2015

Warm...dry...and breezy conditions will persist into the middle
of the week. Highs Monday will be in the middle 60s to middle 70s with
minimum relative humidity values in the upper teens to lower 20s. Northwest winds
will be 15 to 25 miles per hour across the South Dakota plains...strongest in northwest
South Dakota where the relative humidity values will be higher. Tuesday will be very warm
and dry...with highs in the 70s to lower 80s and min relative humidity values 12
to 22 percent. Winds will be southwesterly 10 to 15 miles per hour. A cold
front will pass through the region early Wednesday...bringing
gusty winds of 25 to 35 miles per hour across the western South Dakota plains. Highs
will range from the lower 50s across northeast Wyoming to the lower 70s
across south central South Dakota...with min relative humidity values 20 to 30 percent.


Unr watches/warnings/advisories...
South Dakota...none.


Short term...helgeson
long term...pojorlie
fire weather...pojorlie

National Weather Service Glossary of Abbreviations