Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 171151
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
651 AM CDT FRI OCT 17 2014

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 338 AM CDT FRI OCT 17 2014

UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL MOVE
ACROSS THE REGION TODAY ACCOMPANIED BY SHOWERS. THE AIR IS INITIALLY
QUITE DRY BUT DYNAMICS ARE FAIRLY STRONG SO THERE SHOULD BE CONSIDERABLE
SHOWER ACTIVITY. FAIRLY STEEP LAPSE RATES SO A FEW THUNDERSTORMS
ARE NOT OUT OF THE QUESTION. DO NOT EXPECT ENOUGH TO MENTION IN
THE FORECAST. HIGH TEMPERATURES WILL STRUGGLE TO GET ABOVE 50 IN
THE FAR NORTH BUT RISE INTO THE MIDDLE TO UPPER 50S FURTHER SOUTH
BEFORE THE FRONT GOES BY.

MODELS SUGGEST ANOTHER UPPER DISTURBANCE WILL MOVE THROUGH TONIGHT.
IT MIGHT BE STRONG ENOUGH TO KEEP SCATTERED SHOWERS GOING INTO THE
EVENING HOURS. OTHERWISE EXPECT LAKE EFFECT CLOUDS ACROSS THE
NORTH ALONG WITH SOME RAIN AND SNOW SHOWERS. LOWS WILL LIKELY STAY
ABOVE FREEZING DUE TO CLOUD COVER AND A STEADY WIND.

SATURDAY SHOULD BE A BLUSTERY AND COOL BUT SUNNY DAY BUT WINDS
WILL DIMINISH IN THE AFTERNOON AS SURFACE HIGH BUILD SIN FROM THE
NORTHERN PLAINS.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 338 AM CDT FRI OCT 17 2014

MAIN POINT OF EMPHASIS FOR MOST OF NEXT WEEK WL BE THE DEVELOPMENT
OF A HIGHLY AMPLIFIED MEAN FLOW WITH UPR TROFS OVER THE WRN AND
ERN CONUS...AND AN UPR RDG OVER CNTRL NOAM. AFTER A CHC OF PCPN
SUNDAY NGT/MON ASSOCIATED WITH THE NEWLY FORMED ERN TROF...A DRY
AND MODERATING TEMPERATURE TREND CAN BE EXPECTED ACROSS NE WI THRU
THE MIDDLE OF NEXT WEEK.

RDG OF HI PRES TO SLIDE ACROSS WI SAT NGT AND BRING MOSTLY CLEAR
SKIES...LIGHT WINDS AND A DRY AIR MASS TO THE AREA. NEARLY IDEAL
RADIATIONAL COOLING CONDITIONS TO EXIST AND THIS WL ALLOW TEMPS TO
EASILY FALL TO BELOW NORMAL LEVELS. LOOK FOR MIN TEMPS TO RANGE
FROM THE MID TO UPR 20S NORTH...TO THE MID 30S OVER DOOR COUNTY.

MDLS CONT TO SHOW THE APPROACH OF AN INITIALLY WEAK SHORTWAVE TROF/
ATTENDANT CDFNT TO DROP SE TOWARD THE UPR MS VALLEY ON SUNDAY.
PRECEDING THIS SYSTEM...A RETURN FLOW WL DEVELOP OVER WI WITH A
DECENT SURGE OF WAA TAKING PLACE...ESPECIALLY DURING THE AFTERNOON
HOURS. THE AIR MASS OVER NE WI LOOKS VERY DRY IN THE LWR LAYERS AT
THE ONSET...BUT IT APPEARS ENUF SATURATION TO OCCUR TO BRING CHC
POPS INTO THE FCST AREA SUNDAY AFTERNOON. BEST LIKELIHOOD OF
SATURATION APPEARS TO BE ROUGHLY NORTH OF HWY 29...THUS CHC POPS
FOR NRN WI TAPERING DOWN TO BARELY SLGT CHC OVER SRN SECTIONS OF
THE FCST AREA. MAX TEMPS TO RANGE FROM AROUND 50 DEGS NORTH...LWR
TO MID 50S OVER CNTRL WI.

