Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 272318
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
618 PM CDT SAT SEP 27 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 218 PM CDT SAT SEP 27 2014

BEAUTIFUL EARLY AUTUMN WEATHER TO CONT THRU THE END OF THE WEEKEND
WITH WELL-ABOVE NORMAL TEMPS...LIGHT WINDS AND PLENTY OF SUNSHINE.
THE ONLY REAL FCST ISSUE TO BE HOW EXTENSIVE THE FOG WL BE LATE
TNGT.

THE 19Z MSAS SFC ANALYSIS INDICATED AN AREA OF HI PRES OVER THE
ERN GREAT LAKES...A SERIES OF WEAK LOW PRES AREAS OVER THE NRN
PLAINS/NRN HI PLAINS WITH A QUASI-STNRY BOUNDARY CONNECTING ALL OF
THEM AND A CDFNT STRETCHED FROM HUDSON BAY SWWD TO EXTREME SE
MANITOBA. VSBL SATL IMAGERY SHOWED A MIX OF DAYTIME CU AND HI
CLOUDS OVER WI WITH THE RADAR MOSAIC PICKING UP A FEW SHWRS OVER
IA ASSOCIATED WITH A WEAK UPR LOW PRES SYSTEM.

MDLS CONCUR IN DRIFTING THE WEAK CUT-OFF UPR LOW NWD TOWARD THE NW
IA/SW MN VICINITY TNGT. CURRENT SHWR/ISOLATED TSTM ACTIVITY OVER
NRN IA WL REMAIN TO OUR WEST WITH ONLY HI CLOUDS DRIFTING OVER NE
WI. BIGGEST FCST PROBLEM FOR THE FCST AREA TNGT TO BE THE EXTENT
OF FOG AS LOW-LEVEL MOISTURE CONTS TO SLOWLY INCREASE OVER THE
REGION. ANOTHER NGT OF NEAR IDEAL RADIATIONAL COOLING WL ALLOW
TEMPS TO QUICKLY FALL TO NEAR THE DEW POINTS AND MAKE PATCHY FOG
AN ALMOST FOREGONE CONCLUSION. EXPECT THICKEST FOG TO BE CLOSER TO
LAKE MI AS PER PREVIOUS NGTS WITH A TOUCH OF A SE WIND COMPONENT.
MIN TEMPS SHOULD BE CLOSE TO VALUES SEEN THIS MORNING (PERHAPS A
DEG OR TWO WARMER) WITH MOST LOCATIONS IN THE UPR 40S TO LWR 50S.

THE UPR LOW OVER THE MIDWEST IS FCST TO ESSENTIALLY DESOLVE NEARLY
IN PLACE ON SUNDAY AND WL HAVE NO INFLUENCE ON OUR WEATHER. THE
MAIN WEATHER OF INTEREST TO BE A NEARLY W-E ORIENTATED CDFNT WHICH
IS PROGGED TO DROP SOUTH INTO NRN SECTIONS OF THE GREAT LAKES
SUNDAY AFTERNOON. MOST OF THE MID-LEVEL FORCING TO EXIST ALONG AND
NORTH OF THE CDFNT...THUS DO NOT BELIEVE THE GFS IN TRYING TO
BRING PCPN INTO NRN WI ON SUNDAY. HAVE KEPT ALL OF NE WI DRY WITH
ONE MORE DAY OF TEMPS WELL ABOVE NORMAL (HINT:  GET OUT AND ENJOY
THE DAY!). LOOK FOR MAX TEMPS AWAY FROM LAKE MI TO AGAIN REACH THE
75-80 DEG RANGE...WITH A FEW LWR 80S IN THE TYPICALLY WARMER
LOCATIONS OF CNTRL WI.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 218 PM CDT SAT SEP 27 2014

THE MEDIUM RANGE MODELS CONTINUE TO DIFFER WITH THE TIMING/STRENGTH
OF A SHORTWAVE AND ASSOCIATED BACKDOOR COLD FRONT DROPPING THROUGH
THE NORTHERN GREAT LAKES LATE SUNDAY NIGHT THROUGH MONDAY EVENING.
27/12Z ECMWF A BIT MORE AGRESSIVE WITH PRECIP AMOUNTS...BUT TIMING
IS GENERALLY IN LINE WITH GFS. LITTLE CHANGE MADE TO FORECAST IN
THIS PERIOD OUTSIDE OF RAISING RAIN CHANCES A BIT MONDAY
AFTERNOON. WILL SEE INCREASING CLOUDS ACROSS THE NORTH LATE SUNDAY
NIGHT AND CHANCE OF RAIN TOWARDS DAYBREAK MONDAY. THE FRONT WILL
MOVE ACROSS NORTHERN WISCONSIN MONDAY MORNING AND CENTRAL
WISCONSIN MONDAY AFTERNOON.

UPPER LEVEL RIDGE BUILDS IN FOR TUESDAY INTO MIDWEEK BEFORE LARGE TROF
APPROACHES REGION FROM THE WEST. CHANCE OF PRECIP RETURNS LATER ON
WEDNESDAY...THEN INCREASES THURSDAY AND FRIDAY AS SLOW-MOVING TROF
EDGES EAST. 27/12Z GFS IS A BIT FASTER THAN ECMWF...BUT OVERALL
UPPER LEVEL AND SURFACE PATTERN SIMILAR.

TEMP FORECAST THROUGH PERIOD A BLEND OF BEST PERFORMING MODELS.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 618 PM CDT SAT SEP 27 2014

MOSTLY CLEAR SKIES EXPECTED TONIGHT AND SUNDAY WITH
A CHANCE OF IFR GROUND FOG BETWEEN 09Z AND 13Z SUNDAY. IF ANY FOG
OCCURS IT WILL QUICKLY DISSIPATE.
&&

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

$$

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






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