Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 291715
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1215 PM CDT WED JUL 29 2015

.UPDATE...
ISSUED AT 1123 AM CDT WED JUL 29 2015

AFTER COORDINATION WITH SURROUNDING OFFICES...HAVE CANCELLED THE
WIND ADVISORY FOR THE NORTHERN TIER OF COUNTIES. LATEST DATA
ALREADY SUGGESTING WINDS ALOFT HAVE LEVELED OFF AND WILL BEGIN
DECREASING THROUGH THE AFTERNOON. WE WILL STILL BE ABLE TO MIX
FAIRLY DEEP...AOA 6K FT AGL...AND THE DEPTH OF THIS MIXING WILL
CONTINUE TO PROMOTE WIND GUSTS BRIEFLY TO 40 MPH EARLY THIS
AFTERNOON. HOWEVER...SUSTAINED ADVISORY LVL WIND CHANCES HAVE
DECREASED.

HAVE ALSO LOWERED DEW POINTS SLIGHTLY THROUGH THE AFTERNOON GIVEN
A STRONGER WESTERLY WIND FETCH AND DRY AIR MIXING DOWN FROM ALOFT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT WED JUL 29 2015

WARM...DRY AND BREEZY ACROSS THE AREA TODAY. WENT AHEAD AND ISSUED A
WIND ADVISORY FOR THE FAR NORTHEASTERN COUNTIES TODAY AS ENHANCED
MIXING CARE OF THE LOW SPINNING TO THE NORTH TAKES OFF LATE THIS
MORNING. IF THE SOUNDINGS ARE ON TARGET WILL SEE SOME SUSTAINED
WINDS ABOUT 25 TO 30 MPH WITH A FEW GUSTS TO ABOUT 45 MPH. CLOSER TO
THE LOWER MISSOURI RIVER VALLEY WINDS WILL BE A MORE STANDARD SUMMER
TIME BREEZY AT ABOUT 15 TO 25 MPH BUT EVEN A GUST AROUND 30 MPH
POSSIBLE. THE GOOD MIXING WILL BE FIGHTING THE WET GROUND AND NOT
QUITE SURE HOW WARM TO GO. TEMPERATURES ALOFT FROM ABOUT 925MB TO
850MB WOULD SUPPORT SLIGHTLY WARMER TEMPERATURES THAN FORECAST...AS
WELL AS THESE WELL MIXED DAYS TEND TO GET WARMER THAN FORECAST MANY
TIMES ANYWAY...BUT BELIEVE THAT THE WET GROUND WILL HOLD US BACK A
BIT. SO NO BIG CHANGES FROM THE PREVIOUS FORECAST. ALSO TRICKY ON
THE AFTERNOON DEW POINTS AS IT WILL BE A BALANCE OF WET
GROUND/EVAPOTRANSPIRATION AND MIXING DRY AIR DOWN FROM ALOFT. IF THE
GROUND WERE DRIER THERE WOULD PROBABLY BE SOME FIRE WEATHER CONCERNS
BUT NOT ANTICIPATING ANY PROBLEMS.

BY TONIGHT WINDS WILL DROP OFF AND WITH CLEAR SKIES AND FAIRLY LIGHT
WINDS WILL SEE TEMPERATURES DIP INTO THE MID TO UPPER 50S IN MANY
SPOTS. WHILE FOG SHOULD NOT BE WIDESPREAD SOME LOW LYING AREAS MAY
SEE POCKETS OF REDUCED VISIBILITY.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 356 AM CDT WED JUL 29 2015

PLEASANT SUMMER WEATHER EXPECTED TO CONTINUE THROUGH THE END OF THE
WEEK...AS DEPARTURE OF UPPER LOW TO THE NORTHEAST WILL KEEP US IN
NORTHWESTERLY FLOW ALOFT...BUT DECREASE THE DEEP LAYER GRADIENT OVER
THE AREA.  TEMPS THURSDAY WARM A DEGREE OR TWO CELSIUS ALOFT...AND
WITH A HEALTHY SERVING OF JULY SUNSHINE...SHOULD GET A COUPLE OR
THREE WARMER AT THE SURFACE...BUT WITH MUCH LESS WIND TO MIX DOWN
FOR THE AFTERNOON. ANY INCREASE IN DEWPOINT PRIMARILY
EVAPOTRANSPIRATION IN ACTION...SO LIKELY REMAINING COMFORTABLE IN
THE 50S TO PERHAPS SOME LOWER 60S.

WAVE ZIPPING BY TO THE NORTHEAST WILL PUSH A WEAK BACKDOOR BOUNDARY
SOUTHWARD ON LATER THURSDAY NIGHT AND FRIDAY. PERHAPS ENOUGH MID
LEVEL MOISTURE FOR A FEW MID CLOUDS ACROSS THE NORTHEAST LATER
THURSDAY NIGHT. BOUNDARY WILL CONTINUE TO PUSH QUICKLY SOUTHWARD
THROUGH THE DAY...AND CONVERGENCE WILL LIKELY BE SAFELY SOUTH OF THE
AREA BEFORE ANY THREAT FOR SPOTTY LATE DAY CONVECTION. OTHERWISE...
TEMPS ALOFT WILL LIKELY FALL BACK TO ABOUT WHERE THEY WERE TODAY...
A GOOD MEASURE FOR OUR POTENTIAL.

MODELS CONTINUE TO CONGEAL ON A WAVE ON SATURDAY AND SATURDAY
EVENING IN THE NORTHWEST FLOW...WITH A BIT SHARPER BOUNDARY WORKING
SOUTHEAST. AGAIN A VERY LIMITED POTENTIAL TO GET ANY MEANINGFUL
MOISTURE RETURN...AND OVERALL SHOULD RESTRICT DESTABILIZATION
POTENTIAL. TEMPS ALOFT ONLY MODESTLY WARM...AND WITH LARGE DEGREE OF
DIRECTIONAL SHEAR...WOULD HAVE TO THINK THAT ISOLATED SEVERE STORMS
WITH LARGE HAIL AND DAMAGING WIND WOULD BE IN PLAY FROM LATE
AFTERNOON THROUGH THE EVENING. GOOD SOLID PUSH TO THINGS IN
NORTHWEST FLOW ALOFT...AND SHOULD BE CLEARING MOST OF THE AREA BY
LATER SATURDAY NIGHT.  IN WAKE OF SYSTEM...SUNDAY SHOULD BE A WARMER
DAY WITH JUST A BIT MORE HUMIDITY.

BEYOND THIS COMES A VERY DIVISIVE PERIOD IN TIMING OF WAVES WITHIN
THE NORTHWEST FLOW BETWEEN VARIOUS SOLUTIONS...WITH GENERAL IDEA OF
A STRONGER SYSTEM IMPACTING THE AREA TOWARD TUE/WED. APPROPRIATE AT
THE TIME WOULD BE SOME SMALLISH POPS AND TEMPS FAIRLY CLOSE TO OR A
BIT BELOW NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1214 PM CDT WED JUL 29 2015

VFR CONDITIONS EXPECTED INTO THURSDAY MORNING. BREEZY WINDS THIS
AFTERNOON WILL SUBSIDE QUICKLY THIS EVENING. WINDS WILL REMAIN
LIGHT AND VARIABLE OVERNIGHT...TURNING NORTHWESTERLY BY MID-
MORNING THURSDAY.

&&

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

$$

UPDATE...DUX
SHORT TERM...08
LONG TERM...CHAPMAN
AVIATION...DUX



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