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