Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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516
FXUS63 KMKX 010256
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
856 PM CST SUN JAN 31 2016

.UPDATE...

LATEST NAM HAS COME IN AND IS IN GENERAL AGREEMENT WITH THE OTHER
MODELS BRINGING THE HEAVIEST PCPN THROUGH THE REGION BETWEEN 15Z
TUE AND 00Z WED. TWO NOTICEABLE FACTORS WITH THE LATEST NAM IS
THAT ...1) IT IS ABOUT HALF A STATE FASTER WITH THE 500 MB TROUGH
AND FEATURES BELOW DOWN TO THE SURFACE AND...2) IT IS IN LINE WITH
THE OTHER MODELS BRINGING A 700 MB DRY WEDGE ACROSS SRN WI DURING
THE AFTERNOON/EVENING THAT DRIES OUT THE DENDRITE GROWTH ZONE
WHICH COULD CHANGE PCPN UNDERNEATH TO RAIN/DRIZZLE AND LIMIT SNOW
TOTALS. NO CHANGES TO GOING WATCH AT THIS TIME BUT WILL BE
INTERESTING TO SEE WHAT THE OTHER 00Z MODEL RUNS ARE DOING WITH
TRACK AND VERTICAL TEMPERATURE/MOISTURE PROFILES.

&&

.AVIATION/06Z TAFS/...

MAINLY VFR CONDITIONS UPSTREAM OF TAF SITES AT THIS TIME...SO TRIED
TO DELAY MVFR AND IFR CIGS AND VSBYS FOR SOME OF THE TAF SITES.
SOUNDINGS STILL INDICATING LOWER VSBYS OVERNIGHT...WITH MVFR AND IFR
VSBYS BETWEEN 2-3SM...WITH THE POTENTIAL FOR ALTERNATE MINIMUMS
FOR UES AT THIS TIME. LIGHT NORTHWEST TO WEST WINDS WILL BECOME
LIGHT AND VARIABLE LATER TONIGHT INTO EARLY MONDAY MORNING...WHICH
SHOULD HELP REDUCE VSBYS DUE TO LACK OF LOW LEVEL MIXING.

CIGS WILL BE MAINLY MVFR WITH HEIGHTS BETWEEN 1.5-2.5 KFT...WITH
SOME IFR CIGS FOR UES POSSIBLE. MODEL GUIDANCE IS WANTING TO KEEP
THESE LOWER VSBYS THROUGH THE MONDAY MORNING HOURS BEFORE IMPROVING
TO VFR CONDITIONS FOR ALL TAF SITES AFTER NOON MONDAY.

&&

.PREV DISCUSSION... /ISSUED 326 PM CST SUN JAN 31 2016/

TONIGHT AND MONDAY...FORECAST CONFIDENCE IS MEDIUM.

AREA OF LIGHT TO MODERATE RAIN WILL EXIT THE FAR SOUTHEAST
COUNTIES IN THE NEXT HOUR OR SO...DRIVEN BY A PASSING 850 MB
TROUGH/500 MB VORTICITY MAXIMUM AND SOME LOW LEVEL FRONTOGENESIS
RESPONSE. THERE IS ANOTHER AREA OF LIGHT RAIN OR DRIZZLE THAT MAY
OCCUR OVER THE NORTHWESTERN AND NORTHERN PORTIONS OF THE AREA UNTIL
EARLY EVENING...AND WILL ADJUST POPS IF IT CONTINUES TO EXPAND IN
AREAL COVERAGE. TEMPERATURES SHOULD REMAIN WARM ENOUGH FOR ALL RAIN
IN THIS AREA INTO EARLY EVENING.

UNCERTAINTY EXISTS WITH CLOUD AND FOG TRENDS TONIGHT INTO MONDAY
MORNING. COLD AIR ADVECTION TONIGHT WILL BRING COOLER TEMPERATURES
INTO THE AREA. HOWEVER...AREA FORECAST SOUNDINGS ARE SUGGESTING THAT
LOW LEVEL MOISTURE SHOULD LINGER FOR A TIME TONIGHT...ESPECIALLY IN
THE NORTHERN PORTIONS OF THE AREA BELOW INVERSION. NAM INVERSION IS
QUITE STRONG AND MAY BE OVERDONE...WITH GFS PERHAPS UNDERDONE.

THERE IS CLEARING BEHIND THE CLOUD DECK THAT MAY MOVE INTO THE AREA
LATER THIS EVENING AND INTO MONDAY MORNING...WITH THE SOUTHWESTERN
PORTIONS OF THE AREA HAVING THE BEST SHOT AT THIS. THE LIGHT WINDS
MAY ALLOW FOR PATCHY FOG TO FORM TONIGHT...THOUGH COLDER AND DRIER
AIRMASS MOVING IN MAY LIMIT THIS DEVELOPMENT. FOR NOW...WILL TREND
FROM MOSTLY TO PARTLY CLOUDY TONIGHT INTO MONDAY MORNING...AND KEEP
PATCHY FOG MENTION. LOWS IN THE MID TO UPPER 20S ARE EXPECTED FOR
NOW...BUT WILL DEPEND ON CLOUD COVER.

CLOUDS AHEAD OF STORM SHOULD MOVE INTO THE AREA MONDAY AFTERNOON.
OTHERWISE...DRY CONDITIONS ARE EXPECTED WITH HIGHS IN THE MID 30S.

TUESDAY AND TUESDAY NIGHT - CONFIDENCE...MEDIUM
THE KEY MODEL RUN MAY VERY WELL BE TONIGHT`S 00Z RUN AS THE STORM
SYSTEM NOW ENTERING THE SOUTHWEST US WILL BE FULLY SAMPLED. THIS
CONTINUES TO BE A TRICKY FORECAST DUE TO THE POTENTIAL FOR A MIX OF
PRECIP IN PARTS OF SRN AND ERN WI. THE CURRENT NW/SE SNOWFALL GRADIENT
ACROSS THE CWA STILL LOOKS OK. NOT PLANNING ON MAKING ANY CHANGES
TO CURRENT WATCH AREA ATTM. TRACK OF KEY SURFACE AND UPPER AIR
FEATURES SUPPORTS GOING OUTLINED AREA OF CONCERN. STILL A ZONE OF
LOWER CONFIDENCE ON THE SOUTHERN FRINGE OF THE WATCH AREA SINCE
LATER RUNS COULD STILL SUPPORT A SOUTHWARD SHIFT AND COLDER
SOLUTION...AS THE 12Z GEM IS STILL SHOWING...THOUGH KEY UPPER
FEATURES FROM THIS MODEL WOULD FAVOR A MORE NW PLACEMENT OF THE
LOW AS LAID OUT BY THE ECMWF AND ESP THE GFS. PER COLLAB WITH WPC
AND SURROUNDING OFFICES...STEADY AS SHE GOES FOR NOW. THE 500
MILLIBAR VORT/850 MILLIBAR LOW CENTERS AND POSITIONING OF 200-300
MILLIBAR JET CORRIDORS WOULD SEEM TO SUPPORT THE MORE NORTHERN
TRACK. 12Z ECMWF HAS COME IN WITH A WARMING OF 850 TEMPS INTO THE
SRN AND ERN CWA AS WELL WITH 850 LOW RIDING NEWD THROUGH THE CWA.
LOOKING AT PROJECTED TRACKS OF THE 850 LOW ACROSS SRN WI AND WITH
A SEEMINGLY MORE LIKELY NORTHWARD SURFACE LOW TRACK ACROSS NE IL
INTO FAR SE WI AND LWR MI...THIS WOULD SUPPORT THE HEAVIEST DEF
ZONE SNOW POTENTIAL ACROSS ROUGHLY THE NW 1/3 OF OF THE CWA. THIS
AREA ALSO GETS CLIPPED BY NORTHERN HALF OF CLOSED 700 MILLIBAR LOW
CENTER FOR A TIME TUESDAY AFTERNOON. THERE WILL BE A DECENT SLUG
OF ISENTROPICALLY INDUCED PRECIPITATION AT THE OUTSET ON TUESDAY
AND THIS WILL ALLOW FOR SOME SNOW ACCUMS WITH THE FORCING ACROSS
THE MORE EAST/WEST ORIENTED 850 BAROCLINIC ZONE BEFORE THE
BAROCLINIC ZONE STARTS TO PIVOT A BIT MORE TO THE NORTH AND
NORTHWEST. THIS WOULD THEN ALLOW FOR A TRANSITION TO A MIX OR ALL
RAIN IN PARTS OF SRN WI WHILE FAVORING THE NORTHERN CWA TO REMAIN
ALL SNOW. LIGHTER DEF ZONE SNOWS WILL CONTINUE TUESDAY NIGHT WITH
INCREASING POTENTIAL FOR BLOWING/DRIFTING SNOW. THERE IS CONCERN
FOR THE NORTH AS WELL WHERE A MID LEVEL DRY SLOT COULD BRIEFLY
PLAY HAVOC WITH PRECIP TYPES AND SNOW AMOUNTS BY TUESDAY NIGHT.

