FXUS63 KARX 200720 AFDARX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 220 AM CDT SAT MAR 20 2010 .SHORT TERM...TODAY THROUGH MONDAY NIGHT FOCUS THIS MORNING IS ON THE DEPARTING SNOW...CLOUD TRENDS TODAY AND TONIGHT...AND THEN MAINLY TEMPERATURES. 07Z SURFACE ANALYSIS SHOWS A LOW PRESSURE AREA OVER THE OZARKS... WITH A FRONTAL BOUNDARY REACHING NORTHEAST INTO THE EASTERN GREAT LAKES REGION. HIGH PRESSURE WAS CENTERED OVER MT AND THE WESTERN DAKOTAS. NORTHERLY WINDS ACROSS OUR AREA WAS SENDING COLD AIR IN FROM CANADA...AND WHERE THIS COLD AIR WAS MEETING THE WARM AND MOIST AIR RIDING UP AND OVER THE FRONT...A POTENT BAND OF SNOW HAD SET UP. THE SNOW RAN FROM THE KANSAS CITY AREA...UP ACROSS IA AND INTO NORTHERN IL AND FAR SOUTHERN WI. SEVERAL INCHES OF ACCUMULATION SEEN TO OUR SOUTH...BUT ONLY A LIGHT DUSTING ON GRASSY AREAS REPORTED SO FAR IN OUR ZONES. FOR TODAY...THE AREA OF DEEP FRONTOGENESIS RESPONSIBLE FOR THE UPWARD MOTIONS FOR SNOW PRODUCTION WILL SLOWLY SAG SOUTHWARD AS THE FRONT AND STORM SYSTEM SHIFT TOWARD THE OHIO RIVER VALLEY. WILL HANG ONTO SMALL SNOW CHANCES OVER THE FAR SOUTHERN ZONES THIS MORNING...BUT THAT IS IT. IN FACT...DRY AIR ALSO INVADING FROM THE NORTH SHOULD RESULT IN CLEARING SKIES. AMPLE SUNSHINE TODAY SHOULD HELP OFFSET THE COLD ADVECTION...SO ANTICIPATE HIGHS FROM THE MID 30S TO MID 40S. MODEL SOLUTIONS REMAIN IN RATHER GOOD AGREEMENT THROUGH THE REMAINDER OF THE SHORT TERM PERIOD...WITH ABOVE AVERAGE FORECAST CONFIDENCE. A RIDGE OF HIGH PRESSURE WILL REMAIN ACROSS THE AREA FROM TONIGHT ALL THE WAY THROUGH MONDAY...WITH AN OVERALL SLOW-MOVING WEATHER PATTERN. THE OVERALL PATTERN WILL REMAIN IN PLACE...WITH THE MAIN JET UP ACROSS CANADA...AND PERIODIC SHORT WAVE TROUGH ENERGY HITTING THE WEST COAST AND DIGGING INTO A SLOW MOVING CLOSED CIRCULATION. THIS NEXT CYCLE LOOKS TO SET UP AGAIN BY THE MIDDLE OF NEXT WEEK. A SHORT WAVE TROUGH IN THE NORTHERN STREAM WILL BRING THE NEXT COLD FRONT AND THREAT FOR PRECIPITATION LATE TUESDAY. BUT BEFORE THAT GETS HERE...LOOK FOR TEMPERATURES TO BEGIN TO REBOUND BACK ABOVE NORMAL SUNDAY INTO MONDAY AS LOW LEVEL WARM AIR STARTS TO ADVECT BACK IN UNDER THE RIDGING. ONE LAST THING TO CONSIDER. WITH LIGHT WINDS UNDER THE RIDGING...AND DRY AIR AROUND TO ALLOW FOR MAXIMUM RADIATIONAL COOLING...THOUGHT ABOUT THE NEED TO ADD SOME FOG TO THE FORECAST FOR BOTH TONIGHT AND SUNDAY NIGHT. AVAILABLE MOISTURE LOOKS PRETTY SHALLOW...SO NOT SOLD ON IT COMPLETELY. WILL LEAVE OUT...BUT WILL ALERT LATER SHIFTS TO CONSIDER THIS POSSIBILITY. .LONG TERM...TUESDAY THROUGH FRIDAY AS ALLUDED TO ABOVE...WE LOOK TO HAVE A REPEAT PERFORMANCE OF A NORTHERN STREAM DISTURBANCE BRINGING A FRONT INTO THE AREA...AS A PIECE OF ENERGY AGAIN DIGS INTO THE SOUTHWESTERN STATES AND CLOSES OFF. THE TIMING OF THIS REMAINS IN QUESTION...BUT THE FIRST SMALL CHANCES FROM THE NORTHERN STREAM LOOK TO BE LATE TUESDAY INTO WEDNESDAY. CURRENTLY...THE SOUTHERN PIECE LOOKS TO PASS SOUTH OF OUR REGION...SO NO PRECIPITATION IN THE FORECAST YET. BUT WILL HAVE TO MONITOR THE EVENTUAL TRACK OF THIS FOR LATE NEXT WEEK. NO CHANGES TO THE LONG TERM YET UNTIL THIS BECOMES MORE CLEAR. && .AVIATION... POST-COLD FRONTAL MVFR CLOUDS WILL BE SCOURED OUT AT THE BEGINNING OF THE TAF PERIOD AS DRIER AIR MOVES INTO THE AREA. A STRONG STORM OVER THE CENTRAL U.S. WILL KEEP SOME MID-LEVEL CLOUDS OVER THE TAF SITES UNTIL FULL CLEARING OCCURS. VFR THROUGH THE REMAINDER OF WEEKEND. HOWEVER...WILL BE MONITORING SUNDAY MORNING FOR THE LOWER PROBABILITY THAT SOME RADIATIONAL FOG MAY FORM AT KLSE. IT APPEARS MOISTURE WILL BE A LIMITING FACTOR AT THIS TIME. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT/LONG TERM...MW AVIATION...BAUMGARDT/DAS