418
FXUS63 KUNR 030501
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1001 PM MST FRI JAN 2 2026
KEY MESSAGES
- SOME PATCHY FOG MAY LINGER ALONG THE FOOTHILLS THROUGH SATURDAY
MORNING.
- REMAINING DRY AND UNSEASONABLY MILD THROUGH THE WEEKEND AND INTO
NEXT WEEK.
DISCUSSION
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 123 PM MST FRI JAN 2 2026
LATEST ANALYSIS SHOWS 500HPA WAVE DROPPING SOUTHEAST THROUGH NE
CURRENTLY WITH WINTRY MIX OCCURRING SOUTH OF THE FA WITH WESTERN
CONUS RIDGE HAVING RETREATED WESTWARD SLIGHTLY OVER THE PAST 24
HOURS. NORTHWEST FLOW REMAINS ENTRENCHED OVER THE REGION WITH NEXT
WAVE TO IMPACT THE REGION NOW CRASHING ONSHORE ONTO THE NORTHERN
CA/OR COAST. AT THE SURFACE, THE BAROCLINIC BOUNDARY HAS SAGGED
SOUTHWEST OF OUR SD COUNTIES, WITH MOST PLACES NOW STRUGGLING IN
THE MID 20S FOR TEMPS WITH THE EXCEPTION OF THE BLACK HILLS AND
OUR WY COUNTIES WHO ARE ENJOYING MID TO UPPER 40S BY BEING ABOVE
THE INVERSION LAYER OR ON THE WARM SIDE OF THE BOUNDARY.
WEAK WAA BEGINS AFT 00Z SATURDAY ACROSS THE FA, BUT QUESTIONS
REMAIN ON HOW MUCH WILL ACTUALLY WORK DOWN TO THE SURFACE BASED ON
WEAK SURFACE WINDS KEEPING MIXING AT BAY. HI-RES MODELS DO SHOW
SFC WINDS BECOMING LIGHT WESTERLY AS FRONTAL BOUNDARY BEGINS TO
PUSH BACK TO THE EAST AS A WARM FRONT DURING THE OVERNIGHT HOURS.
AM A BIT WORRIED ABOUT PATCHY FOG LINGERING ALONG THE FOOTHILLS OF
THE BLACK HILLS THROUGH THE MORNING HOURS WHICH WILL AFFECT
SENSIBLE TEMPS. RIGHT NOW, NBM SOLUTION HAS TEMPS SLOWLY RISING
THROUGH THE NIGHT WITH BOUNDARY PUSHING BACK TO THE EAST AND
WESTERLY SFC WINDS. LATEST VISIBLE SATELLITE PIX DO SHOW SOME
CLEARING IN THE CLOUDS WITH THE SUBSIDENCE BEHIND THE EXITING
WAVE, SO PERHAPS IT WILL BE ENOUGH TO KEEP ANY PATCHY FOG AT BAY.
OTHERWISE WESTERN CONUS RIDGE STRENGTHENS AND PUSHES EAST OVER THE
REGION THROUGH THE WEEKEND. FAIRLY VIGOROUS 700HPA WAVE MOVES
THROUGH THE UPPER MIDWEST DURING THE MORNING HOURS ON SUNDAY,
FLATTENING THE RIDGE. THIS DRAGS A SURFACE TROUGH THROUGH THE
REGION WITH GOOD WESTERLY SURFACE WINDS EXPECTED. THERE ARE SOME
MINOR CHANCES FOR SOME HIGHER ELEVATION PCPN AS THIS SURFACE
FEATURE PASSES, BUT NOT ENOUGH CONFIDENCE RIGHT NOW TO INCLUDE IN
THE FORECAST. SUNDAY STILL APPEARS TO BE THE WARMEST DAY HEADING
INTO THE NEXT WEEK. ANOTHER WAVE MOVES THROUGH THE DEVELOPING
UPPER ZONAL FLOW MONDAY NIGHT, BRINGING SOME SMALL CHANCES FOR
PCPN TO THE HILLS AND PARTS OF THE PLAINS.
UPPER FLOW REMAINS ZONAL THROUGH MID-WEEK BEFORE TURNING SOUTHWEST
WITH FALLING 500HPA HEIGHTS AHEAD OF THE DIGGING WEST COAST
TROUGH. THIS WILL USHER IN FALLING 850HPA TEMPS AND INCREASING
CHANCES FOR PCPN TOWARD THE END OF NEXT WEEK.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 957 PM MST FRI JAN 2 2026
PATCHY FOG AND ASSOCIATED MVFR/IFR CONDITIONS MAY DEVELOP ACROSS
NORTHWESTERN SD OVERNIGHT INTO EARLY SATURDAY MORNING. OTHERWISE,
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...WONG
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