FXUS63 KGRB 061141
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
541 AM CST SUN DEC 6 2009

.SHORT TERM...TODAY THROUGH MONDAY. 

FORECAST FOCUS IS ON SNOW FOR LATE TONIGHT AND MONDAY MORNING.

AT 09Z WEAK SURFACE FRONT LIES NEAR GREEN BAY TO THE DELLS. TO THE
SOUTH...TEMPS STILL RATHER MILD IN THE UPPER 20S...TO THE NORTH
TEENS OR LOWER WHERE CLOUDS HAVE EXITED. RADAR SHOWING LIGHT
RETURNS OVER EAST CENTRAL...THOUGH NOTHING SEEN IN OBS SINCE AFTER
MIDNIGHT. QUESTION OF THE DAY IS HOW MUCH CLEARING WILL OCCUR.
LOWER CLOUDS EXITING NORTH AND WEST...THOUGH HIGHER CLOUDS AHEAD
OF TONIGHTS SYSTEM ARE RAPIDLY STREAMING NORTH. HAVE SHOWN TRENDS
IN GRIDS...THOUGH TEXT REMAINS MOSTLY CLOUDY ATTM.

TONIGHT...A WEAK AREA OF LOW PRESSURE IS EXPECTED TO MOVE
NORTHEAST OUT OF THE PLAINS...INTO SOUTHERN LAKE MICHIGAN. QG
FORCING WITH UPPER WAVE MAINLY SOUTH OF AREA WITH FRONTOGENISIS
SEEN FROM 700 TO 600 MB OVER NORTHEAST WI. NAM FURTHER SOUTH WITH
PCPN THEN MAJORITY OF MODELS. HAVE USED A BLEND OF GFS AND
REGIONAL GEM. REAL QUESTION IS CONTRIBUTION FROM LAKE WITH
NORTHEAST FLOW DEVELOPING. DELTA T FROM BAY AND LAKE RUNNING
BETWEEN 13 TO 16...THOUGH WOULD LIKE TO SEE NORTHEAST FLOW AT BIT
STRONGER AND DEEPER...TO AT LEAST 850 MB. MADE SMALL CHANGES TO
TOTALS THIS PACKAGE...TRIMMING BACK A BIT OVER DOOR COUNTY GIVEN
WIND TRAJECTORY. KEPT ADVISORY GOING AS THIS IS FIRST ACCUMULATING
SNOW OF THE SEASON. SYSTEM TO PULL OUT BY MONDAY MORNING WITH
WINDS BACKING NW BY MID MORNING. HAVE MOVED UP ENDING TIME OF SNOW
IN GRIDS.

.LONG TERM...MON NGT THRU NXT SAT. MAJORITY OF THE FOCUS IN THE
LONG-TERM WL BE DEVOTED TO THE POTENTIAL OF THE FIRST MAJOR WINTER
STORM TO THE WRN GREAT LKS THIS SEASON. SOME OF THE MDLS
(NAM/ECMWF) CONT TO WAFFLE WITH THE STORM TRACK WITH THEIR
RESPECTIVE 00Z RUNS NOW SHOWING A MORE NWD TRACK. DUE TO SOME
UNCERTAINTY YET AS TO THE BEST SWATH OF HVY SNOW...HAVE HELD OFF
ON ISSUING ANY WATCH FOR THE TIME BEING.

A BRIEF RESPITE FROM ANY LGT SNOW OR FLURRIES ACROSS NE WI MON NGT
AS A WEAK NW-SE ORIENTATED SFC RDG PASSES THRU THE RGN. EVEN WITH
THE HI PRES NEARBY...EXPECT A GOOD DEAL OF MID/HI CLDS THRU THE
NGT WELL AHD OF THE NXT SYSTEM DEVELOPING OVR THE SRN ROCKIES.
PLENTY OF COLD AIR REMAINS IN PLACE MON NGT...THUS MIN TEMPS
SHOULD EASILY SETTLE IN THE TEENS AWAY FROM LK MI. HAVE LOWERED
READINGS OVR CNTRL/NRN WI AS WNDS WL BE LGT AND CLDS NOT OVERLY
THICK. 

SFC LOW CONTS TO SLOWLY STRENGTHEN AS IT MOVS EAST INTO THE SRN
PLAINS ON TUE. A 140 KT UPR JET WL ROUND THE BASE ON A SHRTWV TROF
OVR THE SRN PLAINS...THUS EXPECT THIS DEVELOPING STORM TO BE
PROGRESSIVE IN NATURE. AN INVERTED SFC TROF IS FCST TO BE PUSHING
EAST INTO WI TUE AFTERNOON AND PROVIDE ENUF CONVERGENCE TO
INTERACT WITH LIFT FROM THE RGT ENTRANCE RGN OF THE UPR JET...TO
BRING A CHC OF LGT SNOW TO THE FCST AREA. THIS SNOW MAY HAVE ENUF
FLUFF TO SEE CLOSE TO AN INCH OF ACCUMULATION ALREADY OVR CNTRL WI
BY SUNSET.

