105
FXUS63 KUNR 180424
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1024 PM MDT TUE MAR 17 2026
KEY MESSAGES
- A MAJOR WARMING AND DRYING TREND WILL TAKE HOLD FOR THE REST OF
THIS WEEK, WITH HIGH TEMPERATURES REACHING THE MID-70S TO
MID-80S BY OUR WARMEST DAYS FRIDAY AND SATURDAY.
- CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED WEDNESDAY FOR
PORTIONS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
ELEVATED TO NEAR-CRITICAL FIRE WEATHER CONDITIONS PERSIST
THROUGH SATURDAY.
- A COLD FRONT WILL CROSS THE REGION BY SUNDAY MORNING, TAKING 30
DEGREES OFF OUR TEMPERATURES.
UPDATE
ISSUED AT 942 PM MDT TUE MAR 17 2026
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED FOR PORTIONS
OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA WEDNESDAY.
HAVE EXPANDED THE RED FLAG WARNING TO INCLUDE NORTHERN CAMPBELL
COUNTY (WY), THE SOUTHERN BLACK HILLS (INCLUDING QURY FIRE), CUSTER
COUNTY PLAINS, AND THE PINE RIDGE AREA. THE INGREDIENTS ARE IN PLACE
FOR CRITICAL FIRE WEATHER CONDITIONS : MIXING OF HIGHER MOMENTUM
ALOFT, RESULTING IN WIND GUSTS 25 TO 40 MPH; AND ANOMALOUSLY WARM
TEMPERATURES (MID 60S TO MID 70S). WHILE CONFIDENCE IN WIDESPREAD
<15 PERCENT RH TOMORROW IS MEDIUM, THE STRONGER WINDS + WARM
TEMPERATURES ARE EXACERBATED BY PERSISTENT DROUGHT CONDITIONS ACROSS
THE WARNED AREA.
FORECAST REMAINS ON TRACK THROUGH THE LATTER HALF OF THE WEEK.
VERY WARM TEMPERATURES WILL PERSIST THROUGH SATURDAY AHEAD OF A
COLD FRONT. TEMPERATURES WILL WARM INTO THE 70S AND 80S THU-SAT.
WHILE COOLER, BUT SEASONABLE, AIR WILL FILTER IN BEHIND THE FRONT,
PRECIPITATION LOOKS WANTING WITH MOST OF THE FORECAST AREA DRY
THROUGH AT LEAST THE EARLY PORTION OF NEXT WEEK.
DISCUSSION
(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 135 PM MDT TUE MAR 17 2026
WELL...THE REST OF THIS WEEK CERTAINLY WON'T FEEL LIKE WHAT WE
EXPERIENCED THIS PAST WEEKEND! ON THE SYNOPTIC SCALE, DEEP TROUGHING
IS NOTED OVER THE EASTERN US AND LONGWAVE RIDGING IS OBSERVED OVER
THE WESTERN US, WITH NORTHEAST WYOMING/WESTERN SOUTH DAKOTA CAUGHT
IN BETWEEN UNDER NORTHWEST FLOW ALOFT. A WARM FRONT HAS LARGELY
CLEARED THE CWA, KICKING OFF A PROGRESSIVE WARMING TREND. THE CENTER
OF THE WESTERN RIDGE WILL BE ANCHORED OVER THE DESERT SOUTHWEST
THROUGH SATURDAY WITH VERY LITTLE MOVEMENT, BUT WILL BE AMPLIFIED
ENOUGH TO KEEP THE ACTIVE STORM TRACK WELL TO OUR NORTH (LARGELY
OVER CANADA) THROUGH THE PERIOD. THE RIDGE WILL THEREFORE BE OUR
DOMINANT SYNOPTIC PLAYER FROM THIS POINT FORWARD, SUPPORTING OUR
WARMING/DRYING TREND AND PERIODICALLY BREEZY CONDITIONS ALONG WITH
SOME ATTENDANT FIRE WEATHER CONCERNS.
TODAY, EXPECT HIGH TEMPERATURES TO TOP OUT IN THE MID-50S TO UPPER-
60S, A STARK CONTRAST TO THE FRIGID CONDITIONS WE BRIEFLY
EXPERIENCED OVER THE LAST COUPLE DAYS. GUSTY NORTHWEST WINDS ARE
ALSO INCREASING THIS AFTERNOON (SURFACE WEATHER STATIONS CONFIRM
SEVERAL GUSTS OF 40 TO 55 MPH SO FAR OVER THE BLACK HILLS REGION),
WITH A CONTINUED EXPECTATION THAT SOME PORTION OF 40-50KT WINDS AT
THE TOP OF THE BOUNDARY LAYER WILL MIX DOWN TO THE SURFACE. ONGOING
HIGH WIND WARNINGS ACROSS THE BLACK HILLS, AND WIND ADVISORIES
NORTH/WEST OF A LINE FROM RAPID CITY TO NEAR BRIDGER TO FAITH...AS
WELL AS OVER THE FAR SOUTHWESTERN SOUTH DAKOTA PLAINS...CONTINUE
UNTIL 6 PM BEFORE WINDS RELAX FOR THE NIGHT. IN THE WARNING AREA, 6-
HOUR PROBABILITIES OF WINDS GUSTING OVER 55 MPH REMAIN 60-80
PERCENT, ESPECIALLY FROM JUST NORTH/WEST OF CUSTER UP TO THE LEAD,
DEADWOOD, AND STURGIS AREAS. A STRAY SHOWER OR SPRINKLE CAN'T BE
RULED OUT WELL SOUTH AND WEST OF GILLETTE AND NEWCASTLE THROUGH THIS
EVENING, BUT LITTLE TO NO QPF IS EXPECTED IF THIS OCCURS. THE WARMER
TEMPERATURES STARTING TODAY WILL RAPIDLY MELT WHAT SNOWPACK REMAINS
ACROSS PORTIONS OF THE REGION FROM OUR RECENT WINTER STORM.
