798
FXUS63 KABR 151844
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
144 PM CDT TUE SEP 15 2026
KEY MESSAGES
- DRY CONDITIONS EXPECTED TODAY BEFORE A WEAK DISTURBANCE TRACKS
OVER THE REGION WEDNESDAY MORNING INTO THE AFTERNOON, BRINGING THE
OPPORTUNITY FOR ISOLATED TO SCATTERED SHOWERS AND WEAK THUNDERSTORMS.
- ANOTHER ROUND OF RAINFALL IS EXPECTED LATE THURSDAY THROUGH
FRIDAY. THE HIGHEST ACCUMULATIONS ARE EXPECTED OVER EASTERN SOUTH
DAKOTA, WHERE PROBABILITY TO SEE AN INCH OF RAIN OR MORE RANGES FROM
40-60%.
DISCUSSION
ISSUED AT 144 PM CDT TUE SEP 15 2026
AS HIGH PRESSURE KEEPS MOVING OVER CENTRAL AND NORTHEASTERN SD
TODAY, IT WILL HELP TO KEEP SHOWERS AND STORM CHANCES OUT THROUGH
TONIGHT. SKIES WILL BE STAYING MOSTLY CLEAR THROUGH THE REMAINDER OF
THE DAY AND INTO THE NIGHT, WHICH WILL HELP THE TEMPERATURES TONIGHT
DROP INTO THE LOW 40S TO LOW 50S. HUMIDITY WILL STAY FAIRLY HIGH
THROUGH THE NIGHT, AND WITH LIGHT WINDS AND FAIRLY SATURATED SOILS
FROM YESTERDAY'S RAIN, THERE COULD BE PATCHY AREAS OF FOG THAT
DEVELOP OVER AREAS EAST OF THE MISSOURI RIVER. THIS FOG WILL BE MORE
LOCALIZED AND SHOULD NOT GO BELOW A MILE IN VISIBILITY.
AN UPPER-LEVEL SHORTWAVE WILL BE MOVING OVER SD EARLY WEDNESDAY
MORNING INTO THE AFTERNOON. THIS WILL HELP SOME STRONGER WINDS ALOFT
TO MOVE IN CENTRAL SD TONIGHT. AS THIS LOW LEVEL JET MOVES OVER,
SOME WARM, MOIST AIR MOVING INTO CENTRAL SD WILL START TO DEVELOP
SOME ISOLATED TO SCATTERED SHOWERS AND STORMS EARLY WEDNESDAY
MORNING. AS THE LOW LEVEL JET MOVES EAST THROUGH THE MORNING INTO
THE AFTERNOON, IT WILL CONTINUE TO CAUSE THESE SCATTERED SHOWERS AND
STORMS OVER CENTRAL AND NORTHEASTERN SD. THESE SHOWERS AND STORMS
WILL BE FAIRLY WEAK AND WILL NOT BECOME SEVERE. RAIN AMOUNTS FROM
THESE SHOWERS AND STORMS LOOK TO NOT BE A LOT, WITH ONLY A 20-40%
CHANCE FOR 0.1 INCH OR MORE RAIN TO FALL MAINLY OVER NORTH CENTRAL
SD.
THE LOW-LEVEL JET WILL STICK AROUND OVER CENTRAL SD THROUGH THE
MORNING AND INTO THE EARLY AFTERNOON. WHILE EARLY IN THE MORNING THE
LAPSE RATES WILL BE WEAKER AND IT WILL BE HARDER FOR THE STRONGER
WINDS TO MIX DOWN, THROUGH THE MORNING AND INTO THE AFTERNOON THE
LAPSE RATES WILL INCREASE, CAUSING STRONGER WINDS TO GET TO THE
SURFACE OVER CENTRAL SD. ENSEMBLES SHOW A 40-80% CHANCE FOR WINDS TO
GUST UP AROUND AND OVER 35 MPH OVER AREAS WEST OF THE MISSOURI
RIVER, AND A 30-50% CHANCE FOR WINDS TO GUST UP AROUND AND OVER 40
MPH OVER CORSON AND DEWEY COUNTIES. THESE WINDS SPEEDS ARE STRONG
BUT THEY DO STAY BELOW WIND ADVISORY CRITERIA FOR NOW. RELATIVE
HUMIDITY VALUES WILL STAY AROUND AND ABOVE 50% IN THE LOCATIONS AND
AROUND THE TIME OF THE STRONGEST WINDS. THIS HELPS TO KEEP THE FIRE
WEATHER CONCERNS LOWER FOR WEDNESDAY.
