Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 310331
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1031 PM CDT THU OCT 30 2014

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.UPDATE...
ISSUED AT 926 PM CDT THU OCT 30 2014

FORECAST APPEARS TO BE ON TRACK...WITH LITTLE CHANGE IN THE
WINTER WEATHER ADVISORY FOR VILAS...AND JUST SOME MINOR TIMING
ADJUSTMENTS TO THE WIND ADVISORY.

STRONG UPPER TROF MOVG THROUGH THE MN ARROWHEAD RIGHT NOW...
WITH SNOW SHOWERS INCREASING OVER NC WI. STARTING TO GET A FEW
REPORTS OF MINOR ACCUMS (LESS THAN AN INCH) IN NW VILAS COUNTY.
HEAVIEST SNOW SHOWERS WILL LIKELY OCCUR OVER THE NEXT 3-5
HOURS...AS SIGNIFICANT LAKE-ENHANCEMENT OCCURS. PARTS OF FAR NE
WI MAY SEE ACCUMS OF 1-2 INCHES...WITH A DUSTING TO A HALF INCH
IN PARTS OF EC WI.

CHANGED THE START TIME OF THE WIND ADVISORY FOR DOOR COUNTY
TO 3 AM...WHICH MATCHED THE TIMING OF OUR GALE WARNING AND
LINED UP NICELY WITH 925/850 MB WIND TRENDS ON THE RAP/NAM12.
MOVED UP THE TIMING FOR THE REST OF THE WIND ADVISORY AREA
TO 5 AM...AS IT APPEARS THAT WINDS WILL BE RAMPING UP BEFORE
12Z. WILL PROBABLY GET REAL CLOSE TO HIGH WIND WARNING
CRITERIA OVER NORTHERN DOOR COUNTY...AND STORM WARNING CRITERIA
FOR MARINE AREAS AROUND DEATHS DOOR...BUT WILL STICK WITH
CURRENT HEADLINES.
&&

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 401 PM CDT THU OCT 30 2014

THERE ARE PLENTY OF ISSUES DURING THIS PART OF THE FORECAST.
THINGS WERE RELATIVELY QUIET DURING THE DAY AS AN UPPER LEVEL
SHORT WAVE FROM THE NORTHERN PLAINS WAS MAKING ITS WAY ACROSS THE
STATE...WITH JUST SCATTERED LIGHT SHOWERS OR SPRINKLES.

AN INTENSE UPPER LEVEL TROUGH IN WESTERN ONTARIO IS EXPECTED TO
PUSH SOUTH ACROSS WISCONSIN TONIGHT AS A RIDGE AMPLIFIES OVER THE
WESTERN CONUS AND MOVES TO THE PLAINS. PRECIPITATION SHOULD
BECOME MORE WIDESPREAD AS THE TROUGH MOVES THROUGH THE STATE...AND
CHANGE TO SNOW AS COLDER AIR ENTERS THE REGION ON STRONG NORTHERLY
WINDS. THE COLD AIR PASSING OVER THE WARMER WATERS OF LAKE SUPERIOR
WILL KEEP SNOW SHOWERS GOING ACROSS THE LAKE SUPERIOR SNOWBELT
REGION OVERNIGHT INTO FRIDAY MORNING WHEN INVERSION HEIGHTS START
TO LOWER AND LAKE SURFACE TO 850MB DELTA-T VALUES DECREASE.
EXPECT 2 TO A LITTLE MORE THAN 4 INCHES OF ACCUMULATION IN VILAS
COUNTY FOR THIS EVENT.

STRONG 925MB AND 850MB WINDS WITH LITTLE DIRECTIONAL SHEAR WILL
MAKE CONDITIONS FAVORABLE FOR STRONG WINDS ACROSS EASTERN
WISCONSIN...WHERE THE 12Z ECMWF HAD 925MB WINDS OF 50 KNOTS AT 12Z
FRIDAY. HAVE GONE WITH A WIND ADVISORY FOR
BROWN...KEWAUNEE...CALUMET AND MANITOWOC COUNTIES FROM 12Z THROUGH
23Z FRIDAY. KEPT THE WIND ADVISORY FOR DOOR COUNTY...WHERE START
TIME IS 05Z DUE TO FAVORABLE FETCH OVER THE BAY...AND EXTENDED IT
FOR ANOTHER 2 HOURS TO 23Z FRIDAY TO MATCH THE REST OF THE WIND
ADVISORY AREA.

