Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 250311 AAB
AFDGRB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GREEN BAY WI
1011 PM CDT TUE MAR 24 2015

NEW INFORMATION ADDED TO UPDATE SECTION

.UPDATE...
ISSUED AT 1011 PM CDT TUE MAR 24 2015

EVENING NAM MODEL RUN HAS LOWERED QPF AMOUNTS OVER EAST CENTRAL
WISCONSIN OVERNIGHT...DOWN FROM THE AROUND A HALF INCH OR SO EARLIER
TODAY TO 0.20 TO 0.35 INCHES. AREA RADAR TRENDS SUGGESTS A GOOD
PORTION OF THE CONVECTION MOVING OVER ILLINOIS MAY STAY SOUTH AND
KEEP THE DEEPER MOISTURE SOUTH WITH IT. DID NOTICE GROUND TRUTH
REPORTS OF 1 TO 1.5 INCHES IN THE TROUGH AXIS OVER SOUTHEAST
MINNESOTA. THIS TROUGH AXIS IS PROGGED TO BISECT THE FORECAST
AREA FROM NORTHWEST TO SOUTHEAST AT 12Z OR DURING THE MORNING
COMMUTE FOR THE BEST TIME OF ACCUMULATING SNOW...PERHAPS 2-3 INCHES
WITH A FEW 4 INCHES POSSIBLE. SNOW MIXED WITH SLEET AND FREEZING
RAIN LATER TONIGHT INTO WEDNESDAY MORNING STILL POSSIBLE TO
SUPPORT THE ADVISORY EVEN IF SNOW AMOUNTS TREND LESS. NO CHANGES
TO ONGOING HEADLINES.

UPDATE
ISSUED AT 856 PM CDT TUE MAR 24 2015

INITIAL BAND OF PCPN WORKING NORTH OVER SOUTHERN WISCONSIN
PRODUCING MIXED PCPN OVER SOUTHWEST WISCONSIN. LITTLE GROUND TRUTH
REPORTS OVER SOUTH CENTRAL AND SOUTHEAST WISCONSIN. THIS INITIAL
BAND TO REACH THE FOX CITIES BETWEEN 9 AND 10 PM AND GRB AROUND 10
PM. THIS INITIAL BAND OF PCPN ALSO WILL BE WORKING INTO A VERY DRY
AIR MASS OVER NORTHEAST WISCONSIN AS PER EVENING UPPER AIR RUN.
MUCH OF THE THE INITIAL MOISTURE WILL LIKELY GET ABSORBED INTO
SATURATING THE AIR MASS...AND WHEN SATURATING...APPEARS TO COOL TO
A MAINLY SNOW VARIETY. AN INTENSE BAND OF CONVECTION WITH THE
SURFACE LOW WORKING NORTHEASTWARD INTO WESTERN ILLINOIS THIS
EVENING AND MAY BE THE LATER NIGHT FOCUS AS IT MAY CLIP PARTS OF
EAST CENTRAL WISCONSIN LATER TONIGHT. AT THIS POINT...NO CHANGES
TO THE HEADLINES.
&&

.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 212 PM CDT TUE MAR 24 2015

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW CANADIAN
HIGH PRESSURE SHIFTING EAST OVER THE EASTERN GREAT LAKES EARLY THIS
AFTERNOON WHILE LOW PRESSURE IS MOVING ALONG THE KANSAS/OKLAHOMA
BORDER.  AHEAD OF THE LOW...AN AREA OF MIXED PRECIPITATION WITH SOME
EMBEDDED THUNDERSTORMS IS OCCURRING OVER IOWA ON THE NOSE OF THE LLJ
AND REGION OF MOISTURE ADVECTION.  THE SHORTWAVE AS THE PRIMARY
UPPER SUPPORT RESIDES OVER WESTERN KANSAS AND LOOKS RATHER
IMPRESSIVE EARLY THIS AFTERNOON.  AS THE LOW HEADS NORTHEAST TOWARDS
SOUTHERN LAKE MICHIGAN TONIGHT...TIMING THE WINTRY PRECIP AND
POTENTIAL AMOUNTS ARE THE MAIN FORECAST CONCERNS.

