Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 290837
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
337 AM CDT WED OCT 29 2014

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SYNOPSIS...
ISSUED AT 332 AM CDT WED OCT 29 2014

LOTS OF CLOUDS...WINDY AT TIMES...AND A BRIEF SHOT OF VERY CHILLY
AIR. IN OTHER WORDS...FAIRLY TYPICAL LATE-AUTUMN WEATHER.

LARGE SCALE PATTERN WL UNDERGO A SIGNIFICANT AMPLIFICATION THE
NEXT FEW DAYS AS A FULL LATITUDE RIDGE BUILDS OVER THE
PLAINS/PRAIRIE PROVINCES...AND A DEEP TROF DEVELOPS OVER ERN NOAM.
DESPITE THE AMPLIFICATION...THE LNGWV PATTERN IS EXPECTED TO
REMAIN PROGRESSIVE DURING THE PERIOD. THE PLAINS RIDGE SHOULD
REACH THE AREA BY LATE IN THE WEEKEND...FOLLOWED BY THE UPSTREAM
TROF EARLY NEXT WEEK.

TEMPS WL BE CLOSE TO SEASONAL NORMALS TDA AND TOMORROW...DROP TO
VERY CHILLY LEVELS FOR A COUPLE DAYS...THEN REBOUND BACK CLOSE TO
SEASONAL NORMALS FOR THE LATTER PART OF THE FCST PERIOD. THE MAIN
OPPORTUNITIES FOR PCPN WL BE WITH STG SHRTWV DIGGING INTO THE
AMPLIFYING ERN NOAM LNGWV TROF LATE IN THE WEEK...AND AGAIN LATE
IN THE PERIOD AS LARGE SCALE TROF PROGRESSES INTO THE AREA. SINCE
MOISTURE WL BE LIMITED WITH EACH OF THESE SYSTEMS...PCPN AMNTS
ARE LIKELY TO END UP BLO NORMAL FOR THE PERIOD. THE EXCEPTION
COULD BE THE LAKE-SUPERIOR SNOWBELT.
&&

.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 332 AM CDT WED OCT 29 2014

EARLY MORNING STLT IMAGERY INDICATED EXPANSIVE CLD DECK OUT TO
THE WEST. THE WRN EDGE OF THE CLDS EXTENDED PAST THE UPSTREAM SFC
RIDGE AXIS AS LOW-LEVEL MOISTURE WAS TRAPPED BENEATH INVERSION. SO
ALTHOUGH SOME HOLES IN THE CLD DECK MAY OPEN UP TDA...ESP IN THE
FAVORED DOWNSLOPE RGN OF ERN WI...IT LOOKS LIKE CLDS WL LINGER TDA
AND INTO TNGT. THAT WL MAKE TEMP FCST TNGT A CHALLENGE...BECAUSE
WINDS WL BE DYING OFF AS THE SFC RIDGE AXIS SHIFTS INTO THE AREA.
RAISED THEM A BIT FM PREV FCST...BUT THIS IS CERTAINLY A LOW-
CONFIDENCE ASPECT OF THE FCST.

FIGURING OUT THE PCPN CHANCE THU IS ALSO A CHALLENGE. THE LATEST
RUNS OF THE MAJORITY OF THE GUIDANCE PRODUCTS...WITH THE NOTABLE
EXCEPTION OF THE ECMWF...HAVE TRENDED FASTER AND MORE AGGRESSIVE
IN BRINGING PCPN TO THE AREA DURING THE DAY THU. THIS SEEMS TO BE
RELATED TO SHRTWV THAT DEVELOPS OUT AHEAD OF SPEED MAX NOW
APPROACHING THE WA COAST. THE SHRTWV TRACKS E AND THEN TURNS SE
INTO THE DEEPENING ERN NOAM LNGWV TROF...AHEAD OF INTENSE NRN
STREAM SHRTWV DIGGING SSEWD FM NRN CANADA. THE APPEARANCE OF THE
DEVELOPING PAC NW SHRTWV ON STLT IMAGERY HAS IMPROVED DURING THE
PAST SEVERAL HRS...LENDING SUPPORT FOR THE TRENDS ON THE
GUIDANCE. BUT MOISTURE WL STILL BE LIMITED...SO OPTED FOR A
MEASURED APPROACH TO ADDING/INCRG POPS. SPREAD POPS ACRS THE AREA
DURING THE DAY...BUT KEPT E-C WI DRY DURING THE MORNING. ALSO
OPTED TO LIMIT POPS TO THE CHC /NW/ AND SLGT CHC /SE/ CATEGORIES.
THE EARLY DAY ARRIVAL OF POPS IN THE N WARRANTED ADDING SOME
MIXED PCPN TO THE FCST FOR THE MORNING.

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 332 AM CDT WED OCT 29 2014

POTENT SYSTEM WILL MOVE ACROSS THE REGION THURSDAY NIGHT INTO
FRIDAY MORNING. THIS SYSTEM WILL BRING AN ACCUMULATING SNOWFALL
TO NORTHERN WISCONSIN...FIRST SNOW FLAKES OF THE SEASON ACROSS
CENTRAL AND EAST-CENTRAL WISCONSIN...STRONG WINDS...AND COLD
WEATHER FOR TRICK OR TREATERS FRIDAY EVENING.

