420
FXUS63 KABR 252340
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
640 PM CDT FRI JUL 25 2025
KEY MESSAGES
- THERE IS A 30 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS EARLY
THIS EVENING THROUGH TONIGHT, MAINLY OVER NORTH CENTRAL INTO
NORTHEAST SOUTH DAKOTA. THEN, THERE IS A 60 PERCENT CHANCE OF
THUNDERSTORMS SATURDAY NIGHT OVER NORTH CENTRAL SD. THERE IS A
MARGINAL RISK FOR SEVERE STORMS (LEVEL 1 OUT OF 5) IN BOTH OF
THESE AREAS. IF STORMS DEVELOP, A FEW WILL BE CAPABLE OF
PRODUCING HAIL TO 1 INCH IN DIAMETER AND WINDS TO AROUND 60 MPH.
- HOT AND HUMID CONDITIONS ARE IN STORE SATURDAY THROUGH MONDAY.
HEAT INDEX VALUES OF 100 TO 105 DEGREES WILL BE COMMON SATURDAY
AFTERNOON, EXCEPT OVER THE HIGHER ELEVATION REGION OF THE
PRAIRIE COTEAU OF NORTHEAST SOUTH DAKOTA.
- SMOKE, ALOFT, IS EXPECTED SATURDAY NIGHT INTO SUNDAY.
- COOLER AIR (HIGHS IN THE 70S TO AROUND 80) AND DRIER, LESS
HUMID, CONDITIONS WILL ARRIVE WEDNESDAY AND CONTINUE THROUGH AT
LEAST FRIDAY.
UPDATE
ISSUED AT 629 PM CDT FRI JUL 25 2025
A CAPPED BOUNDARY LAYER THIS AFTERNOON HOLDS, THOUGH THERE IS AN
AREA OF ELEVATED CONVECTION BETWEEN ABERDEEN AND MOBRIDGE, AND
LATER THIS EVENING AS THE LOW LEVEL JET GETS GOING THIS MAY BE A
FOCUS AREA FOR ELEVATED STORMS. ADDITIONALLY WE HAVE STORMS IN
WESTERN SOUTH DAKOTA, THOUGH THERE IS SOME QUESTION AS WHETHER
THEY WILL MAKE IT INTO THE WESTERN CWA BEFORE A LOSS OF DAYTIME
HEATING. CAMS ALSO INDICATE THAT MORE TOWARDS MORNING CONVECTION
IN NORTH DAKOTA MAY SWING SOUTHEAST INTO THE NORTHEAST PART OF
THE CWA. NO OTHER CHANGES OF NOTE. SEE BELOW FOR UPDATE TO
AVIATION DISCUSSION.
DISCUSSION
ISSUED AT 237 PM CDT FRI JUL 25 2025
AT 2 PM CDT, SKIES ARE MOSTLY SUNNY AND TEMPERATURES ARE WARMING
THROUGH THE 80S, WITH A FEW LOCATIONS OUT OVER CENTRAL SOUTH DAKOTA
ALREADY NOSING UP INTO THE LOW 90S. WINDS ARE SOUTH AROUND 10 TO 20
MPH WITH GUSTS UP TO 30 MPH.
THE UPPER LEVEL FLOW PATTERN THROUGH SUNDAY NIGHT CONSISTS OF A HOT
SUB-TROPICAL UPPER LEVEL RIDGE OVER THE CWA THAT BREAKS DOWN WHEN A
WESTERN CONUS/WEST COAST UPPER LEVEL TROF PROPAGATES OVER INTO
SOUTHERN CANADA/GREAT LAKES REGION NEXT WEEK.
