Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 021811
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
111 PM CDT THU JUL 2 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SYNOPSIS...
ISSUED AT 306 AM CDT THU JUL 2 2015

PRETTY FAVORABLE WEATHER FOR OUTDOOR RECREATION EXPECTED FOR THE
HOLIDAY WEEKEND. TEMPERATURES WILL BE NEAR OR A LITTLE ABOVE
NORMAL. RAIN CHANCES WILL BE CONFINED TO SCATTERED THUNDERSTORMS
IN THE N FRIDAY AFTERNOON AND EVENING...AND ISOLATED STORMS ACROSS
THE AREA SATURDAY AFTERNOON AND EVENING.

THE CURRENT NWLY UPR FLOW REGIME WL COME TO AN END AS THE UPR
RIDGE OVER THE INTERMOUNTAIN WEST SHIFTS WNWWD INTO THE GULF OF
ALASKA. THAT WL RESULT IN DOWNSTREAM TROF CONSOLIDATING OVER
CENTRAL CANADA...SOUTH OF WHICH A WLY UPR FLOW WL DEVELOP ACRS THE
CENTRAL CONUS. THIS PATTERN FAVORS NR OF SLIGHTLY ABOVE NORMAL
TEMPERATURES. PCPN CHCS WL BE TIED TO THE PASSAGE OF FRONTAL
SYSTEMS...AND WL BE LIMITED UNTIL EARLY NEXT WEEK.
&&

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 306 AM CDT THU JUL 2 2015

QUIET WX WL CONTINUE AS ANTICYCLONE LINGERS OVER THE GREAT LAKES
RGN. STLT IMAGERY INDICATED THAT THE PATCH OF AC DROPPING SWD
TOWARD THE AREA WAS SHRINKING. WHAT WL LIKELY BE OF MORE
CONSEQUENCE TO SKYCON FCST WAS FAIRLY THICK LOOKING AREA OF SMOKE
THAT COULD BE SEEN DROPPING SE INTO N-C WI ON VIS STLT IMAGERY
LATE YDA. IT WL BE DIFFICULT TO GAUGE THE EXACT LCN/IMPACT OF
THAT UNTIL THE SUN COMES UP TDA...BUT STARTED THINGS OFF BY
CARRYING HIGHER SKYCON THAN MODEL RH PROGS WOULD SUGGEST. WOULD
NOT BE SURPRISED IF SMOKE IS THICK ENOUGH TO LIMIT SUNSHINE TO THE
POINT WHERE THERE ISN/T MUCH IN THE WAY OF SHADOWS AT TIMES TDA.

THE OTHER MAIN SHORT-TERM FCST ISSUE IS POPS FRIDAY. COLD FRONT
DROPPING SWD FM CANADA DOESN/T LOOK LIKE IT WL REACH THE AREA
UNTIL FRI NGT. HOWEVER...MODELS IN PRETTY GOOD AGREEMENT THAT TAIL
OF FAIRLY STG SHRTWV TRACKING ACRS ONTARIO WL BRUSH THE N DURING
THE AFTN. MODELS SPLIT ABOUT 50/50 ON WHETHER OR NOT THAT WL KICK
OFF PCPN. STAYED CLOSE TO PREV FCST IN HAVING PCPN CHCS ACRS ABOUT
THE NRN 1/3 OF THE FCST AREA DURING THE AFTN.

STARTED WITH MAX/MIN TEMP GRIDS BASED ON A BLEND OF THE TOP
PERFORMING GUIDANCE PRODUCTS...BUT NEEDED TO MAKE SIG ADJUSTMENTS
NR THE LAKE...ESP FRI. LOW-LEVEL FLOW BACKING TO S ON FRI WL
RESULT IN OVER-WATER TRAJECTORIES UP THE LENGTH OF THE LAKE AND WL
KEEP TEMPS NR THE LAKESHORE QUITE A BIT COOLER THAN INLAND.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 306 AM CDT THU JUL 2 2015

THE MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT WITH A
WEAK FRONT SAGGING INTO THE REGION FRIDAY NIGHT...AND A STRONGER
FRONT ARRIVING ON MONDAY. A BLEND OF THE ECMWF AND GFS SHOULD
THEREFORE WORK THROUGH MONDAY NIGHT. THEREAFTER...WILL JUST RIDE
WITH THE EXTENDED INITIALIZATION.

FRIDAY NIGHT THROUGH SATURDAY NIGHT...A WEAK COLD FRONT WILL DROP
INTO NORTHERN WI FRIDAY EVENING AND INTO CENTRAL WI OVERNIGHT.
SINCE CONVERGENCE IS WEAK ALONG THE FRONT AND INSTABILITY WANES
QUICKLY...THINK ANY STORMS FRIDAY EVENING WILL ALSO DISSIPATE
FAIRLY RAPIDLY. THEREFORE THINK THAT ONLY LOW CHANCES OF STORMS IS
REASONABLE...WHICH IS ALREADY PORTRAYED IN THE FORECAST. THE FRONT
WILL REMAIN STALLED OR RETURN NORTH SLIGHTLY ON SATURDAY.
SUBSIDENCE INCREASES ALOFT AS WELL...SO CAN ONLY SEE AN ISOLATED
THREAT OF A STORM. THE FRONT WILL ACCELERATE NORTHWARD ON SATURDAY
NIGHT AS RETURN FLOW INCREASES. ANY WEAK CONVERGENCE WILL SHIFT
NORTH INTO THE U.P. SATURDAY EVENING. SHOULD SEE A WARMER AND MORE
HUMID NIGHT...BUT WILL STICK WITH A DRY FORECAST.

REST OF THE FORECAST...SUNNY...WARM AND HUMID ON SUNDAY WITH
SOUTHERLY FLOW STRENGTHENING.  THE NEXT FRONT WILL BE MOVING INTO
FAR NORTHWEST WI LATE SUNDAY NIGHT.  THE GFS IS A LITTLE QUICKER
BRINGING PRECIP INTO N-C WISCONSIN THAN OTHER GUIDANCE...AND THIS
LOOKS A LITTLE TOO QUICK SO WILL BACK OFF SOME.  THE FRONT WILL MOVE
ACROSS THE REGION MONDAY AND MONDAY NIGHT.  THE GFS PUSHES PWATS IN
EXCESS OF 2.0 INCHES INTO THE REGION ALONG WITH MODERATE INSTABILITY
AND SHEAR.  LOCALLY HEAVY RAINFALL WILL BE POSSIBILITY WITH ANY
STORMS...BUT SEVERE POTENTIAL WILL DEPEND ON FRONTAL TIMING AND
AMOUNT OF HEATING...WHICH IS TOO EARLY TO TELL YET.  TURNING COOLER
AND DRIER BEHIND THE FRONT FOR THE MIDDLE OF NEXT WEEK.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 106 PM CDT THU JUL 2 2015

CLEAR SKIES AND LIGHT WINDS EXPECTED THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS ACROSS
NORTHERN WISCONSIN FRIDAY AFTERNOON AND EVENING AS A COLD FRONT
APPROACHES FROM THE NORTH.



RDM.
&&

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

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......MPC
AVIATION.......RDM


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