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000
FXUS63 KGRB 102334
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
534 PM CST TUE DEC 10 2013

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 246 PM CST TUE DEC 10 2013

LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE EARLIER
CLIPPER EXITING THE REGION OVER NORTHEAST LOWER MICHIGAN.  PARTIAL
CLEARING HAS OCCURRED BEHIND THE SYSTEM ACROSS THE STATE...BUT LIKE
YESTERDAY...STRATO-CU KEEPS RE-DEVELOPING WITHIN THE ARCTIC AIRMASS
DUE TO STEEP LOW-LEVEL LAPSE RATES.  LIGHT SNOW SHOWERS/FLURRIES ARE
NOT AS WIDESPREAD AS YESTERDAY...BUT ARE STILL SHOWING UP ON RADAR
MAINLY OVER CENTRAL AND SOUTHERN WISCONSIN.  THESE LIGHT SNOW
SHOWERS/FLURRIES SHOULD AGAIN SUBSIDE AROUND SUNSET.  THEN ATTENTION
TURNS TO THE VARIOUS SHORTWAVES/CLIPPERS UPSTREAM.  ONE CLIPPER OVER
LAKE WINNIPEG IS ANTICIPATED TO SWING ACROSS LAKE SUPERIOR AND THE
UPPER PENINSULA TONIGHT.  A MORE POTENT WAVE RESIDES OVER MONTANA
WHICH WILL ALSO MOVE ACROSS THE REGION LATE OVERNIGHT.  AS A
RESULT...LIGHT SNOW POTENTIAL AND WIND CHILL HEADLINES ARE THE MAIN
FORECAST CONCERNS IN THE SHORT TERM.

TONIGHT...ANOTHER FAST MOVING CLIPPER SYSTEM WILL SLIDE QUICKLY
SOUTHEAST INTO THE WESTERN GREAT LAKES/NORTHERN MISSISSIPPI VALLEY.
AHEAD OF THE SHORTWAVE...A WEAK SURFACE CIRCULATION WILL MOVE ACROSS
IOWA AND INTO NORTHERN ILLINOIS.  FORCING IS NOT NEARLY AS ROBUST AS
THE PAST CLIPPER...AND THE TRACK IS A COUPLE HUNDRED MILES FURTHER
SOUTH AS WELL.  BUT SEEMS TO HAVE ENOUGH MOISTURE ON THE NORTHERN
PERIPHERY OF THE SYSTEM FOR LIGHT SNOW TO GRAZE CENTRAL AND
EAST-CENTRAL WISCONSIN COUNTIES.  HAVE KEPT THE CHANCE OF SNOW IN
THE FORECAST...BUT DID DELAY THE ARRIVAL A COUPLE HOURS TO MATCH THE
LATEST TRENDS.  AS THE CLIPPER PASSES BY TO THE SOUTH...SHOULD SEE A
SECONDARY SURGE OF ARCTIC AIR ARRIVE LATE TONIGHT.  THEREFORE
ANTICIPATE WIND CHILL READINGS TO FALL OFF QUICKLY OVERNIGHT AS THIS
SURGE OF ARCTIC AIR SPREADS EAST.  ALREADY WILL BE NEAR WIND CHILL
ADVISORY CRITERIA OVER N-C WISCONSIN FOR THE EVENING...SO WILL NOT
TAKE MUCH COLDER AIR FOR CRITERIA TO BE MET.  WILL KEEP THE START
TIME AS PLANNED...THOUGH N-C WISCONSIN MAY SEE THE CRITERIA BREACHED
AN HOUR OR TWO BEFORE ISSUANCE TIME.  LITTLE CHANGE TO LOW TEMPS.

WEDNESDAY...CLEARING SKIES WILL TAKE PLACE WEDNESDAY MORNING AS THE
CORE OF THE ARCTIC AIR MOVES INTO THE FORECAST AREA.  DESPITE MOSTLY
CLEAR TO PARTLY CLOUDY CONDITIONS...TEMPS WILL STRUGGLE TO RISE
ABOVE 0 DEGREES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN.  WIND
CHILL READINGS MAY RISE ABOVE ADVISORY CRITERIA FOR A FEW HOURS
DURING THE AFTERNOON OVER NORTHEAST WISCONSIN...ONLY TO FALL BELOW
AGAIN BY THE START OF THE EVENING.  WILL THEREFORE LET THE WIND
CHILL HEADLINES GO INTO THE NEXT PERIOD.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 246 PM CST TUE DEC 10 2013

CONTINUED COLD TEMPERATURES AND PERIODIC SNOW CHANCES...MOST
NOTABLY FRIDAY NIGHT INTO SATURDAY...WILL BE THE MAIN FCST
CONCERNS.

