631
FXUS63 KUNR 300852
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MDT SUN MAR 30 2025
KEY MESSAGES
- ADDITIONAL LIGHT SNOW AT TIMES TODAY WITH SOME LIGHT ACCUMULATIONS,
MAINLY FROM PARTS OF NORTHEAST WY TO THE BLACK HILLS.
- A SERIES OF DISTURBANCES WILL BRING CHANCES FOR RAIN/SNOW TO THE
REGION THROUGH MID WEEK.
- TEMPERATURES TO REMAIN MOSTLY BELOW SEASONAL AVERAGES THROUGH THE
WEEK.
DISCUSSION
(TODAY THROUGH SATURDAY)
ISSUED AT 252 AM MDT SUN MAR 30 2025
CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE NOW OVER CENTRAL/EASTERN
IA, WITH HIGH PRESSURE CENTERED OVER SOUTH CENTRAL CANADA. NEARLY
STATIONARY FRONTAL BOUNDARY SITS ALONG THE LEE OF THE ROCKIES TO
THE SOUTHERN PLAINS. UPPER LEVEL ANALYSIS SHOWS BROAD UPPER TROUGH
FROM THE ROCKIES TO THE UPPER MIDWEST. MAIN ENERGY WITHIN THE
TROUGH HAS MOVED WELL EAST OF THE AREA OVERNIGHT, BUT LINGERING
WEAK ENERGY CONTINUES TO BRING SOME AREAS OF VERY LIGHT SNOW OR
FLURRIES. SKIES ARE GENERALLY CLOUDY WITH TEMPS MOSTLY IN THE 20S.
THERE COULD BE SOME PATCHY FOG DEVELOPING EARLY THIS MORNING AS
NORTH TO NORTHEAST WINDS REMAIN IN PLACE.
UNSETTLED AND COOLER WEATHER CAN BE EXPECTED FOR A GOOD PORTION OF
THE UPCOMING WEEK AS UPPER PATTERN REMAINS RATHER STAGNANT AND A
SERIES OF UPPER LEVEL DISTURBANCES/TROUGHS MOVE ACROSS THE REGION IN
NEAR ZONAL FLOW. FOR TODAY, THE NEXT DISTURBANCE WILL MOVE INTO
NORTHEAST WY THIS MORNING AND ACROSS MOSTLY SOUTHERN PORTIONS OF THE
FORECAST AREA THROUGH THE AFTERNOON AND EARLY EVENING. DRIER
NORTHERLY LOW LEVEL FLOW TO THE NORTH AND NORTHEAST OF THE BLACK
HILLS WILL HELP TO KEEP PCPN MOSTLY CONFINED TO NORTHEAST WY, THE
BLACK HILLS, AND SOUTHWEST SD. PCPN SHOULD MOSTLY BE IN THE FORM OF
SNOW WITH ANY ACCUMULATIONS BEING ON THE LIGHT SIDE, MOSTLY AN INCH
OR LESS ON COLDER SURFACES. HOWEVER, COULD SEE AS MUCH AS A COUPLE
OF INCHES OR SO ACROSS THE HIGHER ELEVATIONS OF THE WESTERN BLACK
HILLS LATE THIS MORNING AND AFTERNOON. EXPECTED TEMPS NEAR OR
SLIGHTLY ABOVE FREEZING LATE THIS MORNING AND AFTERNOON WILL LIMIT
ACCUMULATION POTENTIAL IN MOST AREAS DURING THAT TIME. HIGHS WILL
REACH THE 30S TO AROUND 40 DEGREES THIS AFTERNOON, WARMEST EAST AND
NORTHEAST OF THE BLACK HILLS. LINGERING PCPN WILL TAPER OFF THIS
EVENING, WITH LOWS GENERALLY IN THE 20S.
MONDAY WILL START OFF MAINLY DRY AND VARIABLY CLOUDY THROUGH THE
MIDDAY HOURS, WITH INCREASING CHANCES FOR MOSTLY RAIN SHOWERS LATER
IN THE AFTERNOON INTO MONDAY NIGHT AS THE FRONTAL BOUNDARY TO THE
WEST STARTS TO MOVE EASTWARD TOWARD THE AREA WITH A PASSING
SHORTWAVE DISTURBANCE. HIGHS WILL REACH THE 40S AND LOWER 50S MONDAY
AFTERNOON WITH INCREASING SOUTHEASTERLY WINDS. A STRONGER UPPER
LEVEL SYSTEM IS THEN FORECAST TO PASS ACROSS THE REGION LATER
TUESDAY INTO WEDNESDAY AND INTENSIFY TO THE EAST OF THE REGION. AT
THIS POINT, THE AIRMASS LOOKS TO BE WARM ENOUGH FOR RAIN IN MOST
AREAS ON THE PLAINS INTO AT LEAST TUESDAY EVENING, WITH A MIX AND/OR
CHANGE OVER TO SNOW ACROSS AT LEAST NORTHEAST WY TO THE BLACK HILLS
AND NORTHWEST SD TUESDAY NIGHT INTO WEDNESDAY MORNING. ENSEMBLE
AVERAGES FROM GFS AND EC SUPPORT MOSTLY MINOR ACCUMULATIONS, THOUGH
PROBABLY OVERDONE IN AT LEAST SOME AREAS. ACCUMULATION POTENTIAL IS
RATHER UNCERTAIN AT THIS POINT, BUT HIGHER ELEVATIONS OF THE
NORTHERN BLACK HILLS AND BEAR LODGE MTS WOULD BE MOST FAVORABLE FOR
MORE IMPACTFUL SNOWFALL, ESPECIALLY WITH ANY UPSLOPE ENHANCEMENT.
LATEST LREF PROBABILITIES FOR 2" OR MORE TUESDAY NIGHT INTO
WEDNESDAY ARE MOSTLY 30 TO 70 PERCENT ACROSS THE NORTHERN BLACK
HILLS, THE HIGHER ELEVATIONS OF NORTHEAST WY, AND PARTS OF NORTHWEST
SD, WITH NBM PROBS A BIT HIGHER ACROSS AT LEAST THE NORTHERN BLACK
HILLS. WILL CONTINUE TO MONITOR.
THE REST OF THE WEEK LOOKS TO REMAIN COOL, WITH NEAR TO SLIGHTLY
BELOW AVERAGE TEMPS. THE UPPER AIR PATTERN LOOKS TO BE LESS
UNSETTLED LATE WEEK, BUT DEVELOPING TROUGH OVER THE WESTERN US COULD
BRING AT LEAST LOW CHANCES FOR SHOWERS AT TIMES, ESPECIALLY FRIDAY
AND SATURDAY.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1051 PM MDT SAT MAR 29 2025
MVFR TO LIFR CONDITIONS WILL CONTINUE ACROSS MUCH OF THE CWA
IN LOW CLOUDS AND LINGERING LIGHT SNOW OVERNIGHT. ANOTHER ROUND
OF LIGHT SNOW/RAIN MIX WILL PUSH INTO THE REGION AFTER 12Z. EXPECT
MVFR TO LIFR CONDITIONS TO PERSIST THROUGH THE TAF PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...26
AVIATION...SE
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