Lake-Effect Snow in Wisconsin, February 13, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
330 AM CST TUE FEB 13 2007

SHORT TERM...TODAY THROUGH WEDNESDAY.

LAKE EFFECT SNOW NEAR LAKE MICHIGAN IS THE MAIN CHALLENGE TODAY. WRF
MODEL RUN BY MQT IS QUITE SIMILAR TO THE NCEP MODELS. WINDS ARE LINED UP
FAIRLY NICELY BUT AIR IS VERY DRY BETWEEN 850MB AND 700MB
AND THERE IS AN INVERSION AT 4000 TO 5000 FEET. THE INVERSION WILL LIFT
SOMEWHAT LATER TODAY AS SYNOPTIC SYSTEM TO OUR SOUTH PRODUCES SOME
VERTICAL MOTION UP HERE. THERE MIGHT ALSO BE SOME SEEDING FROM CLOUDS
ASSOCIATED WITH THAT SYSTEM. THINK THAT THERE MIGHT BE 3 OF SNOW NEAR
THE LAKE MICHIGAN SHORE IN KEWAUNEE AND MANITOWOC COUNTIES BY TONIGHT
WITH LESS FURTHER INLAND. IF THE BAY WERE NOT FROZEN OVER THERE MIGHT BE
SOME LAKE EFFECT IN FOX VALLEY TOO. WINDS BACK AROUND TO MORE
NORTHWESTLY DIRECTION LATE TONIGHT AND WEDNESDAY. THIS WILL BRING COLDER
AIR INTO THE REGION AND KEEP LAKE EFFECT SNOW EAST OF THE LAKESHORE
COUNTIES.

LONG TERM...WED NGT THRU NXT MON. MAIN FCST CHALLENGES INCLUDE:
POTENTIAL FOR LK EFFECT SNOWS FOR VILAS CNTY MID-WEEK...SNOW POTENTIAL
FROM FAST-MOVG SYSTEM LATE THIS WEEK...AND THEN AMT OF WARM-UP LATE IN
THE WEEKEND/EARLY NXT WEEK.

AS THE STG NOREASTER ROARS UP THE NEW ENGLAND COAST...A SHRTWV TROF IS
FCST TO MOV THRU THE WRN GREAT LKS WED NGT. MDLS CONT TO ADVERTISE THAT
THE BEST DYNAMICS TO PASS TO OUR EAST WITH LITTLE LIFT EVIDENT OVR WI.
NW TRAJS REMAIN FAVORABLE FOR SOME LK EFFECT SNOW SHWRS FOR VILAS CNTY
WITH DELTA-T VALUES IN THE LWR 20S AND LK-INDUCED CAPES IN THE 400 TO
500 J/KG RANGE. ONLY THE ICED-OVER WRN SECTION OF LK SUPERIOR WL KEEP
POPS FROM BEING HIGHER. OTHERWISE...PLENTY OF CLDS AND CAA FOR THE REST
OF NE WI WED NGT. DESPITE THE CLDS...A VERY COLD NGT ON TAP ESP AWAY
FROM LK MI WHERE WE MAY BE APPROACHING WND CHILL ADVY CONDITIONS LATE
WED NGT INTO THU MORNING.

THE SHRWTV TROF PUSHES SOUTH AND EAST ON THU WHICH WL ALLOW FOR A SFC
RDG OF HI PRES TO START BUILDING EWD FROM THE PLAINS. THERE COULD BE
SOME LINGERING FLURRIES ACROSS VILAS CNTY THU MORNING BEFORE WNDS BEGIN
TO BACK AND TRAJS BECOME UNFAVORABLE FOR LK EFFECT. ANTICIPATE CLDS TO
BE ON THE DECREASE THROUGHOUT THE DAY...BUT THIS TO HAVE LITTLE AFFECT
ON TEMPS AS READINGS STRUGGLE TO REACH THE LWR TO MID TEENS.

SFC RDG BUILDS INTO THE WRN GREAT LKS THU NGT...THUS QUIET WEATHER
CONDITIONS EXPECTED. ANOTHER RELATIVELY COLD NGT WITH MIN TEMPS
GENERALLY IN THE 5 BELOW TO 5 ABOVE ZERO RANGE. ATTN TURNS TO OUR NW
WHERE A NEW FAST-MOVG NRN STREAM SYSTEM TO BE DROPPING INTO THE UPR
MIDWEST ON FRI. THIS SYSTEM WL BE RIDING ON THE NRN EDGE OF A 150 KT UPR
JET STRETCHED FROM BRITISH COLUMBIA TO THE CNTRL PLAINS. CLDS SHOULD
QUICKLY OVERSPREAD NE WI FRI...BUT THERE IS TIMING ISSUES AS TO THE SPD
WITH WHICH THIS SYSTEM APPROACHES. THE GFS MAINTAINS THE FASTEST SOLN...
HOWEVER THE ECMWF AND UKMET ARE RIGHT ON ITS HEELS. IT WL ALSO TAKE A
LITTLE TIME TO SATURATE THE ATM. PREFER TO ADD A SML POP TO WRN SECTIONS
OF THE FCST AREA FRI AFTERNOON WHERE SATURATION TO OCCUR FIRST.