MOSTLY CLEAR SKIES WILL ALLOW TEMPS TO FALL WELL BLO ZERO WEDNESDAY
EVENING...BUT WAA AND INCREASING CLOUDS WILL PROBABLY RESULT IN
STEADY OR SLOWLY WARMING TEMPS BEFORE DAYBREAK. ENOUGH SATURATION
SHOULD OCCUR OVER OUR SW COUNTIES LATE TO ALLOW SOME LIGHT SNOW OR
FLURRIES TO DEVELOP. STEADY WEST WINDS AND VERY COLD TEMPS WILL
RESULT IN BITTER COLD WIND CHILLS...WHICH WILL LINGER INTO EARLY
THURSDAY. HAVE EXTENDED THE WIND CHILL ADVISORY UNTIL 15Z THU.
WILL EVENTUALLY NEED TO ADD THE LAKESHORE COUNTIES TO THE ADVISORY
FOR WEDS NGT...BUT THAT CAN BE DONE WITH SUBSEQUENT FCSTS.

A VERY STRONG BAROCLINIC ZONE WILL BE IN PLACE FROM THURSDAY INTO
FRIDAY. WITH WAA CONTINUING ON THURSDAY...AND THE RRQ OF AN UPPER
JET...FRONTOGENETIC FORCING AND WEAK SHORT-WAVE ENERGY AFFECTING
THE REGION THU NGT/FRI...ENOUGH FORCING SHOULD BE PRESENT TO
CONTINUE A CHANCE OF LIGHT SNOW/FLURRIES THROUGH THE PERIOD. A
MODEST MODERATION IN TEMPS WILL OCCUR LATE IN THE WORK WEEK...
BUT BACKED OFF A LITTLE ON THE PREVIOUS MAX TEMPS FOR FRIDAY.

ITS STARTING TO LOOK MORE INTERESTING LATE FRI NGT/SATURDAY
AS AN INVERTED SFC TROF MOVES THROUGH THE REGION. LOW-LEVEL
CONVERGENCE IS EXPECTED TO BE QUITE STG IN THE FOX VALLEY/LKSHR
AREAS...AND SYNOPTIC FORCING SHOULD BE PROVIDED BY H8 WAA/ISENT
LIFT AND SOME UPPER JET ENERGY. LAKE-ENHANCEMENT IS LIKELY...WITH
E-SE WINDS OFF LAKE MICHIGAN AND LK-H8 DELTA-T`S OF 14-18 C. WILL
RAISE POPS TO LIKELY OVER THE FOX VALLEY AND ESPECIALLY THE
LAKESHORE COUNTIES...AND MENTION THE POSSIBILITY OF 2-4 INCH
ACCUMS (WITH LOCAL HIGHER AMOUNTS ON THE LKSHR) IN THE HAZARDOUS
WEATHER OUTLOOK.

THE FCST IS UP IN THE AIR SATURDAY NIGHT/SUNDAY...AS SOME OF
THE MEDIUM RANGE MODELS (ESPECIALLY THE GFS) BRING AN UPPER LOW
FARTHER SOUTH (THROUGH WI) AND LINGER THE INVERTED SFC TROF OVER
THE WESTERN GREAT LAKES REGION. ALTHOUGH THE ECMWF WAS STILL
TAKING THE UPPER LOW THROUGH LAKE SUPERIOR...IT HAD SHOWN A
FARTHER SOUTH SOLN A COUPLE DAYS AGO...SO THIS BEARS WATCHING.
AT THE LEAST...IT APPEARS THAT COLD CYCLONIC NORTH FLOW WILL
BRING ANOTHER SHOT OF ARCTIC AIR INTO THE REGION BY SUDAY...AND
CAUSE LAKE-ENHANCED SNOW TO INCREASE OVER NC WI. AT WORST...
ACCUMULATING SNOW COULD CONTINUE ACROSS MUCH OF THE FORECAST
AREA SATURDAY NIGHT INTO SUNDAY MORNING. FOR NOW...HAVE JUST
INCREASED POPS OVER THE LAKE SUPERIOR SNOW BELT. THE ARCTIC
SURGE SHOULD BE BRIEF.

THE CHANCE OF LIGHT SNOW OR FLURRIES WILL CONTINUE EARLY NEXT
WEEK...AS SEVERAL S/W TROFS MOVE THROUGH THE WESTERN GREAT
LAKES...AND THE ARCTIC BAROCLINIC ZONE OSCILLATES OVER THE
REGION.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 533 PM CST TUE DEC 10 2013

ANOTHER IN A SERIES OF WEAK CLIPPER SYSTEMS WILL PASS OVER MAINLY
THE SOUTH HALF OF THE STATE AND NORTHERN ILLINOIS TONIGHT. EXPECT
MAINLY A PERIOD OF VFR CIGS WITH ISOLATED MVFR CIGS DURING PASSAGE
FOLLOWED BY ANOTHER SHOT OF COLD ARCTIC AIR WITH GUSTY WEST WINDS
FOR WEDNESDAY. DRIER AIR WILL DIMINISH CLOUDS QUICKLY FROM WEST TO
EAST FOR VFR CONDITIONS FOR WEDNESDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM WEDNESDAY TO 9 AM CST THURSDAY FOR
WIZ013-020-021-031-037>039-045-048-049-073-074.

WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY
FOR WIZ005-010>012-018-019-030-035-036.
&&

$$

SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH