Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 131129
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
529 AM CST SAT DEC 13 2014

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 254 AM CST SAT DEC 13 2014

CLOUD/FOG TRENDS ALONG WITH LIGHT PCPN WILL BE THE PRIMARY ISSUE
THROUGH SUNDAY.

EARLY THIS MORNING MUCH OF THE FORECAST AREA WAS UNDER BLANKET OF
STRATUS AND FOG. SATELLITE IMAGERY DID SHOW A SMALL POCKET OF
CLEAR SKIES OVER FAR NORTHEAST WISCONSIN NEAR IMT...WITH A MORE
SIGNIFICANT CLEAR REGION WORKING OVER SOUTHWEST WISCONSIN. THIS
CLEARING REGION MAY BRUSH WAUSHARA COUNTY EARLY THIS MORNING BUT
RAPIDLY DEVELOPING STRATUS OVER IOWA WAS QUICKLY FILLING IN THIS
HOLE. GUIDANCE SUGGESTS SKIES TO GO PARTLY CLOUDY THIS AFTERNOON
OVER CENTRAL AND EAST CENTRAL WISCONSIN. IT IS A SMALL POSSIBILITY
DUE TO THE INCREASING WINDS/GRADIENT ACROSS THE AREA. WILL CONTINUE TO
TREND TO MORE CLOUDS FOR NOW.

THIS INCREASING SOUTHWEST FLOW WAS ALSO ALLOWING INCREASING
DEWPOINTS TO WORK OVER THE SNOW COVER EARLY THIS MORNING WITH
WIDESPREAD DENSE FOG OVER WESTERN WISCONSIN STARTING TO SPILL INTO
CENTRAL AND NORTH CENTRAL WISCONSIN. WILL ISSUE A DENSE FOG
ADVISORY FOR THESE LOCATIONS THROUGH MOST OF THE MORNING HOURS AND
MONITOR FOR ANY NEEDED EXPANSION TO THE EAST.

MODELS IN GOOD AGREEMENT WITH LIGHT MEASUREABLE PCPN EVENTUALLY
SPREADING OVER THE AREA THROUGH SUNDAY. CONTINUED INCREASING
DEWPOINTS WILL FURTHER SATURATE THE BOUNDARY LAYER AND MAY
PROMPT ANOTHER DENSE FOG ADVISORY HEADLINE LATE TONIGHT INTO
SUNDAY.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 254 AM CST SAT DEC 13 2014

MEAN FLOW STILL EXPECTED TO SPLIT OVER THE ERN PACIFIC WITH A NRN
STREAM RUNNING ACROSS SRN CANADA (WITH AN OCNL DIP INTO THE NRN
TIER OF STATES) AND A SRN BRANCH RUNNING ACROSS THE SRN HALF OF
THE CONUS. AN ACTIVE START TO THE WORK WEEK AS AN INITIAL SRN
STREAM SYSTEM LIFTS NE INTO THE GREAT LAKES AND BRINGS RAIN...
THEN SNOW TO WI. WEATHER TO TURN QUIET THRU MID-WEEK WITH HI PRES
IN CONTROL...BEFORE ATTENTION TURNS TO THE NEXT SRN STREAM SYSTEM
WHICH MODELS DISAGREE WITH THE EVENTUAL TRACK FOR LATE NEXT WEEK.
TEMPS TO BE MUCH ABOVE NORMAL THRU MON WITH READINGS FALLING TO
ONLY SLIGHTLY ABOVE NORMAL FOR THE BULK OF NEXT WEEK.

SRN STREAM SYSTEM TO BE MOVING ACROSS THE CNTRL/SRN PLAINS SUNDAY
NGT AND CONTINUING TO PUMP WARM/MOIST AIR INTO WI ON S-SW WINDS.
THE DEPTH OF THE SATURATION WL CONT TO INCREASE THRU THE NGT...
THUS AREAS OF DRIZZLE MAY TURN TO RAIN CHCS AFTER MIDNGT.
OTHERWISE...A CLOUDY/MILD NGT IN STORE AND WL HAVE TO WATCH THE
FOG THICKNESS AS LOCALLY DENSE CONDITIONS/POSSIBLE HEADLINES CAN`T
BE RULED OUT. MIN TEMPS TO RANGE FROM THE UPR 30S TO LWR 40S.

