649
FXUS63 KABR 121734 AAB
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1234 PM CDT WED AUG 12 2026
KEY MESSAGES
- THERE IS A SLIGHT RISK (LEVEL 2 OF 5) FOR SEVERE STORMS TO
DEVELOP LATE THIS AFTERNOON ACROSS SOUTHWEST SOUTH DAKOTA AND
MIGRATING INTO SOUTH CENTRAL SOUTH DAKOTA DURING THE EVENING
HOURS. MAIN THREATS INCLUDE UP TO 1 INCH IN DIAMETER HAIL
AND WIND GUSTS OF 60 TO 70 MPH.
- THERE IS A MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE STORMS TO
DEVELOP LATE THIS AFTERNOON WEST RIVER, MIGRATING EAST IN THE
EVENING AND OVERNIGHT. MAIN THREATS INCLUDE UP TO 1 INCH IN
DIAMETER HAIL AND WIND GUSTS UP TO 60 MPH.
UPDATE
ISSUED AT 1232 PM CDT WED AUG 12 2026
THE FOG ACROSS THE AREA HAS DISSIPATED, THOUGH THERE ARE STILL
SOME LOWER CLOUDS OVER THE MISSOURI RIVER THAT SHOULD CONTINUE
TO DISSIPATE FOR THE NEXT COUPLE OF HOURS.
OTHERWISE, THE 18Z AVIATION DISCUSSION HAS BEEN UPDATED BELOW.
UPDATE ISSUED AT 727 AM CDT WED AUG 12 2026
AREAS OF LOCALLY DENSE FOG HAVE CROPPED UP OVER PORTIONS OF
CENTRAL AND EAST CENTRAL SD. THE VISIBILITIES IN THIS FOG COULD
DROP TO 1/4 MILE AT TIMES. AN SPS WAS ISSUED FOR THE NEXT FEW
HOURS BECAUSE OF THE FOG. THIS FOG SHOULD DISSIPATE THROUGH THE
MORNING, WITH THE FOG IN EAST CENTRAL SD ALREADY STARTING TO
DECREASE IN STRENGTH.
UPDATE ISSUED AT 610 AM CDT WED AUG 12 2026
SEE BELOW FOR AN AVIATION FORECAST DISCUSSION FOR THE 12Z TAFS.
DISCUSSION
ISSUED AT 1238 AM CDT WED AUG 12 2026
THE 4-CORNERS UPPER HIGH WEAKENS AND SHIFTS INTO THE SOUTHEAST
CONUS, THOUGH WE STILL REMAIN UNDER A BROAD WEST/NORTHWEST FLOW
REGIME. A PLUME OF MID LEVEL MOISTURE LIFTING OUT OF THE
INTERMOUNTAIN WEST CROSSES SOUTH DAKOTA DURING THE DAY. YOU CAN SEE
THIS BROAD AREA OF MID LEVEL CLOUDS OVER NEVADA/UTAH IDAHO/WYOMING.
THIS MOISTURE, 600MB AND ABOVE, ALSO HAS A VERY DRY SUBCLOUD
LAYER RESULTING INVERTED V TYPE SOUNDINGS. PROFILES ALSO HAVE
WARM AIR ALOFT AND WHILE 700MB TEMPERATURES ARE ONLY +8 TO +11C
WHICH DOESN'T JUMP OUT AS A STRONG CAP, 750MB TEMPERATURE ARE
CLOSER TO +13 TO +15C SO NAM PROFILES INDICATE IT WILL BE
DIFFICULT FOR SURFACE BASED CONVECTION BUT ELEVATED CONVECTION
IS DEPICTED IN CAMS FOR THE EVENING/OVERNIGHT HOURS. HREF MUCAPE
IS ONLY ABOUT 1500J/KG. GIVEN THE PROFILES, WINDS ARE THE MAIN
CONCERN WITH ANY CONVECTION. GIVEN HOW DRY ITS BEEN, DRY
LIGHTING AND FIRES ALSO ARE A CONCERN.
THERE IS ANOTHER PLUME OF MID LEVEL MOISTURE FOR MAINLY THURSDAY
NIGHT INTO EARLY FRIDAY AS WELL. PROFILES ARE CLOSE TO MOIST
ADIABATIC THANKS TO COOLER MID LEVEL TEMPERATURES WITH EASTERLY
STABLE LOW LEVEL FLOW WITH THE SURFACE HIGH JUST ACROSS THE BORDER
IN CANADA. NAM BUFKIT PROFILES SHOW ITS UNSTABLE DURING THE DAY,
THOUGH THERE IS AN UPPER RIDGE MOVING OVERHEAD WITH INCREASING
HEIGHTS AT THAT PARTICULAR TIME.
A SOUTHWEST FLOW REGIME RUNS THROUGH SATURDAY BEFORE FLOW ALOFT
BECOMES MORE WESTERLY, AND ULTIMATELY NORTHWESTERLY FOR NEXT WEEK.
NBM POPS HAVE TRENDED DOWN THIS WEEKEND AND NEXT WEEKEND IN
RESPONSE, ESPECIALLY AS A SURFACE HIGH MOVES ACROSS THE REGION
SUNDAY/MONDAY. OTHERWISE TEMPERATURES WITH THIS COOLER AIRMASS WILL
BE RUNNING ABOUT 5 TO 10 DEGREES BELOW NORMAL THURSDAY THROUGH
SUNDAY.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1232 PM CDT WED AUG 12 2026
TERMINALS KABR,KATY,KPIR,KMBG
MAINLY VFR/MVFR CONDITIONS WILL BE AROUND THIS AFTERNOON AND
EVENING, EXCEPT FOR SOME IFR AT KPIR DUE TO LOW CLOUDS FOR ANOTHER
HOUR OR SO, BEFORE SOME SHOWERS AND STORMS START TO MOVE IN OVER THE
TERMINALS. THE STORMS HAVE A MARGINAL RISK (LEVEL 1 OF 5) TO BECOME
SEVERE IF THEY DEVELOP, WITH OCCASIONAL STRONG WIND GUSTS OF 60-70
MPH POSSIBLE. THESE SHOWERS AND STORMS WILL BE MOVING OUT DURING THE
EVENING AND EARLY OVERNIGHT HOURS. KATY COULD SEE SOME WILDFIRE
SMOKE REACHING THE SURFACE THIS EVENING, THOUGH THIS SMOKE SHOULD
NOT AFFECT VISIBILITY AND CEILINGS.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
UPDATE...12
DISCUSSION...07
AVIATION...12
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