THE INTENSIFYING SHORTWAVE TROF REACHES THE GREAT LAKES REGION
SUNDAY NGT WITH THE CDFNT SWEEPING ACROSS NE WI AFTER MIDNGT.
STRONGEST MID-LEVEL FORCING TO PASS NORTH AND EAST OF THE FCST
AREA...THUS LEAVING THE CDFNT AS THE PRIMARY LIFTING MECHANISM FOR
PCPN. HAVE PLACED THE HIGHER CHC POPS MORE TOWARD FAR NE WI...
CLOSER TO THE BETTER FORCING. MEANWHILE...PARTS OF CNTRL WI MAY
HAVE TROUBLE EVEN MEASURING ANY PCPN AT ALL. PLENTY OF CLOUD COVER
WL HELP TO HOLD TEMPS UP SUNDAY NGT WITH READINGS ONLY FALLING TO
AROUND 40 DEGS NORTH...MID 40S LAKESIDE. A CYCLONIC FLOW TO LINGER
OVER MOST OF WI INTO MON AS THE SHORTWAVE TROF NOW TO EAST CONTS
TO DEEPEN. A PREVAILING N-NW WIND AND MODEST CAA WL ALSO BRING
LAKE ENHANCED CLOUDS/RAIN SHWR POTENTIAL TO N-CNTRL WI. THIS ALL
ADDS UP TO A MOSTLY CLOUDY DAY OVER THE FCST AREA WITH AT LEAST
CHC POPS ACROSS N-CNTRL AND SLGT CHC POPS ELSEWHERE. MAX TEMPS WL
END UP CLOSE TO NORMAL...THANKS MAINLY TO THE MILD START TO THE
DAY.

IMPROVING CONDITIONS ARE EXPECTED STARTING MON NGT AS THE UPR TROF
SHIFTS FARTHER AWAY AND A RDG OF HI PRES BEGINS TO BUILD TOWARD
THE WRN GREAT LAKES. CLOUDS SHOULD GRADUALLY BEGIN TO DECREASE
FROM WEST TO EAST WITH SKIES BECOMING PARTLY CLOUDY ACROSS N-CNTRL
AND CNTRL WI BY DAYBREAK. THIS SFC RDG AXIS SETTLES ACROSS WI ON
TUE ALLOWING SKIES TO BE MOSTLY SUNNY...BRINGING A PLEASANT DAY TO
THE REGION WITH TEMPS AGAGIN CLOSE TO NORMAL (LWR 50S NORTH/MID
50S SOUTH).

BY THE MIDDLE OF NEXT WEEK...THE MEAN FLOW ACROSS THE CONUS TO
HAVE BECOME HIGHLY AMPLIFIED WITH GENERAL TROFFINESS OVER THE WRN
CONUS...A SHARP UPR RDG OVER E-CNTRL NOAM AND A STRONG UPR TROF
OVER THE ERN CONUS. NE WI TO BE UNDER THE INFLUENCE OF BOTH THE
SFC RDG AND THE UPR RDG...THUS QUIET WEATHER TO PREVAIL FOR WED
WITH MAX TEMPS EDGING SLIGHTLY ABOVE NORMAL.

CHANGES IN THE MEAN FLOW ARE ADVERTISED BY THE MDLS HEADED INTO
NEXT THU AS THE MAIN BAND OF WESTERLIES TO RUN FROM THE PACIFIC NW
ACROSS SRN CANADA. A PACIFIC SYSTEM MOVING ALONG THESE WESTERLIES
WL TEND TO FLATTEN THE UPR RDG OVER CANADA...BUT MAINTAIN A WEAKER
UPR RDG ACROSS THE CNTRL CONUS. IN ADDITION...AN AREA OF HI PRES
TO STILL BE IN THE VICINITY OF THE GREAT LAKES...SO DO NOT SEE ANY
OPPORTUNITY FOR PCPN ON THU. IN FACT...A PREVAILING SW WIND SHOULD
BRING WARMER AIR INTO WI WITH MAX TEMPS FOR THU GENERALLY IN THE
55-60 DEG RANGE.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 650 AM CDT FRI OCT 17 2014

A COLD FRONT WILL PRODUCE SCATTERED SHOWERS AS IT MOVES ACROSS
THE AREA. IFR CEILINGS OVER NORTHERN WISCONSIN WILL LIFT INTO MVFR
RANGE BY MIDDAY. FURTHER SOUTH VFR CEILINGS WILL LOWER INTO MVFR
RANGE THIS MORNING. A NORTHWEST FLOW OF COLD AIR MOVING ACROSS
LAKE SUPERIOR WILL KEEP BROKEN CLOUDS BETWEEN 2000 AND 3000 FEET
OVER MOST OF THE AREA TONIGHT. SOME LAKE EFFECT SNOW OR RAIN
SHOWERS ARE POSSIBLE AT D25/ARV/LNL/ARV TONIGHT. VFR CONDITIONS
EXPECTED OVER MOST OF THE REGION SUNDAY.

&&

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

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......RDM






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