Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 241157
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
557 AM CST SAT JAN 24 2015

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 416 AM CST SAT JAN 24 2015

STRATUS COVERED THE REGION...AND WAS HELPING TO KEEP TEMPERATURES
FROM DROPPING OFF EARLY THIS MORNING. MILD READINGS IN THE 30 TO 35
RANGE WERE OBSERVED ACROSS THE FORECAST AREA. A MODIFIED ARCTIC COLD
FRONT SITUATED ALONG THE CANADIAN/U.S. BORDER WAS DROPPING SOUTH
TOWARD WI. A WEAK S/W TROF WAS MOVG THROUGH NORTHERN WI AND THE WSTRN
U.P. AND A JET STREAK WAS APPROACHING FROM LAKE WINNIPEG REGION...
BUT THESE FEATURES WERE MAINLY PRODUCING FLURRIES.

THE ARCTIC COLD FRONT IS EXPECTED TO SAG INTO NORTHERN WI BY MIDDAY...
THEN SHIFT SOUTH INTO CENTRAL WI BY EVG. THE FRONT...COMBINED WITH
THE LFQ OF THE UPPER JET STREAK...SHOULD PRODUCE SCT SNOW SHOWERS
OVER FAR NC WI...AND FLURRIES ELSEWHERE. MILD HIGHS IN THE 30S
WILL OCCUR AHEAD OF THE FRONT...BUT SOME COOLING WILL BE NOTED OVER
NC/NE WI DURING THE AFTERNOON.

THE COLD FRONT WILL INTERACT WITH THE INCOMING CLIPPER SYSTEM TO
PRODUCE SOME LIGHT SNOW OVER MAINLY THE SW HALF OF THE FORECAST
AREA TONIGHT. SNOW ACCUMS UP TO AN INCH ARE ANTICIPATED FROM
MFI-OSH...WITH LIGHTER AMOUNTS FARTHER NORTH. MIN TEMPS ARE A
TOUGH CALL TONIGHT. THE MODIFIED ARCTIC AIR IS EXPECTED TO
OVERSPREAD THE REGION...BUT PERSISTENT CLOUD COVER IS EXPECTED
TO PREVENT A HUGE DROPOFF. HAVE GONE A BIT WARMER THAN MOS
GUIDANCE...BUT IF ANY CLEARING OCCURS OVER NE WI...SOME DOWNWARD
ADJUSTMENTS WILL NEED TO BE MADE.

PATCHY LIGHT SNOW WILL END ACROSS THE SOUTHERN PART OF THE FORECAST
AREA EARLY SUNDAY...WITH PARTIAL CLEARING ANTICIPATED DURING THE
DAY. SUBSEQUENT SHIFTS MAY NEED TO CONSIDER A MORE AGGRESSIVE
CLEARING TREND. CONSIDERED THE POSSIBILITY OF LAKE-EFFECT OFF
LAKE MICHIGAN WITH NE FLOW...BUT VERY DRY AIR AT 850 MB SHOULD
PREVENT ANYTHING OF CONSEQUENCE. A FEW FLURRIES ARE PSBL...BUT
WILL LEAVE THEM OUT OF THE FCST FOR NOW.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 416 AM CST SAT JAN 24 2015

NO REAL CHANGES IN THE 500MB MEAN FLOW AS WESTERN RIDGE WILL DOMINATE
WESTERN NORTH AMERICA...WHILE UPPER TROUGH EXPECTED TO POSITION
ITSELF ACROSS EASTERN NORTH AMERICA. TWO CLIPPER SYSTEMS TO CONTEND
WITH...THE FIRST MONDAY INTO MONDAY NIGHT AND THE NEXT SYSTEM WEDNESDAY
NIGHT INTO THURSDAY. BEYOND THURSDAY...SURGE OF ARCTIC AIR WILL BRING
BITTERLY COLD TEMPERATURES FOR NEXT WEEKEND (JAN 31/FEB 1).

FOR SUNDAY NIGHT...THINK DRY CONDITIONS WILL PREVAIL NEAR LAKE MICHIGAN
SUNDAY EVENING DESPITE LIGHT FLOW OFF THE LAKE DUE TO LACK OF LOW
LEVEL MOISTURE. MOISTURE DOES INCREASE BELOW 850MB OVERNIGHT...THUS
THINK THERE IS SOME POTENTIAL FOR FLURRIES ALONG THE LAKE. NEXT CLIPPER
SYSTEM WILL MOVE ACROSS THE REGION MONDAY INTO MONDAY NIGHT. LARGE
VARIATION IN THE TRACK OF THE STORM...BUT LIKE A FURTHER SOUTH AND
WEST TRACK. WITH THE LAST SEVERAL CLIPPER SYSTEMS...SYSTEM STARTS
FURTHER NORTH AND EAST SEVERAL DAYS OUT FROM THE EVENT...AND THEN
AS WE GET CLOSER TO THE EVENT THE SYSTEM TRACK FURTHER SOUTH AND
WEST.

THE SAME HOLDS TRUE FOR THE WEDNESDAY NIGHT AND THURSDAY SYSTEM.
THIS SYSTEM MAY HAVE A LITTLE MORE WARM AIR TO WORK WITH...THUS
ADDED A CHANCE OF SLEET ALONG WITH SNOW. LATEST ECMWF MODEL WOULD
SUGGEST COLDEST TEMPERATURES WILL OCCUR NEXT WEEKEND.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 546 AM CST SAT JAN 24 2015

A VARIETY OF CIG HEIGHTS WERE OBSERVED ACROSS THE REGION EARLY
THIS MORNING...BUT MOST PLACES WERE IN THE MVFR CATEGORY. LOW
CLOUDS MAY SCATTER OUT LATER THIS MORNING...ALLOWING FOR A PERIOD
OF VFR CONDITIONS IN MANY AREAS. AN ARCTIC COLD FRONT IS EXPECTED
TO SHIFT SOUTH ACROSS THE REGION THIS AFTERNOON AND EARLY EVENING.
SOME LIGHT SNOW SHOWERS OR FLURRIES MAY ACCOMPANY THE FRONT...
AND CIGS WILL LIKELY RETURN TO MVFR AFTER IT PASSES. THE FRONT...
COMBINED WITH A CLIPPER LOW PRESSURE SYSTEM...IS EXPECTED TO BRING
A STEADY LIGHT SNOWFALL TO PARTS OF CENTRAL WI AND THE SOUTHERN
FOX VALLEY TONIGHT. SOME IFR VSBYS ARE ANTICIPATED SOUTH OF A LINE
FROM MFI-OSH.

GUSTY NE WINDS WILL DEVELOP IN THE FOX VALLEY AND LAKESHORE AREAS
DURING THE LATE EVENING AND OVERNIGHT PERIOD.
&&

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

$$

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





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