353
FXUS63 KFSD 051720
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT MON MAY 5 2025
KEY MESSAGES
- LOCALLY ELEVATED FIRE DANGER THIS AFTERNOON WEST OF I-29,
MAINLY WHERE TALL DORMANT GRASSES ARE STILL PREVALENT.
- MAINLY DRY CONDITIONS WILL PERSIST THROUGH THE WEEK, WITH
ONLY LOW (20-30%) CHANCES OF LIGHT RAIN SOUTH OF I-90 MIDWEEK.
- SEASONABLY MILD TEMPERATURES WILL DOMINATE THE WEEK AHEAD
WITH HIGHS IN THE MID 70S TO LOWER 80S. LOWS MAINLY IN THE 40S
TO START THE WEEK, BUT LOWS IN THE 50S WILL BE MORE COMMON BY
THE END OF THE WEEK.
DISCUSSION
ISSUED AT 330 AM CDT MON MAY 5 2025
A STAGNANT PATTERN BENEATH A PROMINENT OMEGA BLOCK OVER THE
PLAINS WILL MAKE TODAY A NEAR CARBON-COPY OF SUNDAY. EAST WINDS
MAY BE A TOUCH STRONGER IN AREAS EAST OF I-29 THIS AFTERNOON,
BUT STILL RELATIVELY LIGHT AT 10-15 MPH. MEANWHILE AREAS WEST OF
I-29, AND ESPECIALLY WEST OF US HIGHWAY 81 WILL SEE MORE BREEZY
SOUTH-SOUTHEAST WINDS, WITH GUST TO AROUND 25 MPH AT TIMES.
HUMIDITY LEVELS REMAIN LOW, GENERALLY BOTTOMING OUT IN THE 25
TO 30 PERCENT RANGE THIS AFTERNOON. THIS COMBINATION OF BREEZY
WINDS AND LOW HUMIDITY COULD RESULT IN ELEVATED FIRE DANGER IN
ISOLATED AREAS WHERE TALL DORMANT GRASSES ARE STILL THE DOMINANT
FUEL TYPE. HOWEVER, GREENING OF NEW GROWTH FINE FUELS APPEARS
SUFFICIENT TO KEEP OVERALL GRASSLAND FIRE DANGER ON THE LOW
SIDE.
MID-WEEK TUESDAY-THURSDAY WILL SEE THE CUTOFF UPPER LOW OVER
THE DESERT SOUTHWEST MOVE SLOWLY EAST FROM THE SOUTHERN ROCKIES
INTO THE SOUTHER/CENTRAL PLAINS, WHILE MID-UPPER LEVEL RIDGING
REMAINS PROMINENT ACROSS THE UPPER MIDWEST. A NORTHERN STREAM
WAVE SLIDES OVER THE RIDGE THROUGH SOUTHERN CANADA, DRAGGING A
FRONTAL BOUNDARY SOUTHWARD THROUGH THE NORTHERN PLAINS TUESDAY
NIGHT. HOWEVER, THE BOUNDARY APPEARS TO WASH-OUT AS IT ATTEMPTS
TO PUSH UNDER THE DOMINANT UPPER RIDGE. AT THE SAME TIME, THE
SOUTHERN LOW TREKS SLOWLY EAST ACROSS OKLAHOMA/KANSAS, AND MUCH
OF THE PRECIPITATION REMAINS CONFINED TO THESE AREAS. HOWEVER,
ENSEMBLES STILL SHOW LOW (20-30%) PROBABILITIES OF MEASURABLE
LIGHT RAIN SOUTH OF I-90 DURING THE DAY WEDNESDAY AND AGAIN
THURSDAY. IF WE SEE ANY RAINFALL, IT SHOULD QUITE LIGHT AS THE
PROBABILITIES TOPPING 0.10" IN THESE SAME PERIODS REMAINS LESS
THAN 10%, WITH ONLY 20-30% PROBABILITY FOR EXCEEDING 0.10" OVER
THE ENTIRE 48-HOUR PERIOD ENDING FRIDAY MORNING. TEMPERATURES
WILL REMAIN SEASONABLY MILD THROUGH THIS MID-WEEK PERIOD, WITH
LOW LEVEL TEMPERATURES CONTINUING TO SUPPORT HIGHS IN THE 70S.
AS WE MOVE INTO FRIDAY AND THE UPCOMING WEEKEND, THE SOUTHERN
PLAINS LOW WEAKENS AS IT MOVES THROUGH THE LOWER MISSISSIPPI
VALLEY, WHILE OUR LOCAL UPPER RIDGE IS ABSORBED BY A STRONGER
RIDGE EXPANDING OVER THE WESTERN HALF OF THE CONUS. THIS WILL
CONTINUE OUR DRY PATTERN, WHILE ALSO ALLOWING TEMPERATURES TO
WARM FURTHER AS WE PROGRESS THROUGH THE WEEKEND. NBM MEAN HIGH
TEMPERATURES SHOW WIDESPREAD LOWER-MID 80S BY SUNDAY, BUT THESE
VALUES ARE BELOW THE 50TH PERCENTILE OF THE NBM MEMBERSHIP (AND
CLOSER TO THE 25TH PERCENTILE IN SOME AREAS), SO SOME POTENTIAL
FOR EVEN GREATER WARMING FOR THE UPCOMING MOTHER'S DAY WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1219 PM CDT MON MAY 5 2025
VFR CONDITIONS ARE EXPECTED FOR THE TAF PERIOD. LIGHT
SOUTH/SOUTHEAST WINDS ARE EXPECTED FOR THE ENTIRE PERIOD WITH
LOCATIONS WEST OF I-29 SEEING SLIGHTLY STRONGER GUSTS UP TO ABOUT 20
KNOTS EXPECTED THIS AFTERNOON. WINDS WILL WEAKEN THROUGH THE EVENING
HOURS AND GO LIGHT AND VARIABLE, MAINLY ALONG AND EAST OF I-29.
WINDS WILL SLIGHTLY RESTRENGTHEN OUT OF THE SOUTH/SOUTHEAST TOMORROW
MORNING TO END THE TAF PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...JH
AVIATION...MEYERS
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