THE SYSTEM IS PROGGED TO LIFT NE INTO THE MIDWEST ON MON AND WITH
MID-LEVEL FORCING/LIFT ON THE INCREASE INTO WI...WE SHOULD SEE
PCPN CHCS ALSO ON THE INCREASE. HIGHER QPF AMOUNTS SHOULD STILL BE
TO OUR SW CLOSER TO THE SYSTEM...THUS THE HIGHEST POPS HAVE BEEN
PLACED OVER CNTRL WI (LIKELY). MON TO BE THE LAST OF THE MILD DAYS
WITH MAX TEMPS TO RANGE FROM THE LWR 40S NORTH...MID TO UPR 40S
E-CNTRL WI.

MODELS HAVE FINALLY COME INTO FAIRLY GOOD AGREEMENT BY TAKING THIS
SYSTEM INTO THE WRN GREAT LAKES MON NGT (THE SFC LOW TO REACH
ROUGHLY SE WI/SRN LAKE MI BY 12Z TUE). THE DEFORMATION ZONE TO
EXTEND FROM SRN MN TO N-CNTRL WI...SO HIGHER QPF MAY NEED TO BE
SHIFTED A BIT TO THE NW FROM THE PREVIOUS FCST. THE MAIN FCST
ISSUE WL BE TIMING OF THE PCPN CHANGEOVER ACROSS NRN AND CNTRL WI
AS COLDER AIR GETS DRAWN INTO THE STATE. SNOW SHOULD BEGIN TO MIX
WITH RAIN DURING THE LATE EVENING N-CNTRL AND THEN OVER FAR NE/
PARTS OF CNTRL WI AFTER MIDNGT. ERN WI SHOULD REMAIN ALL LIQUID
THRU THE NGT. THERE COULD BE MINOR ACCUMULATIONS OVER N-CNTRL WI
BY DAYBREAK (GENERALLY AN INCH OR LESS) AS THE MIX DOES CHANGE TO
ALL SNOW. MIN TEMPS TO RANGE FROM THE MID 20S N-CNTRL...TO THE MID
30S NEAR LAKE MI. RAIN OR MIXED PCPN OVER ERN WI WL EVENTUALLY
SWITCH TO SNOW ON TUE AS COLDER AIR OVERSPREAD THE REGION BEHIND
THE SFC LOW WHICH THE MODELS TAKE INTO NRN SECTIONS OF LWR MI OR
LAKE HURON. ADDITIONAL MINOR ACCUMULATIONS ARE POSSIBLE...ESPECIALLY
TUE MORNING BEFORE DEEPER MOISTURE BEGINS TO PULL AWAY FROM WI
DURING THE AFTERNOON HOURS. HARD TO PUT A TOTAL ACCUMULATION NUMBER
JUST YET DUE TO THE UNKNOWN TIMING OF THE PCPN CHANGEOVER MON NGT
AND THE EXTENT OF MOISTURE OVER THE AREA ON TUE. AN EARLY ESTIMATE
WOULD BE AROUND ONE-HALF INCH OVER E-CNTRL WI TO AS MUCH AS THREE
INCHES N-CNTRL WI WHERE A LITTLE LAKE ENHANCEMENT IS POSSIBLE ON
TUE DUE TO N-NW WINDS OFF OF LAKE SUPERIOR. TEMPS ARE EXPECTED TO
BE STEADY OR SLOWLY FALL THRU THE DAY AS THE CAA TAKES OVER.

