FXUS63 KMKX 032137 AFDMKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 337 PM CST WED DEC 3 2008 .DISCUSSION...AS CURRENT SNOW WINDS DOWN...FORECAST FOCUS ON NEXT SYSTEM FOR FRIDAY NIGHT AND SATURDAY. .SHORT TERM...TONIGHT AND THURSDAY LAST OF THE FRONTOGENETIC BANDS OF MODERATE SNOW MOVING ACROSS SE WI. BACK EDGE OF SNOW...AND CLOUD COVER...DROPPING STEADILY SE. WINTER WEATHER ADVISORY FOR THE NW PORTION OF CWA...WITH THE ADDITION OF LAFAYETTE AND GREEN COUNTIES...ALLOWED TO EXPIRE AT 3PM. ALL BUT MILWAUKEE...RACINE...KENOSHA AND WALWORTH WILL BE CANCELLED AT 6 PM. THE ADVISORY FOR THE SERN-MOST FIVE COUNTIES WILL CONTINUE UNTIL 8 PM. WINDS WILL INCREASE FOR A TIME THIS EVENING...THEN DECOUPLE AS CLOUDS CLEAR. THOUGH HIGH WATER CONTENT SNOW...SOME DRIFTING IN OPEN RURAL AREAS MAY OCCUR. WITH FRESH SNOW COVER TEMPS TONIGHT WILL DROP TO BELOW GUIDANCE VALUES WITH SINGLE DIGITS INLAND...TO LOW TEENS ALONG THE LAKE. MIX OUT TO 925 MB TEMPS OF -13 TO -14C SUPPORTING HIGHS ONLY IN THE LOW TO MID 20S THURSDAY. SECOND SHEARED 500 MB SHORT WAVE MAY GENERATE SCT FLURRIES AS IT PASSES THRU THURSDAY AFTERNOON. SOUNDINGS SHOW STEEP LAPSE RATES UP TO 850 MB...WITH CLOUD BEARING LAYER CENTERED IN DENDRITE GROWTH ZONE...BUT ONLY ABOUT 2K FT DEEP AND DRY AIR ABOVE THROUGH THE COLUMN. ANOTHER COLD NIGHT THURSDAY NIGHT...WITH TEMPS SIMILAR TO TONIGHT. WARM AIR ADVECTION LATE ON FRIDAY WILL ONLY MEAN A FEW DEGREES WARMER FOR HIGHS...BUT NOT MUCH DROP OFF FRIDAY NIGHT. STRONG LAYER Q-VECTOR CONVERGENCE AHEAD OF NEXT SHORT WAVE MOVES IN AFTER MIDNIGHT...ESPECIALLY WEST...SO UPPED POPS TO LIKELY THERE...THEN LIKELY IN THE EAST SATURDAY MORNING AS SHORT WAVE CROSSES REGION. EARLY HIGHS SATURDAY BY THE NOON HOUR...THEN FALLING TEMPERATURES. .LONG TERM...SUNDAY THROUGH WEDNESDAY...ACTIVE...AND COLD...NW FLOW PATTERN KEEPS THE SERIES OF SHORT WAVES MOVING THROUGH THE REGION FOR THE FIRST HALF OF NEXT WEEK. DRY AND COLD WEATHER FOR SATURDAY NIGHT AND SUNDAY WITH RIDGING AND CAA BEHIND DEPARTING SATURDAY SYSTEM. WITH FRESH SNOW COVER AND CLEARING SKIES...SINGLE DIGIT LOWS AND HIGHS BARELY IN THE 20S. WAA FROM NEXT CLIPPER BRINGS A SLIGHT CHC OF SNOW FOR SUNDAY NIGHT...WITH A GOOD CHANCE FOR SNOW WITH PASSAGE OF THE CLIPPER ON MONDAY AND MONDAY NIGHT. MODERATING TEMPERATURES WITH CLOUD COVER AND WAA BUT STILL TEENS FOR LOWS AND HIGHS AROUND 30...THEN A SLOW FALL MONDAY NIGHT. INTERVENING HIGH BRINGS A RETURN OF QUIET AND COLD CONDITIONS FOR TUESDAY AFTERNOON AND NIGHT...WITH A NON-DIURNAL EARLY HIGH...THEN FALLING AFTERNOON TEMPS. MODELS DIVERGE WITH DETAILS FOR WEDNESDAY...WITH GFS AND ECMWF DEVELOPING A LOW ON SRN END OF COLD FRONT OVER TX TUESDAY...AND DEEPENING THE LOW AS IT LIFTS NE TUESDAY NIGHT AND WEDNESDAY. GFS MUCH FARTHER EAST THAN ECMWF...BUT EITHER WAY SRN WI GETS PCPN...EITHER FROM NWRN PORTION OF PCPN SHIELD OF LOW TO THE SE PER ECMWF...OR FROM ANOTHER CLIPPER-TYPE SYSTEM THAT MOVES IN LATER IN THE DAY WEDNESDAY PER GFS. && .AVIATION...MID LEVEL FRONTOGENESIS BAND WITH ASSOCIATED LIGHT TO MODERATE SNOW TO CONTINUE TO MOVE SOUTHEAST ACROSS THE AREA THROUGH EARLY THIS EVENING. EXPECT PREVAILING IFR CONDITIONS...WITH SOME LIFR VISIBILITIES IN MODERATE SNOW BANDS...WITH THIS FEATURE. MVFR CONDITIONS EXPECTED BY 22Z AT KMSN...WITH VFR CONDITIONS BY 03Z THURSDAY. KMKE AND KENW SHOULD REACH THESE CONDITIONS ABOUT 3 TO 5 HOURS LATER. HIGH PRESSURE BUILDING INTO THE NORTHERN PLAINS WILL THEN BRING VFR CONDITIONS TO THE TAF SITES THROUGH 00Z FRIDAY. && .MARINE...SMALL CRAFT ADVISORY EXTENDED THROUGH THURSDAY. STEEP LOW LEVEL LAPSE RATES WITH COLD AIR ADVECTION SHOULD MIX DOWN 25 KNOT NORTHWEST WINDS TONIGHT. OFFSHORE COMPONENT TO WINDS SHOULD KEEP HIGHEST WAVES TOWARD THE OPEN WATERS THROUGH THURSDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR WIZ051- 052-058>060-064-069. WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR WIZ065- 066-070>072. LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THURSDAY FOR LMZ643>646. && $$ SHORT/LONG TERM...09 AVIATION/MARINE...08