Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 040331
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1031 PM CDT FRI JUL 3 2015

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 238 PM CDT FRI JUL 3 2015

MAIN FCST FOCUS TO BE ON SMALL PCPN CHCS OVER THE NEXT 24 HOURS AS
A WEAK FRONTAL BOUNDARY DROPS SOUTH INTO WI TNGT AND IS SLOW TO
DEPART ON SAT.

THE 19Z MSAS SFC ANALYSIS AN AREA OF WEAK LOW PRES IN THE VCNTY OF
WRN LAKE SUPERIOR WITH A CDFNT STRETCHED SW THRU CNTRL MN. AN
ELONGATED AREA OF HI PRES EXTENDED FROM THE CNTRL PLAINS E-NE THRU
SRN SECTIONS OF THE GREAT LAKES. RADAR MOSAIC INDICATED ONE AREA
OF SHWRS/TSTMS GENERALLY AFFECTING CNTRL/ERN SECTION OF UPR MI
(ASSOCIATED WITH A SHORTWAVE TROF) AND A SECOND AREA OF
SHWRS/TSTMS (ASSOCIATED WITH THE CDFNT).

THE SHORTWAVE TROF IS FCST TO PUSH EAST ACROSS NRN SECTIONS OF THE
GREAT LAKES THIS EVENING AND INTO EXTREME SE ONTARIO OVRNGT.
MEANWHILE...THE NEARLY WEST TO EAST ORIENTATED CDFNT WL SAG INTO
CNTRL WI AND PULL UP STATIONARY AS WINDS ALOFT ARE VERY WEAK.
THERE WL CONT TO BE ENUF INSTABILITY INTO THE EVENING HOURS TO
WARRANT ISOLATED/SCATTERED SHWR/TSTM WORDING...PRIMARILY OVER NRN
AND CNTRL WI. THE LOSS OF DAYTIME HEATING SHOULD DIMINISH THE PCPN
BEFORE REACHING SRN SECTIONS OF THE FCST AREA...ALTHO CANNOT
COMPLETELY RULE OUT A STRAY SHWR PAST THE MIDNGT HOUR. HAVE
INTRODUCED SOME PATCHY FOG TO THE FCSTO AS WINDS WL BE LIGHT AND
LOW-LEVEL MOISTURE CONTS TO SLOWLY INCREASE OVER THE REGION.
WARMER NIGHTTIME TEMPS ARE EXPECTED FOR TNGT WITH READINGS ONLY
DROPPING INTO THE LWR TO MID 50S NORTH...UPR 50S TO AROUND 60 DEGS
SOUTH.

THE STALLED FNT SHOULD REMAIN NEARLY STATIONARY OVER CNTRL WI THRU
SAT MORNING BEFORE SLOWLY LIFTING NORTH AS A WRMFNT AS WEAK UPR
RIDGING MOVES INTO THE WRN GREAT LAKES. NOT MUCH CONVERGENCE ALONG
THE BOUNDARY...BUT DAYTIME HEATING SHOULD ALLOW CAPES TO APPROACH
1500 J/KG OVER CNTRL WI WITH LOWER VALUES NORTH AND EAST. LOW-
LEVEL MOISTURE IS EXPECTED TO PERSIST ON SAT AS DEW POINTS CLIMB
INTO THE UPR 50S NORTH...LWR 60S SOUTH. ANTICIPATE ISOLATED TO
SCATTERED SHWRS/TSTMS TO DEVELOP BY EARLY AFTERNOON ACROSS CNTRL/
E-CNTRL WI IN THE VCNTY OF THE FNT...WHERE HIGHER DEW POINTS TO
RESIDE. MAX TEMPS TO RANGE FROM THE UPR 70S TO LWR 80S NORTH...
LWR TO MID 80S SOUTH EXCEPT COOLER NEAR LAKE MI AS WINDS BECOME
ONSHORE.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 238 PM CDT FRI JUL 3 2015

THE MAIN EVENT FOR THIS PERIOD CENTERS ON A COLD FRONT TRACKING
OVER THE WESTERN GREAT LAKES REGION MAINLY MONDAY INTO MONDAY
NIGHT.

BUT FIRST FOR SATURDAY NIGHT...MODELS CONTINUE TO INDICATE ISOLATED
CONVECTION MAY FLAIR UP ALONG BOUNDARY LIFTING NORTHWARD. SOME
MARGINAL UNSTABLE AIR IS NOTED OVER PARTS OF CENTRAL AND NORTH
CENTRAL WISCONSIN...SO WILL INCLUDE A MENTION OF EARLY EVENING
CHANCE FOR SHOWERS OR STORMS IN THIS REGION. UPPER HEIGHTS
CONTINUE TO BUILD AHEAD OF THE APPROACHING TROUGH OVER THE
NORTHERN PLAINS TO ALLOW TEMPS TO CLIMB WELL INTO THE 80S FOR
MANY AREAS SUNDAY.

DEBRIS CONVECTION MAY BE ABLE TO REACH NORTH CENTRAL WISCONSIN
LATE SUNDAY NIGHT...OTHERWISE THE FRONTAL PASSAGE IS TRENDING FOR
MONDAY INTO EVENING...WITH THE LIKELY START FOR EASTERN WISCONSIN
IN THE AFTERNOON. INSTABILITY MARGINAL BUT SHEAR COULD BE A FACTOR
WITH THE SEVERE POTENTIAL IF THE 40-50 KT LLJ WINDS VERIFY MONDAY
AFTERNOON.

HIGH PRESSURE TO THEN DOMINATE FOR MUCH OF THE MIDDLE OF NEXT WEEK
WITH COOLER AND DRIER CONDITIONS. THE NEXT CHANCE OF PRECIPITATION
APPEARS LATER NEXT WEEK WITH THE LATEST TREND PERHAPS PUSHING ANY
PCPN OFF UNTIL NEXT WEEKEND.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1031 PM CDT FRI JUL 3 2015

A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH ACROSS THE
REGION TONIGHT. IT WILL BE ACCOMPANIED BY SCATTERED SHOWERS OR
THUNDERSTORMS BUT MOST PLACES WILL STAY DRY. THE BEST CHANCE OF
SHOWERS AND THUNDERSTORMS IS ACROSS CENTRAL WISCONSIN. VFR
CONDITIONS EXPECTED OTHER THAN DURING ANY BRIEF SHOWERS OR
THUNDERSTORMS THAT MAY OCCUR. THERE IS A LAYER OF SMOKE FROM
FOREST FIRES THAN MAY REDUCE SURFACE VISIBILITIES TO 5 MILES AT
TIMES LATE TONIGHT AND SATURDAY. THE FOURTH OF JULY SHOULD BE
MAINLY DRY WITH JUST A SLIGHT CHANCE OF SCATTERED SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON.
&&

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

$$

SHORT TERM.....AK
LONG TERM......TDH
AVIATION.......RDM


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