238 FXUS63 KFSD 011735 AFDFSD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 1135 AM CST SUN FEB 1 2015 .UPDATE... ISSUED AT 1131 AM CST SUN FEB 1 2015 AS EXPECTED...SEEING A GENERAL DECREASE IN SNOW FROM WEST TO EAST. OBS ARE STILL REPORTING REDUCED VISIBILITIES ALL THE WAY BACK INTO CENTRAL SOUTH DAKOTA HOWEVER IN BLOWING SNOW...SO IN COORDINATION WITH SURROUNDING OFFICES DID EXTEND SOME OF OUR HEADLINES INTO LATE AFTERNOON OR EVENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CST SUN FEB 1 2015 SNOWSTORM HAS BEEN BEHAVING PRETTY WELL DURING THE NIGHT WITH ACCUMULATIONS CONTINUING IN THE WARNING AND ADVISORY AREAS. STORM TOTALS SHOULD RANGE FROM AN INCH OR SO EXTREME NORTH TO AROUND 7 INCHES SOUTHEAST. EVEN WHILE THERE HAS BEEN A LITTLE DROPOFF IN INTENSITY IN SOME AREAS INCLUDING FSD...A MINOR SECONDARY SURGE ASSOCIATED WITH WEST NORTHWESTERLY SHORT WAVE APPEARS TO BE MERGING IN THE MAIN SNOW AREA AND IS LIKELY TO CAUSE A LITTLE RESURGENCE IN INTENSITY. WINDS HAVE PICKED UP AND THE SNOW IS DRIFTING PRETTY WELL AT LOW LEVELS...BUT THE BLOWING SNOW DOES NOT GET UP REAL HIGH AND REALLY CUT VISIBILITIES DOWN...SO WILL CONTINUE TO HANDLE THAT PART OF THE FORECAST WITH PATCHY BLOWING SNOW. THE CURRENT WARNING AND ADVISORY SETUP IS WORKING OUT WELL AND WILL CONTINUE WITH THE SAME. IT DOES APPEAR THAT CONDITIONS WILL IMPROVE A LITTLE FASTER WITH THE SNOW ENDING FAIRLY QUICKLY DURING THE MIDDLE OF THE DAY. HAVE CHOSEN TO LET THE WARNING FAR SOUTHEAST IN NORTHWEST IOWA GO UNTIL 6 PM AS PLANNED...AND WILL LET THE ADVISORY OUT WEST GO UNTIL THE CURRENT NOON EXPIRATION. IN BETWEEN...WILL MOVE UP THE EXPIRATION TIME OF THE HIGHLIGHTS BY 3 HOURS TO 3 PM FROM YKN TO FSD AND IN SOUTHWEST MN. EVENTUALLY WE MAY BE ABLE TO CUT THE HIGHLIGHTS EVEN A LITTLE SOONER. SINCE WE ARE NOT DEALING WITH A BLIZZARD...HIGHLIGHTS EXTENDING INTO THE TIME OF IMPROVING CONDITIONS MAY NOT BE TOO BAD GIVEN THE DRIFTING SNOW AFFECTING TRAVEL. SKIES WILL START TO CLEAR QUICKLY FROM THE NORTH DURING THE MIDDLE OF THE DAY AND IT SHOULD BECOME RATHER CLEAR BY EARLY EVENING. TEMPERATURES WILL GENERALLY FALL SLOWLY EXCEPT FOR A SMALL RECOVERY WEST THIS AFTERNOON AFTER THE BETTER COOLING TAKES PLACE THERE THROUGH THIS MORNING. WIND CHILLS WILL CONTINUE TO GO DOWN TO 5 BELOW SOUTHEAST...AND IN THE TEENS BELOW NORTHWEST BEFORE SLIGHT AFTERNOON RECOVERY. TONIGHT WILL BRING MOSTLY CLEAR SKIES EXCEPT FOR A START OF WARM ADVECTION MID AND HIGH CLOUDS FROM THE WEST LATE. TEMPERATURES WILL DROP TO SEVERAL DEGREES BELOW ZERO. WIND CHILLS MIGHT BARELY TOUCH 20 BELOW IN SOME PLACES LATE WITH THE COOLING. SINCE THESE WIND CHILLS WILLS WILL AT WORST GET BARELY AND BRIEFLY TO ADVISORY CRITERIA...AND GET THERE BECAUSE OF WIND SPEEDS WHICH WILL HAVE DROPPED WELL INTO THE SINGLE DIGITS IN MPH...WILL NOT ISSUE A WIND CHILL ADVISORY. ACTUAL LOW TEMPERATURES SHOULD BE IN THE SINGLE DIGITS BELOW ZERO...AND THERE COULD BE SOME VERY SLIGHT REBOUNDING OF A COUPLE DEGREES FAR WEST