542
FXUS63 KUNR 290856
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
256 AM MDT SAT MAR 29 2025
KEY MESSAGES
- SPRING STORM ENTERING THE REGION THIS MORNING, BRINGING
WIDESPREAD PRECIPITATION THROUGH SUNDAY.
- LOW TO MEDIUM CONFIDENCE ON SNOWFALL AMOUNTS, MAINLY FOR THE
PLAINS WHERE TEMPERATURES COULD BE AN ISSUE.
- ANOTHER SYSTEM BEING TRACKED FOR MID-WEEK COULD BRING
WIDESPREAD PRECIPITATION AGAIN.
DISCUSSION
(TODAY THROUGH FRIDAY)
ISSUED AT 223 AM MDT SAT MAR 29 2025
CURRENT WATER VAPOR DEPICTS SOUTHWEST FLOW ALOFT, AS UPPER TROUGH
SITS OVER THE PAC NW DOWN INTO CA. SHORTWAVE CURRENTLY SITS OVER
WY/CO AREA. SURFACE CHARTS SHOW FRONTAL BOUNDARY STRETCHING FROM
NORTHERN WY DOWN INTO NORTHEASTERN CO. OUT AHEAD OF THE WAVE,
RADAR SHOWS PRECIPITATION HAS ENTERED PARTS OF NORTHEASTERN WY AND
SOUTHWESTERN TO SOUTH CENTRAL SD THIS MORNING.
INITIAL SHORTWAVE LIFTS INTO THE NORTHERN PLAINS EARLY TODAY AND
A SECONDARY WAVE MOVES THROUGH ON SUNDAY. WIDESPREAD
PRECIPITATION OVERSPREADS THE AREA THIS MORNING. LATEST MODEL RUN
HAS BEEN CONSISTENT WITH THE PREVIOUS ON QPF, WITH THE BETTER
FORCING FROM NORTHEASTERN AND EASTERN WY DOWN THROUGH NE AND THE
SOUTHERN HALF OF SD (GENERALLY ALONG AND SOUTH OF I-90). LOW LEVEL
NORTHEASTERLY FLOW WITH DRIER AIR WILL LIMIT PRECIPITATION
POTENTIAL FOR NORTHWESTERN SD. HOW FAR SOUTH THAT DRY AIR IS ABLE
TO GO GENERATES SOME UNCERTAINTY ON PRECIPITATION AMOUNTS ALONG
THE I-90 CORRIDOR.
HREF HAS BEEN PRETTY CONSISTENT THE LAST COUPLE OF RUNS.
PROBABILITY OF QPF 0.5" OR GREATER FOR NORTHEASTERN WY (SOUTH OF
I-90) THROUGH SOUTHWEST TO SOUTH CENTRAL SD SITS IN THE 80-100
PERCENT RANGE. PROBABILITY OF 1.0" OR MORE SITS IN THE 30-50
PERCENT RANGE. SNOWFALL UNCERTAINTY REMAINS A CONCERN, GIVEN
PREVIOUS WARM SURFACE TEMPERATURES AND AIR TEMPERATURES NEAR
FREEZING FOR THIS EVENT. LATEST NBM RUN LOWERED TEMPERATURES
SLIGHTLY, GIVING A BIT HIGHER SNOWFALL AMOUNTS. HAVE ISSUED A
WINTER WEATHER ADVISORY FOR SOUTH CENTRAL SD THROUGH THIS EVENING,
WHERE HREF SHOWING A SIGNAL FOR 1-2" /HR RATES AT TIMES THIS
AFTERNOON. WARMER GROUND/ROAD TEMPS MAY HELP TO LIMIT ANY IMPACTS.
WE MAY SEE A SHORT BREAK LATER SATURDAY BEFORE THE SECOND WAVE
IMPACTS THE REGION ON SUNDAY. HAVING COOLED ENOUGH, PRECIPITATION
WITH THIS WAVE SHOULD BE MAINLY SNOW. THE MAJORITY OF QPF WITH
THIS EVENT FALLS ON SATURDAY, SO SNOW ACCUMULATIONS ON SUNDAY WILL
BE MORE LIMITED, THE EXCEPTION BEING UPSLOPE EFFECTS OVER THE
BLACK HILLS. HAVE OPTED TO FOREGO AN ADVISORY OVER THE HILLS,
GIVEN THE ACCUMULATIONS ARE A BIT MORE SPREAD OUT OVER TIME.
PRECIPITATION SHOULD BE OUT OF THE REGION SUNDAY NIGHT, AND
ATTENTION TURNS TO THE NEXT WAVE COMING MID-WEEK. STILL SOME MODEL
DISCREPANCY ON THE TRACK AND TIMING CURRENTLY, BUT BOTH THE GFS
AND EC TRACK THIS WAVE TRAVERSING OVER THE ROCKIES AND INTO THE
NORTHERN PLAINS SOMETIME TUESDAY INTO WEDNESDAY WITH ANOTHER
CHANCE FOR WIDESPREAD PRECIPITATION. ENSEMBLES CONTINUE TO KEEP AN
ACTIVE WETTER PATTERN THROUGH NEXT WEEKEND.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 955 PM MDT FRI MAR 28 2025
MVFR CONDITIONS WITH RAIN WILL SPREAD ACROSS MUCH OF THE AREA
OVERNIGHT, THEN BECOMING IFR/LIFR AS PRECIP CHANGES TO SNOW
THROUGH THIS MORNING. CONFIDENCE IS STILL LOW ON THE EXACT TIMING
OF THE TRANSITION TO SNOW, HOWEVER IT APPEARS THAT MOST PLACES
WILL SEE SNOW BY 12-15Z.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY FROM 6 AM MDT /7 AM CDT/ THIS MORNING TO
8 PM MDT /9 PM CDT/ THIS EVENING FOR SDZ044-046-047-049-077.
WY...NONE.
DISCUSSION/KEY MESSAGES...DYE
AVIATION...WONG
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