634
FXUS63 KUNR 040052
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
652 PM MDT SUN MAY 3 2026
KEY MESSAGES
- SCATTERED SHRA/ISOLATED TS END EARLY THIS EVENING OVER
SOUTHWEST HALF OF CWA.
- COLD FRONT DROPS THROUGH LATE TONIGHT/MONDAY MORNING WITH GUSTY
NORTHERLY WINDS BEHIND IT AS WELL AS SOME SHOWERS.
- MEAN NORTHWEST FLOW ALOFT BRINGS UNSETTLED WEATHER THROUGH NEXT
WEEKEND.
DISCUSSION
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1203 PM MDT SUN MAY 3 2026
17Z SURFACE ANALYSIS HAD WEAK TROUGH FROM THE BIG HORNS INTO THE
NE PANHANDLE. TROUGH REFLECTION OF COMPACT SHORTWAVE OVER THE BIG
HORNS PER WATER VAPOUR LOOP. 0.5KM VISIBLE SATELLITE MATINEE
DEPICTED AGITATED CU/TCU FIELD ASSOCIATED WITH THESE FEATURES.
FEW LIGHTNING STRIKES NEAR THE BIG HORNS WITH SLOWLY INCREASING
RADAR RETURNS OVER THE BLACK HILLS. ~250J/KG SBCAPE OUT THERE,
FORECAST TO PEAK AROUND 500J/KG PER SPC HREF. RESULT WILL BE
SCATTERED SHRA/ISOLATED TS THROUGH EARLY THIS EVENING OVER THE
SOUTHWEST HALF OF THE CWA. ENOUGH 0-6KM BULK SHEAR TO HELP A STORM
IF BUOYANCY WERE HIGHER, BUT WOULDN'T BE SURPRISED TO SEE A STORM
PUT OUT A 30-40KT WIND GUST GIVEN THE 18Z KUNR SOUNDING.
AFTER THE PRECIPITATION ENDS EARLY THIS EVENING, NEXT UPSTREAM
SHORTWAVE TROUGH CAREENS SOUTHWARD INTO THE NORTHERN PLAINS LATE
TONIGHT/MONDAY MORNING PUSHING A COLD FRONT THROUGH THE CWA.
DECENT PRESSURE RISES BEHIND FRONT WITH FORECAST SOUNDINGS
DEPICTING WELL-MIXED BOUNDARY LAYER LATE MONDAY MORNING INTO THE
AFTERNOON HOURS. RESULT WILL BE GUSTY NORTHWEST WINDS AT TIMES,
ESPECIALLY FROM K2WX-KRCA WHERE NBM PROBABILITY OF >45MPH WIND
GUSTS IS 40-70%. HAVE HOISTED A WIND ADVISORY TO ACCOUNT. BAND OF
800-600MB FRONTOGENESIS WILL SUPPORT SCATTERED SHOWERS
POTENTIALLY ENHANCING DOWNWARD MOMENTUM TRANSFER. TEMPERATURES
WILL BE COOLER/NEAR GUIDANCE.
MEAN NORTHWEST FLOW ALOFT CONTINUES FOR TUESDAY THROUGH NEXT
WEEKEND WITH A PARADE OF SHORTWAVES/SURFACE FRONTS. RESULT WILL BE
ISOLATED/SCATTERED SHOWERS AT TIMES. TEMPERATURES WILL BE 5-10F
BELOW NORMAL TUESDAY/WEDNESDAY, BUT THEN RISE TO 5-10F ABOVE
NORMAL FOR THE WEEKEND. CONFIDENCE IS FAIRLY HIGH UNTIL NEXT
WEEKEND WHEN TYPICAL ENSEMBLE GUIDANCE SPREADS COME INTO PLAY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 652 PM MDT SUN MAY 3 2026
SHOWERS AND THUNDERSTORMS HAVE MOVED OUT OF THE REGION, LEAVING
BEHIND VFR CONDITIONS FOR THIS EVENING AND OVERNIGHT. A COLD
FRONT IS FORECAST TO CROSS THE REGION MONDAY MORNING, INCREASING
WINDS OUT OF THE NW ESPECIALLY RAMPING UP AFTER 11Z/5AM AND
CONTINUING THROUGH THE DAY. THERE IS THE POTENTIAL FOR SHOWERS AS
WELL, ALTHOUGH CONFIDENCE IN DIRECT IMPACTS AT EITHER KRAP OR
KGCC IS SOMEWHAT LOW WITH SOME DIFFERENCES BETWEEN THE CAMS.
OVERALL POTENTIAL SEEMS GREATEST FOR NOW AT KGCC IN THE
14-20Z/8AM-2PM WINDOW, THUS HAVE ADDED A PROB30 -SHRA THERE WITH
PERHAPS SOME CLOUDS DIPPING JUST BELOW VFR THRESHOLDS WITH THAT
ACTIVITY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WIND ADVISORY FROM 9 AM TO 6 PM MDT MONDAY FOR SDZ001-002-012-
013-073-078.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...KSMITH
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