BEFORE DAYBREAK AS THE WARM ADVECTION CLOUDS START TO ARRIVE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM CST SUN FEB 1 2015 ACTIVE WEATHER WILL PERSIST INTO THE MIDDLE OF THE WEEK AS A SERIES OF SHORTWAVE TRAVERSE THE UPPER LEVEL NORTHWEST INTO THE NORTHERN PLAINS. THE FIRST MINOR SHORTWAVE CLIPS THE NORTHEASTERN HALF OF THE FORECAST AREA ON MONDAY AFTERNOON AND EVENING. STRATUS WILL BUILD IN AHEAD OF THE WAVE...HOWEVER MID LEVELS LOOK TO REMAIN PRETTY DRY AS THE WAVE PASSES THROUGH THE REGION. UPPER LEVEL SUPPORT IS GOOD WITH THIS FAST MOVING WAVE...BUT THINK THAT SNOW WILL HAVE A HARD TIME MATERIALIZING. THE BEST POTENTIAL FOR ANY PRECIPITATION WILL BE EAST OF I29...BUT CHANCES FOR MEASURABLE SNOW ARE VERY SLIM. MODEST RETURN FLOW WILL ALLOW TEMPERATURES TO MODERATE SOME...MAINLY IN OUR WESTERN HALF. A LARGE RANGE OF HIGHS ACROSS THE FORECAST AREA ARE EXPECTED...FROM THE MID TEENS EAST TO NEAR 30 IN SOUTH CENTRAL SD. ANOTHER MID LEVEL WAVE DROPPING ALONG THE NORTHWEST FLOW WILL BRING A GREATER POTENTIAL FOR SOME LIGHT SNOWFALL ON TUESDAY. MODELS HAVE COME INTO MUCH BETTER AGREEMENT IN DROPPING THE WAVE ACROSS OUR NORTHEASTERN HALF. WHILE UPPER SUPPORT IS DECENT...MOISTURE AND FRONTOGENETIC LIFT IS MORE IMPRESSIVE THAN MONDAY. A STRONGER WAVE DIGS ACROSS THE NORTHERN PLAINS CLOSE ON THE SECOND WAVES HEELS LATE TUESDAY NIGHT INTO WEDNESDAY. THIS WAVE TRACKS FURTHER SOUTH NEAR THE MISSOURI VALLEY AND I80 CORRIDOR...SO WILL FOCUS SNOW CHANCES IN OUR FAR SOUTH. THE GFS IS SOMEWHAT OF AN OUTLIER IN TRACKING WELL SOUTH OF THE FORECAST AREA. COLDER AIR FILTERING BACK INTO THE REGION WILL PREVENT TEMPERATURES FROM WARMING MUCH FROM TUESDAY NIGHT LOWS. HIGHS WILL ONLY BE IN THE TEENS. UPPER LEVEL RIDGING FINALLY BEGINS TO REBOUND TO OUR WEST ON THURSDAY AND FRIDAY...BECOMING MORE ZONAL ON SATURDAY. WITH SOUTHERLY RETURN FLOW AND WARM AIR ADVECTION DEVELOPING ON THURSDAY...TEMPERATURES MODERATE SOME ON THURSDAY. BUT BY FRIDAY AND SATURDAY...READINGS IMPROVE INTO THE 30S AND EVEN SOME 40S IN SOUTH CENTRAL SD. EXPECT HIGHS TO BE TEMPERED SOME BY THE RECENT HEAVY SNOWFALL...SO LOWERED ALL BLEND HIGHS A FEW DEGREES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1109 AM CST SUN FEB 1 2015 LIFR/IFR VISBYS AND CEILINGS WILL IMPROVE AFTER 20Z AS SNOW TAPERS OFF THROUGH THE LATE AFTERNOON. NORTHERLY WINDS WILL DIMINISH TO LIGHT AND VARIABLE DURING THE EVENING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR SDZ061-062- 065>071. WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR SDZ050- 052>055-057>060-063-064. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ056. MN...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR MNZ098. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ080- 081-089-090-097. IA...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ001>003- 012>014-020>022-031-032. NE...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR NEZ013-014. && $$ UPDATE...JM SHORT TERM... LONG TERM... AVIATION...JM