721 FXUS63 KMKX 190209 AFDMKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 909 PM CDT MON MAR 18 2013 .UPDATE... HOISTED A WINTER WEATHER ADVISORY FOR BLOWING SNOW TONIGHT THROUGH 15Z TUESDAY. STRONG COLD ADVECTION HAS KICKED IN AND AREA SOUNDINGS ON BUFKIT LOOK IMPRESSIVE WITH WIND POTENTIAL AND GUSTY NATURE. EXPECT WEST WINDS OF 20 TO 35 MPH. NORTH/SOUTH ORIENTED ROADS WILL BE MOST IMPACTED WITH ACCUMULATIONS AND BRIEF SIGNIFICANT REDUCTIONS IN VSBY. ROAD CREWS USUALLY SEEM TO PULL OFF FOR THE NIGHT...OR STICK TO THE MAIN ROADS...THUS EXPECT ROAD CONDITIONS TO STEADILY DETERIORATE THROUGH THE NIGHT. CURRENT LOWS LOOK REASONABLE...JUST TRYING TO KEEP UP WITH THE RAPID COLD ADVECTION/TEMP DROP THIS EVENING. IT WILL FEEL LIKE JANUARY TUESDAY MORNING WITH WIND CHILLS IN THE SINGLE DIGITS BELOW ZERO. && .AVIATION/06Z TAFS/... GENERALLY EXPECT MVFR CIGS THROUGH ABOUT 15Z TUESDAY. COULD SEE SOME PERIODS OF VFR CIGS AT TIMES OVERNIGHT. EXPECT CIGS TO LIFT TO VFR AFTER ABOUT 15Z...THEN CLEAR BY AROUND MID DAY OR SO. THE BIGGER STORY WILL BE THE VERY STRONG WESTERLY WINDS OF 20 TO 30KTS. THIS WILL PRESENT SOME BLOWING AND DRIFTING SNOW PROBLEMS FOR AIRPORT OPERATIONS. WINDS ARE EXPECTED TO REMAIN AT THIS LEVEL THROUGH MOST OF TUESDAY...FINALLY DIMINISHING TOWARD LATE AFTERNOON. && .MARINE... THE SMALL CRAFT ADVISORY CONTINUES UNTIL MIDNIGHT...THEN A GALE WARNING GOES INTO EFFECT FOR STRONG WESTERLY WINDS. THE GALE WARNING WILL CONTINUE UNTIL 7 PM TUESDAY EVENING. A SMALL CRAFT ADVISORY WILL THEN LIKELY BE NEEDED FOR A TIME AFTER THE GALE WARNING EXPIRES. && .PREV DISCUSSION... /ISSUED 329 PM CDT MON MAR 18 2013/ VERY SHORT TERM...TONIGHT AND TUESDAY. 998 MILLIBAR SURFACE LOW SHIFTING EAST FROM MN ARROWHEAD. ANOTHER SURFACE LOW LIFTING NORTH FROM NORTHERN INDIANA. FRONTAL BOUNDARY WITH SOME TEETH TIED TO THE FORMER LOW PLOWING INTO WRN WI AND WILL CONTINUE TO SHIFT ACROSS THE AREA INTO THE EARLY EVENING HOURS. PER WATER VAPOR DRY SLOT ON THE WAY FROM ERN IA. NEGATIVE TILT TROUGH LIFTS NORTHEAST HOWEVER ANOTHER SHORTWAVE SCOOTS TO OUR SOUTH THIS EVENING ROUNDING BASE OF TROUGH. MODELS NOT REAL EXCITED ABOUT QPF WITH THIS FEATURE HOWEVER STILL QUITE A BIT OF UPSTREAM PRECIP REPORTS. BUFKIT SOUNDINGS SHOW A WINDOW OF TIME THIS WHERE EVENING WHERE ICE CRYSTAL GROWTH IS LOST SO MENTIONED PATCHY FREEZING DRIZZLE. WHEN SOUNDINGS COOL POST FRONTAL SOUNDINGS SUGGEST MOISTURE ON THE DENDRITIC GROWTH ZONE SO SWITCHED BACK TO FLURRIES. 925 TEMPS DROP TO -14 TO -16C BY 12Z WITH THE GUSTY WEST WINDS. EXPECT SEVERAL LOCATIONS TO REACH THE SINGLE DIGITS WITH WIND CHILLS BELOW ZERO. BROAD CYCLONIC FLOW WITH COLD AIRMASS IN PLACE. MORNING WIND CHILLS BELOW ZERO. SHALLOW INSTABILITY AND MOISTURE IN PLACE BENEATH SUBSIDENCE INVERSION SUGGESTS FLURRY POTENTIAL. HOWEVER PLENTY OF DRY AIR IN THE MID LEVELS. 12Z ECMWF MODIFIES 925 TEMPS MORE SO THAN THE 12Z NAM OR GFS. WILL LEAN TOWARDS THE COLDER SOLUTION GIVEN THE FRESH BLANKET OF SNOW. SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY. SLUG OF COLD AIR THAT OVERSPREADS SRN WI TONIGHT LINGERS IN THE AREA THROUGH THURSDAY BEFORE SOME SLIGHT MODERATION OVER THE WEEKEND. 