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000
FXUS63 KGRB 022304
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
504 PM CST MON MAR 2 2015

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 310 PM CST MON MAR 2 2015

MAIN FORECAST CONCERNS WILL BE SNOW AMOUNTS AND SNOW START TIMES
LATE TONIGHT INTO TUESDAY.

QUIET WEATHER PREVAILED ACROSS THE STATE AS HIGH PRESSURE SPREAD
ACROSS THE GREAT LAKES REGION. THE QUIET WEATHER WILL COME TO AN
ABRUPT END LATE TONIGHT AND TUESDAY MORNING AS ACCUMULATING
SNOWFALL IS EXPECTED ACROSS THE ENTIRE AREA.

THE HIGH PRESSURE WILL PUSH INTO THE EASTERN GREAT LAKES
TONIGHT...AS A LOW PRESSURE SYSTEM DEVELOPS IN THE CENTRAL
PLAINS. THIS WILL ALLOW WARM AIR ADVECTION TO BEGIN...AND
TRANSPORT MOISTURE BACK INTO THE STATE...LEADING TO MID AND UPPER
LEVEL CLOUDS TO INCREASE ACROSS THE AREA THIS AFTERNOON AND
EVENING. THE CLOUDS WILL LOWER AND THICKEN THROUGH THE EVENING AND
EARLY OVERNIGHT HOURS. SOME LIGHT SNOW AND FLURRY ACTIVITY IS
POSSIBLE AFTER 10-11PM AS A RIBBON OF HIGHER RH MOVES THROUGH AND
THE AREA WILL BE IN A FAVORABLE WAA REGIME WITH INCREASING
ISENTROPIC LIFT AND IN THE RRQ OF A DEPARTING JET AND THE LFQ OF
AN APPROACHING JET. ACCUMULATIONS UP TO AN INCH ARE POSSIBLE WITH
THIS ACTIVITY...BUT THE MAJORITY OF THE ACCUMULATING SNOW WILL HOLD
OFF UNTIL TUESDAY AM.

AN AREA OF MODERATE (BRIEFLY HEAVY?) SNOW WILL SPREAD ACROSS THE
AREA ON TUESDAY...AS STRONG WAA...ISENTROPIC LIFT AND QC FORCING
PUSH THROUGH THE STATE. NOSE OF A 40-45 KT LOW LEVEL JET MOVES
INTO EAST-CENTRAL WI AS WELL...WHICH WILL ENHANCE LIFT THERE.
FORCING/LIFT IS GREATEST DURING THE 12-18Z PERIOD...WHEN THE
MAJORITY OF THE SNOW WILL FALL. OPERATIONAL MODELS ARE ON THE
LOWER END OF SNOW TOTALS...GENERALLY BETWEEN 1.5" AND 3.5". NAM
HAS CONTINUED TO BE ON THE LOW SIDE...WITH THE GFS/GEM/ECMWF IN
THE MIDDLE OR TOWARD THE HIGHER VALUES. SREF SNOW PLUMES RANGE
FROM 2 TO 7 INCHES. SO THERE STILL REMAINS SOME CONCERN THIS EVENT
WILL BE TOWARD THE LOWER END OF THINGS... ESPECIALLY WITH THE FAST
MOVEMENT AND NOT IDEAL LIFT IN THE SNOW GROWTH REGION (TEMPS TOO
WARM). WILL CONTINUE TO PLACE THE HIGHEST QPF AMOUNTS (AROUND
0.30") OVER THE FOX VALLEY AND LAKESHORE...WITH LOWER AMOUNTS OVER
THE NORTH. HOWEVER HIGHER SNOW TO LIQUID RATIOS (BETWEEN 15-20 TO 1)
WILL BE OVER NORTHERN WI. SO IN THE END...MOST SPOTS ARE STILL
FORECAST TO RECEIVE 3-4 INCHES...WITH MOST OF THAT FALLING IN A
2-4 HOUR WINDOW. THEREFORE...NO MAJOR CHANGES PLANNED WITH THE
WINTER WEATHER ADVISORY. CONSIDERED DELAYING THE START TIME
SLIGHTLY AS BULK OF SNOW NOT EXPECTED TO PUSH INTO MOST OF NORTH-
CENTRAL UNTIL AFTER 12Z. HOWEVER...THINK ACCUMULATIONS ASSOCIATED
WITH THE LIGHT SNOW OVERNIGHT IS ENOUGH TO KEEP THE 09Z START
TIME. ALSO CONSIDERED STARTING THE ENTIRE FOX VALLEY WITH THE REST
OF THE CURRENT ADVISORY (09Z)...BUT WILL LEAN TOWARD A SLIGHTLY
SLOWER ONSET OF MAIN BATCH OF SNOW SO THE 12Z START TIME SHOULD
WORK OUT.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 310 PM CST MON MAR 2 2015