OTHERWISE...TEMPERATURES SHOULD BE MUCH COLDER WITH HIGHS ONLY IN
THE 30S ON FRIDAY. THE STRONG WINDS AND COLD TEMPERATURES WILL
COMBINE TO PRODUCE WIND CHILLS IN THE TEENS AND 20S.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 401 PM CDT THU OCT 30 2014

A HIGHLY-AMPLIFIED MEAN FLOW THIS WEEKEND WITH UPR TROFS ALONG
BOTH COASTS AND AN UPR RDG OVER CNTRL NOAM...WL GRADUALLY DE-
AMPLIFY TO A CERTAIN DEGREE NEXT WEEK AS THE WRN CONUS UPR TROF
MOVES TO THE EAST EARLY NEXT WEEK. IT IS THIS UPR TROF (AND ITS
ASSOCIATED CDFNT) THAT WL BRING THE NEXT BEST CHC OF PCPN TO NE WI
DURING THE MON AFTERNOON THRU TUE MORNING TIME FRAME. DUE TO THE
PROGRESSIVE NATURE OF THE MEAN FLOW...THE MDLS NOW SEND A CLIPPER-
TYPE SYSTEM TOWARD WI LATE WED OR WED NGT. TYPICAL AUTUMN SWINGS
IN TEMPS EXPECTED WITH READINGS GOING FROM BELOW NORMAL THIS
WEEKEND...TO ABOVE NORMAL EARLY NEXT WEEK...TO THEN SETTLING CLOSE
TO NORMAL BY THE END OF THE PERIOD.

A BROAD AREA OF HI PRES TO EXTEND FROM THE SRN PLAINS THRU THE WRN
GREAT LAKES TO ERN ONTARIO FRI NGT...BRINGING THE COLDEST TEMPS OF
THE YOUNG WINTER SEASON TO THE REGION. MAINLY CLEAR SKIES AND
LIGHT WINDS ARE EXPECTED TO SEND MIN TEMPS INTO THE MID TEENS OVER
VILAS CNTY (WHERE LINGERING SNOW COVER TO EXIST)...TO THE UPR 20S
NEAR LAKE MI. THE SFC HI TO MOVE ACROSS ERN WI TOWARD MIDDAY SAT
AND RESIDE JUST TO OUR EAST BY 00Z SUNDAY. WINDS ARE EXPECTED TO
GRADUALLY VEER THRU THE DAY WITH S-SE WINDS ACROSS CNTRL WI BY
DAY`S END AND A NE WIND FOR ERN WI. WHILE SUNNY SKIES WL PREVAIL
OVER MOST OF THE FCST AREA...THESE NE WINDS MAY BRING SOME LAKE
CLOUDS TO ERN WI. MAX TEMPS WL ONLY REACH THE UPR 30S TO LWR 40S.

A MORE PRONOUNCED RETURN FLOW DEVELOPS OVER WI SAT NGT AS THE SFC
HI HEADS TOWARD THE ERN GREAT LAKES. EVEN WITH MOSTLY CLEAR SKIES...
A 20-30KT SW BOUNDARY LAYER WIND COMBINED WITH THE ONSET OF WAA...
WL PREVENT TEMPS FROM FALLING TOO FAR. THE MOST NOTICEABLE TEMP
RISE TO BE OVER CNTRL WI WHERE READINGS WL BE 5 TO 10 DEGS MILDER
COMPARED TO FRI NGT. LOOK FOR MIN TEMPS TO MAINLY BE IN THE LWR TO
MID 20S...EXCEPT AROUND 30 DEGS NEAR LAKE MI. TOWARD THE END OF THE
WEEKEND...THE WRN CONUS UPR TROF IS PROGGED TO SHIFT EWD INTO THE
ROCKIES AND HELP DISPLACE THE CNTRL NOAM UPR RDG INTO THE E-CNTRL
CONUS. PERSISTENT S-SW WINDS WL CONT TO SEND MILDER AIR INTO WI AS
8H TEMPS WARM TO AROUND +7C BY 00Z MON. THE CONTINUATION OF WAA WL
ALSO START TO TAP GULF MOISTURE...THUS AN INCREASE IN MID/HI CLOUDS
ARE EXPECTED ON SUNDAY. MAX TEMPS SHOULD BE ABOUT 5 DEGS WARMER
THAN SAT...PLACING READINGS IN THE LWR TO MID 40S.