THERE CONTS TO BE SOME MODEL DISPUTE WITH RESPECT TO THE TRAILING
NRN STREAM SHORTWAVE TROF TUE NGT AS THE GFS CONTS TO CLOSE THIS
FEATURE OFF INTO AN UPR LOW OVER ND. OTHER MODELS FAVOR A MORE
PROGRESSIVE EWD MOVEMENT AND BRING THE SHORTWAVE TROF INTO THE
GREAT LAKES. HAVE FOLLOWED THE MAJORITY SOLUTION HERE WITH A SMALL
CHC OF SNOW SHWRS OR FLURRIES ACROSS THE FCST AREA. MAIN CONCERN
WL BE N-CNTRL WI WHERE PREVAILING NW WINDS AND 8H TEMPS AROUND
-12C OVER WRN LAKE SUPERIOR MAY PROVIDE LAKE EFFECT. THIS SYSTEM
DEPARTS THE REGION WED...LEAVING ONLY A MINIMAL CHC OF LAKE EFFECT
SNOW SHWRS PRIMARILY OVER VILAS CNTY. THE REST OF THE FCST AREA
SHOULD SEE PARTLY CLOUDY SKIES AS HI PRES BUILDS OVER THE UPR MS
VALLEY. MAX TEMPS BY WED TO ONLY BE A FEW DEGS ABOVE NORMAL.

A QUIET AND SOMEWHAT SEASONAL STRETCH OF WEATHER EXPECTED FOR THE
LATTER PART OF THE WORK WEEK AS THE SPRAWLING AREA OF HI PRES
SETTLES OVER THE GREAT LAKES. IT WOULD BE NICE IF THE GFS PLAYED
ALONG WITH THE OTHER MODELS/ENSEMBLES AS THE GFS RACES THE NEXT
SRN STREAM SYSTEM ACROSS THE SRN PLAINS (THU) AND OHIO/TN VALLEYS
(FRI). OBVIOUSLY...THIS SOLUTION WOULD BRING MORE CLOUDS...EVEN
PCPN CHCS TO NE WI AT WEEK`S END. HAVE DISMISSED THE GFS AS AN
OUTLIER AND KEEP THU/FRI DRY WITH TEMPS A FEW DEGS ABOVE NORMAL.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 529 AM CST SAT DEC 13 2014

INCREASING MOISTURE TRAPPED UNDER A STRONG INVERSION
WILL PRODUCE WIDESPREAD LIFR/IFR CONDITIONS THIS WEEKEND. CIGS
ARE EXPECTED TO REMAIN LOW THE ENTIRE WEEKEND. DURING THE MORNING
HOURS...VSBYS DUE TO DENSE FOG WILL RANGE FROM WIDESPREAD LIFR
OVER CENTRAL AND NORTH CENTRAL WISCONSIN WISCONSIN TO VFR
CONDITIONS FAR NORTHEAST AND EASTERN WISCONSIN. ANTICIPATE LITTLE
IMPROVEMENT OVER CENTRAL AND NORTH CENTRAL WISCONSIN TODAY BEFORE
DETERIORATING AGAIN TONIGHT INTO SUNDAY. CONDITIONS OVER THE REST
OF THE AREA ALSO EXPECTED TO DETERIORATE TONIGHT INTO SUNDAY.
&&

.HYDROLOGY...
ISSUED AT 254 AM CST SAT DEC 13 2014

THE FLOOD WARNING FOR ICE JAMS ON THE WOLF RIVER IN
KESHENA WILL CONTINUE. CALLS LATE FRIDAY SUGGESTS LITTLE CHANGE IN
THE HEIGHT OF THE ICE AND WATER. WARMER TEMPERATURES THIS WEEKEND
AND RAIN MONDAY MAY PRODUCE RUN OFF AND FLUCTUATING LEVELS THROUGH
TUESDAY. ITS POSSIBLE THE WARNING MAY BE EXTENDED THROUGH TUESDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM CST THIS MORNING FOR WIZ005-010-
018>020-030-031-035>037-045.
&&

$$

SHORT TERM.....TDH
LONG TERM......KALLAS
AVIATION.......TDH
HYDROLOGY......TDH





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