115
FXUS63 KUNR 030509
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1009 PM MST MON FEB 2 2026
KEY MESSAGES
- ACCUMULATING SNOW OVER THE HIGHER NORTHERN BLACK HILLS TUESDAY
- ABOVE AVERAGE TEMPERATURES AND MOSTLY DRY WEATHER FOR THE REST
OF THE WEEK
DISCUSSION
(THIS EVENING THROUGH MONDAY)
ISSUED AT 104 PM MST MON FEB 2 2026
19Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM SOUTHERN AB TO
EASTERN NE WITH A WEAK TROUGH DRAPED ACROSS WESTERN ND/CENTRAL WY.
TROUGH A REFLECTION OF SHORTWAVE OVER THE DAKOTAS PER WATER
VAPOUR LOOP. NOT MUCH MOISTURE AVAILABLE, BUT A FEW RADAR RETURNS
PERKING UP ALONG SURFACE TROUGH AND OVER THE NORTHERN BLACK HILLS.
UPPER RIDGE OVER THE WESTERN CONUS WITH NEXT SHORTWAVE PUSHING
INTO BC, WHICH WILL BE THE MAIN SHORT TERM WEATHER CONCERN.
TONIGHT/TUESDAY, UPPER RIDGE BUILDS OVER THE WESTERN CONUS AS BC
SHORTWAVE SLIPS SOUTHEASTWARD INTO THE NORTHERN PLAINS. THIS
AFTERNOON'S SHORTWAVE EXITS THE CWA WITH SUBSIDENCE/DRYING IN IT'S
WAKE, ENDING RADAR RETURNS. NEXT SHORTWAVE BRINGS A BIT BETTER
MOISTURE WITH WEAK QG/FRONTOGENETIC FORCING FOR TUESDAY. 0-2KM RH
PERKS UP (90%) FOR THE NORTHERN BLACK HILLS AS FROUDE NUMBERS
BECOME FAVORABLE (>1) FOR UPSLOPE FLOW FOR 6-9 HOURS TUESDAY.
FORECAST SOUNDINGS SUGGEST BEST LIFT BELOW THE DGZ WITH MARGINAL
TEMPERATURES BELOW 5500' FOR BETTER SNOWS. HREF QPF PROBABILITY
>0.25" 50-80% FOR THE NORTHERN BLACK HILLS, BUT <50% FOR >0.50".
HAVE BUMPED UP QPF/SNOW AMOUNTS TO ACCOUNT (3-7" FOR THE HIGHEST
PEAKS), BUT WILL HOLD OFF ON HEADLINES GIVEN LOWER CONFIDENCE FOR
AMOUNTS AND BULK OF QPF FALLING DURING THE DAY. WY/SD PLAINS WILL
SEE MUCH LIGHTER QPF WITH A PREFERENCE FOR RAIN/LOWER POPS THAN
THE NORTHERN BLACK HILLS. TEMPERATURES WILL BE NEAR GUIDANCE.
THERMAL RIDGE BUILDS INTO THE AREA FOR THE SECOND HALF OF THE
WEEK, BUT ESPECIALLY FOR THURSDAY WHEN ECMWF EFI INDICATES 80-90%
PERCENTILE MAXT WITH SOME SOT ACTION. THURSDAY SHOULD BE THE
WARMEST DAY OF THE WEEK WITH RECORD TEMPERATURES IN JEOPARDY.
PREPONDERANCE OF ENSEMBLE GUIDANCE PORTRAYS MILD WEATHER INTO NEXT
WEEKEND, ESPECIALLY OVER THE SOUTHWEST HALF OF THE CWA. LIMITED
PRECIPITATION CHANCES WEDNESDAY THROUGH NEXT WEEKEND WITH <20%
CHANCE >0.01" QPF PER LATEST NBM.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1003 PM MST MON FEB 2 2026
A QUASI-STATIONARY FRONT STRETCHES FROM SW ND THROUGH SOUTH-
CENTRAL SD WITH MVFR/IFR CONDITIONS DEVELOPING IN LOW CLOUDS WITH
SOME AREAS OF PATCHY FOG. THESE LOW CLOUDS ARE SLOWLY PUSHING
WESTWARD WITH A LOW CHANCE OF IMPACTING KRAP, ALTHOUGH HAVE KEPT
THEM OUT OF THE FORECAST WITH THE 06Z TAFS.
AN APPROACHING SYSTEM WILL PUSH THROUGH NE WY AND NW SD AFTER 12Z,
BRINGING LIGHT SNOW TO THE AREA WITH MVFR/IFR CONDITIONS,
PARTICULARLY IN THE BLACK HILLS AND ACROSS NW SD. LINGERING IFR
CONDITIONS ALONG THE FRONT ACROSS SOUTH-CENTRAL SD NEAR THE END OF
THE FORECAST PERIOD INTO EARLY WEDNESDAY MORNING.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...SE
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