Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 031627 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1027 AM CST TUE MAR 3 2015

.UPDATE...

MID LEVEL DRY AIR IS WORKING INTO SOUTH CENTRAL WI AND SOUTHEAST
THIS MORNING. WARM AIR ADVECTION IS DIMINISHING OVER SOUTHEAST WI.
THE HEAVIER SNOW/SLEET/FREEZING RAIN MOVED OFF TO THE EAST. THE
LIGHTER PRECIP IS TRANSITIONING TO FREEZING DRIZZLE AS WE LOSE THE
ICE CRYSTALS ALOFT DUE TO THE MID LEVEL DRY AIR.

THE FREEZING DRIZZLE IS BEING OBSERVED ALL THE WAY UPSTREAM TO DES
MOINES IOWA THIS MORNING... SO I EXPECT IT TO PERSIST HERE THROUGH
EARLY AFTERNOON. BY 21Z... MODEL SOUNDINGS SHOW THE WHOLE COLUMN TO
BE MUCH DRIER. IN ADDITION... THE STEEPER LOW LEVEL LAPSE RATES
BEHIND THE SURFACE TROUGH SHOULD ALLOW ANY LOW LEVEL MOISTURE TO
TOUCH THE SNOW GROWTH ZONE ONCE AGAIN. SO ANY LINGERING LIGHT
FREEZING DRIZZLE/DRIZZLE/SNOW SHOULD TAPER OFF DURING THE MID
AFTERNOON. THUS... MOVED THE EXPIRATION TIME OF THE WINTER WEATHER
ADVISORY UP TO 3 PM.

&&

.AVIATION/18Z TAFS/...

LOOK FOR IFR/LIFR CIGS AND VSBYS TO PERSIST UNTIL MID AFTERNOON. THE
HEAVIER PRECIP HAS SHIFTED EAST OVER LAKE MICHIGAN THIS MORNING.
HOWEVER... THE LIGHTER PRECIP IS CHANGING INTO FREEZING DRIZZLE.
THIS FREEZING DRIZZLE IS BEING OBSERVED ALL THE WAY UPSTREAM TO DES
MOINES IOWA... SO EXPECT IT TO CONTINUE OVER SOUTHERN WI UNTIL MID
AFTERNOON. BY THAT TIME... PRECIP WILL EITHER END OR CHANGE INTO
SNOW FLURRIES.

&&

.MARINE...

WEB CAMS ARE SHOWING ROLLING WAVES NEAR THE SHEBOYGAN SHORELINE
SINCE ICE HAS SHIFTED FURTHER OFFSHORE. THUS... HIGH WAVES ARE ALSO
A CONCERN IN ADDITION TO THE GUSTY SSE WINDS.

NO CHANGE TO GOING SMALL CRAFT ADVISORY. WINDS WILL TURN WEST BEHIND
THE TROUGH IN THE EARLY EVENING AND CONTINUE GUSTING WITH THE STRONG
COLD AIR ADVECTION IN THE WAKE OF A COLD FRONT. WHILE WINDS MAY EASE
FOR A TIME BETWEEN THE TROUGH PASSAGE AND THE COLD FRONT LATE THIS
AFTERNOON...IT DOES NOT APPEAR LONG ENOUGH TO SEPARATE THE ADVISORY
INTO TWO PERIODS.

&&

.PREV DISCUSSION... /ISSUED 234 AM CST TUE MAR 3 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE HIGH.

A STRONG 165 KNOT 250 MB JET PUSHES INTO WISCONSIN DOWNSTREAM OF THE
UPPER TROUGH FROM THE NORTH PLAINS TO THE SOUTHWEST U.S.  WEAK UPPER
DIVERGENCE BECOMES MODERATE THIS MORNING BEFORE WEAKENING THIS
AFTERNOON AND EARLY EVENING. WEAK TO MODERATE 700 MB UPWARD MOTION
THROUGH THE MORNING THEN WEAKENING EARLY IN THE AFTERNOON AND
BECOMING DOWNWARD OVER ALL BY THE FAR SOUTHEAST DURING THE
AFTERNOON. A 60 KNOT 700 MB JET MAX INCREASES TO 70 KNOTS AS IT
LIFTS INTO SOUTHEAST WISCONSIN BY NOON.  850 MB WINDS INCREASE THIS
MORNING WITH THE STRONGEST SPEEDS MOVING ACROSS THE UPPER OHIO
VALLEY.  WEAK 700 MB MOISTURE CONVERGENCE INCREASES DURING THE
MORNING AND IS STRONGEST TOWARD SHEBOYGAN AS IT LIFTS NORTHEAST THIS
AFTERNOON. MODERATE 850 MB MOISTURE CONVERGENCE IS STRONGEST OVER
THE FAR SOUTHEAST CLOSER TO THE 850 MB JET MAX.

