829 FXUS63 KFSD 241311 AFDFSD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 811 AM CDT THU OCT 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 350 AM CDT THU OCT 24 2013 THE BACKSIDE OF A TROUGH OF LOW PRESSURE TO THE EAST WILL SLOWLY WORK EAST OF THE AREA TODAY. SOME MID LEVEL CLOUD COVER SHOULD CONTINUE TO FALL APART AS SOUNDINGS SUGGEST THE DEPTH OF THE MOISTURE WITHIN THIS CLOUD DECK IS PRETTY THIN. THIS SHOULD ALLOW FOR A DECENT AMOUNT OF SUNSHINE...WITH SOUTHWEST MINNESOTA THE ONLY AREA THAT COULD SEE SOME STUBBORN PARTLY CLOUDY TO MOSTLY CLOUDY CONDITIONS. HIGHS SHOULD MAINLY BE IN THE MID TO UPPER 40S. AS THE TROUGH EXITS TONIGHT WARM ADVECTION SETS UP BUT A SIGNIFICANT LACK OF MOISTURE WILL NOT SUPPORT ANY PRECIPITATION. WITH WINDS TURNING TO THE SOUTH AND SOUTHWEST OVERNIGHT LOW TEMPERATURES SHOULD FOLLOW A BIT OF A NON DIURNAL PATTERN SO WILL HAVE 12Z FRIDAY TEMPERATURES IN MOST LOCATIONS ABOUT 3 TO 5 DEGREES WARMER THAN EXPECTED LOWS...WHICH WILL BE FROM THE UPPER 20S TO LOWER 30S. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 350 AM CDT THU OCT 24 2013 DRY WEATHER WILL PREVAIL FRIDAY INTO THE WEEKEND. WE WILL SEE DECENT WARM AIR ADVECTION AHEAD OF AN APPROACHING COLD FRONT ON FRIDAY...SETTING UP A WARM DAY ACROSS THE REGION. WENT AHEAD AND CONTINUED THE TREND OF BUMPING UP HIGHS A FEW DEGREES. LOOKING FOR 50S EAST OF THE JAMES RIVER...AND LOW TO MID 60S TO THE WEST. WITH MOSTLY SUNNY SKIES...THE ONLY THING PREVENTING A PERFECT DAY WILL BE A BLUSTERY SOUTHWEST WIND GUSTING 20 TO 35 MPH...STRONGEST OVER SOUTHWEST MINNESOTA. THE COLD FRONT WILL MOVE THROUGH ON FRIDAY NIGHT...ALTHOUGH WITH A LACK OF MOISTURE THIS WILL BE A DRY PASSAGE...PROBABLY WITHOUT EVEN CLOUD COVER. COOLER CONDITIONS CAN BE EXPECTED ON SATURDAY WITH HIGHS RANGING FROM THE MID 40S SOUTHWEST MINNESOTA TO LOW 50S ALONG THE MISSOURI RIVER. MAY SEE SOME AFTERNOON CU DEVELOP IN THE WELL MIXED BOUNDARY LAYER...WITH GREATEST COVERAGE IN THE DEEPER COLD AIR OVER SOUTHWEST MINNESOTA...BUT STILL SHOULD BE PARTLY TO MOSTLY SUNNY. NOT THE STRONGEST WINDS BEHIND THE FRONT...BUT ENOUGH WINDS ALOFT TO SUPPORT A 10 TO 20 MPH NORTHWESTERLY SURFACE BREEZE. WARM AIR ADVECTION INCREASES AGAIN ON SUNDAY AHEAD OF A STRONG WAVE DIVING SOUTH ACROSS WESTERN CANADA. THUS WE WILL SEE HIGHS REBOUND BACK INTO THE 50S TO AROUND 60 UNDER CONTINUED MOSTLY SUNNY SKIES AND RELATIVELY LIGHT SOUTHERLY WINDS AROUND 10 MPH. FORECAST BECOMES MORE COMPLICATED EARLY TO MID NEXT WEEK. A LOT OF ENERGY DIVING SOUTH OUT OF WESTERN CANADA INTO THE WESTERN PORTION OF THE COUNTRY. AND AS CAN BE EXPECTED WITH THIS MUCH ENERGY...MODELS ARE HAVING A TOUGH TIME ON THE EXPECTED EVOLUTION. CURRENT BEST GUESS SUGGESTS COLD FRONT WILL MOVE THROUGH SUNDAY NIGHT...ALTHOUGH MODELS DISAGREE ON HOW FAR SOUTH THIS GETS. SO IN GENERAL LOOKS LIKE MONDAY WILL BE COOLER...BUT EXACTLY HOW COLD WILL DEPEND ON THE SOUTHWARD PROGRESSION OF THE FRONT...WITH THE ECMWF THE COLDEST SOLUTION AND THE GFS THE WARMEST. AT THIS POINT LOOKS LIKE THE UPPER LOW WILL TRY TO CUTOFF SOMEWHERE WEST OF THE ROCKIES. A PIECE OF THIS ENERGY MAY EJECT EAST...WHICH COMBINED WITH INCREASING ISENTROPIC LIFT AHEAD OF THE DIGGING TROUGH...SUGGEST A PERIOD OF PRECIPITATION MONDAY NIGHT INTO TUESDAY WILL BE POSSIBLE. PRECIPITATION TYPE WILL AGAIN BE DEPENDENT ON THE SOUTHWARD FRONTAL PROGRESSION...AND THUS IS UNCERTAIN. FOR NOW MAINLY JUST WENT WITH RAIN AND SNOW MIX...WITH NO REAL PREFERENCE IN ANY ONE SOLUTION AT THIS TIME. THE ONLY THING CERTAIN IS THAT THE PROBABILITY OF SEEING SNOW INCREASES THE FURTHER NORTH YOU GET. MEANWHILE THE MAIN UPPER LOW SHOULD NOT STAY CUTOFF FOR LONG AS IT GETS FORCED BACK INTO THE WESTERLY FLOW. AS IT MOVES ACROSS THE CENTRAL PLAINS...ANOTHER ROUND OF PRECIPITATION IS LIKELY SOMETIME WEDNESDAY INTO THURSDAY. BUT EXACTLY WHERE IN THE PLAINS AND WHEN IS HIGHLY UNCERTAIN. ALSO UNCLEAR IS WHETHER THE LOW KEEPS ITS NORTHERN STREAM COLD AIR CONNECTION...WITH THE LATEST EC SUGGESTING IT DOES NOT. SO THE BEST THING THAT CAN BE SAID IS THAT THE MID WEEK FORECAST REMAINS HIGHLY UNCERTAIN WITH REGARDS TO PRECIPITATION CHANCE AND PRECIPITATION TYPE OVER OUR CWA. AND WITH SO MANY FACTORS COMING INTO PLAY IT WILL LIKELY REMAIN UNCERTAIN FOR DAYS TO COME...SO THE BEST THING TO DO IS JUST WATCH MODEL TRENDS AND TRY TO SLOWLY NARROW IN ON A MOST LIKELY SCENARIO. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 811 AM CDT THU OCT 24 2013 VFR EXPECTED THROUGH 25/12Z. A FEW CEILINGS 3-6K FEET NORTHEAST PART OF THE FORECAST AREA THROUGH 25/00Z...NORTHEAST OF FSD. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...08 LONG TERM...CHENARD AVIATION...08