Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 272252
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
552 PM CDT THU AUG 27 2015

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 328 PM CDT THU AUG 27 2015

AN UPPER LEVEL TROUGH AND SURFACE LOW PRESSURE SYSTEM OVER THE
PLAINS WILL MOVE TOWARD WISCONSIN OVERNIGHT. THE TROUGH IS
EXPECTED TO MOVE ACROSS THE AREA ON FRIDAY AS THE LOW PASSES TO
OUR SOUTH. MODELS WERE FAIRLY SIMILAR IN BRINGING RAIN INTO
CENTRAL WISCONSIN LATE TONIGHT BEFORE SPREADING IT ACROSS THE AREA
DURING THE DAY ON FRIDAY. HIGHEST MODEL QPF WAS MAINLY ACROSS
SOUTHERN WISCONSIN BUT PARTS OF CENTRAL AND EAST CENTRAL WISCONSIN
ARE LIKELY TO GET MORE THAN A QUARTER OF AN INCH OF RAIN DURING
THE DAY ON FRIDAY.

THE SURFACE GRADIENT ACROSS THE STATE WILL NOT BE VERY TIGHT BUT
SHOULD BE STRONGER THAN IT WAS LAST NIGHT. THIS...COMBINED WITH
INCREASING CLOUDS WILL PREVENT FOG FROM BECOMING A PROBLEM AND
KEEP LOWS SEVERAL DEGREES ABOVE NORMAL. USED A BLEND OF THE THREE
BEST PERFORMING MODELS FOR LOWS TONIGHT AND HIGHS ON FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 328 PM CDT THU AUG 27 2015

PCPN TRENDS FOR THE FIRST PART OF THE WEEKEND...AND A RETURN TO
WARMER TEMPERATURES NEXT WEEK...ARE THE MAIN FCST ISSUES.

MODELS ARE OFFERING A COUPLE DIFFERENT SCENARIOS WITH THE WEEKEND
SYSTEM...WITH THE DIFFERENCES ASSOCIATED WITH POTENTIAL PHASING
OF THE MAIN UPPER TROF AND A S/W TROF DROPPING OUT OF SOUTHERN
CANADA LATE FRIDAY NIGHT INTO SATURDAY. THE GFS AND GEM SHOWED
LITTLE PHASING OF THE TWO SYSTEMS...AND A QUICKER EXIT OF THE
PCPN LATE FRIDAY NIGHT/SATURDAY MORNING. THE NAM AND ECMWF
INDICATED SOME PHASING AND A SLOWER DEPARTURE DURING THE DAY ON
SATURDAY. HAVE ONLY MADE MINOR CHANGES TO THE FCST...AND KEPT THE
FOCUS ON HIGHEST POPS/QPF OVER C/EC WI FRIDAY NIGHT INTO EARLY
SATURDAY MORNING. GIVEN THE AVAILABLE MOISTURE (PW`S AROUND 1.5
INCHES) AND DYNAMICS OVER CENTRAL AND EAST CENTRAL WI...A BAND OF
HEAVY RAINFALL SEEMS LIKELY. HAVE BACKED OFF ON THUNDERSTORM
CHANCES A BIT...AND JUST MENTIONED ISOLD WORDING...AS INSTABILITY
IS WEAK.

THE REST OF THE EXTENDED PERIOD WILL BE DOMINATED BY A BUILDING
UPPER LEVEL RIDGE...PREDOMINATELY DRY CONDITIONS...AND MUCH
WARMER TEMPERATURES. A WEAK FRONTAL BOUNDARY MAY BRING A SMALL
CHC OF TSTMS OVER NORTHERN WI DURING THE MIDWEEK PERIOD...BUT
EVEN THAT IS DOUBTFUL ATTM. H8 TEMPS WARMING INTO THE +18 TO +22 C
RANGE DURING THE NEXT WORK WEEK SUPPORT HIGH TEMPS IN THE 80S.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 552 PM CDT THU AUG 27 2015

LGT WINDS EXPECTED AGAIN TNGT...THOUGH HIGH AND MIDDLE CLDS WL BE
OVERSPREADING THE AREA FM THE W. PLENTY OF SUNSHINE ALSO ALLOWED
FOR FAIRLY DEEP MIXING...SO TEMP/DWPT SPREADS WERE CONSIDERABLE.
AS A RESULT...FOG SHOULD NOT BE AS BIG OF AN ISSUE AS LAST NGT.
OTHERWISE...JUST SOME MINOR ADJUSTMENTS TO PCPN TIMING WITH THE
INCOMING SYSTEM WL BE NEEDED FOR THE 00Z TAF PKG.
&&

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

$$

SHORT TERM.....MG
LONG TERM......KIECKBUSCH
AVIATION.......SKOWRONSKI



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