476  
FXUS63 KFSD 010056  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
756 PM CDT WED SEP 30 2020  
   
UPDATE
 
 
ISSUED AT 754 PM CDT WED SEP 30 2020  
 
LOSS OF HEATING HAS ALLOWED WINDS TO SLACKEN EARLY THIS EVENING,  
AND THEREFORE THE RED FLAG WARNING AND WIND ADVISORY HAVE BOTH  
BEEN ALLOWED TO EXPIRE. REMAINDER OF THE FORECAST REMAINS ON  
TRACK.  
 
UPDATE ISSUED AT 424 PM CDT WED SEP 30 2020  
 
WARMER TEMPERATURES WEST OF THE SCATTERED SPRINKLES HAVE RESULTED  
IN RELATIVE HUMIDITY LEVELS DROPPING BELOW 25 PERCENT THROUGH THE  
JAMES RIVER VALLEY AS OF 4 PM. THIS COMBINED WITH VERY STRONG  
NORTHWEST WINDS OF 25 TO 40+ MPH WILL RESULT IN CRITICAL FIRE  
BEHAVIOR THROUGH THE BALANCE OF THE AFTERNOON. CONDITIONS SHOULD  
QUICKLY IMPROVE WITH LOSS OF HEATING TOWARD SUNSET. HAVE EXPANDED  
THE RED FLAG WARNING TO COVER THE MIDDLE JAMES RIVER VALLEY,  
INCLUDING HURON AND MITCHELL, THROUGH 7 PM.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 231 PM CDT WED SEP 30 2020  
 
ADVISORY LEVEL WINDS CONTINUE ACROSS MUCH OF THE FORECAST AREA  
THIS AFTERNOON AS WE'VE REACHED PEAK HEATING. GIVEN THE WEAK COLD  
ADVECTION OVER MINNESOTA, A FEW SCATTERED SHOWERS HAVE DEVELOPED  
ACROSS WESTERN MINNESOTA AND FAR EASTERN SOUTH DAKOTA AND WILL  
CONTINUE THROUGH SUNSET. CRITICAL FIRE WEATHER CONDITIONS WILL  
ALSO PERSIST IN AREAS SOUTH OF INTERSTATE 29.  
 
TONIGHT: GUSTY WINDS WILL SUBSIDE, BUT I'D STILL EXPECT VERY  
CONSISTENT BREEZY NORTHWESTERLY WINDS INTO THURSDAY MORNING. CLOUD  
COVER WILL CONTINUE TO ADVANCE SOUTHEAST OUT OF MINNESOTA  
OVERNIGHT, AND A FEW LINGERING SPRINKLES COULD BE POSSIBLE ALONG  
THE BUFFALO RIDGE. HAVE RAISED TEMPERATURES SLIGHTLY GIVEN THE  
PERSISTENT MIXING, BUT TEMPERATURES IN MOST AREAS WILL FALL INTO  
THE LOWER 40S.  
 
THURSDAY: CLOUD COVER SHOULD BE PREVALENT OVER THE EASTERN HALF OF  
THE CWA INTO THE FIRST PART OF THE DAY. A RATHER CHILLY DAY  
OVERALL AS TEMPERATURES STRUGGLE TO CLIMB THROUGH THE 50S. WINDS  
WILL REMAIN BREEZY BUT WELL BELOW CRITICAL LEVELS.  
 
   
LONG TERM
 
(THURSDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 231 PM CDT WED SEP 30 2020  
 
THURSDAY NIGHT INTO FRIDAY: FROST WILL REMAIN POSSIBLE BY FRIDAY  
MORNING AS SURFACE RIDGING MOVES OVERHEAD. HOWEVER, A FLY A  
OINTMENT WILL BE THE ADVANCEMENT OF WHAT COULD BE AN BROKEN MID TO  
UPPER LEVEL CLOUD DECK THROUGH DAYBREAK. AS A RESULT, HAVE TRENDED  
OVERNIGHT LOWS SLIGHTLY WARMER THAN PREVIOUS GUIDANCE.  
 
FRIDAY: THE DAYTIME HOURS OF FRIDAY WILL AGAIN BE DRY. WINDS WILL  
BEGIN TO TURN MORE SOUTHERLY IN RESPONSE TO AN UPPER TROUGH  
DROPPING SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT INTO SATURDAY.  
TEMPERATURES STRUGGLE TO REACH 60 AGAIN IN MOST LOCATIONS.  
 
FRIDAY NIGHT-SATURDAY: MODELS ARE IN A BIT BETTER AGREEMENT  
BRINGING UPPER TROUGHING TO THE SOUTHWEST OF THE CWA FRIDAY NIGHT.  
THE ECMWF IS MORE EFFICIENT IN PRODUCING LIGHT RAINFALL OVER THE  
SOUTHERN HALF OF THE CWA, WHERE THE GFS IS NEARLY DRY. BLENDED  
GUIDANCE, GIVEN ENSEMBLES INCLUDED, REMAINS DRY. A SECONDARY WAVE  
MOVES THROUGH ON SATURDAY HOWEVER THIS WAVE SHOULD FOCUS ANY RISK  
OF PRECIPITATION EAST OF THE AREA. TEMPERATURES ON SATURDAY REMAIN  
BELOW NORMAL IN THE UPPER 50S AND LOWER 60S.  
 
SUNDAY-WEDNESDAY: ANOTHER EXTENDED PERIOD OF DRY, BREEZY, AND  
WARMER TEMPERATURES BEGINS TO ARRIVE AS WE START NEXT WEEK. SUNDAY  
WILL REMAIN COOLER AND IN THE 50S, BUT TEMPERATURES QUICKLY JUMP  
ABOVE NORMAL MONDAY THROUGH WEDNESDAY. MODEL PERSPECTIVES AND  
COMPARISONS SUGGEST TEMPERATURES COULD EVEN CLIMB A BIT WARMER  
THAN POPULATED GUIDANCE. THERE REMAINS LITTLE TO NO CHANCE OF  
PRECIPITATION THROUGH NEXT WEEK, SO ONGOING DROUGHT AND FURTHER  
ENHANCING OF THE FIRE DANGER RISKS ARE ANTICIPATED.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 636 PM CDT WED SEP 30 2020  
 
STRONGER NORTHWEST WIND GUSTS HAVE BEGUN TO DIMINISH, AND EXPECT  
TO LOSE MOST OF THE GUSTINESS WITHIN AN HOUR OR TWO OF SUNSET.  
WILL SEE SOME GUSTS NEAR TO SLIGHTLY ABOVE 25KT DEVELOP AGAIN BY  
MID-MORNING THURSDAY, CONTINUING THROUGH THE AFTERNOON. HOWEVER,  
WINDS ARE EXPECTED TO REMAIN WELL BELOW LEVELS SEEN THE PAST  
COUPLE OF DAYS IN THE REGION.  
 
MVFR CEILINGS LIKELY TO WORK INTO AREAS NEAR/EAST OF KBKX-KSLB  
LINE, INCLUDING MOST OF SOUTHWEST MN AND THE IOWA GREAT LAKES  
REGION, LATE TONIGHT THROUGH MIDDAY THURSDAY. THESE AREAS COULD  
ALSO SEE SPOTTY SPRINKLES THROUGH THE OVERNIGHT HOURS. OTHERWISE  
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS PERIOD.  
 

 
 
   
FSD WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
MN...NONE.  
IA...NONE.  
NE...NONE.  
 

 
 

 
 
UPDATE...JH  
SHORT TERM...DUX  
LONG TERM...DUX  
AVIATION...JH  
FIRE WEATHER...DUX  
 
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