Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRB 190004
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
604 PM CST THU DEC 18 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 253 PM CST THU DEC 18 2014

CLOUD COVER AND ITS EFFECT ON LOWS TONIGHT ARE THE
MAIN CHALLENGE. CLOUD COVER THIS AFTERNOON CORRESPONDS PRETTY WELL
WITH MODEL 950MB MOISTURE FIELD. THEY GENERALLY CONTINUE TO PUSH
THE CLOUDS TO THE SOUTHWEST FOR THE REST OF THE AFTERNOON AND
EVENING HOURS BEFORE STALLING AS WINDS BECOME LIGHT AND VARIABLE.
AS THE HIGH STARTS TO DRIFT EAST LATE TONIGHT AND FRIDAY THE
CLOUDS WILL LIKELY START TO DRIFT EAST AGAIN. ASSUMING IT WILL BE
CLEAR IN MOST PLACES FOR MUCH OF THE NIGHT WE ARE GOING WITH
COLDER OVERNIGHT TEMPERATURES ESPECIALLY IN THE NORTH WHERE THERE
IS SIGNIFICANT SNOW. FRIDAY SHOULD BE PRETTY CLOSE TO NORMAL
HIGHS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 253 PM CST THU DEC 18 2014

WEATHER PATTERN TURNS MORE ACTIVE AFTER THIS WEEKEND WITH SEVERAL
PERIODS OF PRECIPITATION ORE MORE LIKELY A PROLONGED PERIOD.

A MID LEVEL TROUGH QUICKLY SWINGS OVER THE WESTERN GREAT LAKES
REGION SATURDAY INTO SATURDAY EVENING AS WAA INCREASES OVER THE
AREA SATURDAY NIGHT. BLEND OF MODELS SUGGESTS INCREASING CLOUDS AT
LEAST. ITS POSSIBLE FLURRIES MAY BE NEEDED FOR SATURDAY NIGHT WITH
THE WAA BUT UPPER HEIGHTS ARE INCREASING BRIEFLY AHEAD OF THE NEXT
SHORT WAVE TROUGH.

NEXT SHORT WAVE IS EXPECTED TO DROP INTO THE NORTHERN PLAINS AND
WESTERN GREAT LAKES REGION LATER SUNDAY INTO MONDAY AND GRADUALLY
DEEPEN WHILE DRIFTING OVER THE GREAT LAKES REGION. PROGS SUGGEST
THE SHORT WAVE TROUGH DEEPENS TO A CLOSED LOW JUST SOUTHWEST OF
THE FORECAST AREA AS AN UPPER JET DIVES SOUTHEAST INTO THE CENTRAL
PLAINS. DEALING WITH PIECES OF ENERGY WITHIN THIS UPPER LOW
DRIFTING OVER THE GREAT LAKES REGION WILL BE THE PRIMARY CHALLENGE
FOR NEXT WEEKS FORECAST. ACCUMULATING SNOW IS ANTICIPATED BUT
QUESTIONS PERTAIN IF THIS SNOW WILL ARRIVE IN SHORTER PERIODS
WARRANTING ADVISORY HEADLINES OR WILL THE SNOW ACCUM BE MORE SPREAD
OUT FOR 3 DAY PERIOD THROUGH WEDNESDAY NIGHT OR THURSDAY MORNING.

TO FURTHER COMPLICATE SNOW AMOUNTS THOUGH TUESDAY...TEMP PROFILE
SUGGEST A POSSIBLE RAIN AND SNOW MIX FOR PARTS OF CENTRAL AND EAST
CENTRAL WI UNTIL THE LOW DRIFTS EAST ENOUGH FOR THE COLDER TO
WRAP INTO THE REGION. THIS COLDER AIR MAY HAVE SOME BLUSTERY
NORTHWEST WINDS WITH IT FOR SOME DRIFTING SNOW CONCERNS TOWARD
WEDNESDAY.

FOR THE LATER HALF OF THE WEEK...PROGS ARE IN SOME AGREEMENT WITH
LIFTING THE LARGE CLOSED UPPER LOW SYSTEM TO THE NORTHEAST WHILE A
SYSTEM TRACKS ALONG A BAROCLINIC ZONE STRETCHING FROM THE CENTRAL
PLAINS TO THE OHIO VALLEY...BUT SOUTH OF WISCONSIN AT THIS TIME.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 604 PM CST THU DEC 18 2014

CLOUD TRENDS CONTINUE TO BE A MAJOR FORECAST CHALLENGE. DRIER AIR
MOVED INTO MUCH OF THE AREA FROM THE NORTHEAST...RESULTING IN
CLEARING SKIES AT MOST OF THE TAF SITES BY 23Z. TIME/HEIGHT
SECTIONS FROM THE 12Z NAM SHOWED HIGH RH WITHIN THE FIRST 2-3KFT
OF THE SURFACE THROUGHOUT THE FORECAST PERIOD WHILE THE 12Z GFS
SEEMED TO BE DOING BETTER...RELATIVE TO CURRENT TRENDS...SHOWING
DECREASING LOW-LEVEL MOISTURE. HAVE GONE WITH A BLEND OF CURRENT
TRENDS...THE PREVIOUS FORECAST AND MOS GUIDANCE TO PRODUCE THE 00Z
TAFS...BUT FORECAST CONFIDENCE IS LOW.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......TDH
AVIATION.......MG





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.