Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 051124
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
624 AM CDT SAT SEP 5 2015

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 404 AM CDT SAT SEP 5 2015

A MID LEVEL SHORTWAVE TRACKING THROUGH THE ARROWHEAD OF MINNESOTA
AND ITS ASSOCIATED LINE OF SHOWERS EXTENDING SOUTH OVER THE
MISSISSIPPI RIVER VALLEY IS SPLITTING AS IT HEADS EAST TOWARDS THE
CWA EARLY THIS MORNING. HOWEVER THERE IS A SUBTLE SMALLER
SHORTWAVE THAT IS CURRENTLY SETTING OFF CONVECTION JUST WEST OF
THIS INITIAL SHORTWAVE. DESPITE THIS UPSTREAM CONVECTION THE HI-
RES MODELS KEEP MUCH OF THIS PRECIPITATION AWAY FROM THE CWA.
HOWEVER SINCE THERE IS SOME FORCING WITH THE MID LEVEL SHORTWAVE
WILL LEAVE IN THE SLIGHT CHANCE POPS ACROSS THE AREA TODAY AS
ISOLATED SHOWERS AND THUNDERSTORMS CANNOT BE RULED OUT. WARM AIR
ADVECTION TODAY WILL ALLOW DAYTIME HIGHS TO SOAR INTO THE LOWER TO
MIDDLE 80S AS 850 MB TEMPERATURES SOAR INTO THE UPPER TEENS.
SOUTHERLY WINDS WILL BRING A RETURN OF HUMID CONDITIONS AS
SURFACE DEW POINTS SOAR TO AROUND 70 DEGREES.

OVERNIGHT WILL BE THE SAME STORY AS THE AREA IS USED TO THESE LAST
FEW DAYS...WITH FOG FORMATION OVERNIGHT GIVEN THE ABUNDANT LOW
LEVEL MOISTURE AS HIGH DEW POINTS RETURN COUPLED WITH LIGHT WINDS
AND PARTIAL CLEARING...ESPECIALLY ACROSS THE SOUTHERN CWA. THE
WARM AIRMASS IN PLACE AND HIGH DEW POINTS WILL KEEP OVERNIGHT LOWS
AROUND THE 70 DEGREE MARK ACROSS MOST LOCATIONS...WITH SOME MID
60S POSSIBLE NEAR THE LAKE MICHIGAN SHORELINE WITH COOLER LAKE
TEMPERATURES.

A COLD FRONT WILL TRACK TOWARDS THE UPPER MISSISSIPPI VALLEY ON
SUNDAY...BRINGING INCREASING CLOUDS AND THE CHANCE FOR RAIN ACROSS
THE NORTHERN AND WESTERN CWA...MAINLY DURING THE AFTERNOON HOURS.
WHILE THERE ARE SOME MODELS THAT BRING THE ACTIVITY IN ACROSS THE
WESTERN AND NORTHERN CWA BY THE AFTERNOON HOURS...MOST OF THE NWP
MODELS KEEP MUCH IF NOT ALL OF THE CWA DRY ON SUNDAY. GIVEN SOME
OF THE MODELS HAVE COME IN A BIT WETTER WILL RAISE THE POPS A BIT
BUT WILL STAY IN THE CHANCY CATEGORY GIVEN THE NUMBER OF MEMBERS
THAT ARE STILL DRY.

DESPITE SIMILAR 850 MB TEMPERATURES ON SUNDAY...TEMPERATURES
SHOULD BE WARMER AS ADDITIONAL WARM AIR IS ADVECTED IN AT THE
SURFACE WITH GUSTY SOUTHWESTERLY WINDS. HIGHS WILL RANGE FROM THE
LOWER TO MIDDLE 80S ACROSS THE NORTH WHERE SOME RAIN IS POSSIBLE
ALONG WITH CLOUDS...WITH MIDDLE TO UPPER 80S ACROSS THE SOUTH.
ALTHOUGH 90 DEGREES IS POSSIBLE...DEW POINTS AROUND 70 WILL MAKE
REACHING THAT TEMPERATURE TOUGH. THE COMBINATION OF WARM
TEMPERATURES AND HIGH DEW POINTS WILL CAUSE HEAT INDEX VALUES TO
RISE TO 90 TO 95 ACROSS CENTRAL AND EAST CENTRAL WISCONSIN SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 404 AM CDT SAT SEP 5 2015

500 MB WESTERN RIDGE WILL BUILD DURING THE PERIOD WITH DOWNSTREAM
TROUGHING NOTED ACROSS THE CENTRAL PORTIONS OF NORTH AMERICA.
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO EARLY NEXT WEEK WITH
A GRADUAL RETURN TO NEAR NORMAL TEMPERATURES BY NEXT WEEKEND.

COLD FRONT WILL SLOWLY WORK ACROSS THE REGION SUNDAY NIGHT INTO
LABOR DAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THE
FRONT...ALTHOUGH THE PROBABILITY FOR SEVERE WEATHER IS VERY LOW.
HEAVY RAIN POTENTIAL IS A BETTER BET WITH THE TROPICAL AIR MASS
IN PLACE.

FRONT WILL SLOWLY SAG SOUTH OF THE AREA...HOW FAR SOUTH IS THE
QUESTION AS MODELS ARE SHOWING A WAVE MOVING ALONG THE BOUNDARY
LATE MONDAY NIGHT AND MORE LIKELY TUESDAY. THE QUESTION IS HOW FAR
NORTH PRECIPITATION WILL MAKE IT INTO NORTHERN WISCONSIN. ECMWF
CONTINUES TO BE THE FURTHEST NORTH WITH THE PRECIPITATION...WHILE
THE OTHER MEDIUM RANGE MODELS HAVE THE FRONT FURTHER SOUTH ALONG
WITH THE NORTHERN EDGE OF THE PRECIPITATION. CURRENT FORECAST HAS
A DECENT HANDLE AND DID NOT MAKE ANY SIGNIFICANT CHANCES. HIGH
PRESSURE WILL MOVE INTO THE REGION TUESDAY NIGHT AND WEDNESDAY
WITH MAINLY DRY CONDITIONS. WEAK FEATURE TO THE NORTH COULD BRING
AN ISOLATED SHOWER TUESDAY NIGHT ACROSS NORTHERN WISCONSIN.

NEXT SYSTEM WOULD AFFECT THE AREA LATE WEDNESDAY NIGHT ACROSS
NORTH-CENTRAL WISCONSIN AND ACROSS THE ENTIRE REGION THURSDAY
AND POSSIBLY INTO THURSDAY EVENING ACROSS THE EAST.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 623 AM CDT SAT SEP 5 2015

LOW CLOUDS AND FOG THIS MORNING SHOULD DISSIPATE BY
MIDDAY. A WEAK BOUNDARY WILL MOVE ACROSS THE AREA TODAY AND COULD
PRODUCE ISOLATED THUNDERSTORMS. OTHERWISE VFR WEATHER IS EXPECTED
THIS AFTERNOON THROUGH EVENING. ANOTHER ROUND OF LOW CLOUDS AND
FOG ARE EXPECTED LATE TONIGHT...HOWEVER THE EFFECTS MAY NOT BE AS
BAD AT THE WESTERN TAF SITES WHERE SOME INCOMING CLOUDS COULD KEEP
RADIATION FOG FROM FORMING.
&&

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

$$

SHORT TERM.....KURIMSKI
LONG TERM......ECKBERG
AVIATION.......KURIMSKI


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