AFTER A BRIEF BREAK IN THE CLOUDS SUNDAY NGT AS THE STRONGEST WAA
LIFTS NEWD...LOOK FOR CLOUDS TO INCREASE ONCE AGAIN MON MORNING AS
GULF MOISTURE STREAMS NORTH AHEAD OF A CDFNT. MDLS CONT TO INDICATE
THAT THE CDFNT WL APPROACH WRN WI MONO AFTERNOON WITH THE LEADING
EDGE OF RAIN SHWRS REACHING AT LEAST THE SW THREE-QUARTERS OF THE
STATE BY 00Z TUE. PREVIOUS SHIFTS HAVE ALREADY HAD THIS RAIN CHC
COVERED AND SEE NO REASON TO CHANGE ANYTHING RIGHT NOW. MAX TEMPS
FOR MON WL RANGE FROM THE UPR 40S TO LWR 50S.

PCPN CHCS WL CONT THRU MOST OF MON NGT AS THE CDFNT SWEEPS ACROSS
THE REST OF THE STATE. THE FCST IS A BIT MORE DIFFICULT FOR TUE
DEPENDING ON WHAT HAPPENS WITH THE TRAILING AND WEAKENING UPR TROF.
ONLY THE GEM MAINTAINS PCPN ON TUE AND THAT IS MORE DUE TO A SLOWER
MOVEMENT OF THE CDFNT THAN THE UPR TROF. SINCE THE GEM IS ALONE IN
THIS SCENARIO...HAVE BASED THE FCST ON THE MAJORITY SOLUTION WHICH
SENDS A DRY SLOT ACROSS WI ON TUE WITH SOME WRAP-AROUND CLOUDS
AFFECTING NRN WI. MAX TEMPS LOOK SLIGHTLY ABOVE NORMAL WITH
READINGS IN THE LWR TO MID 40S N-CNTRL WI TO AROUND 50 DEGS E-CNTRL
WI.

ATTENTION THEN FOCUSES ON A CLIPPER SYSTEM WHICH MOVES E-SE INTO
THE UPR MS VALLEY WED AFTERNOON. THERE APPEARS TO BE ENUF MOISTURE
WITH THIS SYSTEM TO AT LEAST BRING A SMALL POP TO NE WI WITH TEMPS
WARM ENUF TO ALLOW ANY PCPN TO FALL AS ALL RAIN. WEAK SFC RIDGING
IS THEN FCST TO MOVE ACROSS THE REGION ON THU BRINGING DRY
CONDITIONS AND SEASONAL TEMPS FOR EARLY NOVEMBER.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1025 PM CDT THU OCT 30 2014

A POWERFUL UPPER LEVEL TROF WILL SHIFT ACROSS THE REGION OVERNIGHT
AS COLDER AIR SURGES INTO THE FORECAST AREA AT THE SURFACE. SNOW
SHOWERS WILL CONTINUE TO SPREAD SOUTHEAST...REACHING EAST CENTRAL
WI AT THE BEGINNING OF THE TAF PERIOD...AND EXITING BY AROUND
DAYBREAK. BRIEF IFR/LIFR VSBYS SHOULD ACCOMPANY THE HEAVIER SNOW
SHOWERS. THE BEST CHANCE OF HEAVY SNOW SHOWERS WILL BE OVER VILAS
COUNTY...WHERE SOME LAKE ENHANCEMENT OFF LAKE SUPERIOR WILL OCCUR.
THE LAKE EFFECT SNOW SHOWERS SHOULD TAPER OFF BY MIDDAY FRIDAY.

THIS SYSTEM WILL ALSO GENERATE VERY STRONG NORTH WINDS LATE
TONIGHT INTO FRIDAY...ESPECIALLY OVER EASTERN WI. WIND GUSTS TO
40 TO 50 MPH ARE EXPECTED IN THE EASTERN FOX VALLEY AND LAKESHORE
AREAS...WITH LOCALLY HIGHER GUSTS POSSIBLE OVER NORTHERN DOOR
COUNTY. THE WINDS WILL GRADUALLY SUBSIDE AND SKIES CLEAR DURING
THE LATE AFTERNOON AND EVENING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 5 AM TO 6 PM CDT FRIDAY FOR WIZ039-040-049-
050.

WIND ADVISORY FROM 3 AM TO 6 PM CDT FRIDAY FOR WIZ022.

LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CDT FRIDAY FOR WIZ005.
&&

$$

UPDATE.........KIECKBUSCH
SHORT TERM.....MG
LONG TERM......KALLAS
AVIATION.......KIECKBUSCH






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