Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 141726
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1226 PM CDT TUE APR 14 2015

.UPDATE...
ISSUED AT 1222 PM CDT TUE APR 14 2015

HAVE GONE AHEAD AND ISSUED A WIND ADVISORY FOR OUR FAR WESTERN
ZONES NEAR SOUTH CENTRAL SD THROUGH WEDNESDAY MORNING. TIGHT
GRADIENT COUPLED WITH 35 TO 45 KNOTS IN THE MIXED LAYER WILL
REMAIN ON TAP FOR THAT AREA THROUGH CLOSE TO 18Z WEDNESDAY. THERE
WILL BE SOME DECOUPLING TONIGHT WHICH SHOULD AT LEAST GET RID OF
THE GUSTS...BUT THAT SAID IT WILL LIKELY REMAIN PRETTY WINDY IN
THAT AREA ALL NIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT TUE APR 14 2015

A WEAK RIDGE OF HIGH PRESSURE WILL MOVE EAST OF THE AREA WITH STRONG
SOUTHERLY WINDS EXPECTED TO DEVELOP TODAY. THE STRONGEST WINDS WILL
BE ALONG AND WEST OF THE JAMES RIVER VALLEY WHERE GUSTS AROUND 40
MPH ARE LIKELY WITH THE LIGHTER WINDS...ALBEIT STILL ABOUT 15 TO 25
MPH...ACROSS NORTHWEST IOWA. AS HAS BEEN THE TREND VERY DRY LOW
LEVEL CONDITIONS COMBINED WITH WARM TEMPERATURES AND STRONG WINDS
BRINGS ABOUT THE NEED FOR A RED FLAG WARNING. WILL HAVE ONE IN
EFFECT FOR ALL BUT NORTHWEST IOWA. HIGHS TODAY WILL BE IN THE 70S.

STRONG WINDS OVERNIGHT WILL KEEP LOW TEMPERATURES ON THE MILD SIDE
IN THE MID TO UPPER 40S. LOW TO MID LEVEL MOISTURE WILL BE ON THE
INCREASE FROM THE SOUTH AND SOUTHEAST LATE TONIGHT WHICH WILL BRING
AN INCREASE IN CLOUD COVER.

.LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 303 AM CDT TUE APR
14 2015

STILL WITH LITTLE CHANGE SINCE YESTERDAY MORNING IS THE WEAK SHORT
WAVE BEING KICKED UP NORTH TOWARD THE AREA WEDNESDAY...AND THE
INCREASE IN BOTH LOW AND MID LEVEL MOISTURE REGARDLESS OF RAIN
CHANCES. LOOKS LIKE THERE WILL BE ENOUGH MARGINAL LIFT WITH THE
MOISTURE INCREASE TO KEEP A FAIRLY SMALL CHANCE OF SHOWERS GOING
WEDNESDAY AND WEDNESDAY NIGHT. AIR STILL LOOKS FAIRLY STABLE AND
GIVEN THE WEAK NATURE OF THE LIFT...WILL GO WITH JUST SHOWERS. THIS
SEEMS BEST GIVEN THE LOW POPS...WITH ONLY A SLIGHT CHANCE OF SHOWERS
TO START WITH...IF THE CONDITIONAL THUNDER THREAT IS SMALL...THAT
PRETTY WELL SINKS THE ACTUAL THREAT. DID PUT A LITTLE THUNDER
MENTION WITH CHANCE POPS SOUTHWEST/SOUTH WEDNESDAY NIGHT AND
THURSDAY AS INSTABILITY INCREASES A LITTLE. RAINFALL AMOUNTS...IF
ANY...WILL BE MEAGER IN ANY EVENT. DAYTIME TEMPERATURES WILL BE
COOLER WEDNESDAY AND THURSDAY BUT STILL MILD.

