372
FXUS63 KFSD 110810
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
310 AM CDT MON MAY 11 2026
KEY MESSAGES
- FROST IS EXPECTED EARLY THIS MORNING. A FROST ADVISORY IS IN
EFFECT UNTIL 9 AM.
- TODAY, TUESDAY AND THURSDAY WILL SEE ELEVATED TO NEAR CRITICAL
FIRE WEATHER CONCERNS. TUESDAY AND THURSDAY APPEAR TO CARRY
THE HIGHEST RISKS WITH VERY STRONG WINDS WITH A DRY AIR MASS.
- WARMER CONDITIONS ARE EXPECTED THIS WEEK WITH HIGHS 10 TO 20
DEGREES ABOVE NORMAL. THURSDAY AND FRIDAY SHOULD SEE HIGHS IN
THE MID 80S TO LOWER 90S.
- DRY WEATHER REMAINS FOR MOST OF THE WEEK. STARTING TO SEE
INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS LATE WEEK INTO
THE WEEKEND.
UPDATE
ISSUED AT 308 AM CDT MON MAY 11 2026
HIGH PRESSURE AT THE SURFACE DRIFTS EAST AND ALLOWS SOUTHERLY FLOW
TO DEVELOP TODAY. WIND GUSTS OF 25 TO 35 MPH ARE LIKELY,
ESPECIALLY NEAR AND WEST OF I-29. WITH THE RELATIVE HUMIDITY
FALLING TO 20 TO 30 PERCENT, ELEVATED FIRE DANGER IS EXPECTED.
LOW PRESSURE TRACKS BY TO THE NORTHEAST OF THE AREA, SWINGING A
FRONT THROUGH TONIGHT INTO TUESDAY MORNING. THIS WILL BRING
STRONGER NORTHWEST FLOW AND CONTINUED DRY AIR, LEADING TO
ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS. FIRE WEATHER
HEADLINES WILL LIKELY BE NEEDED WITH RELATIVE HUMIDITY ONCE
AGAIN AVERAGING 20 TO 30 PERCENT IN THE AFTERNOON AND WIND GUSTS
CLIMBING TO 30 TO 40 MPH.
AFTER A PLEASANT WEDNESDAY, THURSDAY WILL SEE VERY STRONG
SOUTHERLY FLOW DEVELOP. THIS IS ANOTHER DAY WHEN FIRE WEATHER
HEADLINES WILL LIKELY BE NEEDED. AFTERNOON RELATIVE HUMIDITY
WILL ONCE AGAIN AVERAGING 20 TO 30 PERCENT WITH WIND GUSTS 35 TO
45 MPH.
DISCUSSION
ISSUED AT 153 PM CDT SUN MAY 10 2026
PARTLY CLEAR SKIES PERSIST THIS AFTERNOON, ALLOWING HIGH
TEMPERATURES TO WARM TO THE 60S AND 70S. LOW HUMIDITY AND MARGINALLY
BREEZY WINDS WILL KEEP ELEVATED FIRE DANGER CONDITIONS GOING THROUGH
THE REST OF THE AFTERNOON HOURS. TEMPERATURES TONIGHT REMAIN ON
TRACK TO BE ON THE COLD SIDE ONCE AGAIN, FALLING TO THE LOW TO MID
30S TO LOW 40S. THUS, HAVE ISSUED ANOTHER FROST ADVISORY FOR
LOCATIONS ALONG AND NORTHEAST OF A HURON, SOUTH DAKOTA TO SIOUX
FALLS, SOUTH DAKOTA, TO ORANGE CITY, IOWA LINE. THE FROST ADVISORY
IS IN EFFECT FROM 3 AM TO 9 AM MONDAY.
AN UPPER LEVEL TROUGH WILL BEGIN TO PUSH INTO THE NORTHERN PLAINS
FROM CANADA ON MONDAY. WARM AIR ADVECTION (WAA) WILL STRENGTHEN
AHEAD OF THIS WAVE THROUGHOUT THE DAY. THE WAA WILL PUSH HIGH
TEMPERATURES ABOVE AVERAGE ACROSS THE AREA WITH HIGHS INTO THE 70S
AND 80S EXPECTED. DEW POINTS WILL REMAIN LOW THOUGH, RESULTING IN
HUMIDITY VALUES DOWN TO NEAR CRITICAL TO CRITICAL LEVELS. THE LOW
HUMIDITY ALONG WITH BREEZY SOUTHERLY WINDS WITH GUSTS UP TO 20-35
MPH, STRONGEST ALONG AND WEST OF I-29, WILL RESULT IN ANOTHER DAY OF
ELEVATED FIRE DANGER ACROSS THE AREA. WHILE CONDITIONS WILL BE NEAR
CRITICAL TO CRITICAL, GREENING FUELS CONTINUE TO LESSEN THE OVERALL
FIRE DANGER. A COLD FRONT TIED TO THIS UPPER WAVE WILL PUSH THROUGH
THE AREA DURING THE OVERNIGHT HOURS. THE LOW LEVEL JET (LLJ) WILL
STRENGTHEN AHEAD OF THE FRONT, KEEPING BREEZY WINDS GOING THROUGH
THE NIGHT. A FEW SHOWERS TO PERHAPS A THUNDERSTORM OR TWO COULD
DEVELOP ALONG THE FRONT AS WELL. SEVERE WEATHER IS NOT EXPECTED AS
INSTABILITY WILL BE QUITE WEAK, BUT PERHAPS SOME GUSTY WINDS COULD
BE POSSIBLE. LOW TEMPERATURES WILL BE MUCH WARMER, ONLY FALLING TO
THE 50S OVERNIGHT.
