Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 161133
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
633 AM CDT TUE SEP 16 2014

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 352 AM CDT TUE SEP 16 2014

PLEASANT WEATHER EXPECTED TODAY AS SURFACE HIGH OVER IOWA SLIDES
EAST INTO ILLINOIS. WARM ADVECTION WILL CAUSE TEMPERATURES TO
CLIMB TO NEAR SEASONAL NORMALS. CLEAR SKIES EXPECTED THIS EVENING
WITH SOME MID CLOUDS ARRIVING AFTER MIDNIGHT AS A BACKDOOR FRONT
APPROACHES FROM SOUTHERN CANADA. THE FRONT WILL DROP SOUTH ACROSS
THE AREA WEDNESDAY. TEMPERATURES WILL BECOME STEADY OR SLOWLY FALL
AFTER FRONTAL PASSAGE. NOT MUCH MOISTURE AVAILABLE FOR
PRECIPITATION SO WE JUST KEPT A SLIGHT CHANCE OF SHOWERS IN THE
NORTH WHERE LOW LEVEL CONVERGENCE IS BEST.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 352 AM CDT TUE SEP 16 2014

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN ACROSS THE
CONUS...WITH TROUGHS OVER THE EAST AND WEST COASTS AND RIDGING
OVER THE ROCKIES AND WESTERN PLAINS MID-WEEK...PRODUCING NORTHWEST
FLOW OVER THE STATE...TRANSITIONING TO MORE OF A ZONAL FLOW FOR
THE END OF THE WEEK AND WEEKEND. BY EARLY NEXT WEEK...THE PATTEN
LOOKS TO SHIFT BACK TO STRONG RIDGING OVER THE ROCKIES AND CENTRAL
CANADA AND A DEEP TROUGH OVER THE EASTERN U.S...WITH A RETURN TO
THE NORTHWEST FLOW. AS THE RIDGING PUSHES OVER THE GREAT
LAKES...LOOK FOR THE TEMPS TO CREEP CLOSER TO NORMAL READINGS FOR
THE MIDDLE OF SEPTEMBER...THEN TEMPS LOOK TO FALL BACK BELOW
NORMAL EARLY NEXT WEEK.

A WEAK...MOISTURE STARVED...COLD FRONT WILL SAG THROUGH THE AREA
WEDNESDAY AFTERNOON AND EVENING. ANY SHOWER ACTIVITY THAT IS
GENERATED DURING THE DAY SHOULD FADE AS THE ALREADY NARROW RIBBON
OF MOISTURE WILL BE DIMINISHING...AND FORCING FROM A WEAK
SHORTWAVE TROUGH CROSSING THE WESTERN GREAT LAKES WILL BE MOVING
INTO MICHIGAN BY EARLY EVENING. WILL GO WITH DRY FORECAST FOR THE
AREA. PARTIAL CLEARING IS EXPECTED AS HIGH PRESSURE BUILDS INTO
THE REGION...WITH ANOTHER VERY CHILLY NIGHT EXPECTED ACROSS
NORTHERN WI...WITH AREAS OF FROST EXPECTED. SOME PATCHY FOG IS
ALSO POSSIBLE.

THE HIGH PRESSURE SYSTEM WILL BUILD OVER THE CENTRAL GREAT LAKES
REGION ON THURSDAY...THEN WILL SLIDE INTO THE EASTERN GREAT LAKES
THURSDAY NIGHT. THIS WILL BRING DRY WEATHER TO THE AREA...ALONG
WITH BELOW NORMAL TEMPERATURES.

STRONG RETURN FLOW WILL DEVELOP AS THE HIGH PRESSURE SHIFTS EAST
OF THE REGION ON FRIDAY. ALTHOUGH MODELS ARE IN FAIRLY DECENT
AGREEMENT ON KEEPING FRIDAY MORNING DRY...THEN BRINGING AT LEAST
A CHANCE OF SHOWERS/STORMS IN THE AFTERNOON AS A LOW LEVEL JET AND
WARM AIR ADVECTION PUSH TOWARD THE STATE...STILL SOME UNCERTAINTY
AS HOW THIS INITIAL SURGE OF PRECIP WILL PLAY OUT. THE CHANCE FOR
PRECIP CONTINUES FRIDAY NIGHT WITH THE 40-50 KT LOW LEVEL JET
POINTED AT AREA...HOWEVER BEST CHANCE LOOKS TO REMAIN NORTHWEST OF
THE AREA...AHEAD OF A POTENT SHORTWAVE TROUGH...LOW PRESSURE
SYSTEM...AND COLD FRONT. WILL CONTINUE WITH LIKELY POPS ACROSS THE
AREA ON SATURDAY...AS MAJORITY OF THE MODELS HAVE THE COLD FRONT
AND SHORTWAVE CROSSING THE STATE. STILL A LITTLE EARLY TO GET INTO
SEVERE WEATHER SPECIFICS...BUT INSTABILITY WILL BE AN ISSUE...PLUS
0-6KM BULK SHEAR NOT OVERLY IMPRESSIVE...UNDER 40KTS.

MODELS START TO DIVERGE SATURDAY NIGHT ON HOW WRAPPED UP THE LOW
PRESSURE SYSTEM. THE ECMWF LOOKS TO BE AN OUTLIER...DEVELOPING A
DEEP CUT OFF LOW OVER LAKE SUPERIOR BY SUNDAY MORNING...WHILE THE
GFS...GFS ENSEMBLE...AND GEM SHOW A MORE OPEN TROUGH. THE ECMWF
WOULD BRING MORE/DEEPER WRAP-AROUND MOISTURE INTO THE STATE...AND
A BETTER CHANCE FOR SHOWERS SATURDAY NIGHT AND SUNDAY...ESPECIALLY
ACROSS NORTHERN WI. WILL LEAN AWAY FROM THE ECMWF...HOWEVER SOME
WRAP AROUND SHOWERS WILL STILL BE POSSIBLE OVER NORTHERN
WI...WHERE SOME LAKE EFFECT/ENHANCED SHOWERS ARE POSSIBLE.
REGARDLESS OF HOW DEEP THE LOW GETS...COOLER TEMPS WILL PUSH INTO
THE AREA.

DRY WEATHER AND MODERATING TEMPERATURES ARE EXPECTED EARLY NEXT
WEEK...AS RIDGING BUILDS OVER THE PLAINS.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 632 AM CDT TUE SEP 16 2014

VFR CONDITIONS EXPECTED THROUGH TONIGHT WITH MAINLY CLEAR
SKIES. A WEAK FRONTAL SYSTEM WILL MOVE THROUGH THE AREA WEDNESDAY.
IT MIGHT PRODUCE A FEW LIGHT RAIN SHOWERS BUT IT SHOULD REMAIN VFR.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ005-010>013-
018-019-021-030-035-036.
&&

$$

SHORT TERM.....RDM
LONG TERM......BERSCH
AVIATION.......RDM






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