SFC LOW IS PROGGED TO QUICKLY LIFT NE INTO NW SECTIONS OF INDIANA
TUE NGT WHICH IS A BIT FARTHER NORTH OF A TRACK THAT THE MDLS WERE
ADVERTISING 24 HRS AGO. IN FACT...THE ECMWF MADE THE MOST DRASTIC
CHG BY TAKING THE SFC LOW FROM E-CNTRL INDIANA ON ITS 00Z RUN YDA
TO NE IL AS OF 12Z WED. THIS JUST GOES TO SHOW EVERYONE THAT THIS
STORM TRACK IS FAR FROM CERTAIN ATTM. STILL ANTICIPATE THE MDLS TO
WAFFLE FOR ANOTHER COUPLE OF RUNS UNTIL THE MAIN JET COMES ONSHORE
ALONG THE WEST COAST FOR RADIOSONDE DATA TO PROVIDE A BETTER
HANDLE ON ATMOSPHERIC CONDITIONS. NONETHELESS...FULL EXPECT SNOW
TO BE ON THE INCREASE (IN BOTH COVERAGE AND INTENSITY) TUE NGT
ACROSS NE WI AS BOTH FRONTOGENETICAL AND Q-G FORCING INCREASE
ALONG WITH ISEN LIFT. WL ALSO HAVE TO WATCH LOCATIONS NEAR LK MI
AS E-NE WNDS MAY BRING LK-ENHANCED SNOWS TO THE SNOW TOTALS.
FINALLY...WNDS WL STEADILY INCREASE THRU THE NGT AND BE BLUSTERY
BY DAYBREAK ESP OVR E-CNTRL WI. BLOWING AND DRIFTING SNOW WOULD BE
A MAJOR PBLM FOR MORNING COMMUTERS WITH REDUCED VSBYS AND SNOW-
COVERED ROADWAYS.

SNOW WL CONT TO FLY THRU WED MORNING AS THE STORM LIFTS NE TOWARD
LK HURON. WNDS TILL HAVE AN INITIAL NE COMPONENT BEFORE GRADUALLY
BACKING NW AS THE STORM PASSES BY...THUS A CONTINUED LK
ENHANCEMENT TO THE SNOW TOTALS ARE LIKELY NEAR LK MI. BY WED
AFTERNOON...EXPECT THE SNOWS TO BEGIN EASING UP OVR CNTRL WI WITH
STILL SOME ACCUMULATIONS PERSISTING IN THE EAST. AS THE WNDS BACK
NW IN THE AFTERNOON...POTENTIAL EXISTS FOR LK EFFECT SNOW SHWRS TO
DVLP ACROSS N-CNTRL WI. ONE INITIAL PBLM COULD BE THAT THERE IS
TOO MUCH SHEAR FOR SNOW BANDS TO ORGANIZE PROPERLY. BLUSTERY
CONDITIONS TO PREVAIL THRU WED WITH MORE BLOWING AND DRIFTING SNOW
MAKING FOR DANGEROUS DRIVING CONDITIONS.

CYCLONIC FLOW TO LINGER INTO WED EVENING BEFORE EASING DURING THE
OVRNGT HRS. HAVE KEPT A GENERAL LOW-END CHC POP FOR MOST OF THE
FCST AREA WITH THE EXCEPTION OF VILAS CNTRY WHERE TRAJS FAVOR LK
EFFECT SNOW SHWRS EARLY BEFORE WNDS BACK WEST AND TRAJS BECOME
UNFAVORABLE. ONE OTHER THING OF NOTE WL BE THE TUG OF ARCTIC AIR
BROUGHT SOUTH BEHIND THE DEPARTED STORM. 8H TEMPS CRASH INTO THE
-15 TO -20C RANGE WHICH SHOULD SEND MIN TEMPS INTO THE SINGLE
DIGITS TO MID TEENS. WL HAVE TO WATCH WND CHILLS AS WNDS WL BE
SLOW TO DIMINISH OVRNGT. NE WI TO RESIDE ON THE SRN EDGE OF A
BITTERLY COLD AIRMASS ON THU AS A BROAD UPR TROF SETTLES SOUTH
INTO CNTRL/ERN SECTIONS OF CANADA. HAVE KEPT THU DRY FOR NOW AS
WNDS ARE TOO WESTERLY FOR ANY LK EFFECT NORTH AND NO OTHER
TRIGGERS ARE EVIDENT. LOWERED MAX TEMPS A COUPLE OF DEGS WITH
ALMOST ALL OF NE WI ONLY SEEING READINGS IN THE TEENS.

A WEAK CDFNT IS PROGGED TO SWEEP ACROSS WI THU NGT AND MAY BE ABLE
TO PRODUCE A BRIEF SNOW SHWR OR SOME FLURRIES. SINCE MSTR
AVAILABILITY IS SUSPECT...WL NOT ADD ANY PCPN TO THU NGT JUST YET.
OTHERWISE...HI PRES IS FCST TO BUILD INTO THE RGN FOR THE END OF
THE WEEK AND PROVIDE FOR DRY...BUT RATHER COLD CONDITIONS FOR NE
WI. WOULD NOT BE SURPRISED TO SEE SOME MIN TEMPS BLO ZERO FRI
NGT/SAT MORNING.
&&

.AVIATION...MAINLY VFR CONDITIONS TODAY AWAY FROM LAKE SUPERIOR.
CLOUDS WILL INCREASE AND LOWER THIS AFTERNOON AND EVENING AS LOW
PRESSURE MOVES INTO NORTHERN IL. SNOW EXPECTED OVER SOUTHERN TAF
SITES BY MIDNIGHT...WITH VIS/CIGS LAKESHORE TO FOX VALLEY DROPPING
INTO IFR/LIFR RANGE AROUND 10Z.
&&

.MARINE...A PROLONGED PERIOD OF GALE FORCE OR STRONGER WINDS ARE
PSBL TUE NGT THRU THU IN ASSOCIATION WITH THE WINTER STORM MOVG
THRU THE REGION.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST MONDAY 
FOR WIZ022-038>040-048>050.

&&

$$
TE/KALLAS