MODELS ARE CONSISTENT IN A RAPID INCREASE IN PRECIPITATION THIS
MORNING...THEN DIMINISHING FROM THE SOUTHWEST LATE MORNING AND EARLY
AFTERNOON.  BIGGEST ISSUE IS WITH DEVELOPING MIXED PRECIPITATION.
THE NAM WARMS THE 850/700 MB LAYER THE MOST WITH MORE OF A SLEET
AND POSSIBLY FREEZING RAIN POTENTIAL AS THE MORNING GOES ON.  ALL
MODELS SHOW THE PRECIPITATION WOULD START AS SNOW WITH THE WARMING
SOMEWHAT OFFSET BY EVAPORATIVE COOLING AS THE PRECIPITATION BEGINS.
HOWEVER EVEN THE COOLER MODELS HAVE A WARM ELEVATED LAYER VERY CLOSE
TO FREEZING.  PRECIPITATION HAS STARTED OUT AS ALL SLEET IN
DAVENPORT...SO THE WARMER MODELS ARE PREFERRED.

THE 925/700 MB WARM AIR ADVECTION BEGINS TO COOL THIS AFTERNOON.  BY
THIS TIME ANY PRECIPITATION WOULD BE FLURRIES BY EVENING.

SNOW AMOUNTS SHOULD MAINLY BE IN THE 1 TO 3 INCH RANGE...BUT WITH
THE MIXED PRECIPITATION THE ADVISORY LOOKS GOOD.  GREATEST SNOW
AMOUNTS EXPECTED TO BE TOWARD FOND DU LAC AND SHEBOYGAN.

WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE...HIGH

HIGH PRESSURE WILL APPROACH FROM THE WEST ON WEDNESDAY...THEN MOVE
OVERHEAD THURSDAY. EXPECT DRY WEATHER WITH A FAIR AMOUNT OF
SUNSHINE...ESPECIALLY ON THURSDAY. UNFORTUNATELY...A VERY COLD
AIRMASS WILL ARRIVE WITH THE HIGH...WITH WELL BELOW NORMAL
TEMPERATURES EXPECTED. COULD SEE WIND CHILLS APPROACH ADVISORY
LEVELS LATER WEDNESDAY NIGHT INTO EARLY THURSDAY.

FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM

EXPECT A COUPLE OF WEAK WAVES TO MOVE THROUGH PREVAILING NORTHWEST
FLOW FRIDAY THROUGH MONDAY. BEST CHANCE FOR A LITTLE LIGHT SNOW OR
FLURRIES LOOKS TO BE FRIDAY NIGHT AND AGAIN ON SUNDAY. ONLY HAVE
SOME POPS IN THE NORTH FRIDAY NIGHT FOR NOW...BUT INCREASING
CONFIDENCE FOR SUNDAY MAY EVENTUALLY RESULT IN SOME POPS THEN TOO.
OTHERWISE...IT LOOKS QUIET THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK.

MODELS DIFFER WITH TEMPS BY QUITE A BIT BY SUNDAY/MONDAY. THE GFS
HOLDS ONTO COLD AIRMASS OVER THE GREAT LAKES...WHILE THE ECMWF IS
QUICKER TO BRING IN MILDER TEMPS FROM THE SOUTHWEST. WENT WITH A
BLEND OF THE SOLUTIONS FOR NOW...RESULTING IN NEAR NORMAL TEMPS.

AVIATION/12Z TAFS/...

VFR CONDITIONS WILL QUICKLY DETERIORATE WITH THE DEVELOPMENT OF
LIGHT TO MODERATE SNOW SPREADING IN FROM THE SOUTHWEST EARLY THIS
MORNING. EXPECT MVFR CIGS/VSBYS TO DROP RAPIDLY TO IFR/LIFR LEVELS
BETWEEN 12Z THROUGH 15Z...THEN SEE THE SNOW CHANGE TO A MIX OF
SNOW/SLEET/FREEZING RAIN. WILL SEE THE MIXY PRECIPITATION LIGHTEN
FROM THE SOUTHWEST LATE THIS MORNING AND EARLY AFTERNOON.  THE
PRECIPITATION WILL CHANGE BACK TO ALL SNOW AS IT TAPERS OFF FROM
WEST TO EAST BETWEEN 21Z AND 00Z...BUT IT WOULD BE LIGHT.

SOME INDICATIONS THAT STRONG LOW-LEVEL WINDS MAY BRING A PERIOD OF
LOW LEVEL WIND SHEAR IN THE MORNING HOURS AS A STRONG 700 MB/10 THSD
FT JET MAX MOVES ACROSS SOUTHERN WISCONSIN. HOWEVER WINDS AT 2 THSD
FT WILL BE AT 30 TO 35 KNOTS...SO THE LOW LEVEL WIND SHEAR WILL NOT
BE GREAT.

MARINE...

NO CHANGE TO GOING SMALL CRAFT ADVISORY AS MODELS CONTINUE TO SHOW
GUSTY SOUTH WINDS DEVELOPING OVER THE WESTERN NEARSHORE WATERS OF
LAKE MICHIGAN AHEAD OF SURFACE TROUGH AROUND 12Z...THEN TURN WEST
BEHIND THE TROUGH IN THE EARLY EVENING AND INCREASE WITH THE STRONG
COLD AIR ADVECTION WITH THE PASSAGE OF A TRAILING COLD FRONT. WHILE
WINDS MAY EASE FOR A TIME BETWEEN THE TROUGH PASSAGE AND THE COLD
FRONT...IT DOES NOT APPEAR LONG ENOUGH TO SEPARATE THE ADVISORY INTO
TWO PERIODS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR WIZ046-
     047-051-052-056>060-062>072.

LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST WEDNESDAY FOR LMZ643>646.

&&

$$

UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...DDV


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