Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 270946
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
346 AM CST THU NOV 27 2014

.SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH

THE 250 MB UPPER TROUGH AXIS OVER THE GREAT LAKES WILL MOVE TO THE
NORTHEAST U.S. TONIGHT AS THE UPPER LEVEL FLOW BECOMES MORE ZONAL.
THE NOSE OF AN UPSTREAM 130 KNOT JET MAX ACROSS THE NORTHERN PLAINS
PUSHES INTO WESTERN WISCONSIN BY SUNRISE FRIDAY. THIS INCREASES THE
UPPER DIVERGENCE TONIGHT...BUT IT IS WEAK.

A MID LEVEL TROUGH EXITS SOUTHEAST WISCONSIN THIS MORNING RESULTING
IN MID LEVEL DRYING. NAM FORECAST SOUNDINGS STILL SHOW LINGERING LOW
LEVEL MOISTURE BELOW 5 THSD FT.  THE DRYING CONTINUES THIS
AFTERNOON...BUT A SHALLOW...MOIST LAYER REMAINS.

MAIN FORECAST PROBLEM WILL BE HOW QUICK TO BRING IN CLEARING FROM
THE WEST AS THE SURFACE HIGH PRESSURE RIDGE REACHES THE UPPER
MISSISSIPPI VALLEY.  ALSO SOME FLURRY POTENTIAL TIL MID MORNING. THE
GFS MOS CLEARS THE SKIES...WHILE THE NAM MOS KEEPS IT CLOUDY.  WILL
GO WITH A SLOWER CLEARING THAN THE GFS BUT NOT AS PESSIMISTIC AS THE
NAM...WHICH OFTEN OVER DOES THE SHALLOW MOIST LAYER.

HIGHS WILL BE WELL BELOW NORMAL FOR THANKSGIVING.

WARM AIR ADVECTION OCCURS LATER TONIGHT IN THE LOW TO MID LEVELS.
THE MID LEVELS WILL BE DRY INITIALLY.  ISENTROPIC LIFT AND A GRADUAL
SATURATION WILL OCCUR LATE TONIGHT.  SOME LIGHT SNOW MAY REACH THE
GROUND MAINLY NORTHWEST OF MADISON TOWARDS SUNRISE FRIDAY MORNING.

FRIDAY...FORECAST CONFIDENCE MEDIUM.

THE BEST CHANCE FOR SNOW WILL BE FRIDAY MORNING. THIS IS WHEN THERE
WILL BE MAX THETA-E ADVECTION AND ISENTROPIC LIFT OVER SOUTHERN WI.
THE LOW TO MID LEVEL WARM AIR ADVECTION WILL BE PERSISTENT ALL DAY
LONG. BY THE AFTERNOON... THE MID LEVELS WILL BECOME WESTERLY AND
DRY OUT WHILE THE LOW LEVELS REMAIN MOIST AND SOUTHERLY.

IT MAY TAKE A LITTLE WHILE TO SATURATE FROM THE TOP DOWN FRIDAY
MORNING... ESPECIALLY TOWARD SHEBOYGAN. EVENTUALLY... EXPECTING
LIGHT SNOW IN THAT AREA BY LATE FRIDAY MORNING. THEN THE BEST
FORCING AND DEEPER MOISTURE SHIFTS NORTH FOR THE AFTERNOON... SO I
TAPERED OFF THE POPS FROM SOUTH TO NORTH THROUGH THE DAY. BY EARLY
EVENING... THERE MAY STILL BE JUST ENOUGH ISENTROPIC LIFT AND LOW
LEVEL MOISTURE TO SUPPORT FREEZING DRIZZLE TOWARD SHEBOYGAN AS WE
LOSE THE ICE CRYSTAL GROWTH DUE TO DRY AIR ALOFT. OVERALL... I
BACKED OFF ON THE FREEZING DRIZZLE POTENTIAL FOR MOST OF THE
FORECAST AREA. IT SHOULD BE TOO DRY.

SNOW AMOUNTS WILL BE LIGHT WITH UP TO TWO TENTHS OF AN INCH ALONG
AND NORTH OF I-94 AND AROUND AN INCH OR MAYBE TWO TOWARD SHEBOYGAN.

DESPITE THE WARM AIR ADVECTION... MODELS ARE HINTING AT SLIGHTLY
COOLER HIGHS ON FRIDAY THAN WHAT WE HAD IN THERE BEFORE. IT NOW
LOOKS LIKE UPPER 20S TO AROUND 30 FOR A HIGH. THIS IS DUE TO OUR
COLD START AND THE SNOW COVER AND EXPECTED LOW CLOUDS.

.LONG TERM...

FRIDAY NIGHT THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.

