575 FXUS63 KFSD 101725 AFDFSD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 1225 PM CDT THU OCT 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 433 AM CDT THU OCT 10 2013 HIGH AMPLITUDE FLOW ACROSS THE NATION WITH DEEP WESTERN TROUGH AND STRONG PLAINS/MIDWEST RIDGE. MOISTURE ACROSS THE NATIONS MID SECTION IS LACKING...PRETTY MUCH LIMITED TO MID LEVEL SOURCE IN THE SOUTHWESTERN U.S. WEAK SYSTEM ALOFT PUSHING ALONG UPSTREAM SIDE THROUGH NEBRASKA THIS MORNING...BUT ONLY ENHANCING HIGH CLOUDS AT THE TIME. OVERALL...WARM SOUTHERLY FLOW WILL AGAIN DOMINATE THE AREA FOR ANOTHER DAY...AS THE LOW LEVEL GRADIENT AGAIN INCREASES A BIT WITH HIGH PLAINS FALLING PRESSURE IN ADVANCE OF THE MAJOR WESTERN TROUGH. WEAK BOUNDARY ACROSS THE WEST WILL START TO BECOME MORE DIFFUSE OR REORGANIZE FURTHER TO THE NORTHWEST. TEMPERATURES ALOFT SUGGEST HIGHS IN THE NEIGHBORHOOD OF THOSE FROM LAST COUPLE OF DAYS...AND AS LONG AS CIRRUS DIMINISHES WITH PASSAGE OF WAVE TO THE SOUTH...SHOULD SCRAPE UP ANOTHER DAY FROM THE MID 70S TO AROUND 80... OR ABOUT 15 TO 20 DEGREES ABOVE NORMAL FOR MOST. SHOULD GET A LITTLE DECOUPLING EARLY ON TONIGHT...BUT GRADIENT WILL REVERSE THE TREND AND KEEP WINDS UP TONIGHT...AS WELL AS LOW TEMPERATURES OVER THAT WHICH SOME OF THE RADIATIVELY COOLER SPOTS HAVE ATTAINED THE LAST TWO NIGHTS. WITH APPROACH OF CLOSED LOW...A BAND OF STRONG PV ADVECTION WILL MOVE THROUGH THE WESTERN HALF OF THE CWA DURING THE LAST HALF OF THE OVERNIGHT. FAIRLY STRONG UPPER LEVEL FORCING AND 8 TO 9 C/KM MID LEVEL LAPSE RATES SHOULD OVERCOME THE OVERALL DRY ATMOSPHERE TO ALLOW BAND OF SHOWERS/ISOLATED THUNDER TO PRESS EASTWARD THE LAST HALF OF THE OVERNIGHT. INSTABILITY TRENDS TO BE FAIRLY LIMITED...WITH A FEW HUNDRED J/KG ELEVATED CAPE. MOST HIGH RESOLUTION MODELS ALONG WITH SREF INDICATE A NARROW BAND OF PRECIPITATION...PERHAPS TOWARD THE I29 CORRIDOR TOWARD DAYBREAK. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 433 AM CDT THU OCT 10 2013 FRIDAY APPEARS TO BE A VERY WINDY DAY ACROSS THE FORECAST AREA AS AN AREA OF LOW PRESSURE DRIFTS FROM CENTRAL SOUTH DAKOTA INTO NORTHWEST MINNESOTA. WITH THE AID OF MIXING...WINDS WILL PICK UP RAPIDLY THROUGH THE MORNING HOURS AND WITH 30-35 KNOTS OF FLOW AT 925 HPA... MAY APPROACH ADVISORY CRITERIA IN THE EAST. ANY SHOWER ACTIVITY MOVING THROUGH MAY TEMPORARILY STABILIZE THE NEAR SURFACE LAYER KEEPING THE STRONG WINDS ALOFT. UPPER LEVEL SUPPORT QUICKLY SHIFTS NORTHEAST THROUGH THE MORNING HOURS...AND APPEARS TO STABILIZE ON THE