Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 241534
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1034 AM CDT TUE MAR 24 2015

.UPDATE...NO CHANGES PLANNED TO HEADLINES AT THIS TIME. HAVE BEEN
POURING OVER THE PROGGD SOUNDINGS FROM THE RAP AND NAM. SURE HOPE
THE RAP IS THE CORRECT SOLUTION AS THE NAM IS SHOWING A RATHER
SIGNIFICANT ICING EVENT WITH SURFACE TEMPS DROPPING BELOW FREEZING
DURING PEAK PRECIP INTENSITY WITH MAX WARM LAYER OVERHEAD. HOWEVER
KEYING ON THE RAP AT THIS TIME WITH A SLOWER COOLING IN THE
BOUNDARY LAYER. EXPECTING SUSTAINED SE WINDS AND THE INCREASE IN
CLOUD COVER TO NEGATE THE USUAL EVENING DROPOFF. WILL BE WATCHING
THESE TEMP TRENDS CAREFULLY AS THE AFTERNOON WEARS ON. THE 850
MILLIBAR WARM SURGE WILL RAMP UP LATER THIS AFTERNOON AND INTO THE
EVENING HOURS. AT THIS TIME FEEL THE CURRENT HEADLINE IN THE FAR
NORTH LOOKS GOOD. WILL ALSO KEEP AN EYE ON THE FAR WESTERN
COUNTIES FOR SLEET/SNOW ACCUM POTENTIAL AS THERMAL TROUGH/DYNAMIC
COOLING HAS A SAY AS THE EVENT WEARS ON.

PC

&&

.AVIATION/18Z TAFS/...VFR MOSTLY SKC THIS AFTERNOON. MAIN MOISTURE
SURGE ARRIVES TONIGHT WITH STRENGTHENING LLJ. PRECIP PROGGD TO
ARRIVE 23-02Z...SW-NE ACROSS THE CWA. FOR THE EASTERN TAF SITES
BULK OF PRECIP EXPECTED TO BE RAIN WITH SOME MIX POTENTIAL DUE TO
DYNAMIC COOLING LATER IN THE NIGHT. BEST SNOW ACCUMS EXPECTED TO
THE NORTH OF TAF SITES. WILL BE CAREFULLY MONITORING BOUNDARY
CONDITIONS FOR PRECIP TYPE. ALL IN ALL GOING FCST ON TRACK. IFR
CIGS/LIFR CIGS LIKELY AS THE MAIN PRECIP AREA MOVES THROUGH
OVERNIGHT. DECENT CONSENSUS FROM THE NAM/GFS MOS AND LLVL RH
PROGS. PRECIP WINDS DOWN QUICKLY WEDNESDAY MORNING AS WESTERLY
FLOW AND SUBSIDENCE TAKE HOLD IN THE WAKE OF THE TROUGH.

PC

&&

.PREV DISCUSSION... /ISSUED 240 PM CDT TUE MAR 24 2015/

TONIGHT AND WEDNESDAY - FORECAST CONFIDENCE...

UNSEASONABLE WARMTH ACROSS SRN WI WILL BE REPLACED BY MORE NORMAL
MID MARCH TEMPERATURES AS A COLD FRONT SWEEPS THROUGH THE AREA THIS
EVENING. SURFACE LOW TO TRACK THROUGH SRN WI AND DRAG THE COLD FRONT
BY IN ITS WAKE. FRONT MAY GET HUNG UP A BIT WITHIN BAGGIER REGIME OF
THIS SOMEWHAT ELONGATED LOW. HOWEVER RAP/NAM SOUNDINGS CONTINUE TO
SUPPORT A WINDY AND CHILLER REGIME FOR MUCH OF THE NIGHT AFTER THE
EARLY/MID EVENING FROPA. WINDS HIGHEST IN THE EASTERN CWA WHERE
FAVORABLE ONSHORE FETCH AND FRICTIONLESS FLOW MEETS THE LAKESHORE
COUNTIES. SO EXPECTING A FAIRLY RAPID TEMP DROPOFF TO ANY AREAS THAT
HAVE NOT COOLED FROM THE PREFRONTAL LAKE BREEZE DEVELOPMENT. SOME OF
THE EARLIER SOUNDINGS FOR LAKESHORE AREAS RAISED CONCERN FOR A
POSSIBLE WIND ADVISORY BUT THERE HAS BEEN SOME BACKING OFF OF THAT
SO WILL NOT GO THAT ROUTE AT THIS TIME. WILL ALSO KEEP ANY EVENING
POPS CONFINED TO THE NORTH AND NORTHEAST PORTION OF THE CWA CLOSER
TO INFLUENCE OF UPPER JET INDUCED FORCING AND EXTRAP OF COLDER TOPS
ON IR SAT ANIMATION.