ARCTIC AIR WILL RETURN TO WISCONSIN TUESDAY NIGHT
THROUGH THURSDAY AS A SIGNIFICANT UPPER TROUGH DROPS INTO THE
WESTERN GREAT LAKES. SUBZERO TEMPERATURES EXPECTED ACROSS THE
WESTERN HALF OF OUR FORECAST AREA TUESDAY NIGHT AND EARLY
WEDNESDAY WHICH WILL PRODUCE WIND CHILLS OF 20 TO 25 BELOW ZERO.
HIGHS WEDNESDAY SHOULD BE AROUND 25 DEGREES BELOW NORMAL WITH
SUBZERO WIND CHILLS ALL DAY. WEDNESDAY NIGHT SHOULD BE THE COLDEST
NIGHT OF THE WEEK WITH BELOW ZERO TEMPERATURES AND WIND CHILLS OF
20 TO 30 BELOW ZERO. LAKE EFFECT SNOW SHOWERS POSSIBLE IN NORTH
CENTRAL WISCONSIN BUT ICE COVER ON LAKE SUPERIOR AND LESS THAN
FAVORABLE WINDS WILL WORK TO KEEP ACCUMULATIONS DOWN TO LESS THAN
AN INCH.

MILDER TEMPERATURES EXPECTED FRIDAY THROUGH EARLY NEXT WEEK AS THE
LARGE UPPER RIDGE OVER THE WESTERN UNITED STATES MOVE EAST AND
MODIFIED PACIFIC AIR BEGINS TO ARRIVE FROM THE PLAINS STATES. A
FEW CLIPPER LIKE SYSTEMS COULD APPROACH FROM THE NORTHWEST ALONG
THE WESTERN EDGE OF THE COLD AIR AND PRODUCE SOME LIGHT SNOW BUT
THE MODELS ARE NOT CONSISTENT WITH TRACK OR TIME OF ARRIVAL.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 500 PM CST MON MAR 2 2015

NOT MUCH CHG TO FCST THINKING FM PREV TAF PKG. EXPANDING AREA OF
SNOW STILL EXPECTED TO QUICKLY OVERSPREAD THE AREA DURING THE PRE-
DAWN HOURS. THE MOST SIG SNOW WL PROBABLY MV THROUGH DURING THE
MORNING...WITH SNOW TAPERING OFF IN THE AFTN. CAN/T TOTALLY RULE
OUT PCPN CHGG TO FZDZ AS INTENSITY WANES IN THE AFTN...BUT AT
THIS POINT THE PROBABLILITY OF THAT OCCURRING DOES NOT SEEM GREAT
ENOUGH TO WARRANT CARRYING FZDZ IN THE TAFS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR WIZ005-
010>012-018-019-030-035>037-045-048>050.

WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST TUESDAY FOR WIZ013-
020>022-031-038>040-073-074.
&&

$$

SHORT TERM.....BERSCH
LONG TERM......RDM
AVIATION.......SKOWRONSKI