119
FXUS63 KABR 180524 AAC
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1224 AM CDT FRI SEP 18 2026
KEY MESSAGES
- HEAVY RAIN IS EXPECTED BEGINNING THIS EVENING OVER AND
CONTINUING THROUGH FRIDAY EVENING. THE HIGHEST ACCUMULATIONS
ARE EXPECTED OVER SOUTH CENTRAL AND EASTERN SOUTH DAKOTA. THE
PROBABILITY TO SEE TWO INCHES OF RAIN OR MORE REACHES 40-60%
OVER EAST CENTRAL AND SOUTH CENTRAL SOUTH DAKOTA (DECREASING
ELSEWHERE AS YOU MOVE NORTH AND WEST).
- THERE IS A SLIGHT RISK (LEVEL 2 OF 4) FOR EXCESSIVE RAINFALL
LEADING TO FLOODING ACROSS ACROSS THE FORECAST AREA TONIGHT
INTO FRIDAY. THE HEAVIEST RAINFALL IS EXPECTED OVERNIGHT
TONIGHT THROUGH EARLY FRIDAY MORNING.
- NEAR-NORMAL TEMPERATURES CONTINUE TODAY, WITH HIGHS 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 LOW 60S TO LOW 70S.
UPDATE
ISSUED AT 1213 AM CDT FRI SEP 18 2026
DISCUSSION FOR THE 06Z TAFS BELOW.
UPDATE ISSUED AT 905 PM CDT THU SEP 17 2026
RAIN SHOWERS ARE MOVING NORTHEAST ACROSS CENTRAL SD, PRETTY MUCH
ON SCHEDULE WITH THE FORECAST POPS, ALTHOUGH SLIGHT ADJUSTMENTS
WERE HAD. WILL CONTINUE TO SEE THE RAIN THAT'S CURRENTLY ACROSS
NEBRASKA START TO MOVE NORTHEAST INTO SD LATER TONIGHT, WITH
RAIN OVERSPREADING MUCH OF THE AREA AFTER MIDNIGHT AND TOWARDS
12Z FRIDAY MORNING.
DISCUSSION
ISSUED AT 148 PM CDT THU SEP 17 2026
A WEAK AND FAIRLY SMALL UPPER-LEVEL RIDGE WILL BE SITTING OVER SD
THIS AFTERNOON THROUGH THE WEEKEND. THIS RIDGE, AS WELL AS WINDS
FROM THE EAST AND SOUTHEAST ALOFT AND AT THE SURFACE WILL HELP TO
MOVE WARM AND MOIST AIR IN OVER SD. THIS WILL CREATE A SATURATED
ATMOSPHERIC ENVIRONMENT OVER CENTRAL AND NORTHEASTERN SD THROUGH THE
REMAINDER OF TODAY AND INTO FRIDAY. PWAT VALUES ACROSS CENTRAL AND
NORTHEASTERN SD WILL BE AROUND 1.75 INCHES, WHICH IS ABOVE THE 90TH
PERCENTILE AND THE MAXIMUM VALUE FOR THIS TIME OF THE YEAR. THIS
SHOWS HOW MUCH MOISTURE THERE IS OVER CENTRAL AND NORTHEASTERN SD. A
LOW PRESSURE SYSTEM IS MOVING OUT OF COLORADO TODAY AND WILL MOVE
OVER SOUTHERN SD TONIGHT, INTO THIS MOIST ENVIRONMENT. PRECIPITATION
ALONG THE NORTHERN AND WESTERN SIDE OF THE LOW WILL MOVE INTO
CENTRAL SD THIS EVENING AND THEN OVER NORTHEASTERN SD AND WEST
CENTRAL MN TONIGHT. THERE IS A LITTLE BIT OF INSTABILITY OVER
SOUTHERN SD MOVING IN WITH THIS SYSTEM THIS EVENING AND OVERNIGHT.
THIS COULD HELP A FEW STORMS TO DEVELOP AND DUMP A LOT OF RAIN IN
PORTIONS OF SOUTH CENTRAL SD AND A HEAVIER BAND OF PRECIPITATION TO
DEVELOP OVER EAST CENTRAL SD LATE TONIGHT INTO FRIDAY MORNING.
