Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 251757
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1257 PM CDT TUE AUG 25 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 311 AM CDT TUE AUG 25 2015

A LARGE UPPER LEVEL LOW...SEEN ON WATER VAPOR SPINNING OVER THE
NORTH CENTRAL GREAT LAKES...WILL CONTINUE TO INFLUENCE THE WEATHER
TODAY AND TONIGHT AS IT SLOWLY TRACKS NORTH TOWARDS JAMES BAY.
COLD UNSTABLE AIR AND SHORTWAVES WILL CONTINUE TRACKING AROUND
THIS LARGE LOW...MAKING FOR ANOTHER DAY OF MOSTLY CLOUDY SKIES AND
BELOW NORMAL TEMPERATURES ACROSS NORTHEAST WISCONSIN WITH A FEW
SHOWERS POSSIBLE ACROSS THE FAR NORTH. TEMPERATURES TODAY SHOULD
MODERATE A BIT FROM YESTERDAY...AS 850 MB TEMPERATURES WARM 3 TO 5
DEGREES FROM THE DAY BEFORE...WITH HIGHS RANGING FROM AROUND 60
ACROSS THE FAR NORTH...WITH MIDDLE TO UPPER 60S ACROSS CENTRAL AND
EAST CENTRAL WISCONSIN. WINDS WILL INCREASE ONCE AGAIN AFTER
DAYBREAK...HOWEVER THE VAD WIND PROFILE SHOWS WINDS OFF THE
SURFACE ARE MUCH LIGHTER THAN PREVIOUS DAYS SO THEY SHOULD BE
LIGHTER.

AS THE AFOREMENTIONED LOW PULLS OUT OF THE REGION TONIGHT AND
WEDNESDAY...SOME CLEARING IS EXPECTED ACROSS THE WESTERN AND
SOUTHERN AREAS TONIGHT...THEN THE REST OF THE AREA ON WEDNESDAY.
THE CLEARING MAY LEAD TO SOME PATCHY FOG FROM WAUSAU NORTH TO
RHINELANDER LATE TONIGHT. LOWS TONIGHT SHOULD SETTLE INTO THE
MIDDLE TO UPPER 40S ACROSS THE WEST AND NORTH...WITH LOWS AROUND
50 ACROSS EAST CENTRAL WISCONSIN. WITH TEMPERATURES WARMING A FEW
MORE DEGREES ON WEDNESDAY HIGHS ARE EXPECTED TO GET INTO THE UPPER
60S ACROSS THE NORTH...WITH HIGHS IN THE LOWER 70S ACROSS THE
SOUTH.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 311 AM CDT TUE AUG 25 2015

THE MEAN FLOW NEAR AND OVER NOAM TO GENERALLY CONSIST OF AN UPR
TROF OVER THE FAR ERN PACIFIC...AN UPR RDG OVER THE ROCKIES/PLAINS
AND SOME SEMBLANCE OF AN UPR TROF OVER ERN NOAM. FOR NE WI...THE
PRIMARY WEATHER FEATURE OF INTEREST WL BE A SHORTWAVE TROF THAT IS
FCST TO UNDERCUT THE UPR RDG AND PUSH TOWARD THE WRN GREAT LAKES
LATE THIS WEEK. THE FCST CONUNDRUM TO BE THE STRENGTH OF THIS
SYSTEM AND ITS EVENTUAL MOVEMENT...IN WHICH THE MODELS ARE IN
DISPUTE. TEMPS THRU THE CYCLE WL START AT OR BELOW NORMAL...BUT
WARM TO ABOVE NORMAL LEVELS BY THE LATTER PART OF THE WEEKEND.

AN AREA OF HI PRES TO BE SITUATED ALMOST DIRECTLY OVERHEAD WED NGT
WHICH WL PROVIDE MOSTLY CLEAR SKIES...LITTLE IF ANY WIND AND COOL
TEMPS AS NEARLY IDEAL RADIATIONAL COOLING CONDITIONS TO EXIST. MIN
TEMPS COULD DIP INTO THE UPR 30S OVER THE COLDER LOCATIONS OF THE
NORTHWOODS. OTHERWISE...THE REST OF NRN WI TO SEE READINGS IN THE
40-45 DEG RANGE...WITH UPR 40S TO LWR 50S CNTRL/E-CNTRL WI. CANNOT
RULE OUT A LITTLE PATCHY LATE NGT FOG NORTH AS TEMPS APPROACH THE
DEW POINT.

AS THE SFC HI SLIPS TO OUR EAST ON THU..A RETURN FLOW DEVELOPS
OVER WI AS WINDS VEER TO A GENERALY SOUTHERL DIRECTION. ONSET OF
WEAK WAA WL LIFT 8H TEMPS TO AROUND +15C AND THIS SHOULD TRANSLATE
TO MAX TEMPS IN THE LWR 70S LAKESIDE...LWR TO MID 70S NORTH AND
MID TO UPR 70S SOUTH.

