Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 261748
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1248 PM CDT THU MAR 26 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 341 AM CDT THU MAR 26 2015

SHARP UPPER TROUGH WILL MOVE ACROSS THE AREA THIS AFTERNOON AND
EVENING. A SURFACE COLD FRONT IS OUT AHEAD OF IT BY ABOUT SIX
HOURS. IT WILL MOVE THROUGH DURING THE DAY AND BRING WITH IT
COLDER AIR FOR TONIGHT AND FRIDAY. THE UPPER TROUGH COMBINED WITH
INCREASING INSTABILITY OF THE AIR FLOWING ACROSS LAKE SUPERIOR
WILL PRODUCE LAKE EFFECT SNOW SHOWERS ACROSS THE FAR NORTHCENTRAL
PART OF THE FORECAST AREA TODAY. WINDS ARE MOST FAVORABLE FOR LAKE
EFFECT THROUGH THE AFTERNOON HOURS AND THEN WINDS DIMINISH AND THE
AIR BECOMES INCREASINGLY DRY. AN INCH OR SO POSSIBLE IN NORTHERN
VILAS COUNTY WITH SNOW SHOWERS FURTHER SOUTH. HIGHS TODAY SHOULD
BE A FEW DEGREES ABOVE CURRENT TEMPERATURES AND MAY FALL DURING
THE LATE AFTERNOON.

SKIES SHOULD CLEAR OVER MOST AREAS TONIGHT AS DRIER ARCTIC AIR
ARRIVES FROM THE NORTH. SOME CLOUDS MAY DRIFT IN OFF LAKE SUPERIOR
INTO NORTHEAST WISCONSIN AND MAYBE EVEN SOME SNOW FLURRIES. LOWS
SHOULD BE 10 TO 20 DEGREE BELOW NORMAL. WENT A LITTLE WARMER THAN MOS
GUIDANCE DUE TO LACK OF SNOW COVER OVER ALL BUT THE NORTH AND
ENOUGH BOUNDARY LAYER WINDS OVER THE EAST TO KEEP SOME SURFACE
WINDS.

SUNNY AND COLD WEATHER EXPECTED FRIDAY WITH HIGHS AROUND 15
DEGREES BELOW USUAL FOR THIS TIME OF THE YEAR. WENT A BIT HIGHER
THAN GUIDANCE DUE TO LACK OF SNOW.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 341 AM CDT THU MAR 26 2015

COLD NORTHERLY UPPER LEVEL FLOW AND SURFACE HIGH PRESSURE OVER THE
STATE WILL RESULT IN A COLD START TO THIS PART OF THE FORECAST. LIGHT
WINDS AND MOSTLY CLEAR SKIES SHOULD ALLOW TEMPERATURES TO FALL
BELOW ZERO IN FAR NORTHERN WISCONSIN FRIDAY NIGHT.

UPPER LEVEL FLOW STARTS TO BECOME LESS AMPLIFIED AND SURFACE FLOW
IS EXPECTED TO BECOME SOUTH/SOUTHWEST ON SATURDAY SO TEMPERATURES
WILL START TO WARM...BUT HIGHS WILL STILL BE 5 TO 10 DEGREES BELOW
NORMAL.

WARM ADVECTION AHEAD OF A SURFACE LOW MOVING ACROSS SOUTHERN
CANADA AND AN APPROACHING MID LEVEL SHORT WAVE SHOULD KEEP LOWS
CLOSER TO NORMAL ON SATURDAY NIGHT. HOWEVER...CHANCES FOR LIGHT
SNOW RETURN TO THE FAR WESTERN PART OF THE FORECAST AREA LATE
SATURDAY NIGHT. THIS IS A COMPROMISE BETWEEN THE FASTER 00Z GFS
AND SLOWER 00Z ECMWF SOLUTIONS.

BY SUNDAY THERE IS A CHANCE FOR PRECIPITATION ACROSS THE ENTIRE
AREA BUT TYPE IS AN ISSUE...ESPECIALLY DURING THE MORNING. THE
BOUNDARY LAYER SHOULD WARM UP ENOUGH BY SUNDAY AFTERNOON TO KEEP
PRECIPITATION IN THE FORM OF RAIN...BUT COLDER BOUNDARY LAYER
TEMPERATURES WILL ALLOW FOR SNOW IN THE NORTH AND EITHER A MIX OR
SNOW IN CENTRAL AND EAST CENTRAL WISCONSIN DURING THE MORNING.
ANY SNOW AMOUNTS ARE EXPECTED TO BE MINOR AND SHOULD MELT DURING
THE DAY.

THOUGH MODELS DIFFER ON SOME OF THE FINER DETAILS...E.G. THE
SURFACE LOW AND QPF THAT THE EC SHOWED MOVING ACROSS WISCONSIN
MONDAY/MONDAY NIGHT IS NOT SEEN IN THE GFS...THERE IS MORE
CONSISTENCY IN THEIR HANDLING OF A SYSTEM FOR THE MIDDLE OF NEXT
WEEK.

THE LESS AMPLIFIED FLOW WILL RESULT IN A WARMING TREND...AND HIGH
TEMPERATURES SHOULD GRADUALLY INCREASE FROM THE 30S ON SATURDAY
TO THE 50S AND LOWER 60S FOR WEDNESDAY.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1222 PM CDT THU MAR 26 2015

PLENTY OF CLOUDS ROTATING SEWD THRU WI IN RESPONSE TO THE PASSAGE
OF A COLD SHORTWAVE TROF ALOFT. CIGS THRU THE REST OF THE
AFTERNOON TO RANGE FROM HI-END MVFR TO LOW-END VFR. THERE WL ALSO
BE LAKE EFFECT SNOW SHWRS OR FLURRIES AFFECTING N-CNTRL WI AND
POSSIBLY THE RHI TAF SITE. THESE CLOUDS ARE EXPECTED TO GRADUALLY
DECREASE THIS EVENING AS HI PRES BUILDS TOWARD THE REGION...
LEAVING VFR CONDITIONS ACROSS ALL OF NE WI. THIS HI PRES TO THEN
SETTLE OVER THE WRN GREAT LAKES REGION ON FRI...BRINGING PLENTY OF
SUN...LIGHT NORTH WINDS AND COOL CONDITIONS FOR LATE MARCH.

&&

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

$$

SHORT TERM.....RDM
LONG TERM......MG
AVIATION.......AK





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