Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 222251 AAA
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
451 PM CST SAT NOV 22 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.UPDATE...
ISSUED AT 447 PM CST SAT NOV 22 2014

UPDATED TO ISSUE A DENSE FOG ADVISORY FOR MUCH OF CENTRAL
WISCONSIN. VISIBILITIES CONTINUE TO FALL WITH INCREASING SURFACE
DEWPOINTS. THE FOG DEVELOPED IN A WEAK SURFACE RIDGE OVER CENTRAL
WISCONSIN LATE THIS AFTERNOON. ITS POSSIBLE THE DENSE FOG MAY
DISSIPATE A TAD OVER CENTRAL WISCONSIN WITH AN INCREASING PRESSURE
GRADIENT LATER TONIGHT. BUT ITS ALSO POSSIBLE THE DENSE FOG
ADVISORY MAY NEED TO BE EXPANDED OVER THE NORTHERN WISCONSIN SNOW
PACK. SO OVERALL REACTING TO CURRENT CONDITIONS AND WILL MONITOR
FOR POSSIBLE EXPANSIONS TO THE HEADLINE TONIGHT.
&&

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 248 PM CST SAT NOV 22 2014

THE WARM-UP IS WELL UNDERWAY AS TEMPS HAVE FINALLY SURPASSED THE
FREEZING MARK OVER NE WI. MAIN FCST ISSUE FOR TNGT WL BE THE FOG
AND THE POTENTIAL FOR LOCALLY DENSE FOG TO DEVELOP. EXTENT OF
RAINFALL TO BE THE ISSUE FOR SUNDAY AS TWO SYSTEMS TAKE AIM AT WI.

MDLS ALL LIFT A WRMFNT NWD THRU WI TNGT...BRINGING EVEN WARMER...
MORE MOIST AIR MASS INTO THE REGION. FCST SOUNDINGS STILL INDICATE
A DRY WEDGE OF AIR ALOFT...THUS PCPN FOR MOST OF THE NGT WL BE IN
THE FORM OF DRIZZLE. CURRENT INDICATIONS ARE FOR TEMPS TO SLOWLY
RISE OVRNGT...HOWEVER GROUND TEMPS ACROSS THE NORTH ARE STILL
BELOW FREEZING...SO AM WORRIED ABOUT THE POSSIBILITY OF GLAZING ON
AREA ROADS. FORTUNATELY...IT APPEARS THAT PCPN AMOUNTS WL BE
LIMITED ACROSS THE NORTH...THUS WL NOT ISSUE ANY HEADLINES FOR
FREEZING PCPN. OTHERWISE...FOG TO BE THE MAIN CONCERN FOR TNGT
ESPECIALLY ACROSS CNTRL/N-CNTRL WI WHERE A SNOW PACK REMAINS.
VSBYS THAT DO RISE A BIT LATE THIS AFTERNOON/EARLY THIS EVENING
ARE EXPECTED TO BEGIN DROPPING AGAIN WITH THE MOISTURE INCREASE...
LONGER NGTS AND DEW POINTS RISING ABOVE 32 DEGS. THERE IS AN
INCREASING CHC OF SEEING WIDESPREAD FOG WITH LOCALLY DENSE FOG
LATER TNGT. AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE
DECIDED TO FOREGO A DENSE FOG ADVY FOR NOW AND INSTEAD ISSUE A SPS
FOR THE FOG SITUATION.

A STRONG SRN STREAM SYSTEM COMPRISED OF AN INTENSIFYING SFC LOW
AND NEGATIVELY-TILTED SHORTWAVE TROF...IS FCST TO LIFT NEWD INTO
THE MID-MS VALLEY ON SUNDAY. MEANWHILE...A NRN STREAM SHORTWAVE
TROF WL BE MOVING ACROSS THE NRN/CNTRL PLAINS...PRECEDED BY A
CDFNT THAT THE MDLS BRING INTO WRN WI LATE IN THE DAY. INCREASING
FORCING/LIFT FROM SOUTH TO NORTH...COUPLED WITH MORE GULF MOISTURE
(DEW POINTS RISING INTO THE UPR 30S TO LWR 40S)...SHOULD BRING
INCREASING PCPN CHCS TO NE WI. HAVE MAINTAINED THE HIGHEST POPS
ACROSS THE SE 1/2 OF THE FCST AREA...AS WELL AS KEEP THE MENTION
OF FOG. SUNDAY WL BE THE WARMEST DAY NE WI WL GET TO SEE AS COLDER
AIR IS SET TO ARRIVE SUNDAY NGT BEHIND THE CDFNT.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 248 PM CST SAT NOV 22 2014

MAIN FCST CONCERNS REVOLVE AROUND CYCLOGENESIS ASSOCIATED WITH
PHASING NORTHERN AND SOUTHERN STREAM ENERGY SUNDAY NIGHT INTO
MONDAY NIGHT...AND ASSOCIATED PCPN TRENDS...SNOWFALL AMOUNTS
AND WINDS.