TONIGHT...LEANED AWAY FROM THE NAM FOR THIS FORECAST...AS IT APPEARS
TO BE TOO FAR NORTH FROM THE CONSENSUS OF THE GFS/CANADIAN/AND
SREF.  TAKING THE BLEND OF THE CONSENSUS...LOW PRESSURE WILL TRACK
FROM WESTERN MISSOURI TO SOUTHERN LAKE MICHIGAN TONIGHT.  A BEEFY
LLJ UPWARDS OF 50KTS WILL SURGE NORTHEAST AHEAD OF THE LOW AND WILL
BE POINTED AT SOUTHERN WISCONSIN BY MIDNIGHT.  THIS LLJ WILL
TRANSPORT PWATS BETWEEN 0.5 AND 0.75 INCHES ACROSS THE FORECAST AREA
(AS OPPOSED TO 0.15 PWAT CURRENTLY).  WITH THE APPROACH OF THE LOW
AND SHORTWAVE...QG FORCING AND MID-LEVEL FGEN WILL STRENGTHEN TO SUPPORT
AN AREA OF PRECIP SPREADING NORTHEAST INTO CENTRAL WISCONSIN AND THE
SOUTHERN FOX VALLEY BETWEEN 03-06Z...AND THEN ACROSS THE REST OF THE
FORECAST AREA BY 10Z.  THE STRONG LIFT AND AMPLE MOISTURE WILL LEAD
TO A RATHER INTENSE PERIOD OF PRECIP ONCE IT ARRIVES.  TEMPERATURES
ALOFT REMAIN RATHER UNCERTAIN...BUT AM COUNTING ON THE INTENSE
PRECIP RATES AND LIFT TO COOL THE SLIGHTLY ABOVE FREEZING TEMPS
BETWEEN 850-800MB BACK TO OR BELOW FREEZING.  AS A RESULT...AM
THINKING PRECIPITATION TYPES WILL BE MAINLY SNOW WITH SOME SLEET MIX
IN FROM WAUTOMA TO THE DOOR.  AREAS AROUND
MANITOWOC/CALUMET/KEWAUNEE HAVE POTENTIAL TO SEE MIXED PRECIP THE
LONGEST...AND THIS WILL CUT INTO SNOW ACCUMULATIONS THERE SOME.
THOUGH SNOWFALL RATES COULD APPROACH AN INCH PER HOUR IN THE MORE
INTENSE SNOW BANDS...THE QUICK FORWARD MOTION OF THE SYSTEM WILL
ALSO LIMIT ACCUMS.  WILL SHOW A WIDESPREAD 2 TO 4 INCHES...LOCALLY
HIGHER OVER THE FOX VALLEY WHERE WILL HAVE THE HIGHEST AMOUNTS.
THIS LOOKS LIKE A SOLID ADVISORY...PERHAPS TOWARDS A HIGHER END
ADVISORY OVER EASTERN WISCONSIN IF THERE IS LESS OF A MIX...AND
SNOWFALL RATES BECOME AN INCH PER HOUR.  NORTH-CENTRAL WISCONSIN MAY
ONLY SEE 1-3 INCHES...BUT IT WILL BE SNOWING FOR THE MORNING
COMMUTE...THUS AN ADVISORY STILL LOOKS REASONABLE.

WEDNESDAY...SNOW WILL BE ONGOING ACROSS NORTH-CENTRAL AND FAR
NORTHEAST WISCONSIN WHERE AN ADDITIONAL INCH COULD FALL BY
MID-MORNING.  ELSEWHERE...SNOW WILL BE DIMINISHING AS THE LOW TRACKS
TOWARDS NORTHERN LOWER MICHIGAN.  REGARDLESS...THE MORNING COMMUTE
WILL LIKELY BE MESSY FOR MOST LOCATIONS.  BEHIND THE SYSTEM...THE
REGION WILL BE UNDER THE INFLUENCE OF BROAD CYCLONIC FLOW.  DRY
SLOTTING WILL MOVE OVER CENTRAL AND NORTHEAST WISCONSIN DURING THE
AFTERNOON...BUT THE SOUTHERN EXTENT OF THE COMMA HEAD WILL LINGER
OVER N-C WISCONSIN WHERE WILL LEAVE A CHANCE OF RAIN AND SNOW
THROUGH THE DAY.  WEST WINDS WILL BECOME GUSTY DURING THE AFTERNOON
AS LOW LEVEL LAPSE RATES STEEPEN.  GENERALLY REMAINING MOSTLY CLOUDY
WITH HIGHS RANGING FROM THE UPPER 30S TO MIDDLE 40S.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 212 PM CDT TUE MAR 24 2015

COLD CYCLONIC FLOW ALOFT WILL DOMINATE THE WEATHER PATTERN INTO
THE WEEKEND...BRINGING BELOW NORMAL TEMPERATURES ALONG WITH CHANCES
OF RAIN AND SNOW AT SOME POINT WEDNESDAY NIGHT AND THURSDAY. PERSISTENT
NORTHERLY FLOW OFF LAKE SUPERIOR WILL BRING OCCASIONAL SNOW SHOWERS
TO FAR NORTHERN WISCONSIN WHERE SEVERAL INCHES ARE POSSIBLE ACROSS
THE SNOW BELT REGION OF VILAS COUNTY WITH LIGHTER AMOUNTS TO THE
SOUTH. UPPER TROUGH SWINGS ACROSS THE REGION THURSDAY...BRINGING A
CHANCE OF RAIN OR SNOW SHOWERS TO THE REMAINDER OF THE REGION.

THE BIG STORY BEHIND THIS TROUGH WILL BE THE COLD TEMPERATURES
ON FRIDAY. HIGH TEMPERATURES ON FRIDAY WILL ONLY BE IN THE MIDDLE 20S
TO LOWER 30S...OR SOME 10 TO 15 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. VERY COLD TEMPERATURES ARE EXPECTED FRIDAY NIGHT WITH LOWS IN
THE SINGLE DIGITS AND TEENS.

SOME MODERATION IN TEMPERATURES IS EXPECTED ON SATURDAY. NEXT SYSTEM
TO AFFECT THE AREA SATURDAY NIGHT AND SUNDAY. SOME TIMING ISSUES NOTED
IF THIS SYSTEM WOULD OCCUR MORE SATURDAY NIGHT OR ON SUNDAY. THIS
COULD HAVE AN IMPACT ON PRECIPITATION TYPES IF IT SHOULD OCCUR MORE
ON SUNDAY. DRY CONDITIONS EXPECTED SUNDAY NIGHT INTO MONDAY NIGHT
AS HIGH PRESSURE MOVES ACROSS THE REGION. THERE IS A SMALL CHANCE
OF LIGHT RAIN ON TUESDAY...BUT CONFIDENCE IS LOW THAT THIS WOULD
OCCUR.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 534 PM CDT TUE MAR 24 2015

LOOK FOR DETERIORATING CONDITIONS TONIGHT AS A LATE SEASON WINTER
STORM SYSTEM TAKES AIM FOR WISCONSIN. WIDESPREAD IFR OR LIFR
CONDITIONS TO DEVELOP OVERNIGHT AS A MIX OF RAIN/FREEZING
RAIN...SLEET AND SNOW SPREAD OVER THE AREA. MAINLY SNOW IS
EXPECTED NORTH OF A LINE FROM MFI TO SUE...AND A MIX SOUTH.
CONDITIONS TO GRADUALLY IMPROVE TO VFR CONDITIONS FROM SOUTHWEST
TO NORTHEAST AS THE SYSTEM DEPARTS TO THE NORTHEAST WEDNESDAY
MORNING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM CDT WEDNESDAY FOR WIZ030-031-
035>040-045-048>050.

WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM CDT WEDNESDAY FOR
WIZ005-010>013-018>022-073-074.
&&

$$

UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......TDH






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