ATTENTION THEN GETS FOCUSED ON A MID-LEVEL SHORTWAVE TROF THAT
UNDERCUTS THE ROCKIES UPR RDG AND IS PROGGED TO MOVE ACROSS THE
PLAINS INTO THE UPR MIDWEST THU NGT. THE MODELS ARE INDICATING
THAT THIS SYSTEM IS A BIT STRONGER/BETTER ORGANIZED THAT
ADVERTISED 24 HOURS AGO WITH GOOD MID-LEVEL FORCING AND THE AID OF
THE RIGHT ENTRANCE REGION OF THE UPR JET FOR EXTRA LIFT.
INSTABILITY THO STILL LOOKS WEAK...THUS ANY TSTM ACTIVITY THAT MAY
APPROACH NRN OR CNTRL WI LATE THU NGT WL BE NON-SEVERE. THICKENING
CLOUDS WITH A SOUTH WIND WL BRING A MILD NGT TO THE AREA WITH MIN
TEMPS GENERALLY IN THE MID TO UPR 50S. THE MAIN FCST ISSUE IN THE
EXTENDED FCST REVOLVES AROUND FRI AS THE MODELS DISAGREE WITH BOTH
THE STRENGTH AND EVENTUAL MOVEMENT OF THIS SYSTEM. THE GEM AND
ECMWF TAKE THE STRONGEST FORCING AND LIFT TOWARD IA AND IL AS
OPPOSED TO THE GFS THAT MAXIMIZES FORCING AND LIFT ACROSS SRN
SECTIONS OF MN AND WI/FAR NRN SECTIONS OF IA AND IL. A POSSIBLE
PROBLEM WITH THE GFS IS THAT THERE MAY BE SOME CONVECTIVE FEEDBACK
ISSUES...THUS OVERPLAYING BOTH THE STRENGTH OF THE SYSTEM AN ITS
CORRESPONDING PCPN AMOUNTS. HAVE LEANED ON THE ECMWF/GEM WHICH
BRING A DECENT PCPN CHC TO CNTRL AND E-CNTRL WI ON FRI.
INSTABILITY PARAMETERS REMAIN WEAK...THUS ANY TSTMS WOULD REMAIN
WEAK. ANTICIPATE MAX TEMPS ON FRI TO COOL A BIT WITH CLOUDS AND
PCPN IN THE VCNTY. LOOK FOR READINGS TO RANGE FROM AROUND 70 DEGS
N-CNTRL WI/LAKESHORE...LWR TO MID 70S CNTRL/E-CNTRL WI.

EVEN IF THE BULK OF THIS SYSTEM DID PASS TO OUR SOUTH HEADED INTO
FRI NGT...THERE WL BE SHORTWAVE ENERGY MOVING THRU THE SHORTWAVE
TROF...THUS CHC POPS ARE NEEDED THRU THE NGT ALONG WITH A FEW
TSTMS. DUE TO THE OVERALL SLOW MOVEMENT OF THE SYSTEM...IT IS
CONCEIVABLE THAT ENUF LIFT TO STILL BE OVER THE ERN HALF OF WI TO
AT LEAST KEEP A SMALL CHC OF MAINLY LIGHT SHWRS TO NE WI. MAX
TEMPS ON SAT SHOULD BE SIMILAR TO FRI (CLOSE TO SEASONAL NORMALS).

IMPROVING CONDITIONS ARE FCST FOR THE LATTER HALF OF THE WEEKEND
AS UPR HEIGHTS BUILD ACROSS THE CNTRL CONUS IN RESPONSE TO
INCREASING TROFFING ALONG THE WEST COAST. MORE SUNSHINE AND A
RETURN TO S-SW WINDS WL PROVIDE A BOOST TO TEMPS AS READINGS TO
RANGE FROM THE MID TO UPR 70S N-CNTRL/LAKESHORE...TO THE UPR 70S
TO LWR 80S OVER CNTRL/E-CNTRL WI. THE UPR RDG OVER THE CNTRL CONUS
IS EXPECTED TO BUILD TOWARD THE WRN GREAT LAKES ON MON AND KEEP
THE QUIET AND WARM WEATHER INTACT OVER THE FCST AREA. MAX TEMPS TO
RANGE FROM THE MID TO UPR 70S NEAR LAKE MI...TO THE LWR 80S
ELSEWHERE.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1257 PM CDT TUE AUG 25 2015

THE CLOUD SHIELD...WITH MVFR CIGS...AROUND A DEPARTING UPPER
CYCLONE AND SURFACE LOW WILL LIKELY STAY IN PLACE THROUGHOUT THE
NIGHT AND INTO THE MORNING HOURS. THERE MAY ALSO BE SOME AREAS OF
MVFR VSBY IN FOG TONIGHT...MAINLY ACROSS NORTHERN WISCONSIN. ENDED
UP MORE CLOSELY FOLLOWING THE 12Z GFS THAN THE 12Z NAM AND HAVE
CLOUDS DEPARTING DURING THE MORNING ON WEDNESDAY. SHOULD JUST BE
CLR TO SCT CLOUDS AFTER THAT WITH WINDS LESS THAN 10 KNOTS.
&&

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

$$

SHORT TERM.....KURIMSKI
LONG TERM......KALLAS
AVIATION.......MG


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