Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 161809
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
109 PM CDT SAT AUG 16 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 320 AM CDT SAT AUG 16 2014

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST FOR TODAY AS JET
ENERGY AND ASSOCIATED SHORTWAVE DIVES TO THE SOUTHEAST ACROSS THE
CENTRAL GREAT LAKES.

PRIMARY SHORTWAVE ENERGY CURRENTLY CENTERED NORTH OF LAKE SUPERIOR
FORECAST TO MOVE SOUTHEAST TOWARD LAKE HURON DURING THE DAY.
SHORT RANGE GUIDANCE CONTINUES TO SUGGEST THAT BEST UPPER-LEVEL
FORCING WILL REMAIN NORTHEAST OF THE FORECAST AREA AS COLD FRONT
DROPS SOUTH INTO NORTHERN WISCONSIN BY AROUND 15Z. SCATTERED
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ARE CURRENTLY ASSOCIATED
WITH THE FRONT EARLY THIS MORNING WITH THE MORE WIDESPREAD
ACTIVITY CONFINED TO CENTRAL AND EASTERN UPPER MICHIGAN WHERE THE
UPPER-LEVEL FORCING IS SOMEWHAT STRONGER.

FRONT WILL CONTINUE TO DROP SOUTHWARD ACROSS THE REMAINDER OF THE
FORECAST AREA DURING THE AFTERNOON. FRONT WILL LIKELY PUSH
SOUTHWARD MORE RAPIDLY OVER NORTHERN LAKE MICHIGAN INTO NORTHEAST
WISCONSIN BY ABOUT 3 PM THIS AFTERNOON. MODIFIED GRB SOUNDING
WOULD SUGGEST SBCAPES AROUND 1500 J/KG JUST AHEAD OF THE FRONT
OVER CENTRAL AND EASTCENTRAL WISCONSIN. THUS WOULD EXPECT TO SEE
AN UPTICK IN THE COVERAGE AND INTENSITY OF SHOWER AND THUNDERSTORM
ACTIVITY THAT WILL ACCOMPANY THE FRONT. GIVEN VERY MINIMAL UPPER-
LEVEL SUPPORT AND MARGINAL SHEAR EXPECTED...DO NOT EXPECT ACTIVITY
TO REACH SEVERE LIMITS. OVERALL EXPECT ONLY A SCATTERED TO BROKEN
AREA OF PRECIPITATION WITH THE FRONT AS IT MOVES SOUTHWARD ACROSS
THE AREA THIS AFTERNOON. ACTIVITY SHOULD CONTINUE TO PUSH SOUTH
OF THE FORECAST AREA DURING THE EARLY EVENING. WINDS WILL TURN
ABRUPTLY NORTHEAST AND BECOME RATHER GUSTY FOR AN HOUR OR TWO
BEHIND THE FRONT...ESPECIALLY ALONG THE LAKESHORE LATER THIS
AFTERNOON.

COULD BE A LINGERING STRATUS OR SC DECK BEHIND THE FRONT...FOLLOWED
BY SOME GRADUAL CLEARING FROM NORTH TO SOUTH OVERNIGHT. OVERNIGHT
LOWS BE RATHER COOL AND FALL INTO THE MIDDLE 40S NEAR THE
WISCONSIN MICHIGAN BORDER. PARTLY CLOUDY AND SOMEWHAT BREEZY
CONDITIONS WILL BE THE RULE ON SUNDAY AS NORTHEAST BOUNDARY LAYER
FLOW DOMINATES. TEMPS TO BE BELOW NORMAL WITH HIGHS GENERALLY IN
THE LOWER 70S...EXCEPT NEAR THE LAKESHORE WHERE READINGS WILL
LIKELY REMAIN IN THE UPPER 60S.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 320 AM CDT SAT AUG 16 2014

SURFACE HIGH PRESSURE SYSTEM WILL LIKELY DOMINATE SUNDAY NIGHT
INTO MONDAY. NEXT CHANCE OF RAIN WILL BE ASSOCIATED WITH A DEEP
TROUGH DROPPING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS AND
SOUTHERN CANADA. LATEST MODEL RUNS SUGGEST A QUICKER ARRIVAL OF
THE PCPN LIKELY IN THE WARM RETURN SECTOR MONDAY AFTERNOON OVER
WESTERN WISCONSIN. ANTICIPATE THE BEST CHANCE FOR SHOWERS WILL
START LATER MONDAY NIGHT AND ESPECIALLY FOR TUESDAY AND CONTINUING
INTO TUESDAY NIGHT. THE SYSTEM IS PROGGED TO START WEAKENING MID
WEEK AS THE UPPER RIDGE BUILDS INTO THE AREA.

A BIT OF A RANGE IN MODEL SOLUTIONS FOR NEXT WEEK DEPENDING ON
THE STRENGTH AND DURATION OF THE UPPER RIDGE. COULD HAVE A DRY
PERIOD TOWARD THURSDAY PRIOR TO GETTING INTO SOUTHWEST FLOW LATE
IN THE WEEK AND LITTLE MORE ACTIVE PATTERN.

TEMPERATURES APPEAR NEAR NORMAL OR SLIGHTLY ABOVE NORMAL NEXT
WEEK WITH THE BUILDING UPPER RIDGE.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 108 PM CDT SAT AUG 16 2014

SHOWERS WERE INCREASING AHEAD OF A COLD FRONT THAT WAS SLOWLY
MOVING TO THE SOUTH OUT OF UPPER MICHIGAN. MESOANALYSIS INDICATED
INCREASING INSTABILITY ACROSS THE AREA AND RADAR TIME LAPSE SHOWED
AN INCREASE IN SHOWERS...WITH SOME OF THE STRONGER ECHOES PROBABLY
CONTAINING AT LEAST ICCC LIGHTNING IF NOT CG. RHI HAS HAD SHOWERS
BUT MOST OF THE ACTIVITY HAS BEEN NORTH OF THE REMAINDER OF THE
TAF SITES...WITH ONLY SOME SPRINKLES OR BRIEF LIGHT SHOWERS AT
GRB. MVFR CIGS WERE FAIRLY WIDESPREAD AND THERE WERE ALSO SOME IFR
CIGS ACROSS NORTHERN WISCONSIN. SHOWERS AND THUNDERSTORMS SHOULD
CONTINUE ALONG AND AHEAD OF THE FRONT AS IT MOVES SOUTH...WITH
MAINLY MVFR CIGS. VSBYS WITH SHOWERS AND STORMS WILL BE MAINLY
MVFR AND OCCASIONALLY IFR IN HEAVIER RAINFALL. THINK LOW CLOUDS
AND FOG WILL BE AN ISSUE OVERNIGHT...WITH CONDITIONS IMPROVING
DURING THE MORNING.
&&

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

$$

SHORT TERM.....ESB
LONG TERM......TDH
AVIATION.......MG






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