Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 092246
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
546 PM CDT WED JUL 9 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 228 PM CDT WED JUL 9 2014

SCATTERED SHOWERS DEVELOPED LATE THIS MORNING NORTH OF GREEN
BAY AND MOVED SOUTHEAST ACROSS PORTIONS OF DOOR AND KEWAUNEE
COUNTIES THIS AFTERNOON. MEANWHILE...LAKE BREEZE BOUNDARY
MOVING INLAND FROM LAKE MICHIGAN. STILL THINK ISOLATED SHOWERS
COULD STILL DEVELOP ALONG CONVERGENCE OF LAKE BREEZE BOUNDARY
OVER THE NEXT FEW HOURS.

FOR TONIGHT...SKIES WILL BECOME MOSTLY CLEAR AND IT WILL BE
COOL FOR MID JULY STANDARDS. LOWS WILL BE MAINLY IN THE 40S...
A FEW 50S ALONG THE BAY AND LAKE WHILE A FEW 30S ARE POSSIBLE
IN THE COLDER SPOTS ACROSS THE FAR NORTH. IT MAY BE MID JULY...
BUT THE MAV GUIDANCE OUTPUT WAS 34 AT LAND O LAKES. DID THINK
ABOUT ADDING SOME PATCHY FROST AT LAND O LAKES...BUT DECIDED TO
GO A LITTLE WARMER THAN GUIDANCE BASED ON CURRENT DEW POINTS.

ON THURSDAY...FAIR WEATHER CUMULUS SHOULD DEVELOP BY LATE
MORNING...EXCEPT ON AND NEAR LAKE MICHIGAN. WINDS WILL TURN
TO THE SOUTH/SOUTHEAST ACROSS THE REGION. LITTLE CHANGES MADE
TO MAX TEMPERATURES ON THURSDAY.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 228 PM CDT WED JUL 9 2014

THE LATEST GFS ENSEMBLE MEAN INDICATES THAT RELATIVELY ZONAL FLOW
ACROSS THE LOWER 48 EARLY THIS WEEKEND WILL AMPLIFY BY EARLY NEXT
WEEK WITH A DEEP TROUGH CENTERED OVER THE GREAT LAKES.  THE DEEP
TROUGH WILL BRING A RETURN OF COOL AND UNSETTLED WEATHER.  BUT
BEFORE THIS OCCURS...MOST BUT NOT ALL MODELS DEPICT A WEAK SHORTWAVE
MOVING ACROSS THE REGION ON FRIDAY WITH THE ECMWF/NAM BEING THE MOST
AMBITIOUS.  WILL CONTINUE TO SIDE WITH THE CONSENSUS.  THEN THE
MODELS DEPICT A WEAK COLD FRONT SLIDING SOUTHWARD ACROSS NORTHERN
WISCONSIN SATURDAY INTO SATURDAY NIGHT AND ARE COMING AROUND TO THE
IDEA OF MCS ACTIVITY ALONG THE BOUNDARY. SOME DIFFERENCES IN THE
TRACK/TIMING OF THE MCS NOTED...BUT THE ECMWF AND GFS HAVE A LITTLE MORE
AGREEMENT WITH THE DETAILS.  THE ECMWF WILL DO FOR LATER PERIODS.

THURSDAY NIGHT AND FRIDAY...HIGH PRESSURE WILL MOVE TO THE EASTERN GREAT
LAKES WHILE A SHORTWAVE TROUGH TRACKS EAST ACROSS THE NORTHERN
PLAINS AND NORTHERN MISSISSIPPI VALLEY.  RETURN FLOW WILL RAMP UP
COINCIDENT WITH THE SHORTWAVE THOUGH THE MOISTURE RETURN WILL BE
WEST OF THE FORECAST AREA.  SO WILL SHOW INCREASING CLOUDS LATE BUT
KEEP PRECIP OUT OF THE FORECAST.  THE SHORTWAVE AND RETURN FLOW MOVE
ACROSS WISCONSIN ON FRIDAY.  PWATS WILL BE CLIMBING ABOVE 1.5 INCHES
SO PLENTY OF MOISTURE AROUND.  BUT FORCING IN THE FORM OF MOISTURE
TRANSPORT AND DPVA ALONG WITH INSTABILITY ARE MODEST AT BEST.  THE
PREVIOUS SHIFT LOWERED PRECIP CHANCES AND WILL MAKE ONLY COSMETIC
CHANGES.  THOUGH WITHOUT INSTABILITY...WILL DROP THUNDER CHANCES BY
A CATEGORY.

FRIDAY NIGHT AND SATURDAY...THE MOISTURE AXIS WILL BE OVERHEAD FOR
FRIDAY NIGHT AS THE SHORTWAVE SHIFTS EAST OF THE REGION DURING THE
EVENING.  THERE MAY BE SCATTERED DIURNALLY ENHANCED SHOWERS OR
STORMS LINGERING DURING THE EVENING BEFORE A BREAK IN THE ACTIVITY
ARRIVES.  THEN CHANCES OF PRECIP PERK UP AGAIN AFTER MIDNIGHT AHEAD
OF A COLD FRONT WHICH WILL DROP INTO NORTH-CENTRAL WISCONSIN.  WILL
TRY TO SHOW MORE TEMPORAL RESOLUTION IN THE FORECAST TO SHOW THESE
THOUGHTS.  THE FRONT WILL DROP INTO CENTRAL WISCONSIN ON SATURDAY.
IF CLOUDS DO NOT HOLD BACK HEATING...AN 81/68 PARCEL WOULD GENERATE
1500 J/KG OF ML CAPE.  BUT THINKING LOW CLOUDS WILL BE AN ISSUE WITH
AMPLE LOW LEVEL MOISTURE AROUND.  CONVERGENCE ALONG THE FRONT AND
UPPER LEVEL SUPPORT ARE MINIMAL TOO.  WILL KEEP THUNDERSTORM
CHANCES LOW AS A RESULT.

REST OF THE FORECAST...WILL BE WATCHING THE POTENTIAL FOR MCS
ACTIVITY TO CROSS THE REGION SATURDAY NIGHT AHEAD OF THE COLD FRONT.
AS THE COLD FRONT DROPS SOUTH INTO SOUTHERN WISCONSIN...LOOKS LIKE
THE A GREATER LIKELIHOOD FOR ANY MCS TO PASS SOUTH OF OUR REGION.
THE UPPER FLOW WILL BE BUCKLING SUNDAY INTO SUNDAY NIGHT WITH
INCOMING HEIGHT FALLS PUSHING A STRONG COLD FRONT SOUTH ACROSS THE
NORTHERN WISCONSIN.  TIMING LOOKS TO OCCUR SUNDAY NIGHT WHICH WILL
LIMIT SEVERE POTENTIAL...BUT WILL RAISE PRECIP CHANCES. TURNING MUCH
COLDER BEHIND THE FRONT MONDAY AND TUESDAY.  SCATTERED DIURNALLY
ENHANCED SHOWERS WILL BE POSSIBLE MONDAY AND TUESDAY TOO.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 546 PM CDT WED JUL 9 2014

ISOLATED SHOWERS WILL DIMINISH THIS EVENING OTHERWISE
VFR CONDITIONS TO PREVAIL TONIGHT INTO THURSDAY.
&&

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

$$

SHORT TERM.....ECKBERG
LONG TERM......MPC
AVIATION.......TDH





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