Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 281935
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
235 PM CDT SUN SEP 28 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 234 PM CDT SUN SEP 28 2014

SEVERAL FCST ISSUES TO DEAL WITH OVER THE NEXT 24 HOURS AS A
STRONG CDFNT TO MOVE THROUGH THE REGION ON MON. INITIALLY...WL
HAVE TO DEAL WITH ANOTHER ROUND OF FOG TNGT. NEXT...TIMING OF THE
CDFNT INTO NRN WI AFTER MIDNGT AND ASSOCIATED PCPN CHCS. THEN...
THE FNT PUSHES SOUTH THRU THE REST OF NE WI ON MON WITH QPF
AMOUNTS IN QUESTION. LASTLY...HOW STRONG WL THE WINDS BE BEHIND
THE CDFNT?

THE 19Z MSAS SFC ANALYSIS SHOWED A SPRAWLING AREA OF HI PRES OVER
THE GREAT LAKES AND OHIO RIVER VALLEY. A CDFNT EXTENDED FROM ERN
SD NEWD TO NE MN AND THEN EWD ACROSS EXTREME SRN ONTARIO. VSBL
SATL IMAGERY DID INDICATE SOME TOWERING CU OVER UPR MI AND RADAR
WAS PICKING UP ON SCT SHWRS WITH AN EWD MOVEMENT.

THE START OF A SIGNIFICANT WEATHER CHANGE TO OCCUR LATE TNGT OVER
NRN WI AS A STRONG W-E ORIENTATED CDFNT DROPS SOUTH. WHILE PATCHY
FOG WL START THE LATE EVENING/OVERNIGHT HOURS FOR THE ENTIRE FCST
AREA (ONCE AGAIN)...THE CDFNT IS FCST TO MOVE SWD AND REACH AREAS
JUST SOUTH OF HWY 8 BY DAYBREAK. STRONGEST MID-LEVEL FORCING
TRAILS THE FNT...THUS PCPN CHCS LAG THE FROPA BY AN HOUR OR TWO.
THIS TIMING WOULD BRING CHC POPS INTO NRN WI SHORTLY AFTER MIDNGT
WITH HIGHEST VALUES ALONG THE MI BORDER. CNTRL/E-CNTRL WI TO
REMAIN DRY TNGT WITH THE PATCHY FOG BEING THE ONLY CONCERN. MIN
TEMPS SHOULD BE A COUPLE OF DEGS WARMER THAN LAST NGT...WITH THE
EXCEPTION OF NRN WI BEHIND THE CDFNT WHERE READINGS COULD DIP INTO
THE MID 40S.

THE CDFNT DRIVES SOUTH THRU THE REST OF THE FCST AREA MON MORNING
WITH A SHARP WIND SHIFT TO THE NORTH AND A DROP IN TEMPS. EXACTLY
WHEN THIS FNT MOVES THRU WL DETERMINE HOW WARM READINGS WL GET IN
THE MORNING. AS FOR PCPN...STRONGEST Q-G/FRONTOGENETICAL FORCING
TO PUSH TOWARD THE ERN GREAT LAKES...THEREBY CLIPPING FAR NE WI.
HAVE KEPT THE LIKELY WORDING FOR THIS PART OF THE FCST AREA WITH
MEDIUM CHC POPS OVER CNTRL WI WHERE FORCING TO BE THE WEAKEST.
N-CNTRL WI SHOULD SEE PCPN CHCS TAIL OFF DURING THE AFTERNOON AS
DRIER AIR/SUBSIDENCE BEGINS TO PUSH SWD AHEAD OF HI PRES MOVING
ACROSS SRN CANADA. TEMPS TO BE TRICKY TO SAY THE LEAST WITH
MID/LATE MORNING MAXES OVER CNTRL/E-CNTRL WI AND AFTERNOON MAXES
OVER THE NORTH. LATEST THINKING WOULD BE UPR 40S TO MID 50S
NORTH...TO THE LWR 70S FAR SOUTH EARLY BEFORE FALLING THRU THE
AFTERNOON. THE LAST FACTOR TO BRING UP WL BE THE GUSTY N-NE WINDS
BEHIND THE CDFNT OVER ERN WI. SMALL CRAFT ADVYS WL LIKELY BE
NEEDED.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 234 PM CDT SUN SEP 28 2014

EARLY IN THE PERIOD...LINGERING SHOWERS ASSOCIATED WITH BACKDOOR
COLD FRONT WILL BE MOVING OUT EARLY MONDAY EVENING. INCOMING DRY
AIR FROM SPRAWLING CANADIAN HIGH WILL PUSH SOUTH ACROSS THE
AREA...THOUGH SOME UNCERTAINTY WITH SPEED OF CLEARING DUE TO
POSSIBILITY OF LAKE CLOUDS BECOMING TRAPPED BENEATH LOWERING
INVERSION. HIGH PRESSURE WILL BE OVER THE AREA ON TUESDAY AS THE
FRONT STALLS ACROSS IL.

THE FRONT STARTS TO RETURN NORTH TUESDAY NIGHT AND WEDNESDAY AS
THE NEXT SHORTWAVE TROF MOVES TOWARD THE MIDWEST. AIR INITIALLY
DRY...SO RAIN WILL ONLY SLOWLY EDGE EAST INTO EASTERN PART OF
SERVICE AREA. CHANCES FOR RAIN INCREASE WEDNESDAY NIGHT AND
THURSDAY WHEN HEIGHT FALLS ARRIVE AHEAD OF THE DEEP WESTERN NOAM
TROUGH AND COLUMN MOISTENS. GFS CONTINUES TO SHOW SIGNIFICANT RAIN
EVENT THURSDAY NIGHT INTO FRIDAY AS INTENSIFYING LOW PRESSURE
CROSSES THE REGION...BUT BOTH 28/12Z ECMWF AND GEM MOVE FRONT EAST
WITH LITTLE SECONDARY DEVELOPMENT. WILL SIDE WITH ECMWF/GEM BLEND
FOR THIS SYSTEM.

COOL PERIOD CONTINUES AS NW FLOW ESTABLISHES ITSELF ACROSS EASTERN
NOAM.

TEMPS USUAL BLEND OF BEST PERFORMING GUIDANCE.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1212 PM CDT SUN SEP 28 2014

VFR CONDITIONS TO PREVAIL INTO THE MID-EVENING HOURS BEFORE PATCHY
FOG DEVELOPS ONCE AGAIN AND SENDS VSBYS DOWN MAINLY IN THE MVFR
RANGE. THERE IS POTENTIAL ONCE AGAIN FOR THE RHI TAF SITE TO
BRIEFLY DIP TO LIFR RANGE BEFORE CLOUDS BEGIN TO ARRIVE AHEAD OF A
STRONG CDFNT. THIS FNT IS FCST TO DROP INTO NRN WI LATE TNGT AND
THEN SWEEP SWD THRU THE REST OF NE WI MON MORNING. A SHARP WIND
SHIFT TO THE NORTH IS EXPECTED BEHIND THE FNT WITH A CHC OF SHWRS
THRU THE DAY. CIGS WL ALSO DROP INTO THE IFR/MVFR RANGE BEHIND THE
FNT. NRN WI MAY SEE CIGS BEGIN TO RISE LATER MON AFTERNOON AS
DRIER AIR BEGINS TO PUSH INTO THE REGION.
&&

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

$$

SHORT TERM.....AK
LONG TERM......JKL
AVIATION.......AK






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