Winter Storm Watch 1, NWS Milwaukee, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1018 PM CST SAT JAN 3 2015

.UPDATE...FREEZING DRIZZLE HAS GREATLY DECREASED IN COVERAGE OVER
THE LAST HOUR WITH SOME SNOW NOW BEING REPORTED. THE STRONG
SHORTWAVE TROUGH OVER MO IS STILL SET TO TRACK NEWD INTO WRN
LOWER MI SUN AM. THUS EXPECT MORE LIGHT SNOW TO DEVELOP...BUT NOT
BECOME MORE WIDESPREAD UNTIL 08Z OR 09Z. THE SNOW WILL CONTINUE
INTO THE AFTERNOON OVER ERN WI. SNOW ACCUMS OF 1-3 INCHES FORECAST
WITH THE HIGHER AMOUNTS OVER FAR SE WI CLOSER TO THE SHORTWAVE
TROUGH. OTHERWISE ARCTIC FRONT WILL DROP TEMPS THROUGH THE TEENS
AND SINGLE DIGITS THROUGHOUT THE DAY ON SUNDAY. A WIND CHILL
ADVISORY WILL BE NEEDED FOR SUNDAY NIGHT AND MON MORNING.

&&

.AVIATION/06Z TAFS/...AREAS OF FOG...PATCHY FREEZING DRIZZLE AND
LIGHT SNOW WILL GIVE WAY TO WIDESPREAD LIGHT SNOW BY 08Z OR 09Z AS
A STRONG SHORTWAVE TROUGH OVER MO MOVES NEWD INTO LOWER MI SUN AM.
CIGS WILL REMAIN BELOW 1 KFT UNTIL THE MORNING DAYLIGHT HOURS WHEN
THE ARCTIC FRONT WILL RAISE THE CIGS TO MVFR. VSBYS WILL DROP TO
1-2 MILES WITH THE SNOW AND RAISE TO 3-5SM WHEN THE SNOW GETS
LIGHTER DURING THE MID TO LATE MORNING HOURS. ALTHOUGH THE SNOW
WILL LINGER IN EASTERN WI INTO THE AFTERNOON. THE ARCTIC AIR WILL
THEN CLEAR THE LOW CLOUDS FROM WEST TO EAST DURING THE AFTERNOON
WITH VFR CONDITIONS DEVELOPING.

&&

.PREV DISCUSSION... /ISSUED 354 PM CST SAT JAN 3 2015/

TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

AREA OF LIGHT SNOW/LIGHT SLEET/LIGHT RAIN MIX CURRENTLY SHIFTING
NORTHEASTWARD THROUGH THE FAR SOUTHEAST COUNTIES...AND LOOKS TO BE
SLOWLY DIMINISHING AS UPWARD VERTICAL MOTION IS LEAVING THE AREA.
ALREADY REMOVED JEFFERSON AND ROCK COUNTIES FROM THE ADVISORY...AND
MAY REMOVE THE REST BEFORE THE 00Z SUNDAY EXPIRATION TIME IF
WEAKENING TREND CONTINUES.

THE AREA SHOULD SEE PATCHY LIGHT FREEZING DRIZZLE THROUGH THE
EVENING...SUPPORTED BY AREA FORECAST SOUNDINGS. HOWEVER...NOT MANY
REPORTS IN THE AFTERNOON OF FREEZING DRIZZLE FROM AIRPORTS...SO DO
NOT THINK IT WILL BE WIDESPREAD ENOUGH TO CAUSE PROBLEMS ON TREATED
ROADS.

FOG ALSO WILL LINGER THIS EVENING...WITH SOME AREAS SEEING 1/4 TO
1/2 MILE VISIBILITIES AT TIMES. THIS WAS DUE TO LIGHT WINDS AND
SOMEWHAT MOIST LOWER LEVELS. THESE SHOULD RISE WITH THE SNOW COMING
IN LATER TONIGHT.

STRONG 500 MB SHORTWAVE TROUGH SLIDES NORTHEAST LATER
TONIGHT...JUST TO THE SOUTHEAST OF THE AREA. THIS FEATURE WILL BRING
A ROUND OF LIGHT SNOW LATER TONIGHT INTO SUNDAY MORNING...WITH 1 TO 2
INCHES OF ACCUMULATION WEST AND 2 TO 3 INCHES EAST EXPECTED.

GUSTY NORTHWEST WINDS LATE TONIGHT INTO SUNDAY WILL BRING SOME
BLOWING AND DRIFTING SNOW AS WELL. THINK VISIBILITIES WILL REMAIN
ABOVE THE 1/2 MILE THRESHOLD FOR AN ADVISORY...SO HELD OFF ON
ISSUING ONE FOR NOW. LATER SHIFTS CAN EVALUATE THE NEED FOR AN
ADVISORY IF HIGHER SNOW AMOUNTS ARE ANTICIPATED.

