Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | 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 45 46 47 48 49 50

000
FXUS63 KGRB 241720
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1120 AM CST MON NOV 24 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 413 AM CST MON NOV 24 2014

VERY UNUSUAL AND CHALLENGING WINTER STORM. PHASING
OF TWO UPPER JETS WILL PRODUCE DEEPENING SURFACE LOW THAT ROCKETS
OFF TO THE NORTHEAST TODAY AND TONIGHT. IT DOES LEAVES BEHIND A
SURFACE TROUGH BACK INTO OUR AREA AND MORE IMPORTANTLY THE STORM
IS SO VIGOROUS THAT IT WILL DRIVE MOISTURE ALL THE WAY FROM THE
EASTERN UNITED STATES ACROSS SOUTHERN CANADA AND THEN SOUTHWEST
INTO WISCONSIN. 850 MB MOISTURE TRANSPORT VECTORS SHOW THIS
NICELY. THIS SHOULD RESULT IN AN AREA OF SIGNIFICANT SNOW ACROSS
CENTRAL AND EAST CENTRAL WISCONSIN WITH LIGHT SNOWS ELSEWHERE.

THE NUMERICAL WEATHER PREDICTION MODELS TYPICALLY HAVE DIFFICULTY
WITH THESE PHASING SYSTEMS AND SO DO WE FORECASTERS. WAS INITIALLY
RELUCTANT TO ISSUE A WARNING FOR EAST CENTRAL WISCONSIN BECAUSE OF
THE UNCERTAINTY BUT THE SNOW WILL BE THE FIRST REAL SNOW OF THE
SEASON IN MOST OF THIS AREA AND WILL ARRIVE AROUND THE LATE
AFTERNOON AND EVENING DRIVE TIME. WINDS WILL INCREASE AND CAUSE
BLOWING AND DRIFTING SNOW THIS EVENING. LAKE EFFECT POTENTIAL NOT
AS IMPRESSIVE FOR VILAS COUNTY THOUGH WE DECIDED TO KEEP THE
ADVISORY.

THE SNOW WILL END LATE TONIGHT WITH PARTIAL CLEARING TUESDAY.
HIGHS WILL BE MUCH COLDER THAN THE PAST COUPLE OF DAYS AND BE
AROUND 10 DEGREES BELOW NORMAL.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 413 AM CST MON NOV 24 2014

THE LATEST GFS ENSEMBLE MEAN CONTINUES TO INDICATE ABOVE NORMAL
HEIGHTS MOVING INTO THE WESTERN GREAT LAKES DURING THE FIRST WEEK OF
DECEMBER...AS THE DOMINANT NORTHERN STREAM FINALLY RETREATS.  UNTIL
THIS OCCURS...THE FIRST ITEM OF CONCERN IS A POTENTIAL CLIPPER
DURING THE WEDNESDAY AND WEDNESDAY NIGHT PERIOD.  MODELS ARE
TRENDING SOUTH WITH THIS CLIPPER...BUT THERE REMAINS TIMING/TRACK
ISSUES.  THE LATEST SREF IS THE CLOSEST TO MIDDLE OF THE ROAD...AND
GIVEN THE RECENT CONSISTENCY PROBLEMS OF THE MODELS...WILL TRY TO
MINIMIZE ERROR.  THEREAFTER...MODELS ARE SEEMINGLY ALL OVER THE
PLACE AND ITS DIFFICULT TO BE CONFIDENT IN THE DETAILS OF ANY
SOLUTION.  WILL JUST SIDE WITH THE SUPERBLEND.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...A DIGGING SHORTWAVE IN THE
LEFT EXIT REGION OF A BEEFY 140KT JET STREAM WILL DIVE FROM THE
NORTHERN PLAINS TO THE CENTRAL MISSISSIPPI VALLEY TUESDAY NIGHT.
CLOUDS WILL BE ON THE INCREASE AHEAD OF THE SYSTEM...BUT PRECIP
CHANCES LOOK TOO FAR TO THE SOUTHWEST.  THOUGH MOST OF THE ENERGY
FROM THIS SYSTEM WILL PASS OVER CENTRAL OR SOUTHERN
ILLINOIS...GUIDANCE IS STILL INDICATING AN INVERTED TROUGH MOVING
ACROSS WESTERN WISCONSIN IN THE MORNING...AND ACROSS CENTRAL
WISCONSIN DURING THE AFTERNOON.  WILL LOWER PRECIP CHANCES DURING
THE MORNING...AND REDUCE THEM ACROSS THE EAST DURING THE AFTERNOON.
THE INVERTED TROUGH WILL CONTINUE TO MOVE EAST ACROSS EASTERN
WISCONSIN WEDNESDAY NIGHT WHICH WILL KEEP LIGHT SNOW IN THE
FORECAST.  THINKING LESS POTENTIAL FOR ACCUMULATIONS THAN LAST
NIGHT...AND WILL SHOW UNDER AN INCH IN THE FORECAST.  BUT THE AREA
COULD ALSO MISS ANY SNOW ENTIRELY.  THE LONE EXCEPTION WILL BE VILAS
COUNTY WHERE CONDITIONS WILL BE SUPPORTIVE FOR LAKE EFFECT SNOWS.
SOME UNCERTAINTY ABOUT WIND DIRECTION BUT AT LEAST THE NORTHWEST
PART OF THE COUNTY COULD GET AN INCH OR TWO.