MODELS HAVE BEEN FAIRLY CONSISTENT WITH THE LOCATION OF A HEAVY BAND
OF PRECIPITATION, WITH THE HEAVIEST RAINFALL OCCURRING OVER SOUTH
CENTRAL SD, IN A LINE FROM AROUND VIVIAN TO MILLER AND REDFIELD,
LATE THIS EVENING AND OVERNIGHT. ADDITIONALLY, THIS BAND OF HEAVY
RAINFALL WILL MOVE OVER EAST CENTRAL SD BETWEEN WATERTOWN AND SIOUX
FALLS TONIGHT INTO FRIDAY MORNING. THERE IS CURRENTLY A 40-60%
CHANCE OF AREAS ALONG THIS LINE TO RECEIVE 2 INCHES OF RAINFALL OR
MORE. THERE IS A BIT MORE UNCERTAINTY ABOUT THE NORTHERN EDGE OF
THIS LINE OF PRECIPITATION AND HOW FAR NORTH THE CHANCES FOR 1 INCH
OR MORE OF RAINFALL WILL BE. MODELS SHOW A 40-60% CHANCE FOR AN INCH
OR MORE OF RAIN IN A LINE FROM EAGLE BUTTE TO LEOLA AND IN AREAS TO
THE SOUTHEAST UNTIL IT RUNS INTO THE LINE OF HEAVIEST PRECIPITATION
MENTIONS BEFORE, AS THIS LINE HAS 70-90% CHANCE. THE SATURATED
ATMOSPHERE WILL HELP TO GET THESE RAINFALL TOTALS BUT THE STRENGTH
AND TIMING OF THE BAND OF PRECIPITATION WILL ALSO CONTRIBUTE. WITH
THE INSTABILITY OVER SOUTH CENTRAL SD AND THE ABILITY FOR CONVECTION
TO DEVELOP, THE RAIN WILL LIKELY BE HEAVIER FOR A SHORTER PERIOD OF
TIME OVER THIS AREA. EAST CENTRAL SD ON THE OTHER HAND WILL HAVE THE
PRECIPITATION AROUND FOR A MUCH LONGER TIME, LEADING TO HIGHER
RAINFALL AMOUNTS. THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FROM
THIS SYSTEM OVER MOST OF CENTRAL AND NORTHEASTERN SD TONIGHT INTO
FRIDAY. WHILE THE GROUND SHOULD BE ABLE TO TAKE IN A LOT OF THE
WATER, DEPENDING ON HOW FAST IT COMES DOWN AND IN AREAS THAT GET AN
ABUNDANT AMOUNT OF RAIN, THERE COULD BE SOME IMPACTS IN LOW LYING
AND POOR DRAINAGE AREAS AS WELL AS SOME LOCALIZED AREAS OF FLOODING.
ADDITIONALLY, THERE WILL BE MINOR IMPACTS TO RIVERS AND STREAMS FROM
THE POTENTIAL RUNOFF OF THE RAINFALL.
AFTER FRIDAY, THERE WILL BE A COUPLE OF SHORTWAVES THAT MOVE OVER
CENTRAL AND NORTHEASTERN SD THIS WEEKEND. THIS WILL LEAD TO SOME MORE
SCATTERED RAIN SHOWERS MOVING THROUGH OCCASIONALLY DURING THE
WEEKEND. THERE WILL BE SOME COOLER TEMPERATURES MOVING IN WITH THE
LOW PRESSURE SYSTEM STARTING FRIDAY INTO THE WEEKEND. TEMPERATURES
AT THE SURFACE WILL BE AROUND TO SLIGHTLY BELOW NORMAL, WITH HIGHS
GETTING INTO THE LOW 60S TO LOW 70S.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1213 AM CDT FRI SEP 18 2026
TERMINALS KABR,KATY,KPIR,KMBG
THE BULK OF THE RAIN IS CURRENTLY FALLING ACROSS SOUTH CENTRAL
SD, TRACKING NORTHEAST, AND WILL OVERSPREAD THE ENTIRE REGION
THROUGH THE MORNING. RAIN WILL TAPER OFF WEST TO EAST ACROSS
THE REGION THIS AFTERNOON THROUGH TONIGHT. +SHRA IS POSSIBLE AT
TIMES WITH CIGS GRADUALLY LOWERING TO EVENTUALLY BECOME IFR FOR
MOST AREAS. KPIR/KATY HAVE THE POTENTIAL TO DROP TO LIFR THIS
MORNING AND AFTERNOON. THESE LOWER CIGS WILL PERSIST THROUGH THE
END OF THE TAF PERIOD.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
UPDATE...MMM
DISCUSSION...12
AVIATION...MMM
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