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000
FXUS63 KGRB 261053
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
453 AM CST MON JAN 26 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 453 AM CST MON JAN 26 2015

PCPN TRENDS...SNOWFALL AMOUNTS AND POTENTIAL FOR FREEZING DRIZZLE
THROUGH TONIGHT ARE THE MAIN FCST CONCERNS.

A CLIPPER LOW PRESSURE SYSTEM WAS MOVG INTO FAR SW ONTARIO EARLY
THIS MORNING...AND STG PRESSURE FALLS OVER NORTHERN AND CENTRAL
MN SUGGESTED A CONTINUED QUICK SEWD MOVMT. THE SYSTEM WAS BEING
DRIVEN BY THE LFQ OF A 150 KT JET STREAK AND A S/W TROF. STRONG
WAA AHEAD OF THE LOW WAS COMBINING WITH THE UPPER FORCING TO
GENERATE AN AREA OF SNOW OVER EASTERN MN AND NORTHWEST/WEST
CENTRAL WI...THOUGH THE EASTERN EDGE OF THE SNOW BAND WAS ALOFT
DUE TO A LINGERING DRY WEDGE AROUND 850 MB.

BEST FORCING DUE TO THE LFQ OF THE UPPER JET...WAA AND FRONTOGENETIC
FORCING IS EXPECTED TO MOVE THROUGH THE SW HALF OF THE FCST AREA
THIS MORNING AND EARLY AFTERNOON...BRINGING BRIEF POCKETS OF
MODERATE SNOW...AND A QUICK ACCUMULATION UP TO 2 INCHES. THE SNOW
WILL BEGIN DURING THE MORNING COMMUTE IN PARTS OF NC/C WI...THEN
SHIFT EASTWARD INTO EASTERN WI DURING THE LATE MORNING AND EARLY
AFTERNOON. SNOW INTENSITY SHOULD WANE FARTHER EAST DUE TO WEAKER
FORCING...SO DAYTIME ACCUMS OF ONLY A HALF INCH TO AN INCH ARE
EXPECTED OVER NE/EC WI. PATCHY FREEZING DRIZZLE IS POSSIBLE IN OUR
FAR SW COUNTIES LATE IN THE DAY...AS MOISTURE GRADUALLY SHALLOWS
OUT. HIGHS TEMPS WILL BE IN THE 20S.

ADDITIONAL SHORT-WAVE ENERGY WILL PASS THROUGH THE REGION TONIGHT...
AND AN INVERTED SFC TROF WILL LINGER OVER THE FORECAST AREA. MESO
MODELS SUPPORT SOME LAKE-ENHANCMENT OVER EASTERN WI AS LLVL WINDS
BACK FROM SOUTHEAST THROUGH NORTHEAST DURING THE NIGHT. INSTABILITY
IS MARGINAL...WITH LAKE-H8 DELTA-T`S ONLY 12-14 C...BUT STILL
SUFFICIENT FOR SOME ENHANCEMENT...AND THERE SHOULD BE A WELL-
DEFINED CONVERGENCE ZONE OVER EASTERN WI THROUGH THE NIGHT. HAVE
KEPT LIKELY POPS FOR THE MOST OF THE NIGHT OVER NE/EC WI...WITH
ADDITIONAL ACCUMS OF 1 TO 1.5 INCHES MOST PLACES. FARTHER WEST...
PCPN WILL GRADUALLY TAPER OFF TO PATCHY LIGHT SNOW AND FREEZING
DRIZZLE...THOUGH THE TRAVEL IMPACTS OF THE FZDZ SHOULD BE LESSENED
SOMEWHAT AS IT FALLS ON SNOW COVERED OR TREATED ROADS. LOW TEMPS
ARE EXPECTED TO SETTLE INTO THE UPPER TEENS OR LOWER 20S.

WEAK HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY...CAUSING
ANY LINGERING LIGHT PCPN TO END...AND RESULT IN A GRADUAL DECREASE
IN CLOUDS DURING THE DAY. HIGH TEMPS SHOULD REACH THE UPPER 20S
OR LOWER 30S.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 453 AM CST MON JAN 26 2015

MEAN 500MB FLOW WILL BE DOMINATED BY WESTERN NORTH AMERICA RIDGE
AND EASTERN TROUGH. HIGH PRESSURE WILL DOMINATE THE WEATHER
PATTERN TUESDAY NIGHT INTO WEDNESDAY AS CLIPPER SYSTEM APPROACHES
FROM THE NORTHWEST. THE CLIPPER SYSTEM SHOULD AFFECT THE AREA
LATE WEDNESDAY AFTERNOON INTO THURSDAY. SOME TIMING DIFFERENCES
NOTED WITH SYSTEM AMONG THE MODELS... BUT TRENDED TOWARD THE SLOWER
CANADIAN/ECMWF SOLUTION. DRY AIR AHEAD OF THE SYSTEM COULD ALSO
DELAY THE ONSET OF PRECIPITATION.

THIS SYSTEM SHOULD BRING A FEW INCHES OF SNOW TO THE REGION BY
THURSDAY MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
THURSDAY NIGHT...THEN EAST OF THE AREA ON FRIDAY. ARCTIC COLD
FRONT WILL SWING ACROSS THE AREA LATE FRIDAY NIGHT AND SATURDAY
MORNING. THE FRONT WILL BE ACCOMPANIED BY SOME SNOW SHOWER ACTIVITY
AND PROBABLY FALLING TEMPERATURES. LATER SHIFTS MAY NEED TO RAISE
HIGH TEMPERATURES A FEW DEGREES SINCE ECMWF IS SLOWER WITH THE
ARRIVAL OF THE FRONT. SUNDAY SHOULD BE CONSIDERABLY COLDER THAN
SATURDAY.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 928 PM CST SUN JAN 25 2015

NO SIG CHCS TO AVN FCST WITH THE 06Z TAFS. PATCH OF MID CLDS WL
CONT TO SHIFT OFF TO THE SE...BUT WL BE REPLACED BY MUCH MORE
EXPANSIVE CLD DECK THAT WL LOWER WITH TIME. SNOW AHEAD OF INCOMING
SYSTEM LOOKS TO START IN THE 14Z-18Z TIME FRAME W AND 16Z-20Z IN
THE E...WITH PERHAPS SOME SHSN OFF LAKE MICHIGAN WORKING WWD INTO
LAKESHORE AREAS EARLIER. EXPECT MAINLY IFR VSBYS WITH THE SNOW
BAND ON MONDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....KIECKBUSCH
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI