Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 252311
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
611 PM CDT WED MAR 25 2015

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 241 PM CDT WED MAR 25 2015

MAIN FCST CONCERNS CENTER AROUND LAKE EFFECT POTENTIAL LATE
TNGT/WED MORNING FOR N-CNTRL WI...CLOUD TRENDS AND MAX TEMPS FOR
WED.

THE 19Z MSAS SFC ANALYSIS INDICATED A TRIPLET OF WEAK LOW PRES (NE
MN/E-CNTRL LK SUPERIOR AND NW LAKE HURON). A TIGHT PRES GRADIENT
EXISTED BETWEEN THESE LOWS AND HI PRES OVER THE NRN HI PLAINS.
VSBL SATL IMAGERY SHOWED A BLANKET OF LOW CLOUDS OVER THE UPR
MIDWEST AND GREAT LAKES REGION WITH SOME THIN SPOTS OVER SW MN AND
NRN IA. RADAR MOSAIC HAD PICKED UP ON SOME LIGHT SNOW OVER NE
MN/NW WI AND WRN UPR MI ASSOCIATED WITH A MID-LEVEL SHORTWAVE
TROF.

NE WI CAUGHT UNDER A BROAD CYCLONIC FLOW AS THE SHORTWAVE TROF
PUSHES THRU NRN SECTIONS OF THE GREAT LAKES. AS MENTIONED ABOVE...
PLENTY OF CLOUDS ASSOCIATED WITH THIS UPR TROF ALTHO THE THIN
SPOTS ACROSS MN/IA HOLD OUT HOPE FOR SOME THINNING OF THE CLOUDS
ACROSS MOST OF NE WI LATER TNGT. EXCEPTION TO BE N-CNTRL WI WHERE
VEERING WINDS TO THE NW WL INTRODUCE LAKE CLOUDS INTO THAT PART OF
THE STATE. FURTHERMORE...MODELS INDICATE ANOTHER SHORTWAVE TROF TO
DROP SE INTO THE WRN GREAT LAKES AFTER MIDNGT. COLDER AIR ALOFT TO
ACCOMPANY THIS FEATURE...THUS AN INCREASING CHC OF LAKE EFFECT
SNOW SHWRS ACROSS N-CNTRL WI. TRAJS DO BECOME FAVORABLE OVRNGT...
BUT BEGIN TO TURN ALMOST DUE NORTH BY DAYBREAK. IN ADDITION...
DELTA-T VALUES TO REACH THE MID TO UPR TEENS...THEREFORE HAVE KEPT
HI POPS FOR VILAS CNTY AFTER MIDNGT WITH UP TO AN INCH OF
ACCUMULATION. COMBINATION OF CLOUDS AND WIND WL PREVENT TEMPS FROM
FALLING TOO FAR TNGT...DESPITE THE FRESH SNOW COVER. LOOK FOR MIN
TEMPS TO RANGE FROM THE LWR 20S NORTH...MID TO UPR 20S SOUTH.

THE SHORTWAVE TROF SWINGS THRU THE GREAT LAKES ON THU WITH THE
COLD CYCLONIC FLOW PERSISTING THRU THE DAY. LAKE EFFECT SNOW SHWRS
TO PERSIST THRU AT LEAST MIDDAY BEFORE BEGINNING TO WEAKEN IN THE
AFTERNOON AS CANADIAN HI PRES BEGINS TO BUILD INTO THE UPR MS
VALLEY. THE EXPECTED NORTHERLY WINDS FAVOR AREAS EITHER NORTH OR
WEST OF VILAS CNTY...THUS ADDITIONAL ACCUMULATIONS SHOULD BE
LIGHT. PERHAPS ANOTHER INCH POSSIBLE ACROSS NRN SECTIONS OF THE
CNTY WITH LESSER AMOUNTS FARTHER SOUTH. THE REST OF NE WI TO BE
MOSTLY CLOUDY WITH MAX TEMPS IN THE MID TO UPR 20S NEAR THE MI
BORDER...AROUND 40 DEGS FRO WAUTOMA TO SHAWANO.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 241 PM CDT WED MAR 25 2015

TEMPERATURES AND PCPN TRENDS ARE THE MAIN FCST CONCERNS.

A COLD UPPER TROF WILL RESIDE OVER THE GREAT LAKES DURING THE
BEGINNING OF THE PERIOD. LINGERING LAKE-EFFECT SNOW SHOWERS ARE
EXPECTED IN FAR NORTH CENTRAL WISCONSIN THURSDAY NIGHT. ADDITIONAL
ACCUMS SHOULD BE AN INCH OR LESS...AS WIND TRAJECTORIES ARE NOT
IDEAL (N-NNE) AND INCOMING HIGH PRESSURE SHOULD RESULT IN A
DECREASING TREND OVERNIGHT. THE ARCTIC HIGH WILL BRING MUCH BLO
NORMAL TEMPS THROUGH FRIDAY NIGHT...WITH SOME SUB-ZERO MIN TEMPS
POSSIBLE OVER THE FAR NORTH ON SAT MORNING. THE DEEP UPPER TROF IS
EXPECTED TO SHIFT EAST ON SATURDAY.

A S/W TROF...LFQ OF AN UPPER JET AND COLD FRONT WILL AFFECT THE
REGION LATE SATURDAY NIGHT INTO SUNDAY. THE ACTUAL CLIPPER LOW
IS EXPECTED TO PASS TO OUR NORTH...ACROSS NORTHERN LAKE SUPERIOR.
THE GFS MODEL WAS FASTER THAN THE ECMWF/GEM...AND LIKELY TOO FAST.
HAVE COMPROMISED BY GOING WITH A DRY FCST FOR SATURDAY EVG...A SMALL
CHANCE OVER THE NW HALF OF THE CWA LATE SAT NGT...THEN MID-RANGE
POPS ACROSS THE ENTIRE AREA ON SUNDAY. POPS MAY NEED TO RAISED TO
LIKELY WITH SUBSEQUENT FCSTS. WILL PROBABLY SEE LIGHT SNOW OR
MIXED RAIN/SNOW EARLY IN THE EVENT...CHANGING TO RAIN OVER MUCH OF
THE REGION SUNDAY AFTERNOON.

ALTHOUGH DETAILS ARE UNCERTAIN FOR THE NEXT WORK WEEK...THE
GENERAL TRENDS SUPPORT A RETURN TO MILDER TEMPERATURES. THE
BEST CHANCE OF PCPN IS EXPECTED TO OCCUR TUESDAY NIGHT INTO
WEDNESDAY...AS ANOTHER FRONTAL SYSTEM MOVES THROUGH THE STATE.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 611 PM CDT WED MAR 25 2015

A FEW POCKETS OF VFR CONDITIONS MAY OCCUR OVERNIGHT
OVER MAINLY PARTS OF CENTRAL AND EAST CENTRAL WISCONSIN...OTHERWISE
COLD CYCLONIC FLOW WILL TEND TO KEEP MVFR CIGS LOCKED IN OVER THE
AREA TONIGHT INTO THURSDAY. GUSTY WEST WINDS WILL SUBSIDE DURING
THE EVENING HOURS.
&&

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

$$

SHORT TERM.....KALLAS
LONG TERM......KIECKBUSCH
AVIATION.......TDH





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