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000
FXUS63 KGRB 131014
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
414 AM CST FRI DEC 13 2013

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 414 AM CST FRI DEC 13 2013

JET ENERGY MOVING FROM THE SOUTHERN PLAINS TO THE
SOUTHEASTERN UNITED STATES IS FORECAST TO PRODUCE AN INVERTED
TROUGH AT THE SURFACE FROM THE SOUTHERN STATES TO LAKE MICHIGAN.
SYNOPTIC SCALE MOISTURE AND DYNAMICS WILL COMBINE WITH LAKE EFFECT
TO PRODUCE A MODERATE SNOWFALL OVER MUCH OF EASTERN WISCONSIN.

THIS EVENT LOOKS QUITE A BIT LIKE THE ONE OF DECEMBER 28-29 LAST
YEAR WHEN 4 TO 7 INCHES OF SNOW FELL FROM MANITOWOC AND KEWAUNEE
COUNTIES WEST TO THE FOX VALLEY. COLD TEMPERATURES SHOULD MAKE FOR
A BIG SNOW TO WATER RATIO LIKE 20 TO 1 SO THE SNOW SHOULD BE
FLUFFY. WINDS ARE NOT EXPECTED TO BE STRONG SO BLOWING AND
DRIFTING SHOULD NOT BE A MAJOR PROBLEM. THERE IS SOME CHANCE OF A
HEAVY BAND OF SNOW SETTING UP ALONG THE SHORE OF KEWAUNEE AND
MANITOWOC COUNTIES DUE TO THERMAL TROUGHING OVER THE LAKE AND
SHORELINE CONVERGENCE SO WE ISSUED A LAKE EFFECT SNOW WATCH FOR
THE POSSIBILITY OF SIX INCHES OR MORE OF SNOW. DOOR COUNTY COULD
GET HEAVY SNOW TOO...BUT IT IS CLOSE TO THE DRIER AIR ASSOCIATED
WITH THE COLD HIGH TO THE NORTHEAST. EASTERLY TO NORTHEAST FLOW
IS STRONG ENOUGH TO BRING THE LAKE EFFECT OR LAKE ENHANCED SNOW
WELL INLAND SO WE SHOULD GET SEVERAL INCHES OF SNOW WEST OF THE
BAY AND IN THE FOX VALLEY. FURTHER WEST THERE SHOULD BE LIGHTER
SNOW WITH MINOR ACCUMULATIONS.

TEMPERATURES SHOULD NOT VARY MUCH TODAY THROUGH TOMORROW DUE TO
CLOUD COVER AND MAY EVEN RISE OVERNIGHT NEAR THE LAKE AS NORTHEAST
FLOW INCREASES.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 414 AM CST FRI DEC 13 2013

SYSTEM WILL BE DEPARTING THE AREA SATURDAY NIGHT...BRINGING AN END
TO THE ACCUMULATING SNOW EXCEPT OVER THE VERY FAR NORTH. LAKE EFFECT
SNOW SHOWERS WILL MOVE INTO VILAS COUNTY...ONEIDA...FOREST AND
FLORENCE COUNTIES. IT SHOULD BE NOTED THAT SOME OF THE MODELS ARE
STILL SHOWING A LOW LEVEL FLOW OFF LAKE MICHIGAN...SO SNOWFALL TOTALS
SATURDAY EVENING MAY BE ENHANCED FROM KEWAUNEE...DOOR INTO MARINETTE
AND OCONTO COUNTIES. ADVISORY MAY NEED TO BE EXTENDED INTO THE EVENING
FOR THE PREVIOUS MENTIONED COUNTIES.

VERY COLD AIR POURS INTO THE REGION ON GUSTY NORTHWEST WINDS WITH
HIGHS FROM 5 TO 12 ABOVE ACROSS THE REGION. STILL SHOULD BE SOME LAKE
EFFECT SNOW SHOWERS OVER THE NORTH DUE TO COLD NORTHERLY FLOW OFF
LAKE SUPERIOR. NEXT CLIPPER SYSTEM DROPPING SOUTHEAST INTO THE REGION
SUNDAY NIGHT. WITH SUCH A COLD AIR MASS...ANY LOW LEVEL WARM ADVECTION
SHOULD CAUSE LIGHT SNOW TO BREAK OUT...LIKE THE LAST FEW NIGHTS.
MODELS SHOWING 850MB WARM ADVECTION THROUGH THE NIGHT. WANTED TO 60ISH
POPS FOR LIGHT SNOW...BUT ONLY WENT 30-40 POPS DUE TO COORDINATION
PURPOSES. LATER SHIFTS WILL NEED TO BUMP UP POPS. COLD CYCLONIC FLOW
AND UPPER LEVEL DISTURBANCE WILL BRING A CHANCE OF LIGHT SNOW ON
TUESDAY AS WELL.

850MB BAROCLINIC ZONES SETS UP ACROSS THE WESTERN GREAT LAKES
WHICH SHOULD LEAD TO ANOTHER ROUND LIGHT OF PRECIPITATION...MAINLY
ACROSS THE NORTH. LATER SHIFTS ARE GOING TO NEED TO ADDRESS THURSDAY
AS LATEST MODEL RUNS NOW SHOWING WARM AIR POURING INTO THE REGION WITH
850MB TEMPERATURES OF +2C TO +4C OFF THE ECMWF. 1000/850MB THICKNESS
PATTERN WOULD SUGGEST RAIN...FREEZING RAIN OR SLEET AT SOME POINT
ON THURSDAY INTO FRIDAY. TOO EARLY TO GET EXCITED IN THE PRECIPITATION
TYPES AT THIS POINT SINCE MODELS COULD CHANGE DRASTICALLY BETWEEN
NOW AND THE EVENT.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1041 PM CST THU DEC 12 2013

WITH A BAROCLINIC ZONE STRETCHING FROM NORTHERN PLAINS TO THE
GREAT LAKES REGION...CLOUDS WILL CONTINUE TO LOWER OVERNIGHT INTO
FRIDAY. OCCASIONAL FLURRIES WITH SCATTERED LIGHT SNOW WILL
PRODUCE BRIEF PERIODS OF MVFR VSBYS.  DEVELOPING NE WINDS FRIDAY
WILL FAVOR LAKE EFFECT SNOWS ALONG LAKE MICHIGAN.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SATURDAY FOR WIZ022-038-039-048-049-073-074.

LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH SATURDAY
AFTERNOON FOR WIZ040-050.
&&

$$

SHORT TERM.....RDM
LONG TERM......ECKBERG
AVIATION.......TDH