TUESDAY - CONFIDENCE...MEDIUM

500 MILLIBAR NVA BUILDS IN WITH SUSTAINED NW FLOW. SURFACE/850 RIDGE AXIS
REMAINS TO OUR WEST WHICH ALLOWS FOR PLENTY OF MIXING TO SUSTAIN A COOL
NW BREEZE. 925 TEMPS WILL BE DOWN NEAR 0C SO BACK MUCH CLOSER TO NORMAL
CONDITIONS....ALTHOUGH THE SUSTAINED WIND WILL GIVE IT A BELOW NORMAL FEEL.

TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE HIGH

TRANSIENT SURFACE HIGH MIGRATES SOUTHEASTWARD FROM THE NORTHERN
GREAT PLAINS TUESDAY NIGHT...AND INTO THE WESTERN GREAT LAKES REGION
ON WEDNESDAY. WITH NVA ALOFT AND SUBSIDENT MOTION...EXPECT CLEAR
SKIES EARLY TUESDAY NIGHT. CLOUDS WILL INCREASE INTO WEDNESDAY AHEAD
OF A WEAK SHORTWAVE IMPULSE...AS IT EJECTS SOUTHEASTWARD FROM THE
PACIFIC NORTHWEST/NORTHERN ROCKIES INTO THE NORTHERN PLAINS STATES
BY WEDNESDAY AFTERNOON. DRY CONDITIONS WILL PREVAIL FOR THE
PERIOD...WITH HIGHS IN THE 40S ON WEDNESDAY.

WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM

LOW AMPLITUDE SHORTWAVE PROGRESSES EAST-SOUTHEASTWARD FROM THE
NORTHERN PLAINS WEDNESDAY NIGHT INTO THE LOWER GREAT LAKES REGION ON
FRIDAY. MODELS STILL SHOW A SWATH OF LIGHT PRECIPITATION ACROSS THE
AREA WEDNESDAY NIGHT...BUT FORCING IS LIMITED. KEPT LOW POPS FOR
THIS PERIOD WITH A RAIN-SNOW MIX POSSIBLE.

LONG TERM...THURSDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE
MEDIUM

WEAK SHORTWAVE ENERGY WILL CONTINUE ACROSS THE REGION...WITH A
CLOSED UPPER LOW EVOLVING OVER THE NORTHERN GREAT LAKES REGION ON
FRIDAY...BEFORE SHIFTING EAST INTO NEW ENGLAND ON SUNDAY. SLIGHT
CHANCE POPS ARE WARRENTED CWA-WIDE FOR THE THURSDAY NIGHT/FRIDAY
PERIOD AND AGAIN IN THE NE CWA ON FRIDAY NIGHT AND SATURDAY.

AVIATION/00Z TAFS/...SURFACE LOW VCNTY CNTRL WI CONTINUES TO SHIFT
EAST PER 3HR PRES FALLS. WARM ADVECTION REGIME AHEAD OF THE LOW
GENERATING PLENTY OF MID/HIGH LEVEL CLOUDINESS. THE LOW IS EXPECTED
TO TRACK TOWARDS NE IL/SE WI/SW LWR MI VCNTY BY 00Z. THIS WILL BRING
THE COLD FRONT SOUTH THIS EVENING WITH DECENT PUSH OF NNE WINDS
ASSOCIATED WITH POST FRONTAL PRESSURE RISES. STILL LOOKING AT A 01-02Z
WIND SHIFT AT KMKE TO A MORE NORTH/NORTHEAST DIRECTION. POST FRONTAL
EVENING STRATUS POTENTIAL LOOKS TRANSIENT AS DRYING NOTED AFTER 6Z.
PROGS SHOW DRY CONDITIONS AS HIGH PRESSURE WORKS INTO IA/MN REGION LATER
IN THE DAY. HOWEVER STILL A NW BREEZE TUESDAY WITH LINGERING PRESSURE
GRADIENT THOUGH NOT AS GUSTY.

MARINE...UPGRADED GALE WATCH TO GALE WARNING AND STAGGERED START
TIMES A BIT IN A NORTH/SOUTH FASHION TO ACCOUNT FOR THE SOUTHWARD
PROPAGATION OF GALE FORCE WINDS. UPSTREAM POST FRONTAL PRESSURE RISES
ACROSS MN SUPPORT THIS GALE EVENT WITH FAVORABLE NNE FETCH LEADING
TO A SIZABLE BUILDUP IN THE WAVE ACTION.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM CDT WEDNESDAY FOR
     WIZ046-047-051-052.

LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT
     WEDNESDAY FOR LMZ643>646.

&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
WEDNESDAY THROUGH MONDAY...WOOD



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