695
FXUS63 KUNR 231129
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
529 AM MDT THU JUL 23 2026
KEY MESSAGES
- COOL THURSDAY WITH HIGHS IN THE 70S TO LOW 80S ACROSS MUCH OF
THE AREA
- SHOWERS/STORMS MOVE THROUGH TONIGHT INTO TOMORROW. SEVERE
WEATHER ISN'T EXPECTED, THOUGH SOME STORMS MAY BE CAPABLE OF
LOCALIZED HEAVY DOWNPOURS.
- HOT AND DRY CONDITIONS THROUGH THE WEEKEND AND INTO NEXT WEEK.
UPDATE
ISSUED AT 1040 PM MDT WED JUL 22 2026
REGIONAL WEATHER RADAR DEPICTS SHOWERS AND A FEW STORMS MOVING INTO
NORTHEASTERN WY AS AN UPPER LEVEL WAVE AND MONSOONAL MOISTURE MOVES
INTO THE NORTHERN PLAINS. SHOWERS/STORMS SHOULD PUSH INTO WESTERN SD
OVERNIGHT AS THE WAVE MOVES THROUGH. SEVERE THREAT IS MINIMAL
OVERNIGHT INTO TOMORROW AS DEEP LAYER SHEAR IS LACKING. EVENING
SOUNDINGS FOR OUR OFFICE AND SURROUNDING OFFICES DEPICT PWATS
RANGING FROM 1.2 TO 1.6" WHICH IS AROUND 150-175% OF NORMAL FOR THIS
TIME OF YEAR. THIS SHOULD SUPPORT LOCALLY HEAVY DOWNPOURS. HOWEVER,
DUE TO THE CONVECTIVE NATURE OF THE RAINFALL, WHILE SOME SPOTS MIGHT
"BOOM" AND GET UP TO AN INCH OR MORE OF LOCALIZED PRECIP, OTHER
SPOTS MIGHT NOT SEE MUCH, IF ANY, RAIN. CURRENT GUIDANCE SHOWS MOST
LIKELY AREAS TO SEE WIDESPREAD WETTING PRECIP WILL BE ACROSS THE
BLACK HILLS AND ALONG AND SOUTH OF THE I-90 CORRIDOR IN WESTERN SD
WHERE QPF OF 0.25+" IS POSSIBLE IN SOME SPOTS.
STILL LOOKING LIKE THIS WEEKEND WILL BE HOT WITH TEMPERATURES
REACHING THE TRIPLE DIGITS ACROSS MUCH OF THE WESTERN SD PLAINS
INTO NORTHEASTERN WY BY SATURDAY AND SUNDAY. HEAT HEADLINES MAY BE
NEEDED FOR THE WEEKEND. IN ADDITION TO THE VERY HOT TEMPERATURES,
VERY DRY AIR IS ALSO EXPECTED WITH MINIMUM HUMIDITIES PROGGED TO
RANGE FROM 15 TO 20% ACROSS MUCH OF THE AREA. WHILE WINDS THIS
WEEKEND MIGHT NOT QUITE MAKE IT TO OUR CRITICAL CRITERIA, WE COULD
STILL SEE WIDESPREAD ELEVATED TO NEAR CRITICAL FIRE WEATHER
CONDITIONS DEVELOP ACROSS MUCH OF THE AREA THIS WEEKEND INTO EARLY
NEXT WEEK.
DISCUSSION
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 116 PM MDT WED JUL 22 2026
LATEST WATER VAPOR IMAGERY SHOWS CENTER OF UPPER HIGH PRESSURE
LOCATED ACROSS NRN TX/OK WITH RIDGE AXIS POINTED NORTHEAST INTO
PACIFIC NW. MONSOONAL MOISTURE CONTINUES TO STREAM AROUND THE
PERIPHERY OF THE RIDGE. MINOR WAVES ARE LOCATED ACROSS EASTERN
ID/SOUTHWEST MT/WESTERN WY WITH ANOTHER LIFTING NORTHWARD THROUGH
UT. AT THE SURFACE, HIGH PRESSURE LOCATED ACROSS THE EASTERN
DAKOTAS WITH A WEAK LEE TROUGH LOCATED ALONG THE BIG HORNS.
TEMPERATURES AT 18Z ACROSS THE CWA RANGE FROM THE 60S IN THE CLOUD
COVERED AREAS ACROSS THE EAST, TO THE MID 70S TO LOWER 80S IN THE
PARTLY CLOUDY AREAS.
THE BIGGEST ISSUE FACING THE NEAR-TERM FORECAST WILL BE THE
EXPECTED RAINFALL OVERNIGHT INTO THURSDAY. MODELS HAVE BACKED OFF
ON STRENGTH/TIMING AND TRACK OF THE WAVE NOW MOVING THROUGH MT/WY.
DETERMINISTIC MODELS NOW HAVE THIS FEATURE SLIDING JUST A BIT
FURTHER SOUTH THAN PREVIOUS RUNS, TAKING EXPECTED RAINFALL ALSO A
BIT FURTHER SOUTH. EXPECTED PWATS ARE STILL HIGH, RUNNING 150-200%
OF NORMAL OVERNIGHT THROUGH THURSDAY. ENSEMBLES SHOW PROBABILITY
OF 1.75"+ PWATS INCREASING TO 60-90% DURING THE DAY THURSDAY
ACROSS OUR SOUTHERN COUNTIES. HOWEVER, ENSEMBLES ALSO SHOW
PROBABILITIES OF RECEIVING 0.25" OR HIGHER PCPN ONLY ON THE ORDER
OF 30-40%, AND AGAIN MAINLY RELEGATED TO AREAS MAINLY SOUTH OF
I-90. THINGS REMAIN PRETTY TRANSITORY SO NOT TOO WORRIED ABOUT ANY
FLOODING/FLASH FLOODING ISSUES. STILL WOULDN'T BE SURPRISED TO
HEAR OF SOME LOCALIZED 1"+ RAINFALL AMOUNTS BY THE CLOSE OF DAY
THURSDAY, BUT THINKING NOW IT WON'T BE AS WIDESPREAD AS EARLIER
THOUGHT.
AFTER THAT, HOT AND DRY WILL BE THE RULE HEADING INTO NEXT WEEK.
WITH A MORE SPOTTY NATURE TO THE RAINFALL, THERE MAY NOT BE AS
MUCH MOISTURE TO BURN OFF ON FRIDAY THAN PREVIOUSLY THOUGHT.
DETERMINISTIC MODELS HAVE ACTUALLY TRENDED HIGHER FOR FORECASTED
HIGHS ON FRIDAY. WITH 700HPA TEMPS PUSHING +20C AND 850HPA TEMPS
+36C BY 00Z SUNDAY, NOT CONCERNED ABOUT ANY CONVECTION DEVELOPING
OVER THE BLACK HILLS. WILL MOST LIKELY NEED HEAT HEADLINES (AGAIN)
FOR THE UPCOMING WEEKEND.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU JUL 23 2026
VFR CONDITIONS WILL LAST THROUGH THE TAF PERIODS. THE EXCEPTION
WILL BE THE ISOLATED TO SCATTERED SHOWERS AND STORMS THAT DEVELOP
LATER TODAY THAT COULD PRODUCED LOCALIZED MVFR CONDITIONS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...WONG
DISCUSSION...HINTZ
AVIATION...GS
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