85H TEMPERATURES DROP DOWN TO AROUND 14C BELOW ZERO BY 12Z WED AND THE COLD AIR IS REINFORCED BEHIND A PASSING WEAK MID-LEVEL TROUGH WED NIGHT INTO THURSDAY. HENCE OVERNIGHT TEMPS LIKELY TO FALL TO BETWEEN 5 AND 15 DEGREES ABOVE ZERO FROM TUESDAY NIGHT THROUGH THURSDAY NIGHT. THE COLDEST NIGHT MAY VERY WELL BE THURSDAY NIGHT WHEN THE RIDGE AXIS EDGES INTO SOUTH CENTRAL WI...RESULTING IN LIGHTER BOUNDARY LAYER WINDS. THE COLDEST NIGHT FOR WIND CHILLS LOOKS TO BE TUESDAY NIGHT WHEN BOUNDARY LAYER MIXING AND PARTIAL CLEARING RESULTS IN WIND CHILLS FALLING TO BETWEEN 5 AND 15 BELOW ZERO. WEAK PUSH OF ISENTROPIC OMEGA SLIDES SOUTHWEST OF SOUTHERN WI TUESDAY NIGHT. BETTER CHANCE FOR -SHSN ACROSS NORTHERN CWA WED AFTERNOON AS SHARP MID-LEVEL SHORT WAVE ROTATES AROUND UPPER LOW NORTH OF THE GREAT LAKES. AREA OF 400MB POTENTIAL VORTICITY WITH MID LEVEL LAPSE RATES INCREASING TO AROUND 6 DEGREES SLIDES SOUTH ACROSS THE SRN WI FROM MID-AFTERNOON INTO THE EVENING. BEST CHANCE FOR -SHSN IN THE NORTH FROM MID-LATE AFTN. LONG TERM...THURSDAY NIGHT THROUGH MONDAY. UNSEASONABLY COLD CONDITIONS LOOK TO CONTINUE THROUGH THE PERIOD. STATIONARY LONG WAVE TROFING LINGERS OVER SOUTHEAST CANADA INTO THE GREAT LAKES THROUGH THE BULK OF THIS PERIOD WITH COLD W TO NW FLOW CONTINUING. GFS MORE BULLISH ON WEAKENING LONG WAVE TROUGH OVER THE WEEKEND WHICH WOULD ALLOW A GREATER MODERATION IN TEMPS. HOWEVER MORE CONSISTENT ECMWF AS WELL AS GEM-NHEM KEEP PERSISTENT TROUGH AXIS EXTENDING WEST INTO THE WRN GTLAKES THRU THE WEEKEND. THIS SOLUTION RESULTS IN THE SOUTHERN STREAM BECOMING MORE ACTIVE WITH DEEPER RH AND BULK OF PRECIP REMAINING WELL TO THE SOUTH. ECMWF AND ECMWF ENSEMBLE SHOW PERSISTENT COLD LINGERING INTO EARLY NEXT WEEK SO WL FOLLOW THIS SCENARIO AND KEEP TEMPERATURES AVERAGING WELL BELOW NORMAL FOR THE PERIOD. POSSIBLE LAKE EFFECT SNOW SHOWERS OR FLURRIES OVER THE WEEKEND AS LOW LEVEL FLOW BECOMES NORTHEAST AND DELTA-T INCREASES TO 10 TO 16 DEGREES. AVIATION /00Z TAFS/...MAIN SNOW AREA LIFTING NORTHEAST OUT OF SRN WI. LIGHTER PRECIP WILL LINGER INTO TUESDAY WITH BROAD UPPER CYCLONIC FLOW AND 850 COLD POOL. INSTABILITY IS SHALLOW AND MOISTURE DEPTH IS NOT GREAT SO EXPECTING A TRACE EVENT. TRANSITIONING TO MVFR CEILINGS LATER TONIGHT INTO TUESDAY. FOLLOWED NAM MOS CLOSER WITH CLOUD/CEILING TRENDS RATHER THAN THE GFS MOS. MARINE...WILL KEEP A SMALL CRAFT ADVISORY INTO THIS EVENING EVEN THROUGH THERE WILL BE A BRIEF LULL WITH THE TROUGH AXIS. THEN WINDS LIKELY TO REACH GALE FORCE LATER TONIGHT INTO TUESDAY. AS SUCH WILL ISSUE A GALE WARNING FOR THIS PERIOD. WITH COLD TEMPERATURES SOME FREEZING SPRAY LATE TONIGHT INTO WEDNESDAY BUT MOSTLY OF THE MODERATE VARIETY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 10 AM CDT TUESDAY FOR WIZ046-047- 051-052-056>059-062>064-067-068. LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR LMZ643>646. GALE WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT TUESDAY FOR LMZ643>646. && $$ UPDATE...DAVIS TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR TUESDAY NIGHT THROUGH MONDAY...MBK