927
FXUS63 KUNR 272255
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
455 PM MDT SUN APR 27 2025
KEY MESSAGES
-STRONG LOW PRESSURE WILL CROSS THE REGION THROUGH MONDAY,
BRINGING SEVERE WEATHER, WIDESPREAD RAINS, AND BREEZY WINDS
-GRADUAL WARMING TREND AFTER MONDAY WITH ANOTHER CHANCE FOR
SHOWERS WEDNESDAY
DISCUSSION
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1218 PM MDT SUN APR 27 2025
DEEP UPPER TROUGH CURRENTLY PUSHING THROUGH THE ROCKIES TODAY.
THIS SYSTEM WILL EJECT OUT INTO THE PLAINS THIS EVENING,
SUPPORTING A GOOD CHANCE OF THUNDERSTORMS BY EVENING, SOME OF
WHICH MAY BE SEVERE. AMPLE LOW LEVEL MOISTURE HAS ARRIVED IN THE
REGION, ALTHOUGH SHALLOW. THIS IS INDICATED WELL BY THE 23
DEWPOINT AT WHITETAIL PEAK. CONVECTION MAY DEVELOP ON THE BH THIS
AFTERNOON, HOWEVER, STAUNCH CAPPING WILL LIKELY CONFINE ANY
ACTIVITY TO THE BH UNTIL THE MAIN LEAD IMPULSE ARRIVES THIS
EVENING. MAIN PREFRONTAL TROUGH WILL SUPPORT BETTER THUNDERSTORM
CHANCES IN THE LATE AFTERNOON/EVENING WITH SEVERE WEATHER POSSIBLE
AS SUFFICIENT CAPE (1-2 KJ/KG) AND BULK LAYER SHEAR (30-40 KNOTS)
WILL BE IN PLACE. EXPECT AN MCS TO EVENTUALLY DEVELOP AND PUSH
NORTHEAST ACROSS WESTERN SD THIS EVENING WITH HAIL AND DAMAGING
WINDS THE MAIN THREAT. PLENTY OF GULF MOISTURE WILL WRAP INTO THIS
SYSTEM, WHICH WILL FAVOR APPRECIABLE RAINS MONDAY AS THE
DEFORMATION ZONES SLIDES SE INTO THE REGION. EXPECT THE HIGHEST
RAIN TOTALS WILL BE IN THE NORTHERN BH AND FOOTHILLS GIVEN UPSLOPE
ENHANCEMENT, WITH QPF VALUES OVER AN INCH LIKELY THERE. SOME SNOW
WILL ALSO BE POSSIBLE ABOVE 6KFT IN THE BH, WITH SOME LIGHT
ACCUMS POSSIBLE MONDAY. THUNDER WILL ALSO BE POSSIBLE, ESP MONDAY
AFTERNOON ACROSS THE SOUTHEAST HALF. GUSTY NW WINDS CAN BE
EXPECTED MONDAY BEHIND THE COLD FRONT WITH ADV LEVEL WINDS
POSSIBLE ON MUCH OF THE WESTERN SD PLAINS. THINGS DRY OUT SOME THE
REMAINDER OF NEXT WEEK WITH ADDITIONAL CHANCES FOR SHOWERS WED AS
ANOTHER IMPULSE TRAVERSES THE FLOW. EXPECT A GRADUAL WARMING
TREND AS WELL, PEAKING BY NEXT WEEKEND.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 450 PM MDT SUN APR 27 2025
THIS EVENING, THUNDERSTORMS (SOME SEVERE) ARE EXPECTED TO MOVE
THROUGH MAINLY WESTERN SD. HAIL, GUSTY WINDS, AND HEAVY RAIN WILL
BE POSSIBLE, ALONG WITH MVFR/IFR CONDITIONS. EARLY MONDAY MORNING,
RAIN WILL BEGIN TO OVERSPREAD THE AREA, CONTINUING THROUGH THE
AFTERNOON. WIDESPREAD MVFR/IFR CONDITIONS ARE EXPECTED.
ADDITIONALLY, NORTHERLY WINDS WILL INCREASE (20-30 KTS WITH GUSTS
UP TO 45 KTS) IN THE AFTERNOON.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...JC
AVIATION...POJORLIE
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