THIS SYSTEM DIVES SE TOWARD NRN IL FRI NGT AND THEN TURNS MORE EWD
TOWARD THE ERN GREAT LKS ON SAT. THIS TRACK WOULD PLACE HEAVIER SNOWS TO
OUR SOUTH...HOWEVER A BROAD AREA OF Q-VEC CONVERGENCE WOULD BRING A CHC
OF SNOW TO ALL OF NE WI FRI NGT INTO SAT MORNING BEFORE DIMINISHING TO
FLURRIES. THE SNOW MAY LINGER OVR NRN WI AS WNDS TURN NW ON SAT AND
BRIEF SHOT OF CAA ALLOWS LK EFFECT POTENTIAL TO EXIST. FAVORABLE TRAJS
AND CONTINUED CAA MAY CARRY LK EFFECT SNOW SHWRS OR FLURRIES OVR NRN WI
INTO SAT NGT...OTHERWISE ANOTHER RDG OF HI PRES TO PUSH TOWARD THE WRN
GREAT LKS RGN FOR SUNDAY. THE 00Z GFS IS NOW A LITTLE SLOWER WITH THE
START OF ANY WAA ON SUNDAY...THUS HAVE LOWERED MAX TEMPS A COUPLE OF
DEGS.

BY THE END OF NXT WEEKEND...MEAN FLOW BECOME SPLIT WITH ACTIVE NRN
STREAM REMAINING IN SRN CANADA AND WEAKER SRN STREAM HUGGING THE GULF
COAST. PACIFIC AIRMASS TO TAKE OVR THE LWR 48 WHICH WL ALLOW FOR A
GRADUAL WARM-UP IN TEMPS HEADED INTO NXT WEEK. AMT OF WARM-UP MAY BE
TEMPERED BY AMT OF SNOW CVR CURRENTLY LOCATED ACROSS THE MIDWEST. FOR
NOW...APRS THAT TEMPS WL BE AT LEAST CLOSER TO NORMAL BY NXT MON WHICH
HAS NOT HAPPENED OVR NE WI SINCE LATE JAN.

AVIATION...VFR WEATHER EXPECTED AT RHI AND THE WAUSAU AREA AIRPORTS WITH
 MIDDLE AND HIGH CLOUDS AND AN ISOLATED SNOW FLURRY. GRB WILL STRADDLING
THE MVFR/VFR LINE WITH SCATTERED SNOW SHOWERS. NORTHEAST WINDS WILL ALSO
GUST TO 20 KNOTS THROUGH THIS EVENING.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

RDM
WEATHER.GOV/GREENBAY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREEN BAY WI
600 AM CST TUE FEB 13 2007

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-141200-
VILAS-ONEIDA-FOREST-FLORENCE-NORTHERN MARINETTE-SOUTHERN MARINETTE-
LINCOLN-LANGLADE-MENOMINEE-NORTHERN OCONTO-SOUTHERN OCONTO-DOOR-
MARATHON-SHAWANO-WOOD-PORTAGE-WAUPACA-OUTAGAMIE-BROWN-KEWAUNEE-WAUSHARA-
WINNEBAGO-CALUMET-MANITOWOC-
600 AM CST TUE FEB 13 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

LAKE EFFECT SNOW SHOWERS ARE EXPECTED NEAR LAKE MICHIGAN IN KEWAUNEE AND
MANITOWOC COUNTIES THROUGH THIS EVENING. THE COMBINATION OF A FEW INCHES
OF SNOW AND GUSTY NORTHEAST WINDS WILL CREATE SLIPPERY TRAVEL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SNOWFALL REPORTS FROM THE LAKESHORE COUNTIES WOULD BE APPRECIATED.

LMZ521-522-541>543-564-141200-
THE BAY OF GREEN BAY SOUTH OF A LINE FROM CEDAR RIVER MI TO ROCK ISLAND
PASSAGE-LAKE MICHIGAN FROM WASHINGTON ISLAND TO SHEBOYGAN-THE ADJOINING
WISCONSIN WATERS OF LAKE MICHIGAN OUT TO MID-LAKE-
600 AM CST TUE FEB 13 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WATERS OF CENTRAL AND
SOUTHERN GREEN BAY...AND LAKE MICHIGAN FROM ROCK ISLAND PASSAGE
TO SHEBOYGAN.

.DAY ONE...TODAY AND TONIGHT

A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH LATE TONIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

CONDITIONS HAZARDOUS TO SMALL CRAFT WILL CONTINUE PERIODICALLY THROUGH
THE END OF THE WEEK.

RDM
WEATHER.GOV/GREENBAY