Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 291102
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
602 AM CDT MON JUN 29 2015

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 319 AM CDT MON JUN 29 2015

SOME CLEARING HAS CAUSED PATCHY FOG ACROSS PORTIONS OF CENTRAL AND
NORTH CENTRAL WISCONSIN EARLY THIS MORNING...WHICH IS EXPECTED TO
PERSIST THROUGH THE MORNING HOURS. VISIBILITIES ARE FLUCTUATING
QUITE A BIT TO THE FAR WEST...WITH CLEARING BEING THE NECESSARY
COMPONENT FOR ANY DENSE FOG DEVELOPMENT. GIVEN THE VARIABILITY IN
VISIBILITIES WILL HANDLE ANY FOG WITH SPS STATEMENTS AS NECESSARY
AS FOG DOES NOT APPEAR TO BE WIDESPREAD AT THIS TIME.

A SHORTWAVE TROF WILL TRACK THROUGH WISCONSIN THIS AFTERNOON AND
THIS EVENING...BRINGING A RENEWED CHANCE FOR SHOWERS AND
THUNDERSTORMS TO THE AREA. MODELS HAVE BACKED OFF A BIT ON THE
INSTABILITY THIS RUN...WITH MUCAPES OF 1000 TO 1500 J/KG EXPECTED
DURING THE AFTERNOON HOURS. 0-6 KM BULK SHEAR VALUES ARE STILL A
MODEST 20 TO 25 KNOTS. GIVEN THE INSTABILITY AND THE LONG SKINNY
CAPE PROFILES SOME HAIL AND LOCALLY HEAVY RAIN IS POSSIBLE FROM
THESE STORMS ACROSS CENTRAL AND NORTH CENTRAL WISCONSIN.

A COLD FRONT IS THEN PROGGED TO TRACK THROUGH WISCONSIN LATER
TONIGHT AND INTO TUESDAY MORNING...USHERING IN A COOLER AIRMASS
ACROSS THE WESTERN GREAT LAKES. ON TUESDAY YET ANOTHER TROF WILL
TRACK THROUGH THE WESTERN GREAT LAKES...THIS TIME OVER MAINLY THE
EASTERN CWA...BRINGING ANOTHER CHANCE FOR SHOWERS WITH A FEW
RUMBLES OF THUNDER TO NORTHEAST WISCONSIN. INSTABILITY TUESDAY
WILL BE MUCH LESS THAN TODAY WITH MUCAPE VALUES OF ONLY A FEW
HUNDRED J/KG. GIVEN THE LOWER INSTABILITY AND WEAKER SHORTWAVE
WILL KEEP POPS FAIRLY LOW ON TUESDAY...MAINLY IN THE CHANCY
CATEGORY.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 319 AM CDT MON JUN 29 2015

PERSISTENT AMPLIFIED MEAN FLOW CONSISTING OF A WRN CONUS UPR RDG
AND E-CNTRL CONUS UPR TROF WL REMAIN INTACT INTO NEXT WEEKEND. THE
NW FLOW ALOFT OVER WI WL CONT TO SEND MID-LEVEL DISTURBANCES IN
OUR DIRECTION AND TIMING THESE FEATURES HAS PROVEN DIFFICULT AT
BEST. MODELS ARE HINTING AT A LARGE SYSTEM TO MOVE FROM THE GULF
OF ALASKA SEWD INTO WRN CANADA NEXT WEEKEND. THIS SYSTEM WL
FLATTEN THE UPR RDG AND BRING MORE OF A NEAR-ZONAL FLOW TO THE
NRN TIER OF STATES. PCPN CHCS TO REMAIN SPOTTY WITH FRI LOOKING
LIKE THE NEXT CHC OF SEEING ORGANIZED SHWRS/POSSIBLE TSTMS. TEMPS
TO RUN BELOW NORMAL THRU FRI AND THEN SLOWLY WARM TO AROUND NORMAL
NEXT WEEKEND.

WHILE A LINGERING SHWR CANNOT BE RULED OUT OVER ERN WI TUE
EVENING...IT APPEARS THAT THE SHORTWAVE WL HAVE SHIFTED FAR ENUF
EAST TO KEEP THE FCST AREA DRY FOR NOW. OTHERWISE...A WEAK AREA OF
HI PRES IS FCST TO DROP INTO NW WI BY 12Z WED AND PROVIDE ENUF DRY
AIR TO AT LEAST ALLOW SKIES TO BECOME PARTLY CLOUDY. DEPENDING ON
HOW MUCH PCPN FALLS MON AND TUE...WE COULD BE LOOKING AT THE
DEVELOPMENT OF EITHER PATCHY FOG OR A STRATUS DECK. HAVE ADDED THE
PATCHY FOG TO THE FCST FOR NOW. MIN TEMPS WL RANGE FROM THE MID TO
UPR 40S NORTH...LWR TO MID 50S SOUTH.

THIS WEAK SFC HI TO REMAIN PARKED OVER THE WRN GREAT LAKES ON WED
WITH THE PRIMARY SYSTEM TRACK MOVING FROM THE NRN PLAINS SE TO THE
MID-MS VALLEY. UNDER A MIX OF SUN AND CLOUDS WITH MODEST N-NE
WINDS...LOOK FOR MAX TEMPS TO REMAIN BELOW NORMAL AS MAX TEMPS
ONLY REACH THE UPR 60S NEAR LAKE MI...MAINLY IN THE 70-75 DEG
RANGE ELSEWHERE.