THERE COULD BE A FEW THUNDERSTORMS OVER WESTERN SOUTH DAKOTA THIS
EVENING; DEVELOPING WITHIN LEE-OF-THE-ROCKIES/BLACK HILLS LEE-SIDE
SURFACE TROFS. MODELS PROG A LOW LEVEL JET TO DEVELOP AND BE AROUND
OVER/NEAR THE NORTHERN HALF OF THE CWA FOR ADDITIONAL NOCTURNAL
SOURCE OF FORCING FOR THE POTENTIAL OF ADDITIONAL STORM DEVELOPMENT
ALONG THE DAKOTAS BORDER, AND LATER AFTER 06Z SATURDAY, A POTENTIAL
SOURCE OF FUEL TO KEEP ONGOING STORMS GOING. SATURDAY EVENING/NIGHT
IS NOT MUCH DIFFERENT, IN TERMS OF SURFACE TROF AND LOW LEVEL JET
POSITIONS. SATURDAY EVENING/NIGHT'S DEEP LAYER SHEAR APPEARS TO BE
POTENTIALLY BETTER (35+KTS) AND INSTABILITY POTENTIALLY BETTER
(>2500J/KG CAPE) THAN TONIGHT'S. NEVERTHELESS, THE WESTERN/NORTHERN
COUNTIES OF THE CWA ARE IN A MARGINAL RISK (LEVEL 1 OUT OF 5) FOR
THE POTENTIAL OF A COUPLE STORMS CAPABLE OF HAIL UP TO AN INCH AND
THUNDERSTORM WIND GUSTS MORE THAN 58MPH TONIGHT AND SATURDAY
EVENING/OVERNIGHT.
WITH THE SUB-TROPICAL HEAT RIDGE PUMPED UP INTO THIS REGION,
TEMPORARILY FROM THIS AFTERNOON THROUGH SUNDAY, HIGH-END HEAT (TEMPS
5 TO 15 DEGREES ABOVE NORMAL) IS ANTICIPATED ACROSS THE CWA INTO
SATURDAY, WHEN ENOUGH LOW LEVEL MOISTURE IS EXPECTED TO BE AROUND TO
SUPPORT HEAT INDEX VALUES AT OR ABOVE 100 DEGREES. IN ORDER TO
ACCOUNT FOR CORN SWEAT, COLLABORATED A MOVE TO NBM75TH PERCENTILE TO
NUDGE FORECAST DEWPOINTS UP 2 OR 3 DEGREES. THE HEAT ADVISORY HAS
BEEN EXPENDED UP INTO NORTH CENTRAL AND NORTHEAST SOUTH DAKOTA AND
OVER INTO WEST CENTRAL MINNESOTA FOR SATURDAY AFTERNOON.
THE LATEST COMPLETE 84-HOUR RUN OF THE RRFS FOR SMOKE REVEALS THE
NEXT ROUND OF SMOKE ALOFT (VERTICALLY-INTEGRATED SMOKE) MAY BE
WORKING INTO THE REGION FROM THE SOUTHWEST BY LATE SATURDAY
NIGHT/EARLY SUNDAY MORNING. NOT SEEING ALL THAT MUCH FOR NEAR-
SURFACE SMOKE, SO PERHAPS THIS ROUND WILL BE NOTHING MORE THAN
SLIGHTLY REDUCED DIRECT INSOLATION AND A MILKY GRAY APPEARANCE TO
THE SKY ON SUNDAY.
THERE WILL BE A SLOW-MOVING FRONTAL BOUNDARY WORKING SOUTH ACROSS
THE REGION FROM SUNDAY (NORTHWESTERN FORECAST ZONES) THROUGH MONDAY
(SOUTHEASTERN FORECAST ZONES), RESULTING IN A WIND SHIFT FROM
SOUTHERLY, RETURN FLOW WINDS TO MORE OF A NORTH OR NORTHWESTERLY
POST-FRONTAL WIND AS SURFACE HIGH PRESSURE GRADUALLY BUILDS DOWN
OVER THE REGION. THERE ARE CURRENTLY THUNDERSTORM CHANCES BOTH
SUNDAY AND MONDAY AFTERNOONS AND EVENINGS ALONG THIS BOUNDARY, AS
MID-LEVEL TEMPERATURES (THERMAL ADVECTION) DO NOT APPEAR TO BE
WARM/STRONG ENOUGH TO COMPLETELY PRECLUDE THUNDERSTORM POTENTIAL.
