Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 050843
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
243 AM CST THU MAR 5 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 242 AM CST THU MAR 5 2015

LARGE FRONTAL BOUNDARY EXTENDING FROM TEXAS TO THE TN VALLEY
REGION TO THE EAST COAST CONTINUES TO SLOWLY SAG SOUTHEAST OVER
THAT PART OF THE COUNTRY TODAY. SWATH OF WINTER STORM HEADLINES
AND FLOOD WARNINGS ALONG AND NEAR THIS INTENSE BOUNDARY WITH WARM
GULF MOISTURE TO THE SOUTH AND THE ARCTIC AIR TO THE NORTH.

MUCH QUIETER BUT COLDER REGIME TO DOMINATE NORTHEAST WISCONSIN TODAY
INTO TONIGHT AS THE COLD HIGH PRESSURE RIDGE DRIFTS OVER THE GREAT
LAKES AND UPPER MIDWEST.

COLD START THIS MORNING WITH NEUTRAL TEMPERATURE ADVECTION WILL
PRODUCE ANOTHER COLD DAY TODAY UNDER PLENTY OF SUNSHINE.

CHALLENGE TONIGHT WILL DEAL WITH HOW FAST THE TEMPS WILL PLUMMET
PRIOR TO SOME INCREASE IN CLOUDS WITH A NORTHERN STREAM SHORT WAVE
TROUGH DROPPING IN.  PROGS IN GOOD AGREEMENT WITH A CLEAR START
FOLLOWED WITH INCREASING CLOUDS...SO WILL FOCUS MIN TEMPS A FEW
HOURS AFTER MIDNIGHT THEN GO THE STEADY ROUTE. PROGS DO NOT
GENERATE MUCH PCPN BUT WILL KEEP THE SMALL PCPN MENTION OF
FLURRIES DUE TO THE MORNING WEAK WAA PATTERN FOLLOWED BY THE
TROUGH PASSAGE.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 242 AM CST THU MAR 5 2015

MEAN FLOW ACROSS THE GREAT LAKES TO TRANSITION FROM NW THIS
WEEKEND TO SW BY THE MIDDLE OF NEXT WEEK AS THE ERN PACIFIC/WEST
COAST UPR RDG WEAKENS. NE WI WL HAVE TO DEAL WITH A COUPLE OF WEAK
SYSTEMS IN THE NW FLOW THIS WEEKEND...BUT ANY PCPN APPEARS TO BE
LIGHT AS MOISTURE AVAILABILITY IS MARGINAL AT BEST. AS THE FLOW
TURNS WEST THEN SW...PACIFIC AIR WL REPLACE THE ARCTIC AIR OVER
THE ERN HALF OF THE CONUS WITH A SIGNIFICANT WARM-UP ON THE WAY.
EXACTLY HOW WARM WE CAN GET WL BE THE MAIN ISSUE IN THE LONG-TERM.
HOW LONG THIS WARMER AIR CAN HANG AROUND IS OPEN TO DEBATE AS THE
MODELS DIFFER WITH THE HANDLING OF A PACIFIC SYSTEM ACROSS THE NW
CONUS/SW CANADA. MORE ON THIS IN THE COMING DAYS. FOR NOW...LET`S
ENJOY THE MARCH THAW.

THE FIRST OF THESE WEAK SYSTEMS IS FCST TO DIVE SE INTO THE GREAT
LAKES AFTER MIDNGT AS A CLIPPER LOW PRES TO REACH VCNTY LAKE
SUPERIOR BY 12Z SAT. A CDFNT WL ACCOMPANY THE SFC LOW INTO THE WRN
GREAT LAKES...ALONG WITH MODEST FORCING FROM A WEAK MID-LEVEL
SHORTWAVE TROF. THERE DOES APPEAR TO BE ENUF MOISTURE TO SQUEEZE
OUT A LITTLE LIGHT SNOW OR FLURRIES ACROSS THE FCST AREA...ESPECIALLY
OVER NRN WI WHERE BETTER SATURATION IS SHOWN ON THE TIME SECTIONS.
THICKENING CLOUDS WL HELP TO HOLD TEMPS UP WITH MINS ONLY DROPPING
INTO THE TEENS TO AROUND 20 DEGS. THE CLIPPER HEADS TOWARD THE ERN
GREAT LAKES ON SAT WITH A VERY WEAK HI PRES MOVING INTO THE MIDWEST.
ANY LINGERING LIGHT SNOW OR FLURRIES SHOULD END IN THE MORNING WITH
MOSTLY CLOUDY SKIES EXPECTED FOR THE REST OF THE DAY. A MORE MILD
START TO THE DAY WL ALLOW MAX TEMPS TO WARM INTO THE 30-35 DEG RANGE
OVER MOST OF THE FCST AREA.