THE NEXT CHANCE FOR ACCUMULATING PRECIPITATION WILL START THURSDAY
AFTERNOON THROUGH FRIDAY AS A WARM FRONT AND SURFACE LOW PRESSURE
MOVES IN AND TOWARDS CENTRAL AND NORTHEASTERN SD. MODELS ARE STILL
VARYING THE LOCATION OF THIS LOW AND FRONTAL BOUNDARY AS WELL AS DRY
AIR MOVING INTO NORTHEASTERN SD THURSDAY EVENING INTO FRIDAY. THIS
CAUSES DIFFERENT OUTCOMES IN THE LOCATION AND TIMING OF SHOWERS AND
STORMS MOVING THROUGH SD. A MAJORITY OF THE MODELS ARE SHOWING THE
PRECIPITATION MOVING THROUGH MAINLY SOUTH CENTRAL SD TO THE EAST
OVER PORTIONS OF EAST CENTRAL AND SOUTHEASTERN SD, WITH THE BULK OF
THE RAIN OCCURRING OVER EASTERN SD. HOWEVER, SOME MODELS HAVE THE
AREA OF RAIN MORE TO THE NORTH OR TO THE SOUTH, LEADING TO LOWER
CONFIDENCE IN THE LOCATION AND SOME OF THE TIMING OF THE SHOWERS AND
STORMS. DEPENDING ON WHERE THE SHOWERS AND STORMS END UP, AS WELL AS
HOW MUCH DRY AIR MIXES IN, THE RAINFALL AMOUNTS VARY AS WELL. SOME
MODELS HAVE CHANCES FOR 1-3 INCHES OVER CENTRAL AND NORTHEASTERN SD,
WITH THE HIGHEST AMOUNTS OVER EASTERN SD. HOWEVER, OTHER MODELS KEEP
THE VALUES LOWER, WITH 0.5-1 INCH OF RAIN POSSIBLE. THIS IS
SOMETHING TO KEEP AN EYE ON AS MORE MODEL RUNS COME TO MORE OF AN
AGREEMENT. EITHER WAY, THERE IS CURRENTLY A MARGINAL TO SLIGHT
EXCESSIVE RAINFALL OUTLOOK FOR PORTIONS OF CENTRAL AND NORTHEASTERN
SD, WITH THE HIGHEST CHANCES OF FLOODING POTENTIAL TO THE SOUTHEAST
OF THE AREA.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1220 PM CDT TUE SEP 15 2026
TERMINALS KABR,KATY,KPIR,KMBG
VFR CONDITIONS WILL CONTINUE THROUGH THE DAY AND INTO THE
NIGHT. SOME AFTERNOON CUMULUS CLOUDS ARE STARTING TO DEVELOP OVER
PORTIONS OF NORTHERN SOUTH DAKOTA WHICH COULD LOWER THE CLOUD BASES
TO AT TIMES DURING THE AFTERNOON TO BE BETWEEN 3500 TO 7500 FEET,
THOUGH THERE SHOULD ONLY BE A FEW CLOUDS IN THE SKY SO THERE
WILL NOT BE LOW CEILINGS. CONDITIONS SHOULD STAY VFR INTO THE
MORNING FOR MOST TERMINALS, THOUGH WITH HIGHER HUMIDITY AND
LOWER WIND SPEEDS, THERE COULD BE SOME PATCHY SPOTS OF FOG THAT
COULD DEVELOP DURING THE EARLY WEDNESDAY MORNING OVER KATY AND
KABR THAT COULD REDUCE VISIBILITIES SLIGHTLY. NORTHWESTERLY
WINDS WILL START TO TURN THIS EVENING TO BECOME MORE EASTERLY
OVERNIGHT THEN SOUTHEASTERLY DURING THE DAY WEDNESDAY. THE
WINDS WILL PICK UP WEDNESDAY MORNING INTO THE AFTERNOON AND BE
GUSTING UP AROUND 30 MPH OVER KPIR AND KMBG AND UP AROUND 20 TO
25 MPH OVER KABR AND KATY.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
DISCUSSION...12
AVIATION...12
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