Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 270754
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
254 AM CDT THU AUG 27 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 253 AM CDT THU AUG 27 2015

CLEAR SKIES AND LIGHT WINDS HAVE LED TO SOME FOG ACROSS PORTIONS
OF THE CWA EARLY THIS MORNING...MAINLY NORTH OF HIGHWAY 29. PATCHY
DENSE FOG IS EXPECTED ACROSS THE AREA EARLY THIS MORNING UNTIL IT
MIXES OUT SHORTLY AFTER SUNRISE WITH DAYTIME HEATING.

ONCE THE FOG BURNS OFF IT WILL BE A RATHER PLEASANT DAY ACROSS
NORTHEAST WISCONSIN WITH HIGH PRESSURE CONTINUING TO INFLUENCE THE
WEATHER ACROSS THE WESTERN GREAT LAKES. SOUTHERLY WINDS AND WARM
AIR ADVECTION ON THE BACKSIDE OF THE HIGH SHOULD ALLOW AFTERNOON
HIGHS TO SOAR INTO THE LOWER TO MIDDLE 70S.

LOW PRESSURE EMERGING OUT OVER THE NORTHERN PLAINS TODAY WILL
TRACK EAST TOWARDS THE UPPER MISSOURI VALLEY TONIGHT...THEN
TOWARDS THE MID MISSISSIPPI VALLEY ON FRIDAY. THIS SYSTEM WILL
BRING A SHIELD OF SHOWERS AND A FEW THUNDERSTORMS AS IT TRACKS
EAST...WHICH CAN CURRENTLY BE SEEN OVER SOUTH DAKOTA. DESPITE THE
RAIN BEING 36 HOURS OUT...MODEL SOLUTIONS VARY WIDELY THIS RUN
REGARDING WHERE THE RAIN IS EXPECTED TO TRACK ON FRIDAY. THE GEM
MODEL IS SO FAR SOUTH RAIN JUST BRUSHES THE SOUTHERN CWA...WHILE
THE GFS CONCENTRATES THE RAIN ACROSS THE SOUTHERN CWA...WITH THE
NAM FOCUSING ACROSS THE NORTH. THE ECMWF SOLUTION IS SIMILAR IN
PLACEMENT WITH THE NAM...BUT HOLDS OFF THE HEAVY RAIN UNTIL LATE
FRIDAY AFTERNOON AND INTO THE EVENING. GIVEN THE MODEL VARIABILITY
WILL ONLY RAISE POPS SLIGHTLY TO LIKELY AT THIS POINT UNTIL A
CLEARER SOLUTION CAN BE HAD.

WITH ABUNDANT CLOUD COVER STREAMING IN TONIGHT...OVERNIGHT LOWS
ARE EXPECTED TO BE IN THE MIDDLE TO UPPER 50S. ON FRIDAY THE
CLOUDS AND RAIN SHOULD LIMIT HIGH TEMPERATURES...ESPECIALLY ACROSS
THE WEST WITH THE QUICKER TIMING. HIGHS ON FRIDAY ARE EXPECTED TO
RANGE FROM THE UPPER 60S ACROSS CENTRAL AND NORTH CENTRAL
WISCONSIN...WITH HIGHS AROUND 70 ACROSS EAST CENTRAL WISCONSIN.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 253 AM CDT THU AUG 27 2