LITTLE CHANGE SYNOPTICALLY FOR WED NGT OR THU AS THE WEAK SFC HI
RESIDES OVER NRN SECTIONS OF THE GREAT LAKES AND MID-LEVEL
DISTURBANCES SLIDE SEWD JUST TO OUR WEST AND SOUTH. PREFER TO KEEP
THE FCST AREA DRY...BUT THERE WL BE SOME CLOSE CALLS OVER CNTRL WI
AS SHWR/TSTM ACTIVITY SHOULD NOT BE THAT FAR AWAY. TEMPS WL CONT
TO RUN CLOSE TO 5 DEGS BELOW NORMAL FOR EARLY JULY.

THE MAIN FCST STICKING POINT FOR THE END OF THE WORK WEEK WL BE
THE MOVEMENT OF THE NEXT SIGNIFICANT SHORTWAVE TROF PUSHING EWD
OUT OF THE PLAINS. MODELS ARE HAVING ISSUES WITH THIS FEATURE...
AS WELL AS PLACEMENT OF THE PCPN. IF THE TROF ARRIVES THU NGT...
INSTABILITY WL BE LIMITED SO ANY PCPN WOULD BE SCATTERED AT BEST.
IF THE TROF ARRIVES FRI AFTERNOON...INSTABILITY WL BE STRONGER SO
A BETTER CHC OF SEEING SHWRS/TSTMS. DUE TO THE UNRESOLVED TIMING
PROBLEM...HAVE KEPT A FAIRLY LOW POP THU NGT AND A BETTER CHC POP
ON FRI. THE WRN CONUS UPR RDG TO HAVE STARTED TO FLATTEN A BIT...
THUS ALLOWING WARMER AIR TO BEGIN SPREADING EAST. MAX TEMPS FOR
FRI ARE EXPECTED TO STILL BE BELOW NORMAL...BUT BY JUST A FEW
DEGS.

THIS SHORTWAVE TROF IS PROGGED TO DEPART THE WRN GREAT LAKES FRI
NGT AND MAY NEED TO LEAVE A TOKEN POP IN THE FCST UNTIL THE TIMING
BECOMES BETTER DEFINED. MODELS ARE IN FAIR AGREEMENT WITH THE
APPROACH OF SHORTWAVE RIDGING TOWARD NE WI ON SAT. WINDS WL BEGIN
TO GET MORE OF A SOUTHERLY COMPONENT (SW CNTRL WI - SE NEAR LAKE
MI) AND THIS SHOULD PROVIDE A BOOST IN TEMPS...AT LEAST NEAR
NORMAL.

THE MEAN FLOW TO BECOME NEAR-ZONAL FROM THE NRN PLAINS TO THE
GREAT LAKES BY THE END OF THE WEEKEND AND THIS FAST FLOW WL BRING
THE NEXT SHORTWAVE TROF AND A CDFNT TOWARD WI ON SUNDAY. AS ONE
WOULD EXPECT WITH A PATTERN CHANGE...MODELS DIFFER ON HOW FAST TO
SEND THIS SYSTEM AT US ON SUNDAY. SLOWER ALWAYS SEEMS TO BE THE
WAY TO GO...THUS WL ONLY MENTION A SLGT CHC POP FOR NOW. SUNDAY
ALSO APPEARS TO BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH MAX
TEMPS IN THE MID TO UPR 70S NEAR LAKE MI...UPR 70S TO LWR 80S
ELSEWHERE. IF THE PCPN DOES HOLD OFF...PARTS OF CNTRL WI COULD SEE
MID 80S.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 601 AM CDT MON JUN 29 2015

BREAKS IN THE CLOUDS AND LIGHT WINDS HAS BROUGHT SOME FOG DURING
THE EARLY MORNING OVER NC/C WI...WHERE RECENT RAINS HAVE
OCCURRED. COULD SEE SOME PATCHY LIFR/VLIFR CONDITIONS FOR THE NEXT
HOUR OR SO BEFORE THE FOG QUICKLY MIXES OUT.

A SHORT-WAVE TROF AND SFC COLD FRONT WILL AFFECT THE REGION DURING
THE LATE AFTERNOON AND EVENING...AND SHOULD GENERATE NMRS SHOWERS
AND SCT TSTMS IN A MODERATELY UNSTABLE AIR MASS. WILL KEEP TEMPO
GROUPS FOR TSTMS AT RHI/AUW/CWA DURING THE LATE AFTERNOON AND
EARLY EVG HOURS. CONFIDENCE IN THUNDER FOR THE EASTERN TAF SITES
IS NOT AS HIGH GIVEN LESS INSTABILITY...SO WILL PROBABLY HOLD OFF
ON TSTMS IN THE ATW/GRB/MTW TAFS FOR NOW.
&&

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

$$

SHORT TERM.....KURIMSKI
LONG TERM......KALLAS
AVIATION.......KURIMSKI



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