Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 290347
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1047 PM CDT FRI AUG 28 2015

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 219 PM CDT FRI AUG 28 2015

MAIN FCST ISSUE CONTS TO FOCUS ON THE EXTENT OF THE PCPN SHIELD
ACROSS NE WI TNGT/SAT AS TWO SEPARATE SYSTEMS CONVERGE ON THE
GREAT LAKES. THE ONLY THING OF CERTAINTY IS THAT THE HEAVIER QPF
WL BE FOCUSED ON THE SRN HALF OF WI TNGT BEFORE THE PCPN GRADUALLY
PULLS AWAY ON SAT.

THE 19Z MSAS SFC ANALYSIS SHOWED A WEAK AREA OF LOW PRES ON THE
NEBRASKA/IOWA BORDER WITH A WEAK WRMFNT STRETCHED EWD ACROSS CNTRL
SECTIONS OF IOWA. RADAR MOSAIC INDICATED A LARGE AREA OF LIGHT TO
MODERATE RAIN ACROSS SW WI...SE MN...NE IA AND NW IL. THIS PCPN
SHIELD WAS HAVING A HARD TIME MOVING NWD...AWAY FROM THE BETTER
DYNAMICS.

THE WEAK SFC LOW OVER THE MIDWEST IS FCST TO WEAKEN FURTHER TNGT
AND DRIFT SE TOWARD THE IA/MO/IL BORDER. DESPITE THE WEAK SFC LOW
AND LACK OF A SIGNIFICANT LOW-LEVEL JET...PLENTY OF MOISTURE TO BE
AVAILABLE WITH DEW POINTS IN THE 50S TO AROUND 60 DEGS AND PW
VALUES AROUND 1.25". FARTHER ALOFT...MODELS CONT TO SHOW A
SHORTWAVE TROF (WITH EMBEDDED SHRTWVS) PUSHING ACROSS WI TNGT...AS
WELL AS A FAVORABLE RIGHT ENTRANCE REGION OF THE UPR JET ADDING
LIFT ESPECIALLY OVER THE SRN HALF OF THE STATE. THERE IS
SUFFICIENT LOW-LEVEL MOISTURE CONVERGENCE AND MID-LEVEL FORCING TO
BRING/MAINTAIN THIS LARGE BAND OF SHWRS ACROSS ROUGHLY THE SRN 3/4
OF THE STATE LATE THIS AFTERNOON THRU MOST OF TNGT. LIKELY OR
CATEGORICAL POPS PLACED GENERALLY ALONG AND SOUTH OF A LINE FROM
MERRILL TO WAUSAUKEE WITH SCT POPS FARTHER NORTH. INSTABILITY
REMAINS WEAK...THUS NOTHING MORE THAN ISOLATED TSTMS EXPECTED
TNGT. HAVE ALSO ADDED PATCHY FOG TO THE FCST AS ABUNDANT MOISTURE
TO BE PRESENT WITH LIGHT WINDS AT THE SFC. MIN TEMPS TO RANGE FROM
THE LWR TO MID 50S N-CNTRL WI...AROUND 60 DEGS E-CTNRL WI.

SHWR ACTIVITY SHOULD STILL BE IMPACTING ERN SECTIONS OF WI SAT
MORNING AS THE SHRTWV TROF SLOWLY PUSHES TO THE EAST. UPR HEIGHTS
BEGIN TO RISE OVER THE AREA BY SAT AFTERNOON AS THE CNTRL CONUS
UPR RDG TILTS NEWD TOWARD THE WRN GREAT LAKES. MOST IF NOT ALL
PCPN SHOULD BE OVER WITH BY EARLY SAT AFTERNOON WITH GRADUAL
CLEARING SKIES FROM NW TO SE. ANY CLEARING IN ERN WI MAY NOT OCCUR
UNTIL LATE IN THE DAY. MAX TEMPS ON SAT ARE FCST TO BE CLOSE TO
SEASONAL NORMALS WITH MOST LOCATIONS IN THE LWR TO MID 70S.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 219 PM CDT FRI AUG 28 2015

A RETURN TO SUMMERTIME WARMTH IS EXPECTED DURING THE PERIOD.

THE UPPER TROF AND ASSOCIATED RAINFALL IS EXPECTED TO BE EAST OF
THE FORECAST AREA BY SATURDAY EVENING...SO HAVE CONTINUED THE
PREVIOUS DRY FCST. WITH CLEARING SKIES AND LIGHT WINDS ANTICIPATED
OVERNIGHT...COMBINED WITH MOISTURE FROM EARLIER RAIN...FOG LOOKS
LIKE A GOOD BET. HAVE INCREASED FOG COVERAGE FROM PATCHY TO
AREAS...AND SUSPECT THAT AT LEAST LOCALLY DENSE FOG WILL BE A
CONCERN. DRY CONDITIONS ARE ANTICIPATED FOR SUNDAY AND MONDAY AS
A STRONG UPPER RIDGE BECOMES ESTABLISHED OVER THE REGION.
DEVELOPING SOUTH WINDS WILL MARK THE BEGINNING OF A WARMING
TREND...WITH HIGHS WARMING INTO THE LOWER TO MIDDLE 80S BY MONDAY.

SMALL PCPN CHANCES RETURN TO THE FCST FOR THE REST OF THE WORK...
DUE TO A WEAKENING FRONTAL BOUNDARY THAT ARRIVES MIDWEEK...
DIURNAL INSTABILITY...AND ANOTHER COLD FRONTAL BOUNDARY NEXT
FRIDAY. OVERALL...THIS STILL APPEARS TO BE A RELATIVELY DRY PERIOD
FOR MOST OF THE AREA...AS THE PRESENCE OF THE UPPER RIDGE SHOULD
LIMIT THE COVERAGE OF ANY CONVECTION THAT DOES DEVELOP. H8 TEMPS
STAY FAIRLY STEADY IN THE +18 TO +21 C RANGE...SO MAX TEMPS SHOULD
BE MAINLY IN THE 80S...WITH PERHAPS A 90 DEGREE READING OR TWO AT
THE TYPICAL WARM SPOTS IN THE SANDY SOIL AREAS IN CENTRAL
WISCONSIN.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1047 PM CDT FRI AUG 28 2015

AREA OF LIGHT TO MODERATE RAINFALL SLIDING OVER NORTHEAST
WISCONSIN LATE THIS EVENING WAS SLIDING EAST A BIT FASTER THAN
EARLIER PROGGED. MEANWHILE A CLUSTER OF SHOWERS AND STORMS OVER
THE MINNESOTA ARROWHEAD LATE THIS EVENING IS PROGGED TO DROP INTO
UPPER MICHIGAN OVERNIGHT. PROGS SUGGESTS IF THE SHOWERS AND STORMS
CAN HOLD TOGETHER...MAY BRUSH THE FAR NORTHERN PART OF WISCONSIN
OVERNIGHT. WHERE THE PCPN HAS DEPARTED...AREAS OF MVFR CIGS AND
PATCHY IFR CIGS HAVE DEVELOP. ANTICIPATE A PERIOD OF MVFR WITH
SCATTERED IFR CIGS OVERNIGHT BEFORE GRADUALLY IMPROVING TO VFR
CONDITIONS FROM WEST TO EAST ON SATURDAY. MAINLY AREAS OF MVFR FOG
EXPECTED TONIGHT WITH PATCHY IFR/LIFR FOG...AGAIN WILL IMPROVE TO
VFR CONDITIONS LATER SATURDAY MORNING.
&&

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

$$

SHORT TERM.....AK
LONG TERM......KIECKBUSCH
AVIATION.......TDH



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