244
FXUS63 KUNR 121840
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1240 PM MDT MON OCT 12 2026
KEY MESSAGES
- COOLER WEATHER PREVAILS WITH PRECIPITATION CHANCES THROUGH
THURSDAY.
- NEAR-FREEZING TEMPERATURES OVERNIGHT TONIGHT AND TUESDAY AND
THURSDAY NIGHTS.
- BREEZY THURSDAY WITH WARMER WEATHER FOR THE WEEKEND.
DISCUSSION
(THIS EVENING THROUGH MONDAY)
ISSUED AT 1235 PM MDT MON OCT 12 2026
CLOSED UPPER LOW IS CENTERED OVER SOUTHEASTERN OR WITH DEEP
TROUGH AXIS EXTENDING SOUTHWARD OFF SOUTHERN CA COAST. WATER VAPOR
IMAGERY SHOWS SHORTWAVE TROUGH PUSHING NORTH OF THE FORECAST AREA
INTO ND WITH ADDITIONAL MOISTURE AND EMBEDDED VORT MAXES TO OUR
WEST ALONG THE EASTERN PERIPHERY OF THE LOW. A SURFACE COLD FRONT
STRETCHES FROM SOUTHERN MN THROUGH NORTHEASTERN NE BACK INTO
SOUTHWESTERN NE. LOW CLOUDS WITH MIST/FOG PERSIST ACROSS THE
FORECAST AREA EARLY THIS AFTERNOON, ALTHOUGH BREAKS IN THE CLOUDS
ARE BECOMING MORE NUMEROUS AND EXPANSIVE. COLD TONIGHT WITH MANY
AREAS FALLING INTO THE MID TO UPPER 30S.
THE UPPER LOW IS FORECAST TO DIG INTO THE SOUTHWESTERN US WITH THE
TROUGH AXIS SHIFTING FURTHER EAST OVERNIGHT TONIGHT INTO TUESDAY AS
BROAD UPPER LEVEL ASCENT OVERSPREADS THE REGION. LIGHT RAIN POSSIBLE
OVERNIGHT TONIGHT INTO TUESDAY MORNING WITH AMPLE CLOUD COVER.
ADDITIONAL CHANCES OF LIGHT PRECIPITATION ARRIVE EARLY WEDNESDAY
THROUGH THURSDAY MORNING, WITH THE BEST CHANCES FOR WIDESPREAD
PRECIPITATION ALONG THE SD/NE BORDER AND SOUTHWARD.
NORTHERN STREAM TROUGH IS FORECAST TO DROP OUT OF SASKATCHEWAN AND
MANITOBA INTO THE UPPER MIDWEST EARLY THURSDAY, SWINGING A STRONG
COLD FRONT THROUGH THE NORTHERN PLAINS AND UPPER MIDWEST. A STRONG
BELT OF 850-700 MB WIND (~40-60 KNOTS) WILL PUSH INTO ND AND CENTRAL
SD, SIDESWIPING THE FORECAST AREA. THE STRONGEST COLD AIR
ADVECTION WILL REMAIN DISPLACED EAST OF THE FORECAST AREA, WHERE
STRONGEST WINDS CAN BE EXPECTED. DETERMINISTIC NBM GUIDANCE
CONTINUES TO FORECAST 60+ MPH WIND GUSTS ACROSS PORTIONS OF NW SD
AND THE WESTERN SD PLAINS THURSDAY AFTERNOON. HOWEVER, AN
INGREDIENTS-BASED APPROACH COUPLED WITH ENSEMBLE GUIDANCE DOES
NOT SUPPORT WINDS THIS STRONG. THE CURRENT FORECAST HAS WIND
ADVISORY LEVEL WINDS (~45 MPH) FOR PORTIONS OF NW SD INTO THE
WESTERN SD PLAINS THURSDAY AFTERNOON AND EVENING, ALTHOUGH THERE
IS LOW CONFIDENCE THAT THIS SOLUTION VERIFIES; CERTAINLY, THE HIGH
WIND (>60 MPH) POTENTIAL LOOKS UNLIKELY (PROBABILITY < 15%).
WESTERN RIDGING RETURNS NEXT WEEKEND WITH ABOVE AVERAGE TEMPERATURES
FORECAST AND DRY CONDITIONS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1128 AM MDT MON OCT 12 2026
THE WIDESPREAD IFR TO LIFR CONDITIONS HAVE BEEN TRENDING UPWARD
OVER THE LAST FEW HOURS.
LOOKING AHEAD TO THE REST OF TODAY, MVFR TO LOW-END VFR
CONDITIONS ARE EXPECTED FOR NW SD INTO NE WY THROUGH THE DAY,
HIGHER CONDITIONS LIKELY FOR SW SD INTO CENTRAL SD.
WIDESPREAD MVFR TO LOCALIZED IFR CONDITIONS EXPECTED TONIGHT DUE
TO LOW CLOUDS BUT CAN'T RULE OUT LOW VISIBILITY ISSUES IN PARTS OF
NE WY AND AROUND THE BLACK HILLS.
FOR THE WINDS, EXPECT BREEZY NW WINDS THROUGH THE AFTERNOON
BEHIND THE PASSING FRONT, MAINLY ACROSS NORTHEAST WY AND SW SD.
WINDS WILL DIMINISH THIS EVENING WITH LIGHTER WINDS OVERNIGHT.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...SE
AVIATION...GS
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