593
FXUS63 KABR 170528 AAD
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1228 AM CDT THU SEP 17 2026
KEY MESSAGES
- FOG IS POSSIBLE ACROSS PORTIONS OF THE REGION LATE TONIGHT
INTO EARLY THURSDAY MORNING. VISIBILITY MAY BE REDUCED TO LESS
THAN A MILE.
- THERE IS A SLIGHT RISK (LEVEL 2 OF 4) FOR EXCESSIVE AND HEAVY
RAINFALL ACROSS PORTIONS OF CENTRAL AND NORTHEASTERN SD AND
WEST CENTRAL MN THURSDAY AFTERNOON THROUGH FRIDAY EVENING.
THIS HEAVY RAINFALL MAY LEAD TO FLOODING IN SOME AREAS. THE
PROBABILITY TO SEE TWO INCHES OF RAIN OR MORE REACHES 50-70%
OVER EASTERN AND SOUTH CENTRAL SOUTH DAKOTA (DECREASING
ELSEWHERE AS YOU MOVE NORTH AND WEST).
- NEAR-NORMAL TEMPERATURES CONTINUE TODAY AND TOMORROW, AS
HIGHS WILL BE IN THE LOW TO MID 70S ACROSS MUCH OF THE
FORECAST AREA. FRIDAY AND THROUGH THE WEEKEND WILL HAVE
SLIGHTLY COOLER TEMPERATURES, WITH HIGHS GENERALLY IN THE
UPPER 60S TO LOW 70S.
UPDATE
ISSUED AT 1222 AM CDT THU SEP 17 2026
UPDATED DISCUSSION FOR THE 06Z TAFS BELOW.
UPDATE ISSUED AT 945 PM CDT WED SEP 16 2026
AVIATION DISCUSSION UPDATED BELOW TO INCLUDE FOG POTENTIAL LATE
TONIGHT INTO THURSDAY MORNING.
UPDATE ISSUED AT 916 PM CDT WED SEP 16 2026
SHOWERS ARE HOLDING ON A BIT LONGER ACROSS THE EASTERN CWA THAN
PREVIOUSLY FORECAST, SO ADJUSTED POPS TO REFLECT A LATER
DEPARTURE TIME WHILE ALSO INCREASING THE VALUES. SATELLITE SHOWS
A LARGE AREA OF SLOWLY LOWERING STRATUS ACROSS THE EASTERN CWA
AS WELL AND BEEFED UP SKY GRIDS ACCORDINGLY. MODELS CONTINUE TO
SHOW FOG POTENTIAL OVERNIGHT AS WELL. THIS WAS IN THE FORECAST
ALREADY, BUT EXPANDED THE AREAL COVERAGE OF THIS BASED ON SOME
OF THE LATEST GUIDANCE.
DISCUSSION
ISSUED AT 219 PM CDT WED SEP 16 2026
AS OF 2PM, THERE ARE CURRENTLY SOME ELEVATED SHOWERS MOVING OVER
CENTRAL AND NORTHEASTERN SD. THESE SHOWERS WILL BE MOVING EAST AND
SLOWLY DISSIPATING THROUGH THE AFTERNOON INTO THE EVENING. THE
SHOWERS ARE BEING DRIVEN BY A LOW-LEVEL JET MOVING OVER THE WARM AND
MOIST AIR ADVECTING INTO THIS AREA, AND MIXING IN THE ATMOSPHERE
COULD HELP TO GET THE STRONGER SOUTHEASTERLY WINDS TO THE SURFACE.
THERE IS THE POTENTIAL FOR WIND GUSTS TO BE UP AROUND 30-40 MPH FOR
A BIT THIS AFTERNOON. AS THE JET DIES OFF THIS AFTERNOON, THE WINDS
WILL WEAKEN AND SHOWERS START TO DISSIPATE.
AFTER THE SHOWERS MOVE OUT THIS AFTERNOON, PRECIPITATION CHANCES
WILL STAY OUT OF CENTRAL AND NORTHEASTERN SD TONIGHT INTO THURSDAY
MORNING. DURING THIS TIME, THE MOISTURE WILL CONTINUE TO ADVECT INTO
THE STATE BOTH ALOFT AND AT THE SURFACE. THIS WILL HELP TO PRIME THE
ENVIRONMENT FOR THE NEXT SYSTEM TO COME IN. A SURFACE LOW WILL BE
MOVING OUT OF THE SOUTHWEST US TONIGHT AND INTO NE/SD THURSDAY INTO
FRIDAY, WITH A FRONTAL BOUNDARY MOVING INTO THE AREA A BIT BEFORE
THE LOW. SOME MODELS SHOW A FEW SCATTERED SHOWERS MOVING IN EARLIER
IN THE AFTERNOON ALONG THIS BOUNDARY WHILE OTHER MODELS LACK SOME OF
THE INSTABILITY TO DEVELOP ANYTHING ALONG THE BOUNDARY. IN THIS
CASE, PRECIPITATION MOVES IN ALONG THE NORTHERN AND WESTERN SIDE OF
THE LOW THURSDAY EVENING. THE LOW THEN MOVES NORTHEAST THROUGH SD
THURSDAY NIGHT INTO FRIDAY. THE MOST CURRENT MODEL ENSEMBLE RUNS
HAVE SHIFTED THE TRACK OF THIS LOW SYSTEM TO THE NORTH SLIGHTLY, BY
A COUNTY OR TWO, WHICH HAS SHIFTED THE AREA WITH THE HIGHEST
RAINFALL AMOUNTS. THIS SHIFT IN THE TRACK WILL NEED TO BE WATCHED IN
THE COMING ENSEMBLE RUNS TO SEE IF IT CONTINUES TO SHIFT THE
RAINFALL AMOUNTS TO THE NORTH, OR IF THEY START TO MOVE IT BACK TO
THE SOUTH.
