Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 232255
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
455 PM CST SUN NOV 23 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 253 PM CST SUN NOV 23 2014

COMPLEX WEATHER FCST TO SAY THE LEAST OVER THE NEXT 24 HOURS AS
TWO DISTINCT SYSTEMS TRY TO PHASE OVER THE GREAT LAKES. EXACTLY
HOW THIS TRANSPIRES WL DETERMINE THE AMOUNT OF PCPN...PCPN-TYPE
CHANGEOVER AND WHETHER ANY HEADLINES WOULD BE NEEDED.

THE 20Z MSAS SFC ANALYSIS SHOWED ONE AREA OF LOW PRES OVER NRN MN
AND A SECOND LOW PRES OVER THE SRN PLAINS. A CDFNT CONNECTED THE
TWO SFC LOWS AND WAS IMPINGING ON THE MN/WI BORDER. A BROAD
SOUTHERLY WIND AHEAD OF CDFNT HAS PUMPED UP PLENTY OF GULF
MOISTURE INTO THE GREAT LAKES WITH A LARGE AMOUNT OF PCPN LIFTED
INTO WI. TEMPERATURES WERE WELL ABOVE FREEZING...THUS RAIN AND FOG
PREVAIL OVER NE WI.

A SRN STREAM MID-LEVEL SHORTWAVE TROF WL LIFT NE PRECEDED BY A
STRONG AREA OF LOW PRES. THE RADAD MOSAIC FROM THE CNTRL CONUS
INDICATED SEVERAL LARGE BANDS OF PCPN MOVE NORTH FROM THE GULF AND
EXPECT A RAINY NIGHT OVER THE FCST AREA. FOR LATER TNGT...A NRN
STREAM SHORTWAVE TROF IS FCST TO MOVE INTO THE UPR MS VALLEY
PRECEDED BY THE CDFNT THAT IS EXPECTED TO SWEEP ACROSS WI AND
BRING COLDER AIR INTO AT LEAST WRN WI BY DAYBREAK. ENUF COOL AIR
MAY BE ABLE TO REACH WRN SECTIONS OF THE FCST AREA TO ALLOW FOR A
RAIN/SNOW MIX TO OCCUR. THE OTHER ISSUE FOR TNGT IS THE STUBBORN
FOG WHICH HAS REFUSED TO LIFT AT ALL ACROSS NRN AND PARTS OF CNTRL
WI. AS LONG AS THE WARMER AIR MOVES OVER THE SNOW COVER...THIS FOG
MAY NOT DISSIPATE ANY TIME SOON. PLAN ON EXTENDING THE DENSE FOG
ADVY UNTIL AT LEAST 06Z TNGT.

COLDER AIR TO QUICKLY SWEEP ACROSS WI MON MORNING AS THE NRN
STREAM SHORTWAVE TROF ARRIVES AND A SHORTWAVE ROUNDS THE BASE OF
THE TROF AND LIFTS NE TOWARD LWR MI MON AFTERNOON. MDLS HAVE
ATTEMPTED TO FOCUS HIGHEST QPF WITH THIS SHORTWAVE SHOWING STRONG
LIFT/FORCING PUSHING ACROSS THE SE QUARTER OF WI. THIS WOULD PLACE
THE DEFORMATION ZONE IN THIS PART OF THE STATE AND THE BEST
POTENTIAL FOR SNOW ACCUMULATION. LATEST THINKING IS FOR AN INCH OR
LESS OF SNOW TO FALL OVER N-CNTRL/CNTRL WI AND ONE-HALF INCH OR
LESS OVER ERN WI (MAINLY DUE TO THE LATE CHANGEOVER TO SNOW).
ANOTHER PLACE TO WATCH WL BE VILAS CNTY AS THE COLDER AIR ARRIVES
AND WINDS TURN TO THE W-NW. THIS BRINGS LAKE ENHANCEMENT INTO PLAY
ACROSS VILAS CNTY WITH AN INCH OR TWO OF ACCUMULATION EXPECTED MON
AFTERNOON. THE ONSET OF CAA WL BRING EARLY DAY MAX TEMPS WITH
READINGS STEADY TO SLOWLY FALLING THRU THE DAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 253 PM CST SUN NOV 23 2014

PCPN TRENDS...SNOWFALL AMOUNTS...LAKE EFFECT POTENTIAL AND HEADLINES
FOR THE MONDAY AND MONDAY NIGHT PERIODS ARE THE MAIN FCST CONCERNS.

