Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 260818
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
318 AM CDT SUN JUL 26 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 317 AM CDT SUN JUL 26 2015

SATURDAY WAS THE WARMEST DAY OF THE SUMMER SO FAR AT
WAUSAU AND GREEN BAY (87 AT BOTH) AND THE SECOND WARMEST OF THE
YEAR AT RHINELANDER AND OSHKOSH (85 AT EACH). THE NEXT COUPLE OF
DAYS WILL BE THIS WARM OR MAYBE A DEGREE OR TWO WARMER AS HEIGHTS
BUILD AS UPPER RIDGE ARRIVES FROM THE NORTHERN PLAINS.

DRY AIR IN THE LOW AND MID LEVELS SHOULD MAKE FOR A VERY WARM BUT
NOT INCREDIBLY HUMID DAY THIS AFTERNOON. MODEL FORECAST SOUNDINGS
LOOK LIKE SOUNDINGS COMMONLY FOUND IN THE WESTERN HIGH PLAINS WITH
DRY LAPSE RATES TO 700 MB. HIGHS TODAY SHOULD BE A NEAR OR A
DEGREE OR SO ABOVE YESTERDAY.

LOWS TONIGHT WILL BE 3 TO 5 DEGREES ABOVE NORMAL WITH LIGHT WINDS
AND INCREASING MIDDLE AND HIGH CLOUDS AFTER MIDNIGHT. GROUND FOG
POSSIBLE DEPENDING ON THE AMOUNT OF CLOUDS.

SURFACE HIGH MOVES TO THE EAST MONDAY WITH SOUTH WINDS BRINGING
HIGHER DEWPOINTS TO THE REGION. TEMPERATURES MAY NOT BE ANY WARMER
THAN TODAY BUT THE HIGHER HUMIDITIES WILL MAKE IT SEEM HOTTER. A
WARM FRONT APPROACHING FROM THE SOUTHWEST COULD BRING SOME
ELEVATED THUNDERSTORMS LATE IN THE DAY.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 317 AM CDT SUN JUL 26 2015

THE MODEST UPR RDG THAT HAS BEEN PARKED OVER THE CNTRL CONUS FOR
ALMOST A WEEK IS STILL FCST TO RETROGRADE TOWARD THE WRN CONUS
TOWARD THE END OF THIS WEEK. AS THIS OCCURS...AN UPR TROF IS
PROGGED TO MOVE FROM THE PAC NW EWD ACROSS SRN CANADA/NRN TIER OF
STATES AND EVENTUALLY GENERATE A BROAD UPR TROF OVER THE ERN
CONUS. THESE CHANGES WL TURN THE MEAN FLOW FROM SW TO NW OVER
WI...HOWEVER TEMPS WL REMAIN AT OR ABOVE NORMAL UNTIL FURTHER
NOTICE. PCPN CHCS TO BE LINKED TO THE UPR TROF/SFC CDFNT LATE TUE
INTO WED MORNING AND A SECOND CDFNT FRI INTO FRI NGT.

THE PRIMARY FOCUS FOR POSSIBLE SHWR/TSTM DEVELOPMENT MON NGT/TUE
WL BE THE NWD MOVEMENT OF A WRMFNT AND INCREASE IN ISEN LIFT INTO
WI. THE TIMING OF THIS WRMFNT WL BE CRITICAL BECAUSE A FASTER
MOVEMENT COULD PROVIDE A CAP ON TUE AND PREVENT TSTMS FROM FIRING.
ON THE OTHER HAND...POTENTIAL FOR ELEVATED CONVECTION MON NGT
COULD SLOW THE NWD ADVANCE OF THE WRMFNT...THUS ALLOWING A
CONVECTIVE COMPLEX TO MOVE THRU WI WITH THE INCREASING INSTABILITY
AND NO CAP. FOR NOW...PREFER TO RUN A SMALL CHC POP FOR CNTRL WI
MON NGT PRIMARILY DUE TO THE ISEN LIFT AND THEN GO WITH CHC POPS
ON TUE AS THE WRMFNT WL BE IN OUR VCNTY. MAX TEMPS FOR TUE MAY BE
RESTRICTED A BIT BY MORE CLOUDS/PCPN CHCS WITH READINGS IN THE LWR
TO MID 80S N-CNTRL/LAKESHORE...MID 80S TO AROUND 90 DEGS SOUTH.

THE MOST LIKELY TIME FRAME FOR A MORE WIDESPREAD PCPN EVENT WL BE
TUE NGT AS A CDFNT SWEEPS INTO THE WRN GREAT LAKES AND RUNS INTO
THE UNSTABLE AIR MASS OVER WI. THE TRAILING UPR TROF IS FCST TO
MOVE INTO THE UPR MS VALLEY...THUS BETTER FORCING TO ACTUALLY PASS
TO OUR NORTH. SHEAR VALUES ARE RATHER WEAK AND TRAIL THE CDFNT AS
WELL. JUST CANNOT IGNORE THE INSTABILITY WITH THE LIFT FROM THE
CDFNT AND BOUNTIFUL MOISTURE AVAILABLE. LIKELY POP WORDING STILL
LOOKS GOOD FOR NOW ACROSS THE ENTIRE FCST AREA AND WL HAVE TO
WATCH FOR THE POSSIBILITY OF STRONG TO SEVERE TSTMS. THE CDFNT MAY
STILL BE IN THE PROCESS OF EXITING ERN WI WED MORNING...SO WL NEED
TO LEAVE AT LEAST A CHC FOR A LINGERING SHWR OR STORM. CONDITIONS
SHOULD BE IMPROVING BY WED AFTERNOON AS DRIER AIR MASS ADVECTS
INTO THE REGION. DEW POINTS ARE EXPECTED TO STEADILY DROP THRU THE
DAY WITH MAX TEMPS SLIPPING MAINLY INTO THE 80-85 DEG RANGE
(COOLEST N-CNTRL/WARMEST E-CNTRL).

QUIET CONDITIONS ARE EXPECTED FOR WED NGT THRU THU AS HI PRES TO
EXTEND FROM THE CNTRL PLAINS EWD TO THE OHIO RIVER VALLEY. THIS
WOULD PLACE NE WI ON THE NRN FRINGES OF THE SFC HI WITH A
PREVAILING W-NW WIND. COOLER AIR MASS OVER TEH REGION WL SEND
TEMPS CLOSER TO SEASONAL NORMALS FOR LATE JULY.

BY THE END OF THE WEEK...A NW FLOW ALOFT TO EXIST OVER THE GREAT
LAKES AND THIS LEAVES THE REGION VULNERABLE TO SFC CDFNTS OR MID-
LEVEL SHORTWAVES. TYPICALLY...TIMING OF THESE SYSTEMS BECOMES A
PROBLEM AND THIS TIME IS NO EXCEPTION. MODELS DO SHOW A WEAK CDFNT
TO PUSH SE INTO WI EITHER LATE THU NGT OR LATE FRI INTO FRI NGT. A
SECOND CDFNT COULD APPROACH WI AS EARLY AS SAT AFTERNOON OR HOLD
OFF BEYOND THE END OF THIS FCST CYCLE. HAVE FOLLOWED THE CONSENSUS
FOR NOW WHICH BRINGS A CHC OF SHWRS AND TSTMS TO THE FCST AREA
FROM THU NGT INTO SAT. TEMPS ARE FCST TO HOLD AT OR SLIGHTLY ABOVE
NORMAL AS WE HEAD INTO EARLY AUG.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1029 PM CDT SAT JUL 25 2015

WITH THE EXCEPTION OF PATCHY MVFR/IFR VSBYS DUE TO FOG...VFR
CONDITIONS TO PREVAIL OVERNIGHT INTO SUNDAY.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......TDH



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