MODEL SOUNDINGS SHOW SATURATED COLUMNS OF MOISTURE THROUGH THE
ATMOSPHERE WITH TALL, SKINNY CAPE PROFILE OVER MOST OF CENTRAL AND
NORTHEASTERN SD. THESE SOUNDING PROFILES ARE A GOOD SIGN THAT THE
ENVIRONMENT WILL BE ABLE TO SUPPORT ENHANCED RAINFALL RATES THURSDAY
EVENING THROUGH FRIDAY AFTERNOON. MODELS HINT THAT SOME HEAVIER
BANDS OF RAINFALL WILL BE POSSIBLE THURSDAY NIGHT INTO FRIDAY
MORNING TAKING ADVANTAGE OF THE ENVIRONMENT TO DUMP THE BULK OF THE
RAINFALL. THERE CONTINUES TO BE VARIABILITY IN THE MODELS FOR
RAINFALL AMOUNTS FROM A FEW DIFFERENT FACTORS, SUCH AS THE LOCATIONS
AND TRACK OF THE SYSTEM, WHERE THE BANDS OF THE HEAVIEST RAINFALLS
OCCUR, AND HOW LONG THE SYSTEM STICKS AROUND SOME AREAS. THIS LEADS
TO A LARGER SPREAD, OVER 1 INCH BETWEEN THE 25TH TO 75TH PERCENTILES
IN SOME AREAS, IN RAINFALL AMOUNTS AND LOWERS CONFIDENCE. THE MODELS
HAVE BEEN FAIRLY CONSISTENT WITH THE RAINFALL JUST BARELY GLANCING
NORTH CENTRAL SD, WITH BETWEEN 0.25-0.75 INCH OF RAINFALL
ACCUMULATION EXPECTED. THE MODELS HAVE ALSO BEEN CONSISTENT WITH A
BULLSEYE OF RAINFALL AMOUNTS OCCURRING OVER EAST CENTRAL SD
SOMEWHERE, WHERE 1.5+ INCHES EXPECTED. RIGHT NOW, THE ENSEMBLES ARE
SHOWING A 90% CHANCE FOR AREAS IN A LINE FROM PIERRE TO REDFIELD AND
THEN MILBANK, AND AREAS IN EAST CENTRAL, TO GET AN INCH OR MORE OF
RAINFALL BETWEEN THURSDAY AFTERNOON THROUGH FRIDAY EVENING AND 50-
70% CHANCE FOR 2 INCHES. WITH THESE RAINFALL AMOUNTS AND THE
POTENTIAL FOR EVEN MORE TO FALL IN SOME AREAS, THERE IS A SLIGHT
RISK FOR EXCESSIVE AND HEAVY RAINFALL FROM THE SYSTEM. SINCE THE
GROUND IS FAIRLY DRY FROM THE LACK OF PRECIPITATION, IT SHOULD BE
ABLE TO HANDLE A FAIR BIT OF WATER, EVEN AFTER THE RAIN WE HAD THE
OTHER DAY. HOWEVER, IF THE HEAVIEST RAIN BANDS ARE SLOW MOVING OR
CONTINUE TO MOVE OVER THE SAME AREAS FOR A WHILE, THE HEAVY RAINFALL
AMOUNTS COULD START TO IMPACT LOW LYING AND POOR DRAINAGE AREAS AND
POTENTIALLY EVEN CAUSE A LITTLE BIT OF FLOODING.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1222 AM CDT THU SEP 17 2026
TERMINALS KABR,KATY,KPIR,KMBG
CURRENT SATELLITE INDICATES LOWER STRATUS ACROSS THE JAMES VALLEY
AND EASTWARD WITH CIGS DOWN TO MVFR AT KATY. THROUGH THE
OVERNIGHT HOURS INTO THURSDAY MORNING, FG/BR IS FORECAST ACROSS
MUCH OF THE REGION, POSSIBLY AFFECTING THE TAF SITES WHICH
WOULD LEAD TO SUB/ONGOING VFR CIGS. INCLUDED MENTION OF THIS FOR
ALL TAFS AS SOME UNCERTAINTY EXISTS IN OVERALL AREAL COVERAGE
AND DENSITY OF FOG. WILL AMEND WHEN NEEDED.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
UPDATE...MMM
DISCUSSION...12
AVIATION...MMM
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