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...