Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

000
FXUS63 KGRB 301012
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
512 AM CDT THU OCT 30 2014

UPDATED TO ADD SHORT TERM PORTION FOR MORNING FORECAST ISSUANCE

.SYNOPSIS...
ISSUED AT 506 AM CDT THU OCT 30 2014

A BRIEF TASTE OF WINTRY WEATHER LATE TONIGHT THROUGH SATURDAY...THEN
A RETURN TO MUCH QUIETER LATE-AUTUMN CONDITIONS.

STG AMPLIFICATION OF THE LARGE SCALE PATTERN UNDERWAY. AMPLITUDE
SHOULD PEAK EARLY IN THE WEEKEND...WITH DEEP TROFS NR THE WEST
COAST AND OVER THE ERN CONUS...SANDWICHING AND A SHARP FULL-
LATITUDE RIDGE OVER THE PLAINS. THE PATTERN WILL REMAIN
PROGRESSIVE. THAT WL KEEP THE HIGH AMPLITUDE SHORT-LIVED...WITH
THE WRN TROF EXPECTED TO REACH THE AREA EARLY NEXT WEEK.

A SIGNIFICANT SHOT OF COLD AIR WILL AFFECT THE AREA FOR THE END
OF THE WORK WEEK AND START OF THE WEEKEND...THEN TEMPS WILL
REBOUND BACK CLOSE TO OR MAYBE EVEN A LITTLE ABOVE SEASONAL
NORMALS NEXT WEEK. THE MAIN OPPORTUNITIES FOR PCPN WL BE WITH STG
SHRTWV DIGGING ACRS THE REGION AND INTO THE AMPLIFYING ERN NOAM
LNGWV TROF EARLY IN THE PERIOD...AND AGAIN NEXT WEEK WHEN THE
LARGE-SCALE WRN TROF ARRIVES. GIVEN THE LIMITED MOISTURE...PCPN
AMNTS ARE LIKELY TO END UP AOB NORMAL FOR THE PERIOD. THE
EXCEPTION COULD BE THE LAKE-SUPERIOR SNOWBELT.
&&

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 506 AM CDT THU OCT 30 2014

LOTS OF FORECAST DETAILS TO WORK OUT THIS MORNING. INTENSE NRN
STREAM SHRTWV WL DIG SSEWD INTO THE ERN CONUS UPR TROF. RAPIDLY
BUILDING ANTICYCLONE SUPPORTED BY THE SHRTWV RIDGING BEHIND THE
UPR SYSTEM WL DRIVE COLD CANADIAN AIR RAPIDLY SWD INTO THE AREA.
GIVEN THE SOURCE REGION OF THE AIR MASS IN NRN CANADA AND IT/S
RAPID TRANSPORT SOUTH...IT WILL STILL BE VERY CHILLY WHEN IT
ARRIVES. THE COLDER TEMPS COMBINED WITH WINDY CONDITIONS WL
PROBABLY MAKE IT/S ARRIVAL EVEN MORE NOTICABLE.

WILL JUST HIT THE HIGHLIGHTS...

SHRA WITH THE UPR SYSTEM WL CHG TO SNOW AS THE COLDER AIR ARRIVES
IN THE N THIS EVENING. NLY FLOW OFF LAKE SUPERIOR WL RESULT IN
SOME LAKE-EFFECT. THERE IS LIKELY TO BE A PERIOD OF TIME DURING
THE EVENING WHEN THE SYNOPTIC FORCING OVERLAPS THE LAKE-
EFFECT...AND THE MOST VIGOROUOS SHSN ARE EXPECTED THEN. SHSN WL
CONT THE REST OF THE NGT AND INTO FRIDAY MORNING...BUT WL BE
FIGHTING LARGE-SCALE SUBSIDENCE BY THAT POINT. GIVEN IT/S THE
FIRST EVENT OF THE SEASON AND THERE WL BE SOME WIND...CONDITIONS
SEEMED WORTHY OF AN ADVISORY...SO ONE WAS POSTED.

