Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 212103
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
303 PM CST SUN DEC 21 2014

.REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM
LEAD WAVE COMBINED WITH WAA GENERATING LIGHT PRECIP RETURNS ACROSS
WRN CWA. HOWEVER 88-D TRENDS SHOW COVERAGE DECREASING RAPIDLY WITH THIS.
SPOTTY LIGHT RAIN OR LIGHT SNOW WITH THIS BAND. MOIST FLOW CONTINUES
AHEAD OF ADVANCING LOW PRESSURE TROUGH IN THE PLAINS. SURFACE TEMPS
NOT EXPECTED TO DROP MUCH DUE TO SOUTHERLY WINDS AND CLOUD COVER. MID
LEVEL SHORTWAVE EXPECTED TO AMPLIFY AS IT DRAWS CLOSER. WEAKER SHORTWAVE
TO BRUSH SRN WI AFTER 6Z. WILL KEEP POPS CONFINED TO NW CWA CLOSER TO
850 LLJ AXIS AND AREA OF MODEL QPF. WITH MID LEVELS SHOWING A DRY LOOK
ON BUFKIT SOUNDINGS AND ANTICIPATED TEMPS REMAINING ABV ZERO NOT
EXPECTING ANY FREEZING RAIN/DRIZZLE.

.MONDAY - CONFIDENCE...MEDIUM
NEARLY STACKED LOW MOVERS INTO WESTERN IOWA. SHORTWAVE ENERGY WRAPPING
AROUND THIS UPPER LOW SHIFTS INTO SRN WI AND COINCIDES WITH INCREASING
850 MILLIBAR WIND MAX DURING THE AFTERNOON HOURS. MILD AIRMASS WITH HIGHS
IN THE U30S/L40S EXPECTED. NAM SOUNDING IN NW CWA LOOK A SMIDGE COLD
IN THE LOW LEVELS. PREFER THE BETTER HANDLING OF LOW LEVEL TEMP PROFILE
ON THE GFS SOUNDING. BUT PRECIP TYPE STILL QUESTIONABLE INTO THE AFTERNOON
ACROSS THE NW CWA. AREA SOUNDINGS SHOWING SN POTENTIAL WITH SATURATION IN THE
DENDRIDIC GROWTH ZONE. HOWEVER LOW LEVELS WILL DETERMINE EVENTUAL PRECIP
TYPE. SO WILL STILL KEEP MIXED PRECIP INTO THE AFTERNOON THERE WITH VRY LGT
ACCUMS. MUCH OF CWA EXPECTED TO BE RAIN IN THE AFTN THOUGH THE NW IS STILL
VULNERABLE WITH LOWEST 850 TEMPS AND COLDEST 1000-500 MILLIBAR THICKNESSES.

.MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE IS HIGH.

FAIRLY STRONG DYNAMICS ARRIVE MONDAY NIGHT AS THE MAIN CLOSED MID
LEVEL LOW SPINS OVER IOWA INTO SOUTHERN MN...EJECTING DECENT SHORT
WAVE ENERGY NORTHEAST INTO WISCONSIN. THE ASSOCIATED SURFACE LOW
WILL TRACK FROM NORTHWEST IOWA TO NORTH CENTRAL WISCONSIN BETWEEN
6 PM MONDAY THROUGH MID-DAY ON TUESDAY. DECENT WARM AIR ADVECTION
AHEAD OF THE LOW...RESULTING IN STRONG Q-VECTOR CONVERGENCE WHEN
COUPLED WITH THE MID LEVEL SHORT WAVE...SUPPORTS VERY HIGH POPS
INTO THE EVENING. TEMP PROFILES SUPPORT ALL RAIN WITH THE
POSSIBILITY OF A RAIN/SNOW MIX NORTHWEST OF MADISON.

WE SHOULD GET DRY SLOTTED LATER MONDAY NIGHT THROUGH TUESDAY WITH
LOW POPS MOVING IN. LIKELY JUST ANOTHER CLOUDY DAY WITH A SMALL
CHANCE OF RAIN OR SOME DRIZZLE AS THIS FIRST LOW MOVES OFF TO THE
NORTHEAST. TEMPS WILL BE MILD AS WE REMAIN ON THE WARM SIDE OF
THE LOW/TROF.

.TUESDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE
INCREASING.

IF YOU/VE BEEN FOLLOWING THE DISCUSSIONS...YOU KNOW THERE HAS BEEN
AN INCREDIBLE AMOUNT OF MODEL VARIABILITY IN THE HANDLING OF THE
SECONDARY LOW PRESSURE DEVELOPMENT COMING OUT OF THE LOWER
MISSISSIPPI VALLEY FOR THIS PERIOD. THE NEW 12Z RUNS ARE MUCH
TIGHTER AND THE LOWER SPREADS IN POSSIBLE SOLUTIONS PROVIDES
HIGHER CONFIDENCE. THE CONSENSUS LOW TRACK IS FROM THE OHIO VALLEY
NEAR LOUISVILLE TO SOUTHEAST LOWER MICHIGAN...THEN NORTHEAST FROM
THERE. THE SOUTHEAST WISCONSIN FORECAST AREA...INCLUDING THE
MILWAUKEE METRO AREA COULD GET INTO THE FAR WESTERN PRECIP SHIELD
AND GENERATE SOME LIGHT SNOW. BUT TEMPS WOULD PROBABLY STILL BE
WARM ENOUGH TO MELT MOST OF IT.

THE GFS/ECMWF/NAM/GEM KEEP THE HIGHEST IMPACT WEATHER WELL EAST
OF US. OF MINOR CONCERN IS A 12Z SUN PARALLEL HIGH RESOLUTION RUN
OF THE GFS THAT SHOWS A MAJOR LOW MOVING FROM ST. LOUIS TO
MILWAUKEE DURING THIS TIME. IT HAS BEEN ASSESSED AS A SIGNIFICANT
OUTLIER...NOT CLOSE TO ANY OTHER ENSEMBLE RUNS...AND IS BEING
DISCARDED. I MENTION IT AS THIS SOLUTION MAY MAKE IT/S WAY OUT
INTO THE SOCIAL MEDIA WORLD AND RAISE QUESTIONS. AND THE
CAVEAT...WE CAN/T LET OUR GUARD DOWN. THE TRACKS OF THESE LOWS CAN
CHANGE...SO REMAIN UP TO DATE ON THE LATEST FORECAST THROUGH
CHRISTMAS EVE.

.CHRISTMAS DAY...FORECAST CONFIDENCE IS HIGH.

FOR ALL THOSE PLANNING TO TRAVEL ON THE HOLIDAY...IT LOOKS LIKE A
DECENT DAY WITH DRY WEATHER AS HIGH PRESSURE BRIEFLY BUILDS IN.
TEMPS WILL BE IN THE LOWER TO MID 30S.

.FRIDAY...FORECAST CONFIDENCE IS MEDIUM.

LATE THURSDAY NIGHT AND FRIDAY...A FAST MOVING SHORT WAVE ARRIVES
IN THE ZONAL FLOW AND COULD BRING AROUND AN INCH OF SNOW. THE GFS
IS MUCH FARTHER NORTH WITH THE SFC LOW TRACK COMPARED TO THE
ECMWF AND THIS HAS BEEN THE CASE FOR THE LAST FEW RUNS. WPC IS
FAVORING THE ECMWF WHICH WILL SUPPORT A COLDER SOLUTION...WITH
THAT INCH OF SNOW POSSIBLE.

.SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

LOOKS LIKE HIGH PRESSURE RETURNS FOR NEXT WEEKEND. IT LOOKS DRY
WITH TEMPS RUNNING BELOW NORMAL...GENERALLY HIGHS IN THE LOWER TO
MID 20S.

&&

.AVIATION/00Z TAFS/...COMBO OF SHORTWAVE TROUGH MOVING EAST FROM WRN
MN AND WRN IA ALONG WITH SUSTAINED WAA...RESULTING IN MOST
WIDESPREAD PRECIP ACRS EC MN INTO NW WI. BAND OF MORE SCATTERED
PRECIP EXTENDS SOUTHWARD THROUGH SC WI. THIS WILL CONTINUE TO
TRANSLATE EWD THIS AFTN/ERLY EVE MOVING THROUGH THE REST OF SRN WI.
SFC TEMPS ABV FREEZING. RAP BUFKIT SOUNDINGS SHOW THE LOW LEVEL
SATURATION WITH DRY LAYER ABV AND HINTS OF MID LEVEL SATURATION
WITHIN DENDRIDIC GROWTH ZONE...SO CANNOT RULE OUT SOME SNOW...THOUGH
SEEDER FEEDER DRY DEPTH IS FAIRLY LARGE. IFR CIGS AND VSBYS WILL
PREVAIL WITH THE NAM MOS AND CONSSHORT HAVING THE BEST HANDLE ON
CIG/VSBY TRENDS. OVERALL MODELS KEEP MOST OF PRECIP THIS PERIOD
ACROSS WRN AND NRN WI WITH LESS IN THE SE. WITH LOW PRESSURE AND
MORE ORGANIZED SHORTWAVE APPROACHING MONDAY AFTERNOON/EVENING EXPECT
MORE WIDESPREAD RAINFALL MOVING INTO SRN WI. ANY MIXY POTENTIAL
LOOKS TO BE NORTH OR NORTHWEST OF TAF SITES.

&&

.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM PORT WASHINGTON
AND NWD AND STARTS AT 10 PM SOUTH OF PORT WASHINGTON. AS LOW
PRESSURE APPROACHES FROM THE NORTHERN PLAINS...BREEZY SOUTH TO
SOUTHEAST WINDS WILL CONTINUE TO RAMP UP INTO MONDAY NIGHT. THE
SOUTHERLY FETCH WILL GENERATE HIGH WAVES DURING THIS PERIOD. THE
WINDS AND WAVES WILL SUBSIDE ON TUESDAY AS THE WEAKENING LOW
PRESSURE AREA MOVES ACROSS THE REGION. THE SMALL CRAFT ADVISORY WILL
EXPIRE EARLY TUE AM.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM CST TUESDAY
     FOR LMZ644>646.

     SMALL CRAFT ADVISORY UNTIL 3 AM CST TUESDAY FOR LMZ643.

&&

$$

TONIGHT/MONDAY AND AVIATION/MARINE...COLLAR
MONDAY NIGHT THROUGH SUNDAY...DAVIS



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