TUESDAY AND WEDNESDAY LOOK TO REMAIN WARM ACROSS THE AREA AS UPPER
LEVEL RIDGING BUILDS OVER THE CENTRAL CONUS. TUESDAY WILL BE THE
COOLER OF THE TWO DAYS WITH HIGH TEMPERATURES WARMING TO THE 70S.
HOWEVER, WINDS WILL BE QUITE BREEZY OUT OF THE NORTHWEST WITHIN THE
POST FRONTAL COLD ADVECTIVE AIRMASS WITH GUSTS UP TO 30-40 MPH.
HUMIDITY VALUES WILL BE LOW ACROSS THE VAST MAJORITY OF THE AREA AND
WILL HIT CRITICAL THRESHOLDS. DESPITE RECENT GREENING OF FUELS,
TUESDAY CONTINUES TO HAVE THE HIGHEST FIRE DANGER POTENTIAL WITH A
HIGH GFDI. WEDNESDAY WILL BE A LITTLE BIT WARMER WITH HIGHS IN THE
70S TO LOW 80S. THE LOW HUMIDITY WILL PERSIST BUT WINDS WILL BE MUCH
LIGHTER, KEEPING FIRE DANGER AT BAY.
THERE REMAINS UNCERTAINTY REGARDING HOW THE UPPER LEVEL PATTERN WILL
EVOLVE FOR THE REST OF THE WORK WEEK AND WEEKEND. MEDIUM RANGE
GUIDANCE, INCLUDING THE MACHINE LEARNING GUIDANCE, CONTINUE TO VARY
ON HOW THE SHORTWAVE TROUGH OVER THE WEST COAST PROGRESSES. THE MAIN
TWO CAMPS THAT THE MODELS ARE SPLIT OVER IS WHETHER THE UPPER LOW
SLOWS DOWN AND POTENTIALLY CUTS OFF OVER THE WEST COAST OR CONTINUES
EASTWARDS AS A MORE PROGRESSIVE SHORTWAVE. IF THE WAVE STAYS
PROGRESSIVE, THEN RAIN CHANCES COULD INCREASE BEYOND WHAT THEY
CURRENTLY ARE (20-30%). IF THE WAVES CUTS OFF, THEN CHANCES FOR RAIN
COULD DIMINISH. TOUGH TO SAY WHICH SOLUTION IS MOST LIKELY AT THIS
TIME BUT SOMETHING THAT WILL BE MONITORED OVER THE COMING DAYS.
ASIDE FROM RAIN CHANCES, THURSDAY AND FRIDAY CONTINUE TO LOOK VERY
WARM WITH HIGH TEMPERATURES WARMING INTO THE 80S ACROSS THE AREA.
THE MODELS ARE IN SLIGHTLY BETTER AGREEMENT FOR NEXT WEEKEND WITH
ZONAL FLOW TAKING OVER. THIS COULD STILL CHANGE DEPENDING ON HOW THE
PREVIOUSLY MENTIONED UPPER LEVEL LOW EVOLVES BUT FOR NOW, IT DOES
SEEM MOST LIKELY THAT RAIN CHANCES WILL INCREASE ACROSS THE NORTHERN
PLAINS. THIS IS SUPPORTED BY THE ENSEMBLES AS THEY SHOW INCREASING
CHANCES FOR RAIN, UP TO A 30-50% CHANCE FOR EXCEEDING A TENTH OF AN
INCH OF RAIN. SUNDAY HAS THE HIGHEST PROBABILITIES AT THIS TIME.
HIGH TEMPERATURES LOOK TO REMAIN WARM BUT A LITTLE BIT COOLER THAN
THURSDAY AND FRIDAY WITH HIGHS ONLY WARMING TO THE 70S AND 80S.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1226 AM CDT MON MAY 11 2026
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SOUTHEASTERLY WINDS
WILL BE INCREASING THROUGH THE DAY ON MONDAY, GUSTING TO 20 TO
30 KTS WEST OF I-29 BY THE LATE MORNING AND THEN GUSTING TO
AROUND 25 KTS NEAR AND EAST OF I-29 BY THE EARLY AFTERNOON.
BREEZY CONDITIONS WILL CONTINUE INTO THE EVENING AS A COLD FRONT
APPROACHES THE AREA. THIS FRONT WILL MOVE INTO SOUTH-CENTRAL
SOUTH DAKOTA AT THE VERY END OF THE PERIOD. WINDS JUST AHEAD OF
THE FRONT WILL DECREASE BEFORE INCREASING AGAIN AND TURNING
NORTHWESTERLY BEHIND THE FRONTAL PASSAGE.
FSD WATCHES/WARNINGS/ADVISORIES
SD...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR SDZ038>040-
053>056-061-062-067.
MN...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ071-072-080-
081-089-090-097-098.
IA...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ001>003-
012>014-021-022.
NE...NONE.
UPDATE...08
DISCUSSION...MEYERS
AVIATION...SAMET
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