A SHARP 500MB TROUGH AND UPPER LEVEL DISTURBANCE WILL SWING ACROSS
THE AREA LATER THURSDAY NIGHT INTO FRIDAY MORNING. 850MB/925MB
TEMPERATURES COLLAPSE AS SYSTEM MOVES ACROSS THE REGION...THUS
ANY LIQUID PRECIPITATION SHOULD CHANGE OVER TO ALL SNOW FROM
NORTHWEST TO SOUTHEAST. BOUNDARY LAYER TEMPERATURES MAY STILL
SUPPORT A LITTLE RAIN ACROSS EAST-CENTRAL WISCONSIN LATE THURSDAY
NIGHT INTO FRIDAY MORNING. ACROSS THE NORTH...A COUPLE INCHES OF
SNOW IS LIKELY ACROSS MUCH OF THIS REGION. I HAD TO BRING OUT THE
LAKE EFFECT SNOW CHART FOR THE FIRST TIME THIS SEASON. THE FLOW
CHART WOULD SUGGEST 3 TO 5 INCHES OF SNOW ACROSS THE SNOWBELT
REGION OF VILAS COUNTY BETWEEN THURSDAY NIGHT AND FRIDAY
AFTERNOON. THE OTHER BIG STORY WILL BE THE WINDS WITH THIS SYSTEM.
SURFACE LOW EXPECTED TO DEEPEN AS IT MOVES ACROSS LAKE HURON
FRIDAY MORNING. 850MB/925MB WINDS...COMBINED WITH COLD ADVECTION
AND STEEP 1000/850MB LAPSE RATES WOULD SUPPORT WIND GUSTS OF 30 TO
40 KNOTS AS THE COLD FRONT/UPPER LEVEL DISTURBANCE MOVES AWAY FROM
THE REGION. BUFKIT SOUNDINGS ALSO SUPPORTED THESE VALUES. SOME
CONCERN ABOUT DOOR COUNTY WHERE THE WARMER WATERS OF THE BAY OF
GREEN BAY WOULD SUPPORT DEEPER MIXING. A WIND ADVISORY APPEARS TO
BE LIKELY WITH OUTSIDE POTENTIAL FOR WIND GUSTS TO APPROACH OR
REACH HIGH WIND WARNING CRITERIA (50 KNOTS) AT DEATHS DOOR.

THE COMBINATION OF THE STRONG WINDS AND SNOW SHOWERS WILL SURE
MAKE IT FEEL LIKE WINTER AND MAY SHOCK SOME PEOPLE. THE STRONG
WINDS WILL CONTINUE THROUGH THE DAY...ALTHOUGH A GRADUAL DECREASE
IN WIND SPEEDS CAN BE EXPECTED LATER FRIDAY AFTERNOON. DRIER AIR
WORKING INTO THE REGION SHOULD ALLOW FOR DECREASING CLOUDINESS AS
THE AFTERNOON PROGRESSES. FOR TRICK OR TREATERS...TEMPERATURES SHOULD
BE NEAR 30 ACROSS THE NORTH...AND IN THE 30S ELSEWHERE WITH A
NORTHERLY BREEZE. WIND CHILL READINGS WILL BE IN THE 20S FOR THE
MOST PART.

HIGH PRESSURE BUILDS INTO THE REGION FRIDAY NIGHT. WINDS SHOULD GO
LIGHT AND VARIABLE ACROSS THE NORTH WHERE A FRESH SNOW COVER IS
EXPECTED. HAVE LOWERED MINIMUM TEMPERATURES ACROSS THE FAR NORTH WITH
DUE TO THE EXPECTED SNOW COVER. IF SKIES REMAIN CLEAR AND WINDS DROP
OFF AS EXPECTED...WOULD NOT BE SURPRISED IF TEMPERATURES FELL
INTO THE SINGLE DIGITS ABOVE ZERO ACROSS VILAS COUNTY. HIGH PRESSURE
WILL DOMINATE THE WEATHER PATTERN SATURDAY THROUGH SUNDAY NIGHT.
THE NEXT CHANCE FOR PRECIPITATION WILL OCCUR EARLY NEXT WEEK.
BELOW NORMAL TEMPERATES EARLY IN THE WEEKEND WILL RETURN CLOSER TO
NORMAL EARLY NEXT WEEK...ALTHOUGH THE NEW MEX GUIDANCE WOULD
SUGGEST A FEW DEGREES ON THE COOLER SIDE OF NORMAL WHILE THE ECMWF
GUIDANCE WOULD BE A FEW DEGREES ABOVE NORMAL.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 332 AM CDT WED OCT 29 2014

CIGS OVER E-C WI SHOULD GENERALLY REMAIN IN THE LOWER END VFR
CATEGORY. BUT GIVEN THE EXPANSIVE LOW CLDS DECK TO THE W...HARD TO
SEE MUCH IMPROVEMENT IN THE MVFR CONDITIONS ACRS C/N-C WI.
&&

.MARINE...
ISSUED AT 332 AM CDT WED OCT 29 2014

HAVE ISSUED GALE WATCH FOR LATE THURSDAY NIGHT INTO FRIDAY
EVENING. A DEEPENING LOW PRESSURE SYSTEM WILL SWEEP ACROSS
THE REGION THURSDAY NIGHT AND THEN MOVE EAST OF THE AREA ON
FRIDAY. STRONG NORTHWEST TO NORTH WINDS ARE EXPECTED BEHIND
IT WITH GALE FORCE GUSTS OF 40 TO 45 KNOTS. OUTSIDE CHANCE
THAT SOME GUSTS ACROSS NORTHERN DOOR COUNTY COULD APPROACH STORM
FORCE IF THE MODELS WITH THE STRONGER 925MB WINDS ARE CORRECT.
WINDS WILL GRADUALLY SUBSIDE LATE FRIDAY AFTERNOON AND FRIDAY
NIGHT.
&&

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

$$

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






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