147
FXUS63 KUNR 171737
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1137 AM MDT WED JUN 17 2026
KEY MESSAGES
- A WIND ADVISORY CONTINUES THROUGH 8PM MDT WITH NORTHWEST WINDS
GUSTING FROM 45 TO 55 MPH ON THE WESTERN SD PLAINS
- NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS CONTINUE THIS
AFTERNOON ACROSS SOUTHWEST SD.
- BETTER CHANCES FOR PRECIPITATION THIS WEEKEND.
UPDATE
ISSUED AT 1031 PM MDT TUE JUN 16 2026
04Z SURFACE ANALYSIS HAD ELONGATED LOW PRESSURE FROM CENTRAL ND
THROUGH EASTERN CO. WATER VAPOUR LOOP HAD UPPER LOW OVER CENTRAL
CANADA WITH NORTHWEST FLOW ALOFT SPINNING A SERIES OF SHORTWAVES
THROUGH THE NORTHERN PLAINS. LATEST WAVE AFFECTING THE DAKOTAS
WITH SHRA/TS THIS EVENING, TAPPING INTO LIMITED BUOYANCY AS ECHOES
ZIP SOUTHEAST AT 55 MPH.
GOING FORECAST IN PRETTY GOOD SHAPE. BEHIND A COLD FRONT LATER
TONIGHT, EXPECT 30-45KT BOUNDARY LAYER WINDS TO DEVELOP, MIXING
OUT IN THE MORNING ON THE SD PLAINS. WIND GUSTS TO 55 MPH LIKELY
GIVEN FORECAST BUFKIT SOUNDINGS, LATEST MOS, AND NBM GUIDANCE
(60-90% CHANCE 50+ MPH GUSTS).
REST OF FORECAST LEFT LARGELY INTACT WITH WETTER/COOLER PATTERN
CHANCES INCREASING FOR THE WEEKEND.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 135 PM MDT TUE JUN 16 2026
A LOW PRESSURE SYSTEM SPINNING NEAR THE WEST SIDE OF THE HUDSON
BAY IS OUR MAIN WEATHER MAKER FOR THE SHORT TERM FORECAST. IT'S
GIVING THE CWA NORTHWEST FLOW WITH JUST ENOUGH UPWARD VERTICAL
MOTION TO GET SOME SHOWERS AND THUNDERSTORMS GOING IN THE UPPER
GREAT PLAINS. SO FAR, MOST OF THE ACTIVITY HAS BEEN CONTAINED TO
EASTERN SD WHILE THE WESTERN COUNTIES HAVE BEEN DRY FOR THE MOST
PART, SAVE FOR A FEW CELLS THAT HAVE BEEN SHORT-LIVED.
LOOKING AHEAD TO TONIGHT THROUGH TOMORROW NIGHT, CONTINUED
NORTHWEST FLOW WILL KEEP THE CHANCES FOR ISOLATED SHOWERS AND NON-
SEVERE THUNDERSTORMS TO TRACK INTO THE AREA FROM THE NORTH. THESE
CHANCES WILL BE MAINLY CENTERED AROUND LITTLE SHORTWAVES SPINNING
AROUND THE MAIN LOW THAT WILL KEEP SPINNING NEAR HUDSON BAY. TEMPS
TONIGHT WILL DIP INTO THE 50S TO MID 60S AND TOMORROW'S HIGHS
WILL BE MOSTLY IN THE 70S. THE EXCEPTIONS ARE THE FAR NORTHWEST SD
COUNTIES AND THE FAR SOUTHERN SD COUNTIES WHERE TEMPS WILL REACH
THE UPPER 60S AND NEAR 80 RESPECTIVELY. NE WY LOOKS TO REACH THE
LOW TO MID 70S.
TOMORROW'S WINDS WILL BE THE MAIN STORY THOUGH. STRONG NORTHWEST
WINDS AT 15 TO 30 MPH WITH GUSTS NEARING 45 TO 55 ARE LIKELY
WEDNESDAY AFTERNOON. STRONGEST WINDS WILL BE IN THE SD PLAINS.
THERE IS SOME EVIDENCE THAT GUSTS TO 60 MPH ARE POSSIBLE IN THE NW
SD PLAINS BUT NOT ENOUGH TO WARRANT ISSUING A HIGH WIND WARNING
AT THIS TIME, SO DECIDED TO GO WITH A HIGH-END WIND ADVISORY. WILL
UPDATE IF NEEDED.
THURSDAY WILL CONTINUE THE CHANCES FOR ISOLATED SHOWERS AND
STORMS FROM THE NORTHWEST WITH THE COOLER HIGHS IN THE 70S. A BIG
DIFFERENCE WILL BE THE CALMER WINDS WITH EXPECTED NORTHWEST WINDS
AT AROUND 10 TO 20 MPH WITH GUSTS NEARING 30 MPH.
FRIDAY AND THE WEEKEND WILL SEE THE WEATHER PATTERN CHANGE TO A
MORE WESTERLY FLOW. THIS WILL BRING BACK WARMER TEMPS AND MORE
WIDESPREAD THUNDERSTORM CHANCES FOR THE WEEKEND.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1129 AM MDT WED JUN 17 2026
GUSTY NW WINDS WILL AFFECT WESTERN SD AND NORTHEAST WY THROUGH
18/02Z BEFORE DIMINISHING. GUSTS TO 45KTS ARE POSSIBLE BEFORE
DIMINISHING THIS EVENING. AN ISOLATED SHOWER IS POSSIBLE ACROSS
NORTHWEST SD THIS AFTERNOON, WITH MVFR VSBYS POSSIBLE IN THE
SHOWERS. OTHERWISE VFR CONDITIONS ARE EXPECTED AT THE TERMINAL
LOCATIONS THROUGH THE VALID FORECAST PERIOD.
FIRE WEATHER
ISSUED AT 135 PM MDT TUE JUN 16 2026
A COLD FRONT WILL MOVE THROUGH EARLY WEDNESDAY MORNING. BEHIND
THE COLD FRONT, STRONG NORTHWEST WINDS FROM 25 TO 35 MPH WITH
GUSTS FROM 40 TO 55 MPH ARE EXPECTED. MINIMUM RELATIVE HUMIDITY
VALUES WILL DIP AS LOW AS 18 PERCENT, WHICH IS HIGHER THAN NORMAL
(<=15%) THRESHOLDS. HOWEVER, THE STRONG WINDS WILL MAKE UP THE
DIFFERENCE AS WELL AS ANTECEDENT D2 TO D3 DROUGHT AND VERY DRY
WEATHER OVER THE PAST 1-2 WEEKS. THUS, CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED FOR PARTS OF NORTHEASTERN WYOMING AND
SOUTHWESTERN SOUTH DAKOTA LATE WEDNESDAY MORNING THROUGH THE EARLY
EVENING HOURS.
HUMIDITIES ON THURSDAY AND FRIDAY WILL BOTTOM OUT IN THE 20S WITH
WINDS GUSTING TO 15 TO 30 MPH. ELEVATED TO NEAR-CRITICAL FIRE
WEATHER CONDITIONS WILL CONTINUE AS A RESULT.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WIND ADVISORY UNTIL 8 PM MDT /9 PM CDT/ THIS EVENING FOR SDZ001-
002-012>014-025>027-030>032-041>044-046-047-049-072>078.
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR SDZ321-322-325-
326-332-333.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ315-317.
UPDATE...HELGESON
DISCUSSION...GS
AVIATION...HINTZ
FIRE WEATHER...GS
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