BOTH DAYS, DEEP LAYER SHEAR COULD BE AT A PREMIUM, WITH MORE THAN
ADEQUATE INSTABILITY/MID-LEVEL LAPSE RATES TO SUPPORT STRONG TO
SEVERE THUNDERSTORMS. THERE IS A MARGINAL RISK (LEVEL 1 OUT OF 5)
FOR SEVERE THUNDERSTORMS ACROSS THE FAR EASTERN FORECAST ZONES
SUNDAY AFTERNOON/EVENING, WITH HAIL UP TO AN INCH IN DIAMETER AND
THUNDERSTORM GUSTS OVER 58 MPH.
THE UPPER LEVEL RIDGE REPOSITIONS WESTWARD, AS WESTERN CONUS UPPER
LEVEL TROFFING PROPAGATES/RELOCATES TO OVER THE GREAT LAKES
REGION/EAST COAST FROM MONDAY THROUGH THURSDAY OF NEXT WEEK. BY
FRIDAY, MODELS ARE TRYING TO SHIFT THE UPPER RIDGE BACK TO OVER THE
NATION'S MID-SECTION. MONDAY THROUGH THURSDAY, WITH NORTHWEST FLOW
OVER THE REGION, CONDITIONS WILL BE A BIT MORE STABLE/COOL/DRY IN
THE BOUNDARY LAYER. AFTER MONDAY/MONDAY NIGHT, THUNDERSTORM CHANCES
LARGELY BECOME A FUNCTION OF HOW OFTEN CONVECTION CAN DEVELOP OUT
OVER THE NORTHERN HIGH PLAINS EACH AFTERNOON AND THEN ORGANIZE/RIDE
THE INSTABILITY GRADIENT THAT WILL EXTEND SOUTHEASTWARD FROM
MONTANA/WYOMING INTO SOUTH DAKOTA/NEBRASKA, POTENTIALLY CLIPPING
(MAINLY) THE WEST RIVER FORECAST ZONES OF THIS CWA. 850HPA THERMAL
PROGS AND S.A. TABLE STANDARDIZED ANOMALIES SUGGEST HIGH
TEMPERATURES DURING MUCH OF NEXT WEEK WILL BE SOME 5 TO 15 DEGREES
BELOW NORMAL, READING IN THE LOW TO UPPER 70S.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 629 PM CDT FRI JUL 25 2025
TERMINALS KABR,KATY,KPIR,KMBG
VFR CONDITIONS EXPECTED AT ALL TERMINALS. CANT RULE OUT AN
ISOLATED STORM AFTER ABOUT 03Z FOR KMBG, BUT TOO LOW A
PROBABILITY TO INCLUDE IN THE TAF OTHERWISE LOW LEVEL FLOW WILL BE
SOUTHERLY WITH THE DEVELOPMENT OF A LOW LEVEL JET FOR PRIMARILY
THE KPIR AND KABR TERMINALS. THIS LOW LEVEL JET/LLWS MAY ALSO
BRIEFLY IMPACT THE KMBG TERMINAL BEFORE SHIFTING TO THE SOUTHEAST.
ABR WATCHES/WARNINGS/ADVISORIES
SD...HEAT ADVISORY FROM NOON CDT /11 AM MDT/ TO 8 PM CDT /7 PM MDT/
SATURDAY FOR SDZ003>010-015>018-033>037-045-048-051.
MN...HEAT ADVISORY FROM NOON TO 8 PM CDT SATURDAY FOR MNZ039-046.
UPDATE...07
DISCUSSION...10
AVIATION...07
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