TEMPERATURES WILL SLOWLY FALL TONIGHT...THEN DROP QUICKLY ON SUNDAY
WITH THE STRONG COLD AIR ADVECTION. EXPECT HIGHS JUST AFTER MIDNIGHT
TONIGHT WITH FALLING TEMPERATURES ALL DAY INTO SUNDAY NIGHT.
TEMPERATURES SHOULD BE IN THE SINGLE DIGITS BY LATE SUNDAY
AFTERNOON...WITH BELOW ZERO WIND CHILLS IN THE WESTERN COUNTIES.

SHORT TERM...SUNDAY NIGHT THROUGH TUESDAY.

SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE HIGH.

30-35 KT 925 MB WINDS AT 00Z ONLY LOWER SLIGHTLY TO 25 KTS BY 12Z
MONDAY. THIS WILL KEEP SURFACE WINDS AT 10 TO 15 MPH WITH GUSTS
OF 20 TO 25 MPH THROUGH MOST OF THE NIGHT. 925 MB TEMPS FALL TO
-23C TO -25C YIELDING LOWS OF -5F TO -10F FROM THE I-94 CORRIDOR AND
SOUTH AND ALONG LAKE MICHIGAN...WITH -10F TO -12F TO THE NORTH.

THE COMBINATION OF COLD TEMPS AND GUSTY WINDS WILL BRING THE LIKELY
NEED FOR A WIND CHILL ADVISORY FOR SUNDAY EVENING INTO AT LEAST MID-
MORNING MONDAY...ESPECIALLY WITH SCHOOLS BACK IN SESSION AFTER THE
HOLIDAY BREAK. IT WILL REMAIN COLD THROUGH THE DAYLIGHT HOURS WITH
HIGHS ONLY IN THE SINGLE DIGITS ABOVE ZERO.

MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM.

LOOKING AT THE POTENTIAL FOR A EXTREME SNOW/LIQUID RATIO SNOW EVENT
WITH CLIPPER MONDAY NIGHT INTO EARLY TUESDAY MORNING. CONSENSUS OF
MODEL QPF PUTS DOWN 0.2 TO 0.25 INCHES OF LIQUID OVER THE SW HALF OF
THE CWA...WITH 0.12 TO 0.2 ACROSS THE NE HALF. DEEP DENDRITE GROWTH
ZONE THAT IS 300MB TO 350 MB DEEP AND EXTENDS TO THE SURFACE ON
FORECAST MODELS COULD YIELD EFFECTIVE SNOW/LIQUID RATIOS OF 30:1
OR MORE. THAT WOULD PRODUCE SNOW AMOUNTS POTENTIALLY REACHING
WARNING CRITERIA.

THERE WILL BE A NARROW BAND OF HEAVY SNOW AMOUNTS WHERE THE MAX
OMEGA AND HIGHEST QPF COINCIDE WITH THE DEEPEST DENDRITE GROWTH
ZONE. WITH MODEL DIFFERENCES WITH TRACK AND LOCATION OF HIGHEST
QPF...WHICH APPEARS TO BE JUST TO THE SW OF THE CWA PER WPC DAY 3
SNOW GRAPHIC...WILL NOT ISSUE A WATCH AT THIS TIME BUT WILL NEED TO
BE MONITORED.

CLOUDS AND SOME WEAK WARM ADVECTION WITH THE CLIPPER WILL MEAN EARLY
LOWS IN THE SINGLE DIGITS ABOVE ZERO...THEN STEADY OR SLOWLY
RISING TEMPERATURES. TUESDAY HIGHS WILL REACH BETWEEN +10F AND
+15F.

LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE
HIGH.

ANOTHER ARCTIC HIGH BUILDING IN BEHIND THE CLIPPER SYSTEM MEANS DRY
BUT BITTER COLD CONDITIONS FOR MOST OF THE EXTENDED. WIND CHILL
ADVISORIES ARE LIKELY AS LOWS TUESDAY AND WEDNESDAY NIGHT DROP INTO
THE TEENS BELOW ZERO...WITH ENOUGH WIND TO PRODUCE WIND CHILL VALUES
BETWEEN -25 AND -30. HIGHS WEDNESDAY ONLY REACHING THE SINGLE DIGITS
BELOW.

SOME SLIGHT UPWARD MODIFICATION IN TEMPS FOR THE REST OF THE WEEK
BUT STILL WELL BELOW NORMAL. COMBINATION OF GEM SHOWING ANOTHER
CLIPPER PASSING BY TO THE SW THURSDAY...AND ECMWF SHOWING SOME LIGHT
QPF GRAZING THE NE CWA WITH A WEAK SURFACE TROUGH PRODUCES SLIGHT
CHANCE POPS OVER THE NRN CWA.

AVIATION/00Z TAFS/...

EXPECT A LIGHT RAIN...LIGHT SNOW AND LIGHT SLEET MIX AT
WAUKESHA...MILWAUKEE AND KENOSHA TO CONTINUE WEAKENING AND END BY
AROUND 00Z SUNDAY. MAY SEE LIGHT FREEZING DRIZZLE AT TIMES THROUGH
THE EVENING...BUT DO NOT THINK IT WILL CAUSE ICING ISSUES ON TREATED
RUNWAYS.

