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000
FXUS63 KGRB 290425
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1025 PM CST THU NOV 28 2013

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 254 PM CST THU NOV 28 2013

CLOUDS AND SNOW SHOWERS AND FLURRIES SHOULD DIMINISH
THIS EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM MINNESOTA. LAKE
INDUCED MESO LOWS WERE OVER WESTERN LAKE SUPERIOR AND NORTHERN
LAKE MICHIGAN. THE ONE OVER LAKE SUPERIOR WILL PROBABLY DRIFT
SOUTH BUT WEAKEN AS IT APPROACHES VILAS COUNTY. IT MIGHT BRING
SNOW SHOWERS THIS EVENING. THE ONE OVER LAKE MICHIGAN MAY PRODUCE
SNOW SHOWERS OVER NORTHERN DOOR COUNTY FOR AWHILE THIS EVENING
THOUGH IT APPEARS TO BE MOVING SLOWLY AWAY. LOWS TONIGHT WILL
DEPEND A LOT ON CLOUD COVER. FRIDAY SHOULD START OUT MOSTLY SUNNY
BUT MIDDLE AND HIGH CLOUDS WILL INCREASE IN BROAD WARM ADVECTION
DURING THE AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 254 PM CST THU NOV 28 2013

CURRENT SPLIT FLOW PATTERN IS FCST TO CONSOLIDATE AND EVENTUALLY
BECOME AMPLIFIED AS A STRONG UPR RDG DEVELOPS OVER ALASKA AND
ALLOWS A DEEP UPR TROF TO SET-UP OVER THE WRN CONUS. AS THIS
OCCURS...THE MEAN FLOW OVER THE CNTRL CONUS WL BECOME SW AND ALLOW
MILDER/MORE ACTIVE WEATHER PATTERN TO DEVELOP AS GULF MOISTURE
GETS PULLED NWD. MAIN FCST ISSUE FOR NE WI WL BE A LEAD SYSTEM
EXPECTED TO EJECT NEWD FROM THE UPR TROF AND HEAD OUR WAY TOWARD
THE MIDDLE OF NEXT WEEK. PCPN TYPE/AMOUNT OF WARM AIR TO BE THE
BIGGEST CHALLENGE.

A VERY WEAK CLIPPER AREA OF LOW PRES IS FCST TO DROP SE TOWARD
LAKE SUPERIOR FRI NGT AND SWING A CDFNT THRU THE UPR MS VALLEY.
WAA IN ADVANCE OF THIS CDFNT WL NOT ONLY THICKEN THE CLOUDS OVER
NE WI...BUT MAY ALSO ALLOW FOR SOME LIGHT SNOW OR EVEN PATCHY
FREEZING DRIZZLE TO DEVELOP AS FCST SOUNDINGS INDICATE A LACK OF
ICE IN THE CLOUDS. PREVIOUS SHIFT ALREADY HAD THIS POSSIBILITY
MENTIONED FOR N-CNTRL AND PARTS OF CNTRL WI AND SEE NO REASON TO
DEVIATE. TEMPS SHOULD NOT DROP TOO FAR DUE TO THE THICKENING
CLOUDS AND PREVAILING SOUTHERLY WINDS. LOOK FOR MID TEENS N-CNTRL
WI TO MID 20S ALONG LAKE MI.

THE CLIPPER LOW CONTS TO TRACK SE TOWARD NRN SECTIONS OF LAKE
HURON AS THE CDFNT CROSSES WI ON SAT. WL NEED TO CARRY THE
FREEZING DRIZZLE/LIGHT SNOW THREAT THRU THE MORNING HOURS UNTIL
THE FNT MOVES THRU AND LIFT WEAKENS. NOT EXPECTING MUCH IN THE WAY
OF QPF...HOWEVER ANY FREEZING DRIZZLE MAY CREATE SLIPPERY ROAD
CONDITIONS AND WL MENTION THIS POTENTIAL HAZARD IN THE HWO. MAX
TEMPS ARE EXPECTED TO GENERALLY REACH THE 30-35 DEG RANGE.

WINDS WL SHIFT TO THE N-NW BEHIND THE DEPARTED CDFNT WITH 8H TEMPS
DROPPING TO AROUND -10C OVER LAKE SUPERIOR SAT NGT. INSTABILITY
APPEARS MARGINAL AT BEST...BUT WITH DELTA-T VALUES IN THE MID TO
UPR TEENS AND INVERSION HEIGHTS AROUND 5K FT...FEEL AT LEAST A
MINIMAL POP IS NECESSARY OVER FAR NRN WI. THE REST OF THE FCST
AREA WL BE DRY AS AN AREA OF HI PRES MOVES INTO WRN ONTARIO. MIN
TEMPS TO HOLD ABOVE NORMAL WITH READINGS IN THE UPR TEENS NORTH TO
THE MID 20S NEAR LAKE MI. QUIET WEATHER TO CONT ACROSS THE AREA ON
SUNDAY AS NE WI REMAINS ON THE SRN FLANK OF THE CANADIAN HI PRES
MOVING ACROSS ONTARIO. A LACK OF DRY AIR OR SUBSIDENCE WOULD POINT
TO A DECENT AMOUNT OF CLOUDS HANGING AROUND NE WI...THUS LOOK FOR
PARTLY CLOUDY SKIES AT BEST WITH MAX TEMPS TO RANGE FROM AROUND 30
N-CNTRL WI TO THE MID 30S OVER E-CNTRL WI.

CLOUDS ARE EXPECTED TO BECOME MORE PREVALENT SUNDAY NGT AS A WEAK
SHORTWAVE TROF MOVES ACROSS THE NRN PLAINS TOWARD THE UPR MS
VALLEY. WINDS BY THIS TIME SHOULD BE VEERING MORE TO THE E-NE...SO
WL NEED TO WATCH FOR ANY LAKE EFFECT SNOW FROM LAKE MI. NOT TOO
CONCERNED AS OF NOW DUE TO A LACK OF COLD AIR AND DELTA-T VALUES
IN THE MID TEENS. MON IS TRANSITION DAY WITH REGARDS TO THE MEAN
FLOW AS THE UPR TROF DROPS SE INTO THE PACIFIC NW AND UPR HEIGHTS
BEGIN TO RISE ACROSS THE CNTRL CONUS. THE AFOREMENTIONED SHORTWAVE
TROF REALLY DOES NOT MOVE MUCH OR EVEN DRIFTS A BIT NE AS THE UPR
HEIGHTS RISE...THEREFORE DO NTO ANTICIPATE MUCH FROM THIS WEAK
SYSTEM. PLENTY OF CLOUDS TO LINGER OVER NE WI MON WITH PERHAPS AN
ISOLATED SNOW SHWR OR A FEW FLURRIES AROUND AS WEAK ISEN LIFT CONTS.

FCST CONFIDENCE BEGINS TO DROP STARTING ON TUE AS THE MDLS ARE
REALLY STRUGGLING WITH THE MEAN PATTERN CHANGE. ON ONE EXTREME IS
THE GEM WHICH COMPLETELY DOWNPLAYS THE UPR TROF OVER THE WRN CONUS
WITH PRACTICALLY A NEAR ZONAL FLOW ACROSS THE COUNTRY. ON THE
OTHER HAND...THE 12Z ECMWF LOOKS LIKE THE OOZ GFS WITH A PIECE OF
THE UPR TROF LIFTING NE AND CLOSING OFF INTO AN UPR LOW NEAR LAKE
WINNIPEG AND A CDFNT SURGING EWD. THE 12Z GFS HAS LESS UPR
TROFFING AND NO UPR LOW CLOSING OFF IN SRN CANADA. THIS PLETHORA
OF UNCERTAINTY MAKES THE FCST FOR TUE THRU THU VERY UNCERTAIN.
HAVE FAVORED A CONSENSUS MDL SOLUTION FOR NOW WHICH INDICATES ONLY
NUISANCE-TYPE SMALL POPS TO THE FCST FOR TUE AND WED AS E-SE WINDS
BRINGS MOISTURE INTO THE AREA. A BETTER CHC OF PCPN ARRIVES WED
NGT INTO THU AS THE CDFNT MOVES THRU THE REGION ACCOMPANIED BY AN
AREA OF LOW PRES. DEPENDING ON HOW THE THERMAL PROFILES SET-UP...
WE COULD BE LOOKING AT PCPN TYPE ISSUES OVER CNTRL AND E-CNTRL WI.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1021 PM CST THU NOV 28 2013

SOME PATCHY MVFR CIGS MAY LINGER INTO THE OVERNIGHT HOURS...ESPECIALLY
ACROSS THE NORTH. VFR CONDITIONS EXPECTED ON FRIDAY. LIGHT WEST/NORTHWEST
OR VARIABLE WINDS WILL BECOME SOUTH BY FRIDAY AFTERNOON. A FEW GUSTS
TO AROUND 15 KNOTS ARE POSSIBLE AT TIMES FRIDAY AFTERNOON AND FRIDAY
EVENING.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 AM CST FRIDAY FOR WIZ022.
&&

$$

UPDATE.........
SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......