NE WI TO RESIDE BETWEEN SYSTEMS SAT NGT AS THE WEAK HI PRES SHIFTS
SE TOWARD THE TN VALLEY AND THE NEXT SYSTEM PUSHES SE TO JUST EAST
OF LAKE WINNIPEG BY 12Z SUNDAY. CLOUDS ARE EXPECTED TO THICKEN
DURING THE OVRNGT HOURS AS THE SFC HI PULLS AWAY WITH MIN TEMPS
GENERALLY IN THE 15 TO 20 DEG RANGE. THIS NEXT CLIPPER DOES NOT
DIVE AS FAR SE AS ITS PREDECESSOR...INSTEAD TRACKING MORE E-SE
ACROSS SRN ONTARIO ON SUNDAY. A CDFNT/SHORTWAVE TROF COMBINATION
WL SWEEP ACROSS NE WI PRIMARILY DURING THE AFTERNOON AND COULD
HAVE ENUF MOISTURE TO BRING AT LEAST A SMALL CHC OF LIGHT SNOW TO
THE AREA. MAX TEMPS ARE EXPECTED TO REACH THE MID TO UPR 30S (PRE-
FRONTAL WARMING) WHICH MAY ALLOW A LITTLE RAIN TO PERHAPS MIX WITH
THE SNOW. IF THIS WERE TO HAPPEN...IT WOULD BE SOUTH OF HWY 29 IN
THE AFTERNOON.

THE MEAN FLOW ACROSS THE CONUS TO ESSENTIALLY BE ZONAL BY NEXT TUE
WITH THE ACTIVE NRN BRANCH KEEPING ANY SYSTEMS MOVING EWD ACROSS
SRN CANADA. THIS LEAVES NE WI UNDER THE INFLUENCE OF HI PRES OVER
THE OHIO RIVER VALLEY AND A PREVAILING SW WIND INTO THE GREAT
LAKES. MILD PACIFIC AIR WL CONT TO OVERSPREAD WI WITH MAX TEMPS ON
TUE ABLE TO REACH THE LWR TO MID 40S NORTH/LAKESHORE...MID TO UPR
40S ELSEWHERE.

FCST TOWARD THE MIDDLE OF NEXT WEEK BECOMES MORE MUDDLED AS THE
MODELS ARE STRUGGLING WITH THE SPLIT FLOW OVER THE ERN PACIFIC AND
A RESULTANT SYSTEM MOVING SOMEWHERE ALONG FAR SRN CANADA OR NRN
TIER OF STATES. THE GFS IS MUCH MORE AGGRESSIVE WITH THIS SYSTEM
BY TAKING A STRONG SFC LOW ACROSS SRN CANADA AND SENDING A STRONG
CDFNT INTO WI WED AFTERNOON. MEANWHILE...THE ECMWF IS MUCH WEAKER
AND FARTHER SOUTH WITH THE SFC LOW AND ESSENTIALLY SAGS THE MUCH
WEAKER CDFNT INTO NRN SECTIONS OF THE GREAT LAKES ON WED. FOR ALL
INTENSIVE PURPOSES...THIS MAJOR MODEL CONFLICT WOULD NOT IMPACT NE
WI UNTIL AFTER THE END OF THE FCST PERIOD AND MAINLY AFFECTS
TEMPS. UNTIL THEN...WED SHOULD STILL BE A WARM DAY WITH MAX TEMPS
SIMILAR TO TUE.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1029 PM CST WED MAR 4 2015

NOW THAT WINDS HAVE SETTLED DOWN...GOOD FLIGHT CONDITIONS /VFR
CATEGORY/ ARE ANTICIPATED FOR THE NEXT 24 HRS AS HIGH PRESSURE
PASSES SW OF THE AREA.
&&

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

$$

SHORT TERM.....TDH
LONG TERM......AK
AVIATION.......SKOWRONSKI






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