NLY FLOW OVER THE BAY AND LAKE WILL PROMOTE DEEP MIXING...INTO
50 KT WINDS ARND 850 MB. POSTED A WIND ADVISORY FOR THE DOOR.
CURRENT FCST CONDITIONS FOR THE FOX VALLEY EWD TO THE LAKESHORE
WOULD ALSO SUPPORT A WIND ADVISORY. BUT CONFIDENCE IN HITTING
ADVISORY CRITERIA IS A LITTLE LOWER IN THIS AREA /00Z ECMWF
BACKED OFF A BIT ON WINDS/ SO STUCK WITH MENTION IN THE HWO AND
AN SPS. THIS WL ALLOW THE DAY SHIFT THE MAXIMUM FLEXIBILITY TO
ADJUST THE FCST AFTER REVIEWING THE LATEST DATA.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 324 AM CDT THU OCT 30 2014

TEMPERATURES SHOULD GRADUALLY REBOUND TO NEAR NORMAL BY EARLY NEXT
WEEK AS 500MB RIDGE BUILDS ACROSS THE EASTERN UNITED STATES. MAIN
ISSUES FOR THIS PACKAGE WILL BE FRIDAY NIGHT WITH CLOUD COVER AND
POTENTIAL PRECIPITATION CHANCES NEAR THE BAY AND LAKE...AND THEN
AGAIN EARLY NEXT WEEK WITH TIMING OF THE ARRIVAL AND DEPARTURE OF
A SLOW MOVING COLD FRONT.

FOR FRIDAY NIGHT...HIGH PRESSURE WAS EXPECTED TO BUILD INTO CENTRAL
AND WESTERN WISCONSIN...BRINGING CLEAR SKIES AND THE COLDEST
TEMPERATURES OF THE SEASON. THIS STILL HOLDS TRUE ACROSS OUR WEST...
BUT LATEST GFS/WRF MODELS INDICATED 850/925MB WINDS TURNING NORTHEAST
LATE FRIDAY NIGHT INTO SATURDAY MORNING. IF THIS SCENARIO DOES COME
TRUE...WILL NEED TO ADD MORE CLOUDS AND THE POSSIBILITY OF RAIN/SNOW
SHOWERS DUE TO THE FACT THE BAY AND LAKE ARE STILL RELATIVELY WARM.
COULD BE LONG FETCH DOWN THE BAY FOR THE POSSIBILITY OF BAY EFFECT
RAIN/SNOW SHOWERS. THE WINDS AND CLOUDS OFF THE BAY AND LAKE COULD
PLAY HAVOC ON LOW TEMPERATURES FRIDAY NIGHT. SINCE THIS SCENARIO
BY THE WRF/GFS IS A CHANGE FROM PREVIOUS FORECASTS AND THE ECMWF
IS MORE NORTHERLY WITH THE LOW LEVEL WINDS...WILL ADD MORE CLOUDS
TO THE FORECAST AND BUMP UP MINIMUM TEMPERATURES AND HOLD OFF ON
ADDING PRECIPITATION CHANCES. IF MODELS CONTINUE WITH LOW LEVEL
WINDS TURNING TO THE NORTHEAST...DAY SHIFT CAN ADD PRECIPITATION
TO THE FRIDAY NIGHT/SATURDAY MORNING PERIODS.

THE NEXT CHANCE FOR RAIN (SOME SNOW NORTH LATE AT NIGHT/EARLY
MORNING) IS FROM MONDAY THROUGH TUESDAY MORNING. THE WEAK COLD FRONT
WILL APPROACH WISCONSIN ON MONDAY...THEN ACROSS THE REGION MONDAY
NIGHT AND TUESDAY. ANOTHER CLIPPER SYSTEM WILL APPROACH THE AREA FROM
THE NORTHWEST ON WEDNESDAY. HAVE LEFT WEDNESDAY DRY FOR THE MOMENT...
BUT IT IS POSSIBLE THAT PRECIPITATION CHANCES WILL NEED TO BE ADDED
TO THE FORECAST WITH THIS SYSTEM.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 506 AM CDT THU OCT 30 2014

MVFR CIGS STILL HANGING TOUGH ACRS THE N. THOSE WL EVENTUALLY
SHIFT OFF TO THE NE THIS MORNING. MIDDLE AND HIGH CLDS WL HAVE
OVERSPREAD THE AREA BY THEN...BUT THOSE ARE MUCH LESS OF A CONCERN
FOR AVIATION INTERESTS. THE MOST SIG AVIATION CONCERNS THE NEXT 24
HRS WL BE SNOW ACRS THE N LATE TNGT INTO FRIDAY MORNING...AND STG
WINDS ACRS THE AREA LATE TNGT AND FRIDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM CDT FRIDAY FOR
WIZ022.

LAKE EFFECT SNOW ADVISORY FROM 9 PM THIS EVENING TO 11 AM CDT
FRIDAY FOR WIZ005.
&&

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI









USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.