BACKSIDE OF THE WAVE. THEREFORE...MAY NOT BE MANY SHOWERS AROUND THROUGH THE AFTERNOON HOURS WITH STRONG WINDS CONTINUING TO SURFACE. MODELS SUGGEST COLD FRONT WILL PUSH INTO THE WESTERN EDGE OF THE FORECAST AREA...AND STRONG COLD AIR ADVECTION MAY LEAD TO WIND GUSTS APPROACHING HIGH WIND CRITERIA. HAVE ISSUED A SMALL ADVISORY FOR AREAS IN THE WEST...BUT EXPECT ADVISORY WILL BE NEEDED TO BE EXPANDED FURTHER EAST. IN ADDITION...THERE IS A CHANCE THAT WINDS IN SOUTH CENTRAL SOUTH DAKOTA COULD REACH HIGH WIND WARNING CRITERIA...ESPECIALLY IN BRULE...CHARLES MIX AND GREGORY COUNTIES. FUTURE SHIFTS WILL NEED TO KEEP AN EYE ON THESE LOCATIONS FOR POTENTIAL UPGRADE TO THE HEADLINES. VERY DRY AIR WORKS INTO THE FORECAST AREA BEHIND THE FRONT FRIDAY EVENING INTO SATURDAY. WITH LOW LEVEL COLD AIR ADVECTION CONTINUING THROUGH THE NIGHT FRIDAY NIGHT...KEPT WIND ADVISORY GOING THROUGH 05Z BUT COULD NEED TO KEEP THE ADVISORY LINGERING LONGER IN THE EAST IF IT IS EXPANDED. WITH WINDS CONTINUING THROUGH MUCH OF THE NIGHT...SHOULD BE A WARM AND WINDY NIGHT ACROSS THE AREA. SATURDAY WILL BE A MIXY DAY WITH UNIDIRECTIONAL NORTHWEST FLOW. HAVE UNDERCUT DEW POINTS WITH DRY AIR ALOFT. WITH SURFACE RIDGE BUILDING INTO THE AREA...EXPECT WINDS TO RAPIDLY DECREASE SATURDAY EVENING ONCE MIXING CEASES. WITH DRY AIR REMAINING ACROSS THE AREA AS SURFACE RIDGE MOVES ACROSS THE AREA...HAVE UNDERCUT GUIDANCE TEMPERATURES SATURDAY NIGHT. MAY NEED TO ADD FROST WORDING TO THE FORECAST...BUT WITH 925 HPA TEMPERATURES IN THE 3-5 C RANGE...DO NOT EXPECT HARD FREEZE QUITE YET. NEXT SYSTEM APPEARS TO MOVE INTO THE FORECAST AREA SUNDAY NIGHT INTO MONDAY BEFORE EXITING ON TUESDAY. HAVE CONTINUED TO INCREASE POPS WITH THIS SYSTEM....AND WITH LIMITED INSTABILITY KEPT PRECIP AS RAIN SHOWERS FOR NOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1220 PM CDT THU OCT 10 2013 GENERAL VFR CONDITIONS THROUGH THE TAF PERIOD. MODERATE SOUTHEASTERLY WINDS THROUGH TONIGHT WILL BEGIN TO RAMP UP AFTER 14Z ON FRIDAY. WITH A LOW LEVEL JET DEVELOPING OVER THE AREA TONIGHT...WILL HAVE LOW LEVEL WIND SHEAR AT KFSD AND KSUX DURING THE OVERNIGHT HOURS. MAY ALSO HAVE A BRIEF PERIOD OF SHOWERS MOVE ACROSS THE AREA AFTER 10Z TONIGHT...WITH BETTER CHANCES NORTH OF INTERSTATE 90. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WIND ADVISORY FROM 1 PM FRIDAY TO MIDNIGHT CDT FRIDAY NIGHT FOR SDZ050-052-057>059-063>065-068-069. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHAPMAN SHORT TERM...CHAPMAN LONG TERM... AVIATION...JM