FXUS63 KGRB 080928
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
328 AM CST TUE DEC 8 2009

...MAJOR SNOWSTORM TO AFFECT THE AREA THE NEXT COUPLE DAYS...NO
CHANGES TO HAZARD /HEADLINE/ TYPES OR TIMING WITH THIS ISSUANCE...

.SYNOPSIS...HIGHLY AMPLIFIED LNGWV PATTERN IN PLACE ACRS NOAM.
SHARP UPR RIDGE ALONG THE WEST COAST...WITH DEEP DOWNSTREAM TROF
OVER THE DESERT SW. MAJOR SHRTWV AND SPEED MAX LOCATED IN THE BASE
OF THE TROF. VERY LONG WAVELENGTH DOWNSTREAM TO THE NEXT LNGWV
FEATURE WL ALLOW EJECTING SHRTWV AND ASSOC CYCLONE TO PULL THE
TROF AXIS EWD INTO THE GREAT LAKES RGN. LNGWV TROF REMAINING OVER
THE NRN CONUS IN THE WAKE OF THE STORM WL GRADUALLY BROADEN DURING
THE REMAINDER OF THE FCST PERIOD. BUT WITH WRN RIDGE HANGING
TOUGH...ARCTIC HIGH PRESSURE SHOULD CONT TO RIDGE INTO THE NRN
PLAINS.

PCPN AMNTS SHOULD END UP ABV NORMAL DUE TO INTENSE CYCLONE THAT WL
CROSS THE REGION THE NEXT FEW DAYS. TEMPS WL START OUT NEAR
NORMAL...THEN DROP BELOW NORMAL AS COLD AIR IS DRIVEN SWD BEHIND THE
DEPARTING CYCLONE...THEN WL PROBABLY MODERATE SOME BUT STILL REMAIN
SOMEWHAT BLO NORMAL FOR THE REST OF THE PERIOD.
&&

.SHORT TERM...TDA/TNGT/WED. INTENSE CYCLONE THAT WL DRIVE NEWD FM
THE SRN PLAINS AND INTO THE GREAT LAKES RGN BY WED AFTN IS LIKELY
TO BE OF A CLASS THAT IS ONLY SEEN A FEW TIMES A DECADE. SYSTEM
HAS SOME SIMILARITIES TO 04 JAN 82 /MKE/...30 NOV 85 /GRB/...AND
15 DEC 87 /MKE/ SNOWSTORMS. NEGATIVELY TILTED SHRTWV WL RESULT IN
RAPID DEEPENING OF THE CYCLONE AS IT HEADS NE OVERNIGHT. GFS THE
MOST CONSISTENT WITH THE TRACK...BUT THINK SYSTEM WL TRACK A
LITTLE FARTHER NW THAN SHOWN ON GFS...PROBABLY UP TO NEAR MKE BY
12Z WED. OVERALL...GOING FCST IN PRETTY GOOD SHAPE SO NO CHANGES
TO HEADLINES AND MAIN CHGS WERE TO ADD TEMPORAL RESOLUTION TO
GRIDS FOR TDA/TNGT. THINK AXIS OF HEAVIEST SNOWFALL WL BE A LITTLE
FARTHER W THAN WHAT WE HAD GOING. PULLED AMNTS DOWN ON THE
LAKESHORE BY LOWERING SNOW-TO-WATER RATIOS. ALSO ADDED MENTION
THAT SNOW COULD BE MIXED WITH SOME RAIN NEAR THE LAKESHORE LATE
TNGT AND EARLY WED. BUT EVEN AFTER THOSE CHGS...SNOW TOTALS IN NEW
SNOWFALL GRIDS STILL PRETTY MUCH FIT INTO RANGES SET FORTH IN WSW
OF PREV FCST...SO WL STAY THE COURSE WITH THOSE AMNTS IN WSW
PRODUCT FOR NOW.

LIGHT SNOWS STREAKING OUT AHEAD OF THE STORM WERE ADVANCING ACRS IA
EARLY THIS MORNING. THOSE SHOULD OVERSPREAD THE AREA DURING THE
DAY...PERHAPS A LITTLE FASTER THAN EARLIER EXPECTED. ALSO BUMPED
TIMING OF INITIAL CHC POPS UP ALONG THE LAKESHORE AS RADAR MOSAIC
INDICATED MESOSCALE LAKE BAND ON THE ERN SHORE OF THE LAKE ACRS FROM
KEWAUNEE. ONCE WINDS FLIP ARND TO THE E...SOME FLURRIES OR SNOW
SHOWERS COULD BACK UP INTO THE WRN SHORE OF THE LAKE.