SLOW DRYING FROM THE NORTH IS STILL EXPECTED THURSDAY INTO FRIDAY.
THIS MEANS MOSTLY TOSSING THE OPERATIONAL GFS WHICH FORCES RIDGING
NORTH AND KEEPS THE AIR MOIST OVER THE AREA...IT SEEMS TO BE AN
OUTLIER HERE. THE EC BENDS IN THE GFS DIRECTION FROM THE PREVIOUS EC
RUN BUT NOT TOO MUCH...STILL BRINGING SOME DRYING...WITH A LINGERING
SMALL CHANCE OF SHOWERS SOUTH FRIDAY...AND THAT WILL BE THE
FORECAST.

FRIDAY NIGHT AND SATURDAY LOOK DRY AND CONTINUED MILD...AGAIN NOT
GOING WITH THAT GFS. SUNDAY THROUGH MONDAY THEN LOOK POTENTIALLY
SHOWERY AS THE UPPER LOW TO THE SOUTH IS EJECTED NORTH NORTHEAST.
THIS IDEA FITS WITH BOTH THE EXTENDED GUIDANCE AND THE LATEST EC.
COOLING SHOULD START BY MONDAY AS THE DIGGING ROCKIES WAVE EJECTING
THE SOUTHERN LOW APPROACHES THE AREA. THIS SHOULD LEAD TO COOL
TEMPERATURES NEXT WEEK BEYOND THE CURRENT FORECAST PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1222 PM CDT TUE APR 14 2015

VFR WILL PREVAIL THROUGH WEDNESDAY MORNING. THE BIGGEST AVIATION
CONCERN IS STRONG SOUTHERLY WINDS GENERALLY WEST OF INTERSTATE 29.
IN FACT APPROACHING CENTRAL SD...WINDS WILL GUST FREQUENTLY TO
AROUND 35 KNOTS INTO EARLY EVENING...AND WILL REMAIN QUITE WINDY
IN THAT AREA ALL NIGHT.

&&

.FIRE WEATHER...
ISSUED AT 303 AM CDT TUE APR 14 2015

 A COMBINATION OF VERY STRONG SOUTHERLY WINDS...HUMIDITY VALUES
IN THE TEENS AND TEMPERATURES IN THE 70S NECESSITATE A RED FLAG
WARNING FOR MANY LOCATIONS. THE LEAST LIKELY LOCATION WILL BE
ACROSS NORTHWEST IOWA WHERE MORE PRECIPITATION HAS FALLEN RECENTLY
AND WINDS WILL LIKELY BE IN THE 15 TO 25 MPH RANGE VERSUS 20 TO 40
MPH IN CENTRAL SOUTH DAKOTA. SOUTHWEST MINNESOTA WILL BE JUST A
TOUCH MARGINAL WITH WIND SPEEDS...ESPECIALLY IN THE SOUTHEAST
CORNER...BUT WITH HUMIDITY VALUES IN THE TEENS IN THE AFTERNOON
STILL VERY DANGEROUS FIRE WEATHER CONDITIONS.

DESPITE THE COOLER AND MORE MOIST ENVIRONMENT PROJECTED FOR THE
NEXT SEVERAL DAYS...VERY HIGH FIRE DANGER POTENTIAL FOR PART OF
THE NORTHERN FORECAST AREA WILL STILL BE POSSIBLE WEDNESDAY...
FRIDAY...AND SUNDAY DURING WHICH TIMES DECENT WINDS ARE EXPECTED.
THIS IS PARTLY BASED ON PROJECTIONS MENTIONED ELSEWHERE THAT THE
GFS OVERDOES THE SPREAD AND PERSISTENCE OF MOISTURE INTO THE AREA
THE NEXT FEW DAYS. STILL...RED FLAG CONDITIONS ARE NOT FORESEEN
WITH THE HIGHER HUMIDITY.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ255>258.

     WIND ADVISORY UNTIL 1 PM CDT WEDNESDAY FOR SDZ050-052-057-058-
     063-064.

MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ900.

IA...NONE.
NE...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ249.

&&

$$

UPDATE...MJ
SHORT TERM...08
LONG TERM...
AVIATION...MJ
FIRE WEATHER...08



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