REST OF THE FORECAST...THINK MOST OF THE LIGHT SNOW WILL HAVE EXITED
THE REGION EXCEPT FOR THE SNOW BELT...BUT THE SNOW THERE TOO SHOULD
BE WINDING DOWN.  THE REST OF THURSDAY AND THURSDAY NIGHT SHOULD BE
DRY THANKS TO HIGH PRESSURE.  THEN SHOULD SEE A CHANCE OF WARM
ADVECTION SNOWS ON FRIDAY AND FRIDAY NIGHT ACROSS THE NORTH.  ONCE
THE TRAILING COLD FRONT MOVES THROUGH SATURDAY OR SATURDAY
NIGHT...ARCTIC HIGH PRESSURE WILL RETURN FOR SUNDAY INTO MONDAY.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1120 AM CST MON NOV 24 2014

SNOW WILL CONTINUE TO OVERSPREAD THE REST OF NE WI THIS AFTERNOON
AS COLDER AIR GRADUALLY FILTERS EWD ACROSS THE STATE. THIS SNOW
WILL THEN PERSIST INTO THE EVENING AS A NEGATIVELY-TILTED
SHORTWAVE TROF LIFTS NE INTO THE GREAT LAKES. HEAVIEST SNOW STILL
EXPECTED TO FALL SOUTH OF A LINE FROM WISCONSIN RAPIDS TO
MARINETTE. CIGS/VSBYS TO BE REDUCED TO IFR CONDITIONS WITH LOCALLY
LIFR CONDITIONS IN HEAVIER BURSTS OF SNOW. IMPROVEMENT IS NOT FCST
TO TAKE PLACE UNTIL AFTER MIDNGT WHEN MVFR CONDITIONS RETURN ALTHO
LIGHT SNOW LIKELY TO STILL BE FALLING. A RETURN TO VFR CONDITIONS
TO OCCUR FROM WEST TO EAST ON TUE AS A RDG OF HI PRES APPROACHES
WI.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR WIZ036-037-045-
048.

WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 AM CST
TUESDAY FOR WIZ020-022-031-038>040-049-050-074.

WINTER WEATHER ADVISORY UNTIL 3 AM CST TUESDAY FOR WIZ030-035.

WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
TUESDAY FOR WIZ010-018-019-021-073.

LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ005.
&&

$$

SHORT TERM.....RDM
LONG TERM......MPC
AVIATION.......AK





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