Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 231122
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
622 AM CDT THU OCT 23 2014

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 408 AM CDT THU OCT 23 2014

THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH OVER THE DAKOTAS PUSHING AN OCCLUDED FRONT INTO THE NORTHERN
MISSISSIPPI VALLEY. AHEAD OF THE FEATURES...A CHANNEL OF DEEP
MOISTURE IS EXTENDING FROM NORTHERN MEXICO INTO MINNESOTA AND
WESTERN WISCONSIN.  A FEW SHOWERS ARE DEVELOPING ALONG THE LEADING
EDGE OF THIS MOISTURE CHANNEL FROM IRONWOOD TO LA CROSSE.
HOWEVER...THE MAIN BAND OF BROKEN RAIN SHOWERS IS MOVING EAST OVER
EASTERN MINNESOTA.  CLEAR SKIES RESUME BEHIND THE OCCLUDED FRONT OVER
THE DAKOTAS.  THE MAIN FORECAST CONCERNS INCLUDE TIMING OF RAIN
CHANCES AS THE SHORTWAVE AND OCCLUDED FRONT MOVE ACROSS THE REGION
TODAY.

TODAY...A SHORTWAVE TROUGH OVER THE DAKOTAS WILL PUSH A DECAYING
OCCLUDED FRONT EAST ACROSS THE STATE.  AHEAD OF THE TROUGH AND
FRONT...WILL SEE DECENT MOISTURE WITHIN THE THETAE AXIS SPREAD EAST
WITH PWATS UPWARDS OF AN INCH.  BUT FORCING AND INSTABILITY ARE ONLY
MODEST SO ALTHOUGH MOST PLACES WILL SEE LIGHT RAIN...AMOUNTS SHOULD
ONLY REACH A TENTH OR TWO.  ADJUSTED THE TIMING OF THE BAND OF RAIN
ACROSS THE AREA SLIGHTLY SLOWER BASED ON THE LATEST GUIDANCE.  AMPLE
DRY AIR SHOULD KEEP AREAS ALONG THE BAY AND FOX VALLEY DRY THROUGH
THE MORNING THEN SHOULD SEE THE HIGHEST RAIN CHANCES ARRIVE BETWEEN
18-21Z.  TEMPS WILL HAVE A CHANCE TO REACH INTO THE MIDDLE 50S
ACROSS EASTERN WISCONSIN BEFORE THE RAIN ARRIVES...BUT TEMPS WILL
LIKELY STRUGGLE TO REACH 50 OVER NORTH-CENTRAL WISCONSIN SINCE RAIN
WILL ARRIVE DURING THE MORNING.

TONIGHT...WHATS LEFT OF THE LIGHT RAIN WILL BE IN THE PROCESS OF
EXITING EASTERN WISCONSIN EARLY IN THE EVENING AND THINK RAIN
CHANCES WILL HAVE MOSTLY EXITED THE LAKE SHORE BY 03Z.  PLENTY OF
DRY AIR ALOFT WILL ARRIVE BEHIND THE SHORTWAVE...AND INCREASING
SUBSIDENCE WILL LOWER THE INVERSION.  PROGGED SOUNDINGS INDICATE LOW
LEVEL MOISTURE WILL BECOME TRAPPED BELOW THIS INVERSION AS SKIES
CLEAR OVERNIGHT.  LOOKING UPSTREAM...VISIBILITIES ARE FALLING RIGHT
BEHIND THE CLOUD LINE OVER NEBRASKA AND SOUTH DAKOTA.  THIS SUPPORTS
A DECENT SETUP FOR FOG LATE TONIGHT AND WILL ADD TO THE FORECAST
EVERYWHERE.  LOWS IN THE UPPER 30S TO MIDDLE 40S.

FRIDAY...ONCE ANY MORNING FOG BURNS OFF...SHOULD SEE A GOOD DEAL OF
SUNSHINE UNTIL THE AFTERNOON WHEN A WEAK DISTURBANCE MOVES INTO
CENTRAL WISCONSIN.  SHOULD SEE CLOUDS INCREASE THERE...BUT MOSTLY
SUNNY CONDITIONS SHOULD PREVAIL ELSEWHERE.  SOUTHWEST WINDS WILL
PUSH HIGHS INTO THE LOWER TO MIDDLE 60S.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 408 AM CDT THU OCT 23 2014

NORTHWEST UPPER FLOW FORECAST BY THE MODELS FOR
FRIDAY NIGHT THROUGH SUNDAY. MILDER THAN USUAL WEATHER EXPECTED AS
THE SURFACE HIGH MOVING IN IS FROM THE NORTHERN PLAINS INSTEAD OF
FROM CANADA. UPPER FLOW BECOMES SOUTHWEST SUNDAY NIGHT AND
CONTINUES UNTIL AN UPPER TROUGH SWINGS THROUGH TUESDAY NIGHT.

THE FIRST ROUND OF PRECIPITATION MAY ARRIVE SUNDAY NIGHT OR MONDAY
AS A WARM FRONT AS A WARM FRONT FORMS AND MOVES NORTH FROM
ILLINOIS. LOW LEVEL WARM ADVECTION AND CONVERGENCE SHOULD GENERATE
SHOWERS AND THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS
EXPECTED MONDAY NIGHT AND TUESDAY AS A SURFACE LOW MOVES NORTHEAST
ALONG THE COLD FRONT. THE LOW INTENSIFIES AND LIFTS TO THE
NORTHEAST TUESDAY NIGHT AND THE SHOWERS SHOULD DIMINISH.

COOLER AND DRIER WEATHER EXPECTED FOR WEDNESDAY AND THURSDAY AS
A BIG SURFACE HIGH PRESSURE SYSTEM DROPS SOUTH FROM CANADA.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 622 AM CDT THU OCT 23 2014

AN OCCLUDED FRONT WILL BE MOVING ACROSS THE STATE AND WILL BRING A
BROKEN BAND OF LIGHT SHOWERS TO THE REGION BEFORE EXITING EASTERN
WISCONSIN EARLY THIS EVENING. EXPECT CIGS TO GRADUALLY FALL TO MVFR
OVER CENTRAL WISCONSIN BY MIDDAY WITH THE APPROACH OF THE FRONT.
DURING THE EVENING...MVFR TO IFR CIGS MAY PERSIST ESPECIALLY OVER
THE EASTERN HALF OF WISCONSIN AS THE FRONT PASSES OVER THE AREA. RESIDUAL
BOUNDARY LAYER MOISTURE AND LIGHT WINDS MAY ALSO ALLOW FOR SOME
AREAS OF FOG TO DEVELOP DURING THE EVENING AS WELL.  THE FOG MAY
BECOME LOCALLY DENSE OVERNIGHT.
&&

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

$$

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






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