652
FXUS63 KUNR 151922
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
122 PM MDT SUN MAR 15 2026
KEY MESSAGES
- GUSTY NORTHWEST WINDS WILL SLOWLY DIMINISH THIS EVENING, WITH A
CHILLY NIGHT IN STORE ACROSS THE AREA.
- WARM FRONT LIFTING THROUGH THE CWA TUESDAY WILL BRING THE NEXT
CHANCE OF LIGHT RAIN/LIGHT SNOW.
- MUCH ABOVE SEASONAL NORMS EXPECTED FOR THE WEDNESDAY THROUGH
FRIDAY TIME FRAME.
DISCUSSION
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 119 PM MDT SUN MAR 15 2026
UPPER LEVEL ANALYSIS SHOWS 500HPA LONGWAVE TROUGH RUNNING FROM NW
MINNESOTA SOUTH INTO CENTRAL TEXAS. WATER VAPOR IMAGERY SHOWS
DRYING TAKING PLACE ACROSS EASTERN MT INTO THE WESTERN DAKOTAS,
AND THIS IS VERIFIED BY CLEARING CLOUD SHIELD ACROSS THE CWA IN
THE LATEST VISIBLE SATELLITE IMAGERY. AT THE SURFACE, VIGOROUS LOW
PRESSURE IS LOCATED ACROSS NORTHERN MO. HIGH PRESSURE IS BUILDING
INTO THE WESTERN DAKOTAS OUT OF THE SOUTHERN CANADIAN PROVINCES.
ON RADAR, MUCH OF THE SNOW HAS ENDED ACROSS THE AREA, WITH THE
EXCEPTION OF A SMALL AREA ACROSS THE SOUTHERN BLACK HILLS. THIS
APPEARS TO BE IN RESPONSE TO AN AREA OF 850-700 HPA FRONTOGENESIS
COUPLED WITH SOME LOCALIZED SURFACE CONVERGENCE GOING ON. WITH
THAT AREA ALSO BEING CLEAR MOST OF THE DAY, STEEPENING 700HPA
LAPSE RATES ARE ALSO PLAYING A ROLE IN THE SNOW DEVELOPMENT AS
WELL.
AS THE SURFACE HIGH CONTS TO BUILD INTO THE REGION, GUSTY
NORTHWEST WINDS WILL DIMINISH THROUGH EVENING BECOMING
LIGHT/VARIABLE ACROSS THE WESTERN CWA, BUT STILL NORTHWEST ACROSS
SOUTHCENTRAL SD. THE CLEARING SKIES AND FRESH SNOWPACK WILL ALLOW
TEMPS TO FALL TO AROUND ZERO FOR MANY LOCATIONS. SUSPECT THAT AS
WINDS GO NEARLY CALM AND WITH THE FRESH SNOWPACK, SOME LOCATIONS
WILL GO SUB-ZERO BY MORNING. MONDAY WILL BE A NEUTRAL DAY, WITH
NOTHING REALLY GOING ON TEMP ADVECTION WISE. WE MAY SEE A FEW
FLURRIES GET WRUNG OUT ACROSS THE FAVORED LOCATIONS IN THE HIGHER
BLACK HILLS, BUT SHOULDN’T ADD TO ANY TOTALS.
THE NEXT ROUND OF PCPN SHOWS UP ON TUESDAY WHEN A WARM FRONT
LIFTS THROUGH THE CWA. 700HPA THETA-E FORCING IS PRETTY IMPRESSIVE
AS IT PASSES THROUGH, AND 850HPA TEMPS START OFF SUB-ZERO C BUT
WARM QUICKLY AS THE FRONT PASSES THROUGH. ALSO NOTICED THAT 700HPA
WINDS INCREASE BEHIND THE FRONT TO 50+ KTS, LEADING TO A FAIRLY
BREEZY DAY ON TUESDAY. MAY NEED SOME WIND HEADLINES FOR TUESDAY
AFTERNOON, BUT WILL LET THAT RESOLVE ITSELF ONCE WE GET CLOSER.
OTHERWISE, ADVERTISED WARM-UP FOR THE WED-FRI TIMEFRAME IS STILL
IN STORE, WITH 850HPA TEMPS CLIMBING TO NEAR +20 C. MIGHT BE
DEALING WITH SOME FIRE WEATHER CONCERNS TOWARD THE END OF THE WEEK
WITH TEMPS CLIMBING WELL ABOVE SEASONAL NORMS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1211 PM MDT SUN MAR 15 2026
STRONG NORTHWEST WINDS CONTINUE TO PRODUCE AREAS OF BLOWING SNOW
AND IFR VSBYS IN THE WAKE OF THIS MORNING'S WINTER STORM, WITH
SOME LOW CLOUDS HOLDING ON AT KGCC AND A FEW DIMINISHING SNOW
SHOWERS STILL OUT AND ABOUT AS WELL. MODEL GUIDANCE HAS BEEN
RELATIVELY USELESS IN ACCURATELY CAPTURING TRENDS THIS MORNING, SO
FORECAST CONFIDENCE ON EXACT TIMING FOR IMPROVEMENT ON ANY OF
THESE ELEMENTS IS RELATIVELY LOW. WINDS ARE FORECAST TO GRADUALLY
DECREASE OVER THE NEXT SEVERAL HOURS AND THEN DROP OFF
DEFINITIVELY BY SUNSET, THUS ALL TERMINALS SHOULD RETURN TO VFR
CONDITIONS AT LEAST BY 00-01Z/6-7PM, IF NOT SOONER. WILL CONTINUE
TO MONITOR SFC OBS AND AMEND AS NEEDED. VERY LIGHT WINDS AND JUST
A FEW HIGH-LEVEL PASSING CLOUDS ARE EXPECTED TONIGHT AS QUIETER
WEATHER SETTLES IN.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...KSMITH
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