SURFACE LOW PRESSURE CROSSING THE NORTHERN PLAINS WILL HELP TO DRAW
WARMER TEMPERATURES INTO SOUTHERN WI ON SATURDAY. TEMPERATURES WILL
DROP A LITTLE IN THE EVENING BUT THEN RISE AND HOLD STEADY AROUND 30
AFTER MIDNIGHT. TEMPERATURES WILL RISE THROUGH THE DAY SATURDAY...
REACHING THE LOWER 40S IN MOST AREAS. SOUTHEAST WI COULD SEE MID
40S. THE SNOW COVER AND PROBABLE FOG AND LOW CLOUDS FROM MELTING
SNOW COULD LIMIT OUR TEMPERATURES SO I KEPT THEM ON THE CONSERVATIVE
SIDE.

THERE WILL NOT BE A LOT OF MOISTURE WITH THIS WARMTH... SO WE WILL
FINALLY GET INTO A PERIOD OF QUIET WEATHER WITH MILD TEMPERATURES.
MODELS ARE STILL TRYING TO PAINT LIGHT QPF ACROSS SOUTHERN WI... BUT
THEY MAY BE PICKING UP ON MELTING SNOW AND FOG POTENTIAL OR POSSIBLY
SOME LIGHT DRIZZLE. THERE IS TOO MUCH UNCERTAINTY FOR THAT SO I KEPT
IT OUT OF THE FORECAST.

SATURDAY NIGHT THROUGH SUNDAY NIGHT... FORECAST CONFIDENCE HIGH.

A COLD FRONT WILL DROP DOWN THROUGH WI SATURDAY NIGHT INTO SUNDAY
MORNING. TEMPS WILL REMAIN STEADY IN SOUTHEAST WI THROUGH THE NIGHT
AND SUNDAY... THEN DROP QUICKLY SUNDAY EVENING IN THE WAKE OF THIS
FRONT. WINDS WILL BE A LITTLE BRISK OUT OF THE NORTHWEST SUNDAY
AFTERNOON WITH THE STEEP LOW LEVEL LAPSE RATES DUE TO COLD AIR
ADVECTION. THE WEATHER LOOKS DRY WITH THIS FRONTAL PASSAGE ON SUNDAY.

MONDAY THROUGH TUESDAY... FORECAST CONFIDENCE MEDIUM.

THE COLD AIR WILL HANG AROUND THROUGH MONDAY NIGHT WITH DRY HIGH
PRESSURE OVERHEAD. LOW PRESSURE CROSSING ONTARIO OR LAKE SUPERIOR
WILL ALLOW FOR WARMER TEMPERATURES IN SOUTHERN WI ON TUESDAY. AN
ASSOCIATED COLD FRONT MAY BRING LIGHT SNOW TO PORTIONS OF EAST
CENTRAL WI TUESDAY NIGHT.

WEDNESDAY THROUGH THURSDAY... FORECAST CONFIDENCE LOW.

THE GFS TRIES TO BRING A SYSTEM INTO THE MIDWEST THAT WOULD HAVE
MIXED PRECIP OVER SOUTHERN WI WEDNESDAY NIGHT THROUGH THURSDAY. THE
ECWMF MAINTAINS A DRY FORECAST WITH HIGH PRESSURE OVER THE AREAS.
USED CONSENSUS POPS AND TEMPS FOR NOW WITH LOW CONFIDENCE.

&&

.AVIATION/12Z TAFS/...

THE SNOW WILL BE MOVING OUT BUT THERE COULD STILL BE SOME LINGERING
FLURRIES THROUGH MID MORNING.  EXPECT A PERIOD OF MVFR CLOUDS THIS
MORNING BEFORE A GRADUAL DECREASE IN CLOUDS FROM THE WEST DURING THE
AFTERNOON AS A RIDGE OF HIGH PRESSURE MOVES INTO WISCONSIN EARLY
THIS EVENING.

CLEARING WILL BE SHORT LIVED AS MOISTURE INCREASES IN THE MID AND
UPPER LEVELS LATE TONIGHT.  SOME MVFR LIGHT SNOW MAY REACH THE
GROUND MAINLY NORTHWEST OF MADISON TOWARDS SUNRISE FRIDAY MORNING.

&&

.MARINE...

NORTHWEST WINDS WILL BE BREEZY THURSDAY. THERE MAY BE A FEW GUSTS TO
25 KNOTS...AND WAVES TO 4 FEET TOWARD OPEN WATERS. OVERALL
THOUGH...CONDITIONS SEEM TOO BORDERLINE FOR A SMALL CRAFT ADVISORY.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
FRIDAY THROUGH WEDNESDAY...MRC



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