660 FXUS63 KFSD 271713 AFDFSD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 1113 AM CST FRI NOV 27 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM CST FRI NOV 27 2015 AREAS OF LOW CLOUDS MOVING SOUTH OVER OUR MN AND IA COUNTIES...AND ALSO BETWEEN THE BIG SIOUX AND JAMES RIVERS...THE LATTER BATCH WITH A FEW FLURRIES...SHOULD MOVE SOUTH OF THE AREA OR DISSIPATE LATER THIS MORNING AS THE LOW LEVEL AIR CONTINUES TO DRY. OTHERWISE EXPECT SKIES TO ME MOSTLY CLEAR TODAY AND TONIGHT...EXCEPT PARTLY CLOUDY FAR SOUTH WITH MID AND HIGH CLOUDS PERSISTING OVER THE SOUTHERN SKY THERE. THESE CLOUDS WILL START TO PUSH NORTH BY THE END OF TONIGHT. WINDS WILL SLOWLY BUT STEADILY DECREASE TODAY AND BECOME LIGHT TONIGHT. TEMPERATURES ARE GOING TO BE ON THE COLD SIDE. HIGHS IN THE 20S TODAY WILL BE ACCOMPANIED BY A LINGERING BREEZE. LOWS TONIGHT SHOULD BE IN THE 7-13 RANGE. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 342 AM CST FRI NOV 27 2015 FIRST HALF OF THE WEEKEND LOOKS DRY BUT SEASONABLY COOL AS SURFACE AND UPPER LEVEL RIDGING MOVE EAST ACROSS THE REGION. CHANGES THEN BEGIN TO TAKE SHAPE FOR THE LATTER HALF OF THE WEEKEND...AND MORESO EARLY NEXT WEEK...AS BROAD TROUGH CURRENTLY ACROSS THE WESTERN CONUS SWINGS OUT INTO THE PLAINS. MODELS SHOWING FAIRLY GOOD AGREEMENT IN TIMING AND TRACK OF THIS SYSTEM...AT LEAST GOOD FOR THIS RANGE. THIS BOOSTS CONFIDENCE THAT A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL SPREAD OVER THE REGION LATE SUNDAY NIGHT THROUGH TUESDAY...BUT MORE ON THAT LATER. PRECEDING THE MAIN SURGE OF PRECIPITATION...WEAK LIFT OVER FAIRLY ABUNDANT LOW LEVEL MOISTURE COULD PRODUCE SPOTTY LIGHT PRECIP AS EARLY AS SATURDAY NIGHT/SUNDAY. WILL CARRY SOME LOW POPS ACROSS OUR WEST DURING THIS TIME FRAME...AS THERE IS SOME INDICATION OF MID LEVEL MOISTURE WEST OF THE JAMES VALLEY TO SUPPORT ICE INTRODUCTION INTO THE LOWER LEVEL CLOUDS. FARTHER EAST THOUGHT...LACK OF MOISTURE IN THIS ICE-INTRODUCTION LAYER COULD RESULT IN AREAS OF DRIZZLE...OR UNFORTUNATELY GIVEN SUB-FREEZING LOW LEVEL TEMPERATURES...FREEZING DRIZZLE. CONFIDENCE IN EXTENT OF THE LOW LEVEL MOISTURE OR DEGREE OF LIFT IS LOW...SO WILL NOT INTRODUCE FREEZING DRIZZLE TO THE FORECAST JUST YET. BUT WILL BE SOMETHING TO MONITOR IN COMING FORECASTS... ESPECIALLY GIVEN THAT SUNDAY CLOSES OUT THE HOLIDAY TRAVEL PERIOD. BY SUNDAY NIGHT...ESPECIALLY AFTER 06Z...DEEPER SURGE OF MOISTURE BEGINS TO WORK NORTHWARD AHEAD OF THE DEEPENING UPPER TROUGH. THIS SHOULD LEAD TO MORE WIDESPREAD PRECIP SPREADING INTO THE REGION FROM NEBRASKA LATE SUNDAY NIGHT...THEN LINGERING ACROSS MUCH OF THE AREA MONDAY/MONDAY NIGHT AS UPPER LOW SLOWLY EAST ACROSS NEBRASKA/IOWA. AT THIS POINT...NOT SEEING SIGNIFICANT MID-LEVEL FRONTS WHICH COULD FOCUS PRECIP INTO TIGHTER BANDS...THOUGH MAY HAVE TO WATCH FOR THIS AS WEAK TROWAL DEVELOPS ACROSS CENTRAL/NORTHERN PORTIONS OF THE CWA LATER MONDAY. INSTEAD...WITH THE LACK OF SHARP MID-LEVEL THERMAL BOUNDARY...SHOULD SEE BROAD AREA OF LIGHT TO MODERATE PRECIPITATION. WITH PROLONGED NATURE OF THE PRECIPITATION THREAT...COULD VERY WELL SEE EVENT TOTAL SNOWFALL AMOUNTS REACH 4-6 INCH RANGE OR MORE...BUT AT THIS TIME IT APPEARS THESE AMOUNTS WOULD BE SPREAD OVER A 24-36 HOUR PERIOD. TO FURTHER COMPLICATE THE FORECAST...BOTH GFS AND ECMWF NOW INDICATE A WARM LAYER ALOFT OVER FAR EASTERN PORTIONS OF THE REGION SUNDAY NIGHT...AS THE PRECIPITATION IS BEGINNING TO EXPAND INTO THE AREA. THUS HAVE INTRODUCED A MENTION OF MIXED PRECIPITATION...MAINLY EAST OF HIGHWAY 60/KSUX-KOTG LINE. THIS SYSTEM SLOWLY SHIFTS EAST INTO THE GREAT LAKES TUESDAY...AND REMAINDER OF THE WEEK FROM TUESDAY NIGHT ON LOOKS DRY...BUT AGAIN SEASONABLY COOL GIVEN THE EXPECTED FRESH SNOW COVER FROM EARLIER IN THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1111 AM CST FRI NOV 27 2015 VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM...JH AVIATION...