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000
FXUS63 KGRB 051203
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
603 AM CST THU DEC 5 2013

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 316 AM CST THU DEC 5 2013

RATHER QUIET PERIOD COMPARED TO PREVIOUS TWO MID SHIFTS THOUGH
STILL NEED TO DEAL WITH HEADLINES. DEEPENING LOW EXITING TO THE
NORTH AND PASSAGE OF COLD FRONT LATE LAST EVENING BRING ISSUES
WITH WINDS THROUGH MUCH OF THIS PERIOD.

MAIN FORECAST IS DRY AND COLD THROUGH FRIDAY. HAVE ADDED A BIT
MORE FLURRY ACTIVITY FOR THE MORNING HOURS AS SHORT WAVE MOVES
THROUGH. MODELS ALSO SHOWING SOME FGEN FORCING SHIFTING EAST AND
WEAKENING. CORRESPONDS WITH CURRENT FLURRY ACTIVITY OVER WESTERN
WI/EASTERN MN. DRIER AIR MASS TO MOVE IN WITH ARCTIC HIGH
PRESSURE...THIS AND STRONG SUBSIDENCE WILL WORK TO ERODE CLOUDS
OVER MUCH OF THE AREA TODAY. WINDS CONTINUE TO GUST BETWEEN 20 AND
30 KTS OVER CENTRAL AND NORTHEAST WI EARLY THIS MORNING. GRADIENT
TO REMAIN STRONG INTO THE EVENING HOURS. WINDS EXPECTED TO REMAIN
STRONG ENOUGH TO SEND WIND CHILLS DOWN TO BELOW ZERO OVER ENTIRE
CWA TONIGHT...WITH ADVISORY LEVELS EXPECTED OVER NORTH CENTRAL
AFTER MIDNIGHT. WILL ISSUE HEADLINE WITH THIS ISSUANCE. CONTINUED
COLD INTO FRI WITH MAX TEMPS SOME 20 DEGREES BELOW NORMAL.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 316 AM CST THU DEC 5 2013

THE MAIN STORY DURING THE PERIOD WL BE THE BITTERLY COLD ARCTIC
OUTBREAK WHICH WL ARRIVE IN TWO PIECES AS A PROMINENT LONGWAVE
TROF GRADUALLY WORKS EAST ACROSS THE CONUS. BESIDES THE UNUSUALLY
COLD AIR FOR DECEMBER...THE OTHER FEATURE OF INTEREST TO BE A
SHORTWAVE TROF/SFC LOW SYSTEM EXPECTED TO PRECEDE THE UPR TROF
INTO THE GREAT LAKES SUNDAY NGT/MON. DEPENDING ON THE TRACK OF THE
SFC LOW...POTENTIAL FOR ACCUMULATING SNOW EXISTS. PART 2 OF THE
ARCTIC INTRUSION TO SETTLE OVER NE WI THRU THE MIDDLE OF NEXT WEEK
WITH TEMPS 20 TO 30 DEG BELOW NORMAL.

THE BROAD AREA OF ARCTIC HI PRES TO STRETCH FROM BRITISH COLUMBIA
SEWD THRU THE NRN HI PLAINS TO THE CNTRL PLAINS WITH AN EWD
EXTENSION REACHING TOWARD THE SRN GREAT LAKES FRI NGT. DESPITE THE
APPROACH OF THE SFC HI...WEST WINDS IN THE 5 TO 15 MPH RANGE WL
COMBINE WITH THE ARCTIC AIR MASS TO PRODUCE DANGEROUS WIND CHILL
READINGS. A WIND CHILL ADVY WL LIKELY BECOME NECESSARY FOR AT
LEAST NRN AND PARTS OF CNTRL WI.

THE HI PRES MOVES INTO THE GREAT LAKES ON SAT WHICH WOULD AT LEAST
LIMIT ANY WIND GUSTS (SUSTAINED WINDS TO BE AROUND 10 MPH). A
SUNNY DAY FOR THE MOST PART ALTHO SOME HI CLOUDS COULD ARRIVE
DURING THE AFTERNOON AS THE NEXT SYSTEM ORGANIZES OVER THE
ROCKIES. MAX TEMPS TO RANGE FROM ONLY 5 TO 10 ABOVE N-CNTRL...TO
THE MID-TEENS ALONG LAKE MI.

