638
FXUS63 KUNR 100432
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1032 PM MDT MON MAR 9 2026
KEY MESSAGES
- SNOW ON TUESDAY. ACCUMULATIONS LESS THAN AN INCH ON THE PLAINS
WITH 1 TO 4 INCHES IN THE BLACK HILLS.
- WINDY AND WARM ON THURSDAY.
- UNSETTLED WEATHER FRIDAY THOUGH THE WEEKEND.
DISCUSSION
(TONIGHT THROUGH MONDAY)
ISSUED AT 951 PM MDT MON MAR 9 2026
UPPER AIR ANALYSIS SHOWS A LOW AMPLITUDE TROUGH ACROSS THE WESTERN
HALF OF THE CONUS. A ~170KT JET STREAK IS BEGINNING TO MOVE ONSHORE
THE PAC NW COAST. AT THE SURFACE, NORTHERLY FLOW CONTINUES BEHIND
THE FRONT, WHICH HAS NOW PUSHED INTO CENTRAL NEBRASKA.
TONIGHT/TUESDAY...THE TROUGH WILL DEEPEN AS THE JET STREAK CROSSES
THE NW CONUS. STRONG FORCING WILL SUPPORT THE FORMING OF A BAND OF
PRECIP ACROSS NE WY THROUGH NW SD TUESDAY MORNING, THEN WILL SLIDE
SOUTHWARD ACROSS THE CWA THROUGH THE AFTERNOON AND EVENING. PRECIP
IS EXPECTED TO START AS SNOW ACROSS NW SD...AND PERHAPS AS RAIN
BEFORE CHANGING OVER LATER IN THE AFTERNOON SOUTH OF THE I-90
CORRIDOR, AS TEMPS WARM INTO THE 40S. MOST SNOW WILL STRUGGLE TO
STICK ACROSS THE PLAINS, GIVEN ABOVE FREEZING AIR/GROUND TEMPS AND
ISOLATION THIS TIME OF YEAR, BUT THE BEST CHANCE FOR ACCUMULATING
SNOW WILL BE OVER NW SD IN THE MORNING BEFORE TEMPS RISE AND PERHAPS
SOUTH CENTRAL SD AS TEMPS FALL IN THE EVENING. THE COLDER BLACK
HILLS AND BEAR LODGE MOUNTAINS WILL RESULT IN HIGHER ACCUMULATIONS,
BUT THERE COULD STILL BE HINDERING FROM GROUND TEMPS/INSOLATION.
MODELS HAS SETTLED ON 1 TO 4 INCHES CENTERED ACROSS THE NORTHERN
BLACK HILLS, SO HAVE ISSUED A WINTER WEATHER ADVISORY 15Z-06Z.
WARMER WEATHER WILL WORK BACK INTO THE REGION WEDNESDAY AND
THURSDAY. HIGHS ON THURSDAY COULD REACH WELL INTO THE 60S ACROSS
MUCH OF THE AREA. A STRONG SHORTWAVE IS PROGGED TO CROSS THE
NORTHERN PLAINS ALONG WITH A DEEPENING SURFACE LOW. A STRENGTHENING
PRESSURE GRADIENT WILL BRING GUSTY WINDS TO THE CWA. A COLD FRONT IS
THEN EXPECTED THURSDAY AFTERNOON, WHICH WILL INCREASE WINDS FURTHER.
COULD SEE GUSTS TO 65 MPH. RAIN CHANGING TO SNOW WILL ALSO BE
POSSIBLE WITH THE FRONTAL PASSAGE. COOLER AND UNSETTLED WEATHER IS
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND, BUT THERE IS HIGH
UNCERTAINTY AS TO HOW THE PATTERN WILL PAN OUT.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1032 PM MDT MON MAR 9 2026
CLOUDS ARE EXPECTED TO CONTINUE TO THICKEN AND SLIGHTLY LOWER FROM
NORTH TO SOUTH OVERNIGHT, ALTHOUGH LATEST GUIDANCE HAS BACKED OFF
ON SEEING CIGS DROP BELOW OVC025 OR SO OVER KGCC AND KRAP UNTIL
THE MOST ORGANIZED PRECIPITATION WITH THIS NEXT SYSTEM ARRIVES
TUESDAY AFTERNOON. THUS, HAVE NUDGED CIGS IN THE TAFS A BIT HIGHER
OVERNIGHT THAN THE PREVIOUS FORECAST. RAIN/SNOW WILL DEVELOP
TUESDAY MORNING ACROSS NW SD INTO THE BLACK HILLS, CHANGING TO
SNOW AS IT SLIDES SOUTHWARD ACROSS THE REST OF THE FORECAST AREA
DURING THE AFTERNOON AND EVENING. THIS MAIN PUSH WILL BRING
WIDESPREAD MVFR TO BORDERLINE IFR CIGS/VSBYS. NUDGED START TIME ON
THESE IMPACTS TO 19Z/1PM AT KGCC AND 21Z/3PM AT KRAP BASED ON THE
LATEST HREF SUITE OF CAMS AND NBM GUIDANCE, ALONG WITH AN INCREASE
IN NORTHERLY WINDS WITHIN AN HOUR OR SO OF THESE TIMES.
CONFIDENCE IN CIGS, VSBYS, AND PRECIP TIMING TUESDAY AFTERNOON IS
MODERATE, WITH SOME ADDITIONAL TWEAKS POSSIBLE. PRECIP WILL END
TUESDAY EVENING FROM NW TO SE WITH GRADUALLY IMPROVING CIGS
OVERNIGHT INTO WEDNESDAY MORNING, LIKELY BACK TO VFR PRIOR TO
DAYBREAK WEDNESDAY.
FIRE WEATHER
ISSUED AT 951 PM MDT MON MAR 9 2026
ELEVATED FIRE WEATHER CONDITIONS RETURN WEDNESDAY, BUT CRITICAL
FIRE WEATHER CONDITIONS MAY DEVELOP THURSDAY WITH A SHARP WARM UP,
VERY DRY AIR, AND WIND GUSTS POTENTIALLY EXCEEDING 50-60 MPH.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY FROM 9 AM TUESDAY TO MIDNIGHT MDT
TUESDAY NIGHT FOR SDZ024.
WY...WINTER WEATHER ADVISORY FROM 9 AM TUESDAY TO MIDNIGHT MDT
TUESDAY NIGHT FOR WYZ057.
DISCUSSION/KEY MESSAGES...13
AVIATION...KSMITH
FIRE WEATHER...13
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