238
FXUS63 KUNR 242319
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
519 PM MDT FRI OCT 24 2025
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES EXPECTED FOR THE WEEKEND
- ELEVATED FIRE WEATHER CONDITIONS EXPECTED AS WELL FOR THE
WEEKEND
- COOLER AND UNSETTLED WEATHER MOVING IN SUNDAY NIGHT THROUGH
MONDAY
DISCUSSION
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 133 PM MDT FRI OCT 24 2025
LATEST WATER VAPOR IMAGERY SHOWS 500 HPA WAVE DROPPING INTO
NORTHEAST ND/NORTHWEST MN WITH A FEW CLOUDS IMPACTING NORTHEAST
SD/WESTERN MN. ANOTHER LARGER CLOSED 500HPA LOW IN THE VCNTY OF
4-CORNERS SLOWLY DRIFTING TO THE SOUTH & EAST. 500HPA RIDGE
EXTENDS FROM SOUTHERN CA THROUGH CENTRAL MT AHEAD OF STRONG
LONGWAVE TROUGH PUSHING ONSHORE ACROSS THE WESTERN CONUS. AT THE
SURFACE, HIGH PRESSURE IS FIRMLY IN CONTROL ACROSS THE CWA WITH
GENERALLY LIGHT WINDS AND A FEW HIGH THIN CLOUDS DOTTING THE SKY.
TEMPS AROUND 18Z ARE A FEW DEGREES EITHER SIDE OF 60 DEGREES F.
FIRST DETAIL TO KEEP TRACK OF IS THE STRATUS DECK THAT IS LIFTING
NORTHWARD OUT OF NE AND INTO SC/SE SOUTH DAKOTA. IF THIS DECK
MOVES INTO OUR FAR SOUTHEASTERN COUNTIES, IT COULD KEEP THE
OVERNIGHT LOWS UP A CATEGORY OR TWO, AND KEEP THEM DOWN A CATEGORY
FOR SATURDAY. THE HRRR 850HPA RH VALUES SHOW THIS CLOUD DECK
STAYING JUST EAST OF TRIPP COUNTY FOR NOW, BUT IT WILL BE CLOSE
FOR SURE.
NEXT CONCERN WILL BE POTENTIAL FIRE WEATHER ISSUES FOR SATURDAY
AND SUNDAY. LEE TROUGHING SETS UP DURING THE DAY SATURDAY,
INCREASING THE SURFACE WIND SPEEDS ACROSS THE CWA. 850HPA TEMPS
ACROSS THE WEST ARE 16-18C...SETTING UP FOR HIGHS WELL ABOVE THE
SEASONAL NORM. ACROSS OUR WY COUNTIES AND THE SD PLAINS ENSEMBLE
MEAN RH VALUES FALL TO AROUND 20% WITH MEAN SFC WINDS FROM 15 TO
20 MPH. ON SUNDAY AS THE 500HPA RIDGE SLIDES EAST AND SW FLOW
DEVELOPS ALOFT, SFC PRE-FRONTAL TROUGH MOVES THROUGH AIDING IN
KEEPING BREEZY/WINDY CONDITIONS IN PLACE. HIGH TEMPERATURES WILL
PROBABLY BE A LITTLE COOLER WHEN COMPARED TO SATURDAY, BUT THE
ELEVATED FIRE WEATHER CONDITIONS LOOK TO PERSIST ACROSS THE FAR
SOUTHWESTERN COUNTIES WHERE RH VALUES STILL REMAIN AOA 20% WITH
THE WINDS.
LAST CONCERN DEALS WITH PCPN PROBABILITIES SUNDAY NIGHT INTO
MONDAY AS MAIN COLD FRONT PUSHES THROUGH. MODELS ARE SHOWING
FAIRLY STRONG WINDS BEHIND THE FROPA WITH 3-4MB PRESSURE RISES ON
THE BACKSIDE, PLUS GOOD CAA AS SEEN AT 850HPA AND DOWNSLOPING ON
THE 700HPA THETA-E SURFACE. FEEL THAT PCPN WILL FIRST START OFF AS
-SHRA ALONG AND AHEAD OF COLD FROPA SUNDAY EVENING/EARLY NIGHT
BUT WILL TRANSITION OVER TO -SN (ESPECIALLY OVER THE HILLS AND NW
SD) DURING THE OVERNIGHT HOURS. THERE IS SOME CONCERN THAT EVEN
THE FOOTHILLS/NEAR PLAINS COULD SEE SOME FLAKES OF SNOW MONDAY
MORNING. OF INTEREST WAS THAT THE GFS WAS ACTUALLY SHOWING ADVRY
CRITERIA SNOWFALL BY MONDAY AFTERNOON ACROSS OUR FAR NW COUNTIES.
AFTER MONDAY, WEAK UPPER LEVEL RIDGING WILL MOVE BACK INTO THE
AREA BRINGING DRIER AND SEASONABLE CONDITIONS TO THE AREA THROUGH
MID-WEEK WHEN ANOTHER SYSTEM IS PROGGED TO DROP THROUGH THURSDAY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 516 PM MDT FRI OCT 24 2025
VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH THE TAF
PERIOD. SKIES REMAIN MOSTLY CLEAR WITH THE OCCASIONAL HIGH LEVEL
CIRRUS. BREEZY SOUTHERLY WINDS CAN BE EXPECTED SATURDAY.
FIRE WEATHER
ISSUED AT 133 PM MDT FRI OCT 24 2025
ELEVATED FIRE WEATHER CONDITIONS WILL BE IN PLACE SATURDAY ACROSS
NORTHEAST WYOMING, INTO THE BLACK HILLS AND THE WESTERN SD PLAINS.
HIGHS WILL CLIMB INTO THE LOW TO MID 70S WITH RELATIVE HUMIDITIES
FALLING TO AROUND 20 PERCENT. WINDS WILL BE SOUTHERLY FROM 10 TO
20 MPH WITH GUSTS TO NEAR 30 MPH AT TIMES.
ELEVATED FIRE WEATHER CONDITIONS WILL RETURN FOR SUNDAY, MAINLY
ACROSS THE WESTON COUNTY PLAINS INTO FAR SOUTHWESTERN SD.
AFTERNOON RELATIVE HUMIDITIES WILL AGAIN BE AROUND 20 PERCENT WITH
AFTERNOON HIGHS AROUND 70. SOUTH WINDS AT 15 TO 20 MPH WILL SWITCH
TO THE WEST AS A DRY FRONT MOVES THROUGH DURING THE AFTERNOON
HOURS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...JC
FIRE WEATHER...HINTZ
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