660 
FXUS63 KFSD 081959
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
259 PM CDT TUE JUL 8 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 258 PM CDT TUE JUL 8 2014

BREEZY NORTHWEST WINDS WILL CONTINUE THROUGH THE LATE AFTERNOON 
HOURS DUE TO MECHANICAL MIXING.  SHOULD SEE THE GUSTS DECREASE 
FAIRLY MARKEDLY THIS EVENING...BUT MAY HANG ON TO SLIGHTLY STRONGER 
WINDS THAN ANTICIPATED THROUGH THE EVENING DUE TO LINGERING LOW 
LEVEL COLD AIR ADVECTION IN THE EAST.  COULD ALSO HAVE AN 
AFTERNOON/EARLY EVENING SHOWER IN EASTERN CWA WITH NEARLY UNCAPPED 
ENVIRONMENT.  SHEAR PROFILES ARE VERY LINEAR...SO ANY STORMS THAT 
DEVELOP WOULD LIKELY STRUGGLE TO BECOME ORGANIZED.  

SURFACE HIGH PRESSURE REMAINS ACROSS THE AREA ON WEDNESDAY. WITH 
MIXING...WILL LIKELY DEVELOP A LIGHT NORTHWEST WIND...ESPECIALLY 
ACROSS THE EASTERN HALF OF THE FORECAST AREA THAT WILL LINGER 
THROUGH THE DAY.  WITH DRY ATMOSPHERE...KEPT DRY FORECAST GOING WITH 
SLIGHTLY BELOW NORMAL TEMPERATURES. 

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE JUL 8 2014

THE CHANCES FOR SHOWERS AND THUNDERSTORMS NOT VERY GOOD ON WEDNESDAY 
NIGHT AS THE SLIGHTLY MORE UNSTABLE AIR LOOKS TO REMAIN SOUTH AND 
WEST OF THE AREA. AND WITH LOW LEVEL FLOW MAINLY SOUTHEAST THE 
ADVECTION OF THIS MORE UNSTABLE AIR NOT OCCURRING. WILL MAINTAIN 
SOME SMALL POPS IN THE WESTERN CWA AS A WEAK WAVE MOVES THROUGH. 

BY THURSDAY A STRONGER WAVE WILL MOVE EAST ALONG THE ND/SD BORDER 
WHICH WILL TURN WINDS A LITTLE MORE SOUTHERLY AND 
SOUTHWESTERLY...AIDING IN CONVERGENCE AND DESTABILIZATION. THIS WILL 
BRING THE NEED FOR INCREASED POPS BUT THE CHANCE FOR SEVERE PRETTY 
SLIM WITH GENERALLY LESS THAN 1000 J/KG OF SKINNY CAPE. THIS THREAT 
WILL CONTINUE INTO THURSDAY NIGHT AND EXIT TO THE EAST LATE THURSDAY 
NIGHT AND FRIDAY MORNING. 

ANOTHER WEAKER WAVE WILL MOVE THROUGH ON FRIDAY AND WILL NEED SOME 
LOWER END POPS TO COVER THIS THREAT. ONCE AGAIN INSTABILITY MARGINAL 
SO THE SEVERE THREAT ALSO MARGINAL.

IN THE OUTER PERIODS(FRIDAY THROUGH TUESDAY)...MODELS STILL TRENDING 
AND CONVERGING TOWARDS A CHILLY SUMMERTIME PATTERN. A DEEP LARGE 
SCALE TROUGH/LOW PRESSURE IS EXPECTED TO DIG INTO THE GREAT LAKES 
REGION SUNDAY INTO MONDAY BRINGING MUCH COOLER AIR TO THE REGION. A 
FEW OF THE RUNS ARE COOL ENOUGH THAT THE NORTHEAST THIRD OF THE CWA 
MIGHT NOT MAKE IT TO 70 DEGREES. THIS PATTERN SUGGESTS TEMPERATURES 
MUCH BELOW NORMAL FOR MONDAY AND TUESDAY. STATISTICAL GUIDANCE 
SOMEWHAT SUPPORTIVE OF THIS WITH THE MEX NUMBERS BELOW CLIMATOLOGY 
AND THE ENSEMBLE MEAN EVEN COOLER. A COUPLE OF WEAK WAVES WILL MOVE 
THROUGH OVER THE WEEKEND WHICH COULD BRING A FEW SHOWERS AND 
THUNDERSTORMS BUT MONDAY AND TUESDAY SHOULD SEE MAINLY COOL AND 
STABLE AIR WITH LOWER PROBABILITIES OF RAINFALL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1239 PM CDT TUE JUL 8 2014

GUSTY NORTHWEST WINDS WILL PREVAIL THROUGH THE AFTERNOON AND
EVENING HOURS. WINDS WILL DROP RAPIDLY TOWARDS SUNSET. WINDS WILL
REMAIN LIGHT THROUGH THE MORNING HOURS ON WEDNESDAY...MIXING OUT
TO NORTHWEST THROUGHOUT THE DAY. SCATTERED CUMULUS AROUND 4-5K
FEET WILL DIE AWAY THIS EVENING...WITH MOSTLY CLEAR SKIES EXPECTED
OVERNIGHT THROUGH WEDNESDAY MORNING. 

&&

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

$$

SHORT TERM...
LONG TERM...08
AVIATION...