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000
FXUS63 KGRB 091729
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1129 AM CST MON DEC 9 2013

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.UPDATE...
ISSUED AT 604 AM CST MON DEC 9 2013

MADE UPDATES TO WSW HEADLINES AS ACCUMULATING SNOW NOW OVER IN THE
EAST. WIND CHILL ADVISORY ISSUED TO START LATE THIS AFTERNOON.
STILL HAVE QUESTIONS ON END TIME WITH SYSTEM COMING IN LATER
TONIGHT. AT THIS TIME HAVE ENDED IT AT 6AM.
&&

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 411 AM CST MON DEC 9 2013

SYSTEM EXITING REGION WITH CLEARING WORKING IN THIS MORNING. IN
COORDINATION WITH MKX HAVE MAINTAINED HEADLINE OVER THE EAST
THOUGH HAVE DROPPED WEST. ROADS CONTINUE TO HAVE ISSUES...WITH
LIGHT SNOW STILL ACCUMULATING. ISSUE FOR TODAY IS INCREASING WINDS
AND FALLING TEMPERATURES. WIND CHILL VALUES EXPECTED TO
DROP...MEETING HEADLINE CRITERIA AROUND 22Z AND CONTINUE AT LEAST
THROUGH MIDNIGHT. WITH CURRENT HEADLINE OUT WILL HOLD OFF ON
ISSUING. WINDS PICKING UP LATER THIS MORNING...EXPECTED TO CREATE
CONSIDERABLE BLOWING OF THE LIGHT SNOW.

TONIGHTS FOCUS ON CLIPPER SYSTEM DROPPING SOUTH OUT OF
CANADA...PASSING THROUGH WI EARLY TUE. FIRST IN A SERIES OF SUCH
SYSTEMS EXPECTED TO AFFECT STATE. SYSTEM IS COMPACT...BUT HAS SOME
GOOD DYNAMICS. MID LEVELS SHOWING SOME INSTABILITY. HAVE BUMPED
POPS UP INTO LIKELY CATEGORY. MOISTURE LIMITED...SO AMOUNTS
EXPECTED TO BE LIGHT. WINDS AND TEMPS MODERATE SOME AHEAD OF
SYSTEM OVERNIGHT...WITH QUESTIONS ON ENDING TIME FOR ANY WIND
CHILL HEADLINE.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 411 AM CST MON DEC 9 2013

MDLS REMAIN CONSISTENT IN FLATTENING OUT THE MEAN FLOW OVER THE
CONUS THRU THE END OF THE WEEK...HOWEVER ANOTHER UPR TROF IS FCST
TO MOVE ACROSS THE COUNTRY NEXT WEEKEND. THE MAIN FCST ISSUES TO
BE ON FAST-MOVING WEAK SYSTEMS RACING ACROSS THE CONUS AS THE FLOW
FLATTENS. TRYING TO TIME THESE SYSTEMS HAS BEEN A CHALLENGE FOR
THE MDLS AND MAKES PCPN TIMING FOR THE LATTER PART OF THE FCST
SKETCHY AT BEST. AFTER THE SECOND ARCTIC PEAKS AT MID-WEEK...TEMPS
SHOULD AT LEAST WARM INTO THE 20S...BUT REMAIN BELOW NORMAL UNTIL
FURTHER NOTICE.

THE NEXT WEAK WEATHER SYSTEM IS FCCT TO MOVE ALONG THE BAROCLINIC
ZONE FROM THE MIDWEST TOWARD SRN SECTIONS OF THE GREAT LAKES TUE
NGT. WHILE ANY SURFACE REFLECTION IS PRACTICALLY NEGLIGIBLE...
THERE WL BE A SHORTWAVE MOVING THRU THE W-NW FLOW AND PROVIDE ENUF
MID-LEVEL FORCING TO GENERATE SOME LIGHT SNOW. HIGHER POPS TO BE
TO OUR SOUTH...CLOSER TO THE TRACK OF THE SHORTWAVE...HOWEVER THE
NRN EXTENT OF THE PCPN MAY GRAZE SRN SECTIONS OF THE FCST AREA.
ANY SNOW ACCUMULATIONS ARE EXPECTED TO BE MINOR (AROUND ONE-HALF
INCH) GENERALLY SOUTH OF A ISW-MTW LINE. FOR NRN WI...SOME BREAKS
IN THE CLOUD COVER WL ALLOW FOR TEMPS TO TANK WITH READINGS IN THE
DOUBLE DIGITS BELOW ZERO. THIS ARCTIC AIR...COMBINED WITH WEST
WINDS NEAR 10 MPH...WL LIKELY REQUIRE WIND CHILL HEADLINES ACROSS
NRN AND PARTS OF CNTRL WI. THIS SYSTEM QUICKLY EXITS TO THE EAST
ON WED AS A LARGE AREA OF HI PRES BUILDS ACROSS THE CNTRL CONUS.
EXPECT TO SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES AND VERY COLD
CONDITIONS ACROSS NE WI WITH MAX TEMPS POSSIBLY NOT EVEN REACHING
ZERO OVER THE NORTHWOODS.

