233
FXUS63 KABR 280118 AAB
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
818 PM CDT SUN JUL 27 2025
KEY MESSAGES
- THERE IS A 40 TO 60 PERCENT CHANCE OF STRONG TO SEVERE
THUNDERSTORMS OVER EASTERN SD LATE THIS AFTERNOON INTO THE EARLY
OVERNIGHT HOURS. THERE IS AN ENHANCED RISK, OR LEVEL 3 OUT OF
5, FOR SEVERE THUNDERSTORMS CAPABLE OF PRODUCING STRONG WINDS OF
70 MPH AND HAIL UP TO AROUND 2 INCHES IN DIAMETER, AS WELL AS A
FEW TORNADOES. THE BIGGEST THREAT AREA IS LOCATED SOUTHEAST OF
A LINE FROM TINTAH, MN TO ANDOVER, SD TO NEAR REDFIELD, SD.
- HOT AND HUMID CONDITIONS TO CONTINUE OVER SOUTH CENTRAL SOUTH
DAKOTA ON MONDAY, WITH HEAT INDEX VALUES OF 100 TO 105 DEGREES
EXPECTED. HEAT ADVISORIES ARE IN EFFECT MONDAY AFTERNOON INTO
THE EVENING.
- LOFTED SMOKE THAT HAS DRIFTED OVER THIS AREA, FROM WILDFIRES
OVER THE WESTERN STATES, SHOULD PERSIST THROUGH AT LEAST
TUESDAY.
- THERE IS A 50-70% CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY
EVENING. THERE IS A SLIGHT RISK, LEVEL 2 OUT OF 5, FOR SEVERE
STORMS CAPABLE OF PRODUCING STRONG WINDS OF 70 MPH AND HAIL UP
TO AROUND 2 INCHES IN DIAMETER ACROSS CENTRAL, NORTH CENTRAL AND
NORTHEAST SOUTH DAKOTA INTO WEST CENTRAL MINNESOTA.
- COOLER AIR IS EXPECTED TUESDAY THROUGH AT LEAST SATURDAY, WITH
HIGHS MAINLY IN THE MID 70S TO LOW 80S.
UPDATE
ISSUED AT 815 PM CDT SUN JUL 27 2025
ALLOWED TODAY'S HEAT ADVISORY TO EXPIRE AS TEMPERATURES AND HEAT
INDICES HAVE FALLEN BELOW 100 DEGREES.
UPDATE ISSUED AT 634 PM CDT SUN JUL 27 2025
ONGOING SEVERE WEATHER ACROSS THE EASTERN FORECAST AREA. A SEVERE
THUNDERSTORM WATCH WITH THE POTENTIAL FOR TORNADOES REMAINS IN
EFFECT UNTIL 5Z. STORMS ARE CONTINUING TO FORM ALONG A NUMBER OF
OUTFLOW BOUNDARIES.
DISCUSSION
ISSUED AT 232 PM CDT SUN JUL 27 2025
AT 2 PM CDT, SKIES ARE MOSTLY SUNNY AND TEMPERATURES ARE WARMING
THROUGH THE 80S AND 90S, WITH A FEW LOCATIONS OUT OVER CENTRAL AND
SOUTH CENTRAL SOUTH DAKOTA ALREADY NOSING UP INTO THE MID TO UPPER
90S. THERE IS A FRONTAL BOUNDARY TRYING TO WORK DOWN INTO NORTH
CENTRAL SOUTH DAKOTA. AHEAD OF THE FRONT, WINDS ARE SOUTHEAST AROUND
10 TO 15 MPH WITH GUSTS UP TO 25 MPH. A FEW ELEVATED THUNDERSTORMS
PERSIST EARLY THIS AFTERNOON OVER FAR NORTHEAST SOUTH DAKOTA INTO
WEST CENTRAL MINNESOTA. ALSO MONITORING A COUPLE OF OUTFLOW
BOUNDARIES. ONE OF THEM WAS GENERATED BY THE PREVIOUSLY WARNED STORM
THAT MOVED THROUGH GRANT AND SOUTHERN BIG STONE COUNTIES OF THIS CWA
EARLIER. THE OUTFLOW BOUNDARY IS ANALYZED FROM ABOUT WATERTOWN TO
BRANDT AND COULD SERVE AS A FOCUS FOR STORMS LATER THIS
AFTERNOON/EVENING, ONCE DAYTIME HEATING IS FULLY COMPLETE.
