368
FXUS63 KUNR 231725
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 AM MDT WED APR 23 2025
KEY MESSAGES
-A SYSTEM MOVING THROUGH THE REGION TONIGHT INTO THURSDAY WILL
BRING RAIN AND CHANCES FOR THUNDERSTORMS TO WESTERN SD AND
NORTHEASTERN WY. SOME AREAS ON THE WESTERN SD PLAINS AND THE
BLACK HILLS COULD SEE 0.25" OR MORE.
-SEMI-ZONAL ACTIVE PATTERN WILL BRING NEAR DAILY CHANCES FOR
PRECIPITATION, WITH A STRONGER SYSTEM EXPECTED THURSDAY AND
ANOTHER SUNDAY INTO MONDAY
-TEMPS WILL FLUCTUATE IN THE PERIOD AS A FRONTAL BOUNDARY WAVERS
OVER THE REGION, WITH THE COOLEST DAY THURSDAY
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 258 AM MDT WED APR 23 2025
CURRENT RAP REANALYSIS DEPICTS UPPER LEVEL WESTERLY, UNSETTLED
FLOW OVER THE NORTHERN PLAINS. WATER VAPOR IMAGERY SHOWS SOME MID
LEVEL MOISTURE WHICH HAS BEEN SUPPORTING MOSTLY CLOUDY SKIES AND
SCATTERED SHOWERS.
SHORTWAVE ENERGY MOVING INTO THE REGION TODAY WILL TRIGGER A FEW
AFTERNOON SHOWERS ACROSS THE SOUTHERN TIER OF THE CWA THIS
AFTERNOON. A FEW STORMS ARE ALSO POSSIBLE, ESPECIALLY TOWARDS THE
NE BORDER WHERE MODEST BUOYANCY (300-500 J/KG MU CAPE) WILL BE
PRESENT. BETTER CHANCES FOR PRECIP WILL ARRIVE LATER WEDNESDAY
NIGHT AND THURSDAY AS BETTER LIFT AND MOISTURE MOVE INTO THE
REGION. MOST OF THE CWA SHOULD SEE AT LEAST MEASURABLE PRECIP WITH
LREF PROBS POINTING AT A 70-100% CHANCE FOR >0.1" QPF OVER PRETTY
MUCH ALL OF THE CWA. NORTHEAST FLOW ON THURSDAY WILL SUPPORT
HIGHER QPF AMOUNTS ACROSS THE NORTHERN AND EASTERN BLACK HILLS AND
FOOTHILLS (50-90% PROBS FOR >0.25" PER LREF). SOME SPOTS ACROSS
THE WESTERN SD PLAINS COULD SEE EVEN HIGHER AMOUNTS, DEPENDING ON
WHERE EXACTLY THE STRONGEST MID-LEVEL FGEN SETS UP. RAIN COULD
CHANGE OVER TO SNOW ACROSS THE BLACK HILLS AND POTENTIALLY
NORTHWESTERN SD INTO NORTHEASTERN WY AS COLDER AIR FILTERS INTO
THE REGION. NOT ANTICIPATING MUCH SNOW ACCUMULATION OVER THE LOWER
ELEVATIONS DUE TO TIME OF DAY AND RECENT MILD TEMPS, BUT THE
BLACK HILLS COULD PICK UP AN INCH OR TWO OF SNOW - POTENTIALLY
MORE IF COLDER TEMP PROFILES MATERIALIZE AND THE CHANGEOVER TO
SNOW OCCURS EARLIER.
UNSETTLED FLOW CONTINUES THROUGH THE WEEKEND WITH OCCASIONAL
LOBES OF SHORTWAVE ENERGY ADVECTING ACROSS THE REGION, SUPPORTING
SLIGHT CHANCES FOR SHOWERS FRIDAY INTO SATURDAY. A STRONGER SYSTEM
APPROACHES THE REGION ON SUNDAY AS A STRENGTHENING UPPER LEVEL
TROUGH DEEPENS OVER THE ROCKIES AND EJECTS OVER THE PLAINS AND SFC
LEE CYCLONE DEVELOPS. SEVERE WEATHER IS POSSIBLE SUNDAY AFTERNOON
ACROSS THE WESTERN SD PLAINS AS THE WARM SECTOR PUSHES INTO THE
REGION. HOWEVER, THE THREAT RIGHT NOW LOOKS TO BE CONDITIONAL AS
BOTH THE DETERMINISTIC GFS AND EURO POINT TO THE BETTER UPPER
LEVEL FLOW (AND THUS THE BETTER SHEAR) MOVING INTO THE REGION
LATER SUNDAY EVENING INTO OVERNIGHT SUNDAY. IF THAT SHEAR MOVES
INTO THE REGION EARLIER AND COINCIDES WITH THE BEST BUOYANCY ON
SUNDAY AFTERNOON, COULD SEE SOME SEVERE WEATHER ACROSS THE WESTERN
SD PLAINS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1124 AM MDT WED APR 23 2025
VFR CONDITIONS ARE GENERALLY EXPECTED TODAY AND INTO EARLY THIS
EVENING. ISOLATED SHOWERS HAVE DEVELOPED FROM KIEN TO KICR AND
THESE WILL LIFT SLOWLY NORTHWARD INTO THE AFTERNOON HOURS. ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE IN THE AFTERNOON AND EVENING
ACROSS FAR SOUTHERN SD. AREAS OF MVFR/IFR CONDITIONS WILL DEVELOP
TONIGHT, ESPECIALLY LATE TONIGHT, AS UPSLOPE FLOW INCREASES OVER
THE REGION AND PRECIPITATION BECOMES MORE WIDESPREAD. SOME SNOW
WILL LIKELY DEVELOP OVER THE BLACK HILLS AND POSSIBLY FAR
NORTHWEST SD OVERNIGHT.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...WONG
AVIATION...SE
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