THE BROAD AREA OF HI PRES IS EXPECTED TO STRETCH FROM THE SRN
PLAINS TO THE OHIO RIVER VALLEY WED NGT WITH A NWD EXTENSION OF
THE RDG AXIS MOVING ACROSS THE WRN GREAT LAKES. WHILE MOST OF THE
NGT WL BE MOSTLY CLEAR...ANTICIPATE SOME INCREASE IN CLOUDS OVRNGT
INTO CNTRL WI AHEAD OF THE NEXT SHORTWAVE/ONSET OF ISEN LIFT AS
WINDS BEGIN TO BACK SW. THE BIG STORY THO FOR WED NGT TO BE THE
FRIGID CONDITIONS AS MIN TEMPS MAY APPROACH 20 BELOW ZERO OVER THE
COLDER SPOTS OF N-CNTRL WI AND EVEN AREAS ALONG LAKE MI COULD DIP
BELOW ZERO. THIS LITTLE SYSTEM TO ZIP THRU WI THU MORNING...BUT
APPEARS TO BE MOISTURE STARVED. ANTICIPATE AT LEAST SOME FLURRIES
ACROSS THE FCST AREA AND PERHAPS A LOW-END CHC POP. EITHER WAY...
NOT GOING TO SEE MUCH THRU THE DAY WITH TEMPS ONLY RECOVERING INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...MID-TEENS E-CNTRL WI.

AS THE MEAN FLOW FLATTENS OUT BY FRI...THE CRUX OF THE ARCTIC AIR
WL RETREAT BACK INTO CANADA AS 8H TEMPS OVER WI RISE INTO THE -10
TO -15C RANGE. BELIEVE THE GFS IS WAY TOO OPTIMISTIC IN BRINGING
THE NEW PACIFIC AIR MASS EWD AND FAVOR THE COLDER GEM/ECMWF. PCPN
CHCS LOOK MINIMAL AS THE WEAK ISEN LIFT CONTS...WITH THE MDLS
HINTING AT A SMALL CHC OF SNOW ACROSS NRN SECTIONS OF THE GREAT
LAKES. LOOK FOR MAX TEMPS ON FRI TO BE ABLE TO REACH THE UPR TEENS
NORTH...20 TO 25 DEG RANGE ELSEWHERE.

STILL A LOT OF QUESTIONS TO PCPN CHCS FRI NGT INTO SAT AS SOME OF
THE MDLS TRY TO BRING A PHASING SYSTEM ACROSS THE E-CNTRL CONUS.
IF THIS WERE TO OCCUR...AT LEAST CHC POPS WOULD BECOME NECESSARY
MAINLY FRI NGT...BUT DUE TO THE UNCERTAINTY ON HOW ALL OF THIS
WOULD PLAY OUT...PREFER TO KEEP MOST OF THIS PERIOD DRY. AN
EXCEPTION COULD BE NEAR LAKE MI WHERE POTENTIAL NE WINDS WOULD
GENERATE SOME LAKE EFFECT SNOW SHWRS...PRIMARILY ON SAT. MDL
UNCERTAINTY CARRIES OVER THRU SUNDAY AS THE NW FLOW ATTEMPTS TO
RE-ESTABLISH ITSELF OVER THE GREAT LAKES. TO WHAT EXTENT THIS
OCCURS WOULD DETERMINE WHERE THE BAROCLINIC ZONE TO SET-UP AND
PROVIDE A TRACK FOR POSSIBLE CLIPPER SYSTEMS TO RIDE. ONCE AGAIN...
UNTIL THIS PATTERN BECOMES BETTER ESTABLISHED...PREFER TO KEEP THE
FCST DRY.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1128 AM CST MON DEC 9 2013

LIGHT SNOW AND FLURRIES ARE STUBBORNLY STICKING AROUND
CENTRAL AND NORTH-CENTRAL WISCONSIN AT MIDDAY...AND HAVE TO EXTEND
LOWER VSBYS IN LIGHT SNOW INTO MID-AFTERNOON.  WEST WINDS WILL ALSO
REMAIN GUSTY THROUGH THE AFTERNOON BEFORE THE GUSTINESS SUBSIDES BY
EARLY THIS EVENING.  A PERIOD OF VFR CONDITIONS WILL THEN FOLLOW
UNTIL LATE TONIGHT...AND THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL
BRING A QUICK ROUND OF SNOW AND LOWERING CIGS LATE TONIGHT INTO
TUESDAY MORNING.  VSBYS IN THE SNOW TO AT LEAST FALL INTO THE IFR
RANGE...AND POSSIBLY LOWER BASED ON OBSERVATIONS OVER MONTANA.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY
FOR WIZ005-010>013-018>021-030-031-035>037.
&&

$$

UPDATE.........TE
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......MPC