CONSIDERING THE TYPICAL PROBLEMS THAT MODELS HAVE WITH PHASING
SYSTEMS...THERE IS VERY GOOD AGREEMENT ON THE TRACK AND STRENGTH
OF THE SFC LOW THAT DEEPENS AS IT LIFTS NE THROUGH THE GREAT
LAKES ON SUNDAY NIGHT AND MONDAY. 12Z MODELS AND ENSEMBLE MEANS
SHOW SOLID SUPPORT FOR A LOW REACHING SOUTHERN LAKE MICHIGAN
AROUND 06Z/MON...NORTHERN LOWER MI 12Z/MON...EAST OF LAKE SUP
18Z/MON...THEN JUST SOUTH OF JAMES BAY BY 00Z/TUE...WITH A
MINIMUM PRESSURE SOMEWHERE BETWEEN 970-980 MB. MODEL CONCENSUS
SHOWS STEADY RAIN OVERSPREADING THE AREA SUNDAY NIGHT...WITH
A MIX OF RAIN/SNOW ARRIVING IN OUR FAR WESTERN COUNTIES LATE.
THE RAIN/SNOW LINE WILL QUICKLY PROGRESS EAST ACROSS THE CWA
MONDAY MORNING...REACHING THE LKSHR TOWARD MIDDAY. DEEP
CYCLONIC FLOW WILL CONTINUE INTO THE MONDAY NIGHT AS THE LOW
GRADUALLY PULLS AWAY FROM THE REGION. SNOWFALL TOTALS ON MONDAY
AND MONDAY NIGHT ARE EXPECTED TO BE IN THE 3 TO 6 INCH
RANGE...EXCEPT 5 TO 9 INCHES IN VILAS COUNTY...WHERE A PERIOD OF
LAKE ENHANCEMENT WILL OCCUR. THESE AMOUNTS MATCH UP FAIRLY WELL
WITH WWD TOTALS. FAVOR THE STRONGER WINDS SEEN ON MAV GUIDANCE...
AS THE SYSTEM WILL BE FAIRLY WOUND UP. A GALE WARNING MAY NEED TO
BE ISSUED FOR MONDAY AFTERNOON AND EVENING.

A WEAK SFC RIDGE WILL BRING DRIER AIR AND CAUSE WINDS TO BACK
WEST ON TUESDAY...WHICH WILL BRING AN END TO LINGERING LAKE
EFFECT OVER NC WI. DRY CONDITIONS WILL PERSIST INTO TUESDAY
NIGHT...ALTHOUGH CLOUDS WILL BE ON THE INCREASE LATE.

MODELS ARE STILL STRUGGLING WITH A CLIPPER SYSTEM THAT IS FCST
TO MOVE THROUGH THE REGION WED/WED NGT. THE ECMWF IS STILL
STRONGEST WITH THIS SYSTEM...AND WOULD WARRANT LIKELY POPS
AND A MENTION OF SNOW ACCUMS IN THE FCST. HOWEVER...OTHER
MODELS ARE NOT AS ROBUST...SO WILL JUST KEEP CHC POPS FOR NOW.
A PERIOD OF LAKE-EFFECT WILL PROBABLY OCCUR OVER NC WI ON
THURSDAY...AS WINDS TURN NNW IN THE WAKE OF THE CLIPPER.

FRIDAY AND SATURDAY LOOK GENERALLY DRY...WITH COLD TEMPERATURES
ENTRENCHED OVER THE REGION.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 451 PM CST SAT NOV 22 2014

WIDESPREAD LIFR/IFR CIGS WITH AREAS OF LIFR/IFR VSBYS WILL
CONTINUE TONIGHT INTO SUNDAY. RAIN WILL BE ON THE INCREASE LATE SUNDAY
AS A DEEPENING LOW PRESSURE SYSTEM LIFTS NORTHEAST FROM THE MID
MISSISSIPPI VALLEY REGION INTO THE LOWER GREAT LAKES DEVELOPS BY
SUNDAY EVENING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ018>020-030-031-
035>037.
&&

$$

UPDATE.........TDH
SHORT TERM.....KALLAS
LONG TERM......KIECKBUSCH
AVIATION.......TDH






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