WEDNESDAY - CONFIDENCE...MEDIUM
COLDER AIRMASS IN PLACE NORTHERLY FLOW BEHIND DEPARTED SYSTEM.
SOME LIGHT QPF IN THE MORNING SO HAVE SOME ADDITIONAL LIGHT SNOW
CHANCES. DIMINISHED AND CONFINED MORE TO THE EAST IN THE
AFTERNOON. ANY ACCUMS...QUITE LIGHT.

THURSDAY - CONFIDENCE...MEDIUM
QUIET DAY. WEAK WAA WITH WESTERLY 850 FLOW. WAVE TO OUR NORTH
AND NORTHWEST. QPF ACROSS NRN WI.

FRIDAY AND SATURDAY - CONFIDENCE...LOW
DETAILS ON SHORTWAVE ACTIVITY AND TIMING THEREOF ARE RESULTING IN
THE MAINTAINING OF THE SUPERBLEND POPS THIS PERIOD. CERTAINLY MORE
COLD ADVECTION SHOWING UP ON THE GFS VERSUS THE ECMWF.

SUNDAY - CONFIDENCE...LOW
LOOKS DRY WITH WEAK SFC/850 RIDGING. HOWEVER THERMAL PROFILES
ARE OFF 5-6C SO WILL GO WITH THE SUPERBLEND FOR NOW.

AVIATION/00Z TAFS/...EXPECT THE RAIN TO MOVE EAST OF MILWAUKEE
AND KENOSHA OVER THE NEXT HOUR OR TWO. RAIN MAY REACH MADISON FROM
THE NORTH DURING THIS PERIOD...BUT NOT CONFIDENT SO LEFT VICINITY
WORDING IN TAFS FOR NOW.

LOW CEILINGS BELOW ALTERNATE MINIMUMS WITH THE RAIN SHOULD IMPROVE
TO 3 MILES OR GREATER AT THE EASTERN TAF SITES INTO EARLY THIS
EVENING. CEILINGS AND VISIBILITIES TONIGHT INTO MONDAY MORNING ARE
UNCERTAIN AT ALL SITES...AND WILL DEPEND ON IF AND HOW MANY CLOUDS
REMAIN OVER THE AREA.

LIGHT NORTHWEST TO WEST WINDS WILL BECOME LIGHT AND VARIABLE LATER
TONIGHT INTO EARLY MONDAY MORNING. WILL LEAVE 3 TO 5 MILE FOG IN
TAFS WITH GRADUALLY IMPROVING CEILINGS. VFR CONDITIONS SHOULD THEN
OCCUR LATER MONDAY MORNING AND AFTERNOON...WITH MIDDLE TO HIGH
CLOUDS MOVING INTO THE AREA.

MARINE...GUSTY ONSHORE WINDS ARE EXPECTED TUESDAY INTO TUESDAY
EVENING...AS THE STRONG LOW PRESSURE SYSTEM MOVES NORTHEAST TOWARD
THE AREA. THIS SHOULD GENERATE HIGH WAVES DURING THIS TIME...LINGERING
INTO WEDNESDAY.

THE GUSTY WINDS WILL SHIFT OFFSHORE LATER TUESDAY NIGHT INTO WEDNESDAY
..AS THE LOW MOVES NORTHEAST AWAY FROM THE AREA. THIS SHOULD PUSH
THE HIGH WAVES TOWARD AND OVER THE OPEN WATERS LATER ON WEDNESDAY
INTO WEDNESDAY NIGHT.

A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR TUESDAY INTO
WEDNESDAY OR WEDNESDAY NIGHT IN LATER FORECASTS. GALE FORCE GUSTS
MAY OCCUR AT TIMES ON TUESDAY AS WELL...AND THIS POTENTIAL WILL HAVE
TO BE WATCHED.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH LATE TUESDAY
     NIGHT FOR WIZ046-047-051-056>058-062-063-067.

LM...NONE.
&&

$$

UPDATE...REM
TONIGHT/MONDAY AND AVIATION/MARINE...WOOD
MONDAY NIGHT THROUGH SUNDAY...COLLAR



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