Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 191959
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
ISSUED BY NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
259 PM CDT TUE AUG 19 2014

.TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.

DAYTIME HEATING HELPING BRING SCATTERED TO BROKEN CUMULUS FROM
MORNING LOW STRATUS OVER MOST OF THE AREA. STILL AN AREA OF LOW
STRATUS OVER VILAS COUNTY...WHICH MAY PUSH FURTHER SOUTHEAST INTO
THIS EVENING GIVEN CURRENT TRENDS. SOME SUNSHINE HELPING GENERATE UP
TO 500 J/KG OR SO OF TALL SKINNY MEAN LAYER CAPE ACROSS THE AREA.

500 MB LOW CONTINUES TO SLOWLY SHIFT EAST INTO THE UPPER PENINSULA
OF MICHIGAN...WITH VARIOUS VORTICITY MAXIMA ROTATING THROUGH THE
REGION. BROKEN LINE OF SHOWERS CONTINUE TO DEVELOP ON SURFACE
TROUGH/WEAK COLD FRONT ACROSS NORTHERN PORTIONS OF THE AREA. OTHER
SCATTERED SHOWERS WERE SEEN OVER OTHER PORTIONS OF THE AREA.

500 MB LOW WILL CONTINUE TO SLOWLY SHIFT EAST ACROSS THE UPPER
PENINSULA OF MICHIGAN TONIGHT INTO WEDNESDAY...BEFORE MOVING FURTHER
TO THE SOUTHEAST. EXPECT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TO CONTINUE INTO THE EARLY EVENING HOURS ACROSS MOST
OF THE AREA.

THINKING THAT STORMS INTO EARLY THIS EVENING WILL BE MORE ISOLATED
IN AREAL COVERAGE...AS SURFACE BOUNDARIES BESIDES TROUGH MENTIONED
ABOVE ARE RELATIVELY WEAK. IF A STORM DOES PERSIST...IT COULD BRING
BRIEF HEAVY RAINFALL/GUSTY WINDS AND SMALL HAIL GIVEN SLOW STORM
MOVEMENTS. ISOLATED SHOWERS MAY LINGER IN THE FAR NORTHEASTERN
PORTIONS OF THE AREA LATER TONIGHT INTO EARLY WEDNESDAY...CLOSER TO
THE UPPER LOW CENTER.

OTHER ISSUE WILL BE FOG TONIGHT. WINDS WILL WEAKEN WITH RELATIVELY
MOIST AIRMASS LINGERING ACROSS THE AREA. THIS SHOULD ALLOW FOR AREAS
OF FOG TO DEVELOP BY LATE EVENING ACROSS THE AREA...ALONG WITH LOW
STRATUS DECK OVER PORTIONS OF THE AREA. THIS MAY LIMIT DENSE FOG
POTENTIAL...THOUGH STILL ADDED MENTION IN VILAS/ONEIDA COUNTIES.
LOWS IN THE MID 50S TO AROUND 60 ARE EXPECTED TONIGHT...WITH 70S ON
WEDNESDAY.

.WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE IS
MEDIUM.

WED EVENING SHOULD BE QUIET AS HIGH PRESSURE MAINTAINS THE
LARGEST INFLUENCE. LATE WED NGT INTO THU...A STRONG SURFACE WARM
FRONT WILL LIFT NORTH TOWARD THE AREA...ACCOMPANIED BY SOME DECENT
AND RATHER DEEP WARM AIR ADVECTION. IN ADDITION...THE UPPER RIDGE
AXIS WILL BE OVERHEAD...BUT THE MODELS DEPICT A SHORT WAVE
HITTING THE TOP OF THE RIDGE AND FLATTENING IT A BIT AS IT EJECTS
OUT OF A WESTERN U.S. TROF. SO...WILL HAVE THE CHANCE OF RAIN
ARRIVING OVER THE SOUTHERN FORECAST AREA AFTER MIDNIGHT WED
NGT...THEN SPREAD ACROSS THE ENTIRE AREA FOR THU INTO THU NIGHT.
THE WARM FRONT MAY HANG UP OVER THE AREA AND WITH A CONSTANT
INFLUX OF WARM AND MOIST AIR IMPINGING ON THE FRONT DUE TO
PERSISTENT WEAK TO MODERATE LOW LEVEL JET WE SHOULD SEE SHOWERS
AND STORMS FROM TIME TO TIME. DEWPOINTS WILL BE ON THE
RISE...MAKING THINGS FEEL MUCH MORE HUMID THAN WE/VE SEEN IN A
WHILE.

.FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.

LOTS OF MODEL DISCREPANCY AS WE HEAD INTO THIS PERIOD AND MOVE
THROUGH THE WEEKEND. THE NAM AND THE ECMWF BRING A BIT OF A LULL
IN ANY ACTIVITY LATE IN THE WEEK WITH WEAK HIGH PRESSURE MOVING
IN AS THE WARM FRONT AND IT/S PARENT LOW MOVE EAST. RAIN CAN/T BE
RULED OUT ALTOGETHER...BUT THIS SHOULD BE A SOMEWHAT QUIET PERIOD.
THE GFS ON THE OTHER HAND IS AN OUTLIER WITH A STRONG LOW PRESSURE
SYSTEM MOVING INTO SOUTHERN MN BY FRIDAY...RESULTING IN THE
ADVANCEMENT OF ANOTHER WARM FRONT INTO THE AREA...THUS A MUCH
WETTER SCENARIO FOR FRIDAY INTO FRIDAY NIGHT. WILL HEDGE TOWARD
THE NAM/ECWMF...BUT BY KEEPING POPS IN...RECOGNIZE THE POTENTIAL
FOR THE GFS TO BE RIGHT. TEMPS WILL BE WARM BY FRIDAY...ESPECIALLY
SOUTH OF GREEN BAY...HITTING THE LOWER TO MID 80S. DEWPOINTS WILL
REMAIN ELEVATED AS WELL MAKING THE APPARENT TEMPERATURE FEEL MUCH
WARMER.

SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE IS MEDIUM.

THE PATTERN REMAINS UNSETTLED WITH A SERIES OF SHORT WAVES PUSHING
THROUGH ON AN ACTIVE MID LEVEL FLOW. NATURALLY...THE MODELS ARE
NOT IN AGREEMENT ON THE PLACEMENT OF SFC DETAILS AND ARE OUT OF
PHASE AT TIMES. THUS...A MODEL BLEND IS THE BEST APPROACH
HERE...AND THAT JUST RESULTS IN AN EXTENDED FORECAST PEPPERED WITH
CONTINUED CHANCES OF SHOWERS AND STORMS. HOPEFULLY...WE CAN ADD
MORE TEMPORAL RESOLUTION AS WE GET CLOSER. TEMPS AND DEWPOINTS
WILL REMAIN ELEVATED THROUGH THE WEEKEND WITH A COOL DOWN EXPECTED
BY THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...

AREA OF MAINLY MVFR CEILINGS MAY BECOME MORE SCATTERED TO BROKEN
ACROSS TAF SITES THIS AFTERNOON WITH DAYTIME HEATING.
STILL...AT LEAST BROKEN SKIES ARE LIKELY TO LINGER...ESPECIALLY
AT RHINELANDER. THEY MAY BECOME VFR CATEGORY FOR A TIME LATER
THIS AFTERNOON INTO EARLY EVENING.

SCATTERED SHOWERS AND SOME THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON INTO EARLY THIS EVENING...WITH TROUGH OF LOW PRESSURE
CROSSING THE REGION. WILL USE VICINITY SHOWER/THUNDER WORDING IN
TAFS FOR NOW. MAY SEE BRIEF HEAVY RAINFALL/WIND GUSTS AND SMALL
HAIL IN STRONGEST STORMS.

CHANCES FOR SHOWERS WILL GRADUALLY DIMINISH ACROSS TAF SITES
TONIGHT INTO WEDNESDAY...AS TROUGH OF LOW PRESSURE MOVES AWAY.
LIGHT WINDS AND LINGERING MOISTURE WILL BRING ANOTHER NIGHT OF LOW
CEILINGS WITH SOME FOG DEVELOPMENT. SHOULD SEE IFR
CEILINGS/VISIBILITIES...WITH LIFR POSSIBLE AT TIMES. DENSE FOG IS
NOT OUT OF THE QUESTION...THOUGH LOW CLOUDS MAY LIMIT THIS RISK TO
LOW LYING AREAS.

SHOULD SEE MVFR/VFR CEILINGS BECOME SCATTERED TO BROKEN BY
WEDNESDAY AFTERNOON. WINDS WILL REMAIN LIGHT.

&&

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

$$
SHORT TERM...WOOD
LONG TERM...DAVIS



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