AT MADISON...EXPECT ONLY PATCHY LIGHT FREEZING DRIZZLE INTO THIS
EVENING...AGAIN IT SHOULD NOT CAUSE ISSUES ON TREATED RUNWAYS.
CEILINGS AND VISIBILITIES MAY DROP TO AROUND ALTERNATE MINIMUMS AT
TIMES AT ALL TAF SITES THROUGH THIS EVENING.

BETWEEN 07Z AND 09Z SUNDAY...LIGHT SNOW WILL MOVE INTO ALL TAF
SITES. IT WILL END AT MADISON AROUND 14Z SUNDAY...BUT LINGER AT THE
EASTERN SITES UNTIL THE 18Z TO 20Z PERIOD. EXPECT 1 TO 2 INCHES AT
MADISON...AND 2 TO 3 INCHES AT THE EASTERN SITES. THINK HOURLY
SNOWFALL RATES WILL BE UP TO TWO TO FOUR TENTHS OF AN INCH PER HOUR.

GUSTY NORTHWEST WINDS WILL DEVELOP BY 10Z TO 12Z SUNDAY AND
LINGER SUNDAY INTO SUNDAY NIGHT. THIS WILL CREATE BLOWING AND
DRIFTING SNOW THROUGH SUNDAY. THIS MAY REDUCE VISIBILITIES TO IFR
CATEGORY AT TIMES. ONCE THE SNOW ENDS...EXPECT MVFR CEILINGS AND
VISIBILITIES.

MARINE...

GUSTY NORTHWEST WINDS WILL KICK IN EARLY SUNDAY MORNING IN THE WAKE
OF THE LOW PRESSURE SYSTEM AND ARCTIC COLD FRONT...AS THE PRESSURE
GRADIENT BECOMES TIGHT. A SMALL CRAFT ADVISORY IS IN EFFECT FROM
LATE TONIGHT THROUGH LATE MONDAY MORNING. TEMPERATURES WILL BE
VERY COLD NEXT WEEK...AND SHOULD RESULT IN A FREEZING SPRAY
HAZARDS FROM TIME TO TIME.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 4 AM SUNDAY TO 10 AM CST MONDAY FOR
     LMZ643>646.

&&

UPDATE...GEHRING
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...REM

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
455 PM CST SAT JAN 3 2015

WIZ046-047-051-052-056>060-062>072-042300-
MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE-
WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE-
LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA-
455 PM CST SAT JAN 3 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN.

.DAY ONE...TONIGHT

LOOK FOR SNOW TO MOVE INTO THE AREA AFTER MIDNIGHT...LINGERING
INTO SUNDAY...AS LOW PRESSURE PASSES BY TO THE SOUTHEAST. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE EXPECTED TONIGHT INTO SUNDAY. IN
ADDITION...BLUSTERY NORTHWEST WINDS WILL DEVELOP
OVERNIGHT...CAUSING AREAS OF BLOWING SNOW INTO SUNDAY MORNING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY

MORE ACCUMULATING SNOW IS EXPECTED MONDAY NIGHT INTO TUESDAY...AS
LOW PRESSURE PASSES TO THE SOUTH OF WISCONSIN. SNOWFALL OF 3 TO 5
INCHES IS EXPECTED AT THIS TIME.

BITTERLY COLD AIR WILL SETTLE OVER THE REGION ON SUNDAY...AND
LINGER THROUGH MUCH OF NEXT WEEK. WIND CHILLS ARE EXPECTED TO DROP
TO 20 TO 30 BELOW ZERO SUNDAY NIGHT...AND AGAIN TUESDAY NIGHT AND
WEDNESDAY NIGHT. WIND CHILL ADVISORIES WILL LIKELY BE NEEDED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED. HOWEVER...SNOW AND ICE
REPORTS ARE APPRECIATED.

LMZ643>646-042300-
SHEBOYGAN TO PORT WASHINGTON WI-
PORT WASHINGTON TO NORTH POINT LIGHT WI-
NORTH POINT LIGHT TO WIND POINT WI-
WIND POINT WI TO WINTHROP HARBOR IL-
455 PM CST SAT JAN 3 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN.

.DAY ONE...TONIGHT

A SMALL CRAFT ADVISORY GOES INTO EFFECT LATE TONIGHT...AS
NORTHWEST WINDS PICK UP BEHIND STRENGTHENING LOW PRESSURE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY

THE SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT THROUGH MONDAY
MORNING...AS LOW PRESSURE MOVES FROM THE CENTRAL GREAT LAKES INTO
SOUTHERN CANADA. A FEW GUSTS TO GALE FORCE WILL BE POSSIBLE ON
SUNDAY TOWARD THE OPEN WATERS.

REM/WOOD
WWW.WEATHER.GOV/MKX