600
FXUS63 KUNR 191743
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1043 AM MST TUE NOV 19 2024
KEY MESSAGES
- STRONG WINDS CONTINUE THROUGH WEDNESDAY WITH ELEVATED FIRE
WEATHER CONDITIONS ON THE WESTERN SOUTH DAKOTA PLAINS
UPDATE
ISSUED AT 1041 AM MST TUE NOV 19 2024
UPDATED TO ISSUE A HIGH WIND WARNING FOR THE BLACK HILLS,
BEGINNING THIS EVENING AND CONTINUING THROUGH WEDNESDAY.
NAM/HRRR/RAP FORECAST SOUNDINGS SHOW 50-60 KT WINDS MIXING TO THE
SURFACE FROM 700-750 MB. THIS IS SUPPORTED BY THE 12Z HREF, WHICH
SHOWS A 80-90% CHANCE OF WINDS >58 MPH OVER THE BLACK HILLS
TONIGHT INTO WEDNESDAY. ALSO EXTENDED THE WIND ADVISORY FOR THE
SPEARFISH FOOTHILLS, WHICH WAS GOING TO EXPIRE THIS EVENING, BUT
NOW GOES THROUGH WEDNESDAY.
DISCUSSION
(TODAY THROUGH MONDAY)
ISSUED AT 145 AM MST TUE NOV 19 2024
CURRENT SURFACE MAP PLACES 983MB LOW ACROSS SOUTHWESTERN
MINNESOTA. INITIAL PUSH OF COLD AIR IS MOVING THROUGH CENTRAL
SOUTH DAKOTA WITH NORTHWEST WINDS GUSTING 50-55MPH ACROSS THE
WESTERN SOUTH DAKOTA PLAINS. WATER VAPOR SHOWS UPPER LOW LIFTING
NORTHWARD OVER SOUTHERN MINNESOTA WHILE NORTHERN STREAM LOW OVER
NORTHERN MONTANA SLOWLY MOVES EASTWARD. THE PAIR OF UPPER LOWS
CONSOLIDATE LATE TODAY ALONG THE MINNESOTA/NORTH DAKOTA/MANITOBA
BORDER THEN SHIFTS SLOWLY SOUTHEAST ON WEDNESDAY. WITH BEST
PRESSURE RISES SHIFTING EAST OF THE FORECAST AREA EARLY THIS
MORNING, THERE WILL BE DOWNWARD TREND IN WIND GUST SPEEDS. HREF
PROBABILITY OF GUSTS >50MPH IS ONLY 20-40% ACROSS NORTHWEST SOUTH
DAKOTA FOR MUCH OF THE DAY. THE MERGING OF MID/UPPER LOWS LATER
TODAY RESULTS IN STRONGEST BL-700MB WINDS LATE THIS EVENING
THROUGH MID DAY WEDNESDAY...AIDED BY STEEP LOW LEVEL LAPSE RATES
AND STRONG SUBSIDENCE. HREF PROBABILITY OF WIND GUSTS >55MPH
INCREASES TO 60-100% ACROSS THE NORTHWESTERN SOUTH DAKOTA PLAINS
LATE THIS AFTERNOON AND REMAINS ABOVE 50% THROUGH WEDNESDAY
AFTERNOON. NO CHANGES TO WIND HEADLINES. WHILE RELATIVE HUMIDITY
REMAINS WELL ABOVE CRITICAL THRESHOLDS (AROUND 50% IN NORTHWEST
SOUTH DAKOTA TO 25-35% IN SOUTHWEST/SOUTH CENTRAL SOUTH DAKOTA),
THE WINDS COULD RESULT IN RAPID FIRE GROWTH ON THE PLAINS.
UPPER RIDGE BUILDS IN THE NORTHERN PLAINS THURSDAY/FRIDAY WITH
WARMER/DRIER CONDITIONS. WARMEST TEMPERATURES WILL BE ACROSS
SOUTHWESTERN SOUTH DAKOTA WITH LREF GIVING 30-50% PROBABILITY OF
TEMPERATURES IN THE MID 50S ON SATURDAY. RIDGE BREAKS DOWN OVER
THE WEEKEND WITH A MORE ACTIVE PATTERN EARLY NEXT WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY)
ISSUED AT 1028 AM MST TUE NOV 19 2024
VFR CONDITIONS ARE GENERALLY EXPECTED ACROSS THE AREA THROUGH THE
FORECAST PERIOD, THOUGH SOME MVFR CONDITIONS COULD DEVELOP AT
TIMES ACROSS FAR NORTHWEST INTO CENTRAL SD LATER TODAY AND
TONIGHT. GUSTY NORTHWESTERLY WINDS WILL PERSIST THROUGH TONIGHT,
ESPECIALLY ACROSS THE SD PLAINS. GUSTS OF 40 TO OVER 50 KTS CAN BE
EXPECTED AT TIMES FROM THE NORTHWEST TO SOUTH CENTRAL SD PLAINS,
WHILE NORTHEASTERN WY, THE BLACK HILLS, AND FAR SOUTHWESTERN SD
MAY SEE GUSTS NEAR OR OVER 30 KTS AT TIMES. SOME LLWS MAY DEVELOP
TONIGHT INTO WEDNESDAY MORNING OVER PARTS OF THE BLACK HILLS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...HIGH WIND WARNING UNTIL 5 PM MST /6 PM CST/ WEDNESDAY FOR SDZ001-
002-012>014-031-032-043-044-046-047-049-072-073-077-078.
HIGH WIND WARNING FROM 8 PM THIS EVENING TO 5 PM MST WEDNESDAY
FOR SDZ024-028-029.
WIND ADVISORY UNTIL 5 PM MST WEDNESDAY FOR SDZ025-026.
WY...NONE.
UPDATE...KP
DISCUSSION/KEY MESSAGES...7
AVIATION...DYE
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