WELL DEFINED LINKED JET STRUCTURE WL BE IN PLACE TNGT. WAVELENGTH OF
EJECTING SHRTWV WL SHORTEN WITH TIME AS STG WAA CAUSES BUILDING
DOWNSTREAM RIDGE TO TRY AND WRAP BACK ARND THE SYSTEM. THE RESULT
WL BE INTENSE UPPER DIVERGENCE AFTER 06Z TNGT...AND THAT SHOULD
RESULT IN HEAVY SNOW SPREADING NWD ACRS THE AREA. WINDS WILL ALSO
BE ON THE INCREASE AS DEEPENING SFC LOW HEADS TOWARD FAR SE WI.
VERY CONCERNED THERE WL BE A PERIOD OF BLIZZARD CONDITIONS OVER
E-C WI LATE TNGT AND EARLY WED AS WINDS SWING AROUND THROUGH 040
DIRECTION AND COME RIGHT DOWN THE UNFROZEN BAY. CONSIDERED UPGRADE
TO BLIZZARD WARNING...BUT THAT WL ONLY BE PART OF THE EVENT...AND
WINDS WL PROBABLY DIMINISH RIGHT AFTER THAT AS SFC LOW STARTS TO
GET IN SO CLOSE THAT GRADIENT RELAXES. WL LEAVE IT FOR DAY SHIFT
TO MAKE FINAL DECISION ON POSSIBLE UPGRADE. IT/S ALSO NOT OUT OF
THE QUESTION THERE WL BE SOME THUNDER AT THE LEADING EDGE OF THE
DRY SLOT PUNCHING NWD TOWARD E-C WI.

WL BE COMING OUT WITH VERY STRONGLY WORDED WSW/SPS PRODUCT LATER
THIS MORNING TO MAKE SURE WE GET THE WORD OUT THAT THIS IS GOING TO
BE A VERY HIGH END EVENT.

.LONG TERM...WEDNESDAY NIGHT THRU NEXT MONDAY. AFTER THE
EXCITEMENT OF THE STRONG STORM TUESDAY NIGHT AND WEDNESDAY...
THE WEATHER WILL GET QUITE A BIT QUIETER. 

DRY AND COLD NORTHWEST FLOW WILL PRETTY MUCH PREVAIL THURSDAY AND
FRIDAY. WE MIGHT GET CLOSE TO WIND CHILL ADVISORY CRITERIA BUT
WILL NOT MENTION IN FORECAST AS WE WANT PEOPLE TO CONCENTRATE ON
THE UPCOMING WIND AND SNOW. WE MIGHT HAVE TO INCLUDE MENTION OF
WIND CHILLS ONCE THE SNOW ENDS AND THE WINTER STORMS WARNINGS HAVE
ENDED.

WINDS ARE GENERALLY TOO WESTERLY FOR SIGNIFICANT LAKE EFFECT SNOW 
IN VILAS COUNTY DESPITE THE MORE THAN ADEQUATE INSTABILITY. UPPER
TROUGH FORECAST TO SWING THROUGH SATURDAY OR SATURDAY NIGHT AND
BRING A REINFORCING PUSH OF COLD AIR. NOT MUCH MOISTURE AVAILABLE
FOR FOR PRECIPITATION SO WILL LEAVE FORECAST DRY.
&&

.AVIATION...VFR CONDITIONS ACRS THE AREA NOW...AND WL PROBABLY LAST
MOST OF THE MORNING. THEN THINGS WL DETERIORATE THIS AFTN...ALL
THE WAY DOWN TO THE VLIFR TNGT.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...

WINTER STORM WARNING FROM NOON TODAY TO MIDNIGHT CST WEDNESDAY 
NIGHT FOR WIZ030-031-035>040-045-048>050-

WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST 
WEDNESDAY NIGHT FOR WIZ005-010>013-018>022-073-074-

&&

$$
SKOWRONSKI/RDM