337
FXUS63 KUNR 140453
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1053 PM MDT TUE OCT 13 2026
KEY MESSAGES
- COLD TONIGHT, ESPECIALLY NORTHWESTERN SD WHERE A FREEZE WARNING
IS IN EFFECT. COLDER AIR OVERNIGHT THURSDAY WITH WIDESPREAD
FREEZING TEMPERATURES.
- PRECIPITATION CHANCES OVERNIGHT THROUGH WEDNESDAY; HEAVIEST
AMOUNTS ALONG NE/SD BORDER.
- BREEZY THURSDAY WITH WIND ADVISORY (45+ MPH GUSTS) WINDS
POSSIBLE (~55%).
- ABOVE AVERAGE TEMPERATURES RETURN FOR THE WEEKEND.
UPDATE
ISSUED AT 1005 PM MDT TUE OCT 13 2026
LITTLE CHANGE TO THE OVERALL FORECAST. PRECIPITATION MOVES INTO
THE REGION WEDNESDAY MORNING AS SURFACE LOW OVER NORTHERN CO
TREKS NORTHEAST. TWEAKED THE OVERNIGHT TEMPERATURES SLIGHTLY
WARMER GIVEN THE CLOUD COVER THAT'S EXPECTED TO LINGER OVERNIGHT.
STILL SHOULD SEE TEMPERATURES IN NORTHWESTERN SD DROP TO AT OR
JUST BELOW FREEZING. FREEZE WARNING REMAINS IN EFFECT FOR HARDING,
PERKINS, AND ZIEBACH COUNTIES THROUGH WEDNESDAY MORNING. EXPECT
PRECIPITATION TO LINGER THROUGH WEDNESDAY, WITH THE HIGHER QPF
AMOUNTS EXPECTED SOUTH OF I-90.
HAVE CONTINUED THE TREND OF LOWERING POST-FRONTAL WINDS FOR
THURSDAY, WITH THE NBM CONTINUING TO RUN HIGH (MAX GUSTS 60MPH+).
LATEST HIGH-RES GUIDANCE CONTINUES TO KEEP MAX GUSTS MORE IN THE
40 TO 50 MPH RANGE THURSDAY.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 107 PM MDT TUE OCT 13 2026
WATER VAPOR IMAGERY HIGHLIGHTS A CLOSED LOW CENTERED IN SOUTHERN
NV. FURTHER UPSTREAM, A STRONG VORT MAX IS LOCATED JUST OFF THE BC
COASTLINE WITH UPPER LEVEL MOISTURE STREAMING INTO WESTERN
CANADA. SURFACE HIGH PRESSURE HAS SETTLED ACROSS EASTERN
MT/WESTERN ND WITH TEMPERATURES ACROSS THE FORECAST AREA IN THE
40S. LOW CLOUDS WILL LINGER THROUGH THE AFTERNOON, LIMITING HIGH
TEMPERATURE POTENTIAL TO THE MID TO UPPER 40S FOR MOST OF THE AREA
AND LOW TO MID 50S ACROSS SOUTHERN SD. TEMPERATURES ARE FORECAST
TO FALL BELOW FREEZING ACROSS PORTIONS OF HARDING, PERKINS, AND
ZIEBACH COUNTIES, PARTICULARLY CLOSER TO THE SD/ND BORDER; HAVE
ISSUED A FREEZE WARNING FOR THESE COUNTIES. CLOUD COVER MAY BE A
LIMITING FACTOR, HOWEVER, ENOUGH CLEARING IS EXPECTED ACROSS THIS
AREA FOR TEMPERATURES TO BOTTOM OUT. SOUTH OF THE WARNED AREA,
CLOUD COVER IS EXPECTED TO KEEP TEMPERATURES ABOVE FREEZING AND
LIMIT THE POTENTIAL OF FROST DEVELOPMENT.
CHANCES FOR PRECIPITATION INCREASE WEDNESDAY MORNING INTO THURSDAY
AS THE CLOSED LOW EJECTS INTO THE CENTRAL PLAINS. MOST OF THE RAIN
WILL BE CONFINED TO AREAS ALONG AND SOUTH OF I-90 WHERE 0.5-0.75"+
OF RAIN POSSIBLE FOR SOUTHERN CAMPBELL/WESTON COUNTIES IN WY AND
AREAS ALONG THE SD/NE BORDER.
THE NORTHERN STREAM WAVE THAT IS CURRENTLY LOCATED OFF THE BC COAST
WILL SWING THROUGH SOUTHERN CANADA INTO THE NORTHERN PLAINS AND
UPPER MIDWEST LATE WEDNESDAY INTO THURSDAY WITH A COLD FRONT TO PUSH
THROUGH THURSDAY. AS HAS BEEN THE CASE FOR A FEW DAYS, CONSIDERABLE
SPREAD REMAINS AMONG DETERMINISTIC AND ENSEMBLE GUIDANCE REGARDING
THE ULTIMATE STRENGTH OF THE WINDS BEHIND THE FRONT. THE STRONGEST
CORE OF 850-750 MB WINDS ARE FORECAST TO REMAIN DISPLACED TO OUR
NORTH AND EAST, COINCIDING WITH THE GREATEST COLD AIR ADVECTION.
FORECAST SOUNDINGS HIGHLIGHT POTENTIAL FOR WIND ADVISORY LEVEL
WINDS (WIND GUSTS > 45 MPH) ACROSS NORTHWESTERN SD THROUGH THE
WESTERN SD PLAINS THURSDAY AFTERNOON. OVERALL FORECAST CONFIDENCE
REMAINS LOW, HOWEVER. THE NBM CONTINUES TO FORECAST HIGH WIND
STRENGTH WINDS(GUSTS > 60 MPH), WHICH SEEM OVERDONE AND UNLIKELY
GIVEN THE INGREDIENTS THAT WILL BE IN PLACE.
CLEARING SKIES AND COLD AIR BEHIND THE FRONT WILL RESULT IN
WIDESPREAD SUB-FREEZING TO FREEZING TEMPERATURES ACROSS THE FORECAST
AREA THURSDAY NIGHT INTO FRIDAY MORNING. MUCH WARMER THIS WEEKEND
WITH HIGHS IN THE 60S AND 70S AS UPPER RIDGING BUILDS OVER THE
WESTERN HALF OF THE US.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1045 PM MDT TUE OCT 13 2026
LOW CLOUDS CONTINUE TO LINGER AROUND WESTERN SD AND NORTHEASTERN
WY. WINDS OVERNIGHT WILL BE LIGHT ACROSS THE AREA. RAIN WILL SET
IN WEDNESDAY MORNING AND LAST THROUGH MOST OF THE FORECAST PERIOD.
TIMING FOR THE SPOTTY SHOWERS REMAINS SOMEWHAT UNCERTAIN, BUT IT
WILL LIKELY START IN THE MORNING HOURS (14-18Z). PRECIP WILL BE
LIGHT DURING THIS TIME, BUT MVFR/IFR CEILINGS ARE LIKELY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...FREEZE WARNING FROM 2 AM TO 8 AM MDT WEDNESDAY FOR SDZ001-002-
014-078.
WY...NONE.
UPDATE...DYE
DISCUSSION...SE
AVIATION...SCHWEIGERT
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