THE WARMING TREND CONTINUES ALL THE WAY THROUGH SATURDAY WITH HIGHS
SURGING INTO THE MID-60S TO MID-70S WEDNESDAY, 70S TO NEAR 80
THURSDAY, AND MID-70S TO LOWER 80S FRIDAY AND SATURDAY, WHICH WILL
PLACE OUR REGION 25 TO 30 DEGREES ABOVE CLIMATOLOGICAL NORMALS FOR
MID-MARCH! AT THIS TIME, THERE IS ONLY A 10-20 PERCENT CHANCE OF
EXCEEDING 80 DEGREES THURSDAY AFTERNOON FOCUSED OVER THE SOUTHWEST
SOUTH DAKOTA PLAINS, BUT THOSE PROBABILITIES INCREASE AND EXPAND
SIGNIFICANTLY FOR FRIDAY AND SATURDAY (THE TWO WARMEST DAYS). DRIER
HUMIDITY VALUES AND SOME MODEST WIND WILL ALSO RESULT IN A SEVERAL
DAY STRETCH OF NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS
(MORE ON THAT IN THE FIRE WEATHER SECTION BELOW). NOTABLE CHANGE
ARRIVES BY SUNDAY MORNING, HOWEVER, AS A COLD FRONT CROSSES THE
REGION BRINGING AN INCREASE IN HUMIDITY AND CHOPPING 30 DEGREES OFF
OUR TEMPERATURES, WITH HIGHS ONLY EXPECTED TO REACH THE UPPER-40S TO
MID-50S SUNDAY AFTERNOON. 500MB HEIGHT CLUSTER ANALYSIS AND EOF
PATTERNS SHOW REMARKABLY GOOD AGREEMENT IN THE TIMING AND AMPLITUDE
OF THIS SHORTWAVE TROUGH/FRONTAL FEATURE. IT'S POSSIBLE SOME RAIN
AND SNOW SHOWERS WILL ACCOMPANY THE FRONT (ALONG WITH A BIT OF
WIND), OTHERWISE DRY CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
AND, ONLY ONE MODEL CLUSTER (REPRESENTING ABOUT 30% OF THE MODEL
ENSEMBLE SPACE) IS RUNNING WETTER THAN THE MEAN, EVEN THEN STILL
COMING IN AT UNDER 0.10 INCHES QPF. THUS, SIGNIFICANT PRECIPITATION
DOES NOT SEEM LIKELY AT THIS JUNCTURE TO HELP MODERATE OUR DRY LATE-
WINTER.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1023 PM MDT TUE MAR 17 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. GUSTY
WEST/NORTHWEST WINDS WILL DEVELOP BY 18/18Z, ESPECIALLY ON THE
OPEN PLAINS WITH GUSTS FROM 25-35KTS.
FIRE WEATHER
ISSUED AT 942 PM MDT TUE MAR 17 2026
BEYOND WEDNESDAY, ELEVATED TO NEAR-CRITICAL FIRE WEATHER CONDITIONS
ARE EXPECTED FOR MUCH OF THE FORECAST AREA. VERY WARM TEMPERATURES
WILL PERSIST THROUGH SATURDAY WITH 80S EXPECTED ACROSS THE LOWER
ELEVATIONS THURSDAY THROUGH SATURDAY. DRIEST CONDITIONS EXPECTED
ACROSS NE WY INTO SOUTHWESTERN SD THU-SAT, ALTHOUGH STRONGEST WINDS
WILL NOT OVERLAP WITH LOWEST RH, WHICH MAY MITIGATE FIRE WEATHER
CONDITIONS THU-FRI. THE STRONGEST WINDS THU-FRI ARE FORECAST ACROSS
NW SD, WHERE RH VALUES WILL BE ABOVE CRITICAL THRESHOLDS.
COLD FRONT WILL BRING COOLER (MORE SEASONABLE) TEMPERATURES TO THE
AREA SUNDAY, ALTHOUGH NO PRECIPITATION LOOKS LIMITED WITH THE
FRONTAL PASSAGE.
UNR WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING FROM 10 AM TO 7 PM MDT WEDNESDAY FOR SDZ321-322-
325-326.
WY...RED FLAG WARNING FROM 10 AM TO 7 PM MDT WEDNESDAY FOR WYZ314-315-
317.
UPDATE...SE
DISCUSSION/KEY MESSAGES...KSMITH
AVIATION...HELGESON
FIRE WEATHER...SE
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