DETAILS ARE STILL SOMEWHAT SKETCHY WITH THE PHASING LOW PRESSURE
SYSTEM THAT WILL BE PULLING OUT OF THE AREA ON MONDAY NIGHT. EVEN
THOUGH THE MAIN LOW WILL BE NEARING JAMES BAY CANADA BY MONDAY
EVENING...MODELS CONTINUE TO PRODUCE MODERATE QPF THROUGH THE
NIGHT...ESPECIALLY OVER THE SE HALF OF GRB CWA. THIS APPEARS TO BE
RELATED TO THE PRESENCE OF AN UPPER DEFORMATION ZONE...WHICH WILL
BE COINCIDENT WITH A PERSISTENT STRONG SFC TROF AND THE AXIS OF
BEST MOISTURE. HAVE USED A BLEND OF VARIOUS MODELS AND WPC QPF
AMOUNTS FOR MONDAY NIGHT...WITH UPWARD ADJUSTMENTS IN VILAS
COUNTY...WHERE LAKE-ENHANCEMENT WILL OCCUR. SNOW TOTALS FROM
18Z/MON THROUGH 12Z/TUE ARE CLOSE TO ADVISORY CRITERIA (3-4
INCHES IN 18 HOURS) SE OF A LINE FROM WAUTOMA TO MARINETTE...BUT
HAVE OPTED TO HOLD OFF ON HEADLINES FOR THIS AREA NOW. THIS
MATCHES UP WITH ARX/MKX...AS THEY HAVE DECIDED TO HOLD OFF ON
HEADLINES FOR THE COUNTIES BORDERING OUR SOUTHERN CWA. LAKE-
ENHANCEMENT WILL PUSH VILAS COUNTY OVER THE ADVISORY THRESHOLD
THOUGH...SO WILL ISSUE A LAKE-EFFECT SNOW ADVISORY FOR MONDAY
AFTERNOON AND NIGHT...WITH 3 TO 6 INCH ACCUMS EXPECTED.

LINGERING LAKE-EFFECT SNOW SHOWERS WILL END ON TUESDAY MORNING...
WITH DRY CONDITIONS CONTINUNING THROUGH TUESDAY NIGHT. ECMWF
HAS TRENDED SLOWER AND FARTHER SOUTH WITH THE CLIPPER SYSTEM
ON WED/WED NGT...WHICH IS MORE IN LINE WITH MOST OTHER MODELS.
WILL ONLY CARRY CHC POPS...EXCEPT OVER VILAS COUNTY ON WEDS
NGT...WHEN ANOTHER ROUND OF LAKE-EFFECT IS EXPECTED. THE LES
WILL CONTINUE IN FAR NC WI INTO THURSDAY.

STAYED WITH EXTENDED MODEL BLEND FOR DAYS 5-7...WITH CONTINUED
COLD CONDITIONS...AND ONLY SMALL PCPN CHANCES.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 454 PM CST SUN NOV 23 2014

A DEEPENING LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL CONTINUE
TO PRODUCE LIFR/IFR CONDITIONS OVERNIGHT DUE TO CIGS AND FOG. A
COLD FRONT PASSING OVER THE AREA TOWARD MONDAY MORNING WILL
IMPROVE CIGS AND VSBYS BUT ALSO TURN THE RAIN OVER TO SNOW. GUSTY
NORTHWEST WINDS LATER MONDAY MAY PRODUCE SOME BLOWING AND DRIFTING
SNOW OVER OPEN AREAS INCLUDING RUNWAYS.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ005-010>013-
018-019-021-030-035-036.

LAKE EFFECT SNOW ADVISORY FROM NOON MONDAY TO 6 AM CST TUESDAY
FOR WIZ005.
&&

$$

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






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