THE UPPER LEVEL FLOW PATTERN REMAINS LARGELY UNCHANGED THROUGH THE 7-
DAY FORECAST PERIOD, CONSISTING OF A HOT SUB-TROPICAL UPPER LEVEL
RIDGE OVER THE CWA BREAKING DOWN OVER THE NEXT 24 TO 36 HOURS WHEN
ENERGY IN A WESTERN CONUS/WEST COAST UPPER LEVEL TROF PROPAGATES
OVER INTO SOUTHERN CANADA/GREAT LAKES REGION AND EVENTUALLY TO THE
EAST COAST THIS WEEK, SLOSHING UPPER TROFFING FROM THE WEST COAST
OVER TO THE EAST COAST. THE UPPER LEVEL RIDGE BUILDS BACK INTO THE
WESTERN CONUS FOR A FEW DAYS AS A RESULT, WITH THIS CWA UNDER WEAK
NORTHWEST FLOW ALOFT.
AS THE FRONTAL BOUNDARY SLOWLY WORKS SOUTHWARD LATE THIS AFTERNOON
THROUGH TONIGHT, SHORT RANGE/RAPID UPDATE MODELS DEPICT VALUES FOR
BOTH DEEP LAYER AND LOW LEVEL INSTABILITY AND SHEAR THAT ARE
SUPPORTIVE OF SUPERCELLULAR THUNDERSTORMS (INITIALLY) WITH LARGE
HAIL, DAMAGING THUNDERSTORMS AND A FEW TORNADOES. CAM GUIDANCE
SUGGESTS CONVECTION (RUNNING PARALLEL/NEARLY PARALLEL TO THE
BOUNDARY) WILL GROW INTO A LINEAR (MAINLY WIND) CONVECTIVE SYSTEM
AND MOVE OFF INTO SOUTHEAST SOUTH DAKOTA AND SOUTHWEST MINNESOTA
DURING THE LATE EVENING/EARLY OVERNIGHT HOURS. SPC HAS UPDATED THE
DAY 1 OUTLOOK TO INCLUDE AN ENHANCED RISK (LEVEL 3 OUT OF 5) FOR
SEVERE THUNDERSTORMS ACROSS A PORTION OF NORTHEAST SOUTH DAKOTA AND
WEST CENTRAL MINNESOTA.
WITH THE SUB-TROPICAL HEAT RIDGE REMAINING OVER THE REGION THIS
AFTERNOON INTO TONIGHT BEFORE SHIFTING DOWN TO ACROSS SOUTH CENTRAL
SOUTH DAKOTA ON MONDAY, HIGH-END HEAT/HUMIDITY (TEMPS 5 TO 15
DEGREES ABOVE NORMAL) THIS AFTERNOON ACROSS THE SOUTHERN/EASTERN CWA
SHOULD BE IN PLAY, ONCE AGAIN. THE HEAT ADVISORY FOR THIS
AFTERNOON/EVENING REMAINS IN EFFECT UNTIL 8 PM CDT FOR HEAT INDICES
BETWEEN 100F AND 105F DEGREES. WITH THE HOT/HUMID AIR BEING
SUPPRESSED TO SOUTH CENTRAL SOUTH DAKOTA MONDAY AFTERNOON/EVENING,
MAINLY SOUTH OF U.S. HIGHWAY 14 ALONG THE I-90 CORRIDOR, HEAT INDEX
VALUES AT OR ABOVE 100 DEGREES ARE EXPECTED. IN ORDER TO ACCOUNT FOR
CORN SWEAT, UTILIZED NBM75TH PERCENTILE FOR A THIRD CONSECUTIVE DAY
TO NUDGE FORECAST DEWPOINTS UP 2 OR 3 DEGREES, CLOSER TO WHAT'S BEEN
BEING OBSERVED OVER THE PAST FEW DAYS. A HEAT ADVISORY FOR MONDAY
AFTERNOON/EVENING HAS BEEN ISSUED FOR CENTRAL SOUTH DAKOTA FROM 1 PM
CDT TO 8 PM CDT.
GOES GEOCOLOR SATELLITE IMAGERY DEPICTS, FAINTLY, A LAYER OF SMOKE
ALOFT OVER THE REGION. THE LATEST HRRR AND COMPLETE 84-HOUR RUN OF
THE RRFS FOR SMOKE SUGGESTS THAT THIS SMOKE ALOFT (VERTICALLY-
INTEGRATED SMOKE) WILL PERSIST OVER THE REGION THROUGH TUESDAY
NIGHT. STILL NOT SEEING ALL THAT MUCH FOR NEAR-SURFACE SMOKE THROUGH
TUESDAY NIGHT. HOWEVER, BY WEDNESDAY, THIS LOW LEVEL NORTHERLY WIND
ADVECTION PATTERN COULD HAVE SOME LOW TO MODERATE AMOUNTS OF
UNPLEASANT NEAR-SURFACE SMOKE WORKING DOWN INTO THE CWA.
THIS SLOW-MOVING FRONTAL BOUNDARY IS FORECAST TO BE JUST ABOUT
STALLED OUT ACROSS THE FAR SOUTHERN FORECAST ZONES ON MONDAY. SOUTH
OF THE BOUNDARY, THE HOT/HUMID SOUTHERLY WINDS WILL PERSIST FOR ONE
MORE DAY, WHILE A NORTH OR NORTHWESTERLY POST-FRONTAL WIND WILL HAVE
ESTABLISHED OVER THE CWA BEHIND THE BOUNDARY SUNDAY EVENING THROUGH
MONDAY MORNING, AS SURFACE HIGH PRESSURE GRADUALLY BUILDS DOWN OVER
THE REGION. THERE ARE CURRENTLY THUNDERSTORM CHANCES ON MONDAY FOR
WHAT, PRESUMABLY, IS EXPECTED TO BE AN ACTIVE EML (DESPITE POST-COLD
FRONTAL LOW LEVEL CAA AND DRY AIR ADVECTION WITHIN THE BOUNDARY
LAYER OVER MOST OF THE CWA). DEEP LAYER SHEAR ON MONDAY IS EXPECTED
TO BE AT A PREMIUM, WITH MORE THAN ADEQUATE INSTABILITY/MID-LEVEL
LAPSE RATES TO SUPPORT STRONG TO SEVERE THUNDERSTORMS. THERE IS A
SLIGHT RISK (LEVEL 2 OUT OF 5) FOR SEVERE THUNDERSTORM POTENTIAL
ACROSS THE ENTIRE CWA ON MONDAY, WITH HAIL UP TO AN INCH IN DIAMETER
AND THUNDERSTORM GUSTS OVER 58 MPH. MONDAY'S POTENTIAL RAINFALL ALSO
CARRIES WITH IT THE POTENTIAL FOR TRAINING/EXCESSIVE-RAIN-PRODUCING
THUNDERSTORMS RUNNING ALONG A NEARLY WEST/EAST-ORIENTED FRONTAL
BOUNDARY.
ONCE 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 FRIDAY OF NEXT WEEK, SEVERAL
DAYS OF STABLE HIGH PRESSURE AIRMASS WILL ADVECT TO AND REMAIN OVER
THE CWA. FRIDAY/SATURDAY, MODELS ARE TRYING TO SHIFT THE UPPER RIDGE
BACK TO OVER THE NATION'S MID-SECTION WHILE FLATTENING IT SOME.
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 REMAIN, OVERALL, UNCHANGED IN THEIR DEPICTION
OF TEMPERATURES DURING MUCH OF NEXT WEEK; SOME 5 TO 15 DEGREES BELOW
NORMAL, RESULTING IN READINGS IN THE MID 70S TO LOW 80S. BEYOND
SATURDAY, GUIDANCE DOES SUGGEST THE UPPER RIDGE'S INFLUENCE WILL
BEGIN TO BE FELT, ONCE MORE, WITH LOW LEVEL WAA BUMPING TEMPERATURES
BACK UP TO EARLY AUGUST CLIMO-NORMALS.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 634 PM CDT SUN JUL 27 2025
TERMINALS KABR,KATY,KPIR,KMBG
GENERALLY, VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON.
HOWEVER, THERE ARE THUNDERSTORMS NEAR KATY THIS EVENING THAT MAY
BRING LARGE HAIL, STRONG, ERRATIC WINDS AND HEAVY RAIN TO KATY
THROUGH 4Z.
ABR WATCHES/WARNINGS/ADVISORIES
SD...HEAT ADVISORY FROM 1 PM CDT /NOON MDT/ TO 8 PM CDT /7 PM MDT/
MONDAY FOR SDZ033-035>037-045-048-051.
MN...NONE.
UPDATE...20
DISCUSSION...10
AVIATION...20
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