AS LEE-SIDE CYCLOGENESIS DEVELOPS OVER THE SRN ROCKIES SAT NGT...
WINDS JUST ABOVE THE SFC WL BEGIN TO VEER SE AND HAVE THE ARCTIC
AIR SLOWLY RETREAT. EXPECT CLOUD COVER TO GRADUALLY INCREASE THRU
THE NGT...BUT DRY CONDITIONS TO PREVAIL AS THE SFC HI TO STILL BE
JUST TO OUR EAST. MIN TEMPS COULD BE TRICKY DEPENDING ON HOW FAST
THE CLOUDS ARRIVE SINCE WINDS ARE FCST TO BECOME LIGHT/VARIABLE.
STILL ANTICIPATE SUB-ZERO READINGS ACROSS NRN/CNTRL WI...JUST A
QUESTION AS TO HOW FAR TEMPS CAN DROP. FOR NOW...HAVE TEMPS IN THE
SINGLE DIGITS BELOW ZERO ROUGHLY NW OF A LINE FROM ISW-MNM. EVEN
THO THE SFC LOW IS PROGGED TO BE FAIRLY WEAK OVER THE SRN PLAINS/
OZARKS VICINITY ON SUNDAY...THE COMBINATION OF LOW-LEVEL ISEN LIFT
AND MID-LEVEL FORCING FROM SHORTWAVE ENERGY EJECTED NEWD FROM THE
LONGWAVE TROF...SHOULD ALLOW FOR AT LEAST A CHC OF LIGHT SNOW TO
REACH WI...ESPECIALLY DURING THE AFTERNOON. DO NOT EXPECT MUCH IN
THE WAY OF ACCUMULATION DURING THE DAYLIGHT HOURS AS STRONGER LIFT/
FORCING STILL TO OUR SOUTH. MAX TMEPS ON SUNDAY TO BE `WARMER`...
BUT REMAIN A GOOD 10 TO 15 DEGS BELOW NORMAL.

THE MDLS ARE FAIRLY CONSISTENT IN LIFTING THE SFC LOW NEWD THRU
SRN/CNTRL IL TO SRN SECTIONS OF LK HURON SUNDAY NGT WITH A SLOW
STRENGTHENING THRU THE NGT. THIS TRACK WOULD FAVOR THE SE HALF OF
WI WITH ACCUMULATING SNOW...THEREFORE HAVE PLACED THE HIGHEST POPS
OVER E-CNTRL WI. THE SFC LOW WL CONT TO DEEPEN AS IT LIFTS INTO SE
CANADA WITH THE SNOW GRADUALLY TAPERING OFF FROM SW TO NE ON MON.
STILL A TAD EARLY TO DETERMINE SNOW ACCUMULATION NUMBERS...BUT THE
MORNING COMMUTE ON MON COULD BE SLOW AND SLIPPERY.

THE SECOND SURGE OF ARCTIC AIR WL OVERSPREAD THE REGION BEHIND THE
SYSTEM WITH 8H TEMPS PROGGED TO DROP TO AROUND -20C BY 12Z TUE.
MIN TEMPS MON NGT TO FALL BELOW ZERO OVER ALL BUT THE LAKESHORE
AREAS AND WHEN COMBINED WITH WEST WINDS IN THE 10 TO 20 MPH RANGE...
WIND CHILL HEADLINES WL ONCE AGAIN BECOME NECESSARY. MDLS HAVE MADE
A CHANGE FOR TUE BY SWEEPING A SHORTWAVE TROF THRU THE GREAT LAKES
ACCOMPANIED BY A WEAK CLIPPER-TYPE AREA OF LOW PRES. HAVE ADDED A
SMALL POP TO THE FCST TO COMPENSATE FOR THIS SYSTEM. DRY AND VERY
COLD CONDITIONS TO PREVAIL OVER THE AREA TUE NGT/WED AS ANOTHER
LARGE AREA OF HI PRES MOVES SEWD ACROSS THE CNTRL CONUS. TEMPS WL
CONT TO RUN ANYWHERE FROM 15 TO 25 DEGS BELOW NORMAL.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 538 AM CST THU DEC 5 2013

UPPER SHORT WAVE MOVING THROUGH NORTHERN WI AT THIS TIME. SOME
LIGHT SNOW WITH FEATURE AND STRONG WINDS COMBINING TO PRODUCE MVFR
VSBYS IN SNOW. FEATURE WILL PULL OUT OF REGION THIS MORNING. CLOUD
COVER ALREADY DIMINISHING OVER THE AREA...WITH MOSTLY CLEAR SKIES
EXPECTED IN THE AFTN. GRADIENT BETWEEN DEPARTING LOW AND HIGH OVER
THE PLAINS WILL KEEP STRONG/GUSTY WINDS GOING THROUGH THIS EVENING.

&&

.MARINE...
ISSUED AT 316 AM CST THU DEC 5 2013

EXPECT WINDS TO GUST INTO GALE RANGE TOO FREQUENTLY
TODAY TO STAY WITH SMALL CRAFT OVER THE BAY AND NORTH LAKE.
SUBSIDENCE AND INCREASING INSTABILITY TO BRING HIGHER WINDS DOWN
THIS MORNING INTO THE AFTERNOON.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST FRIDAY FOR
WIZ005-010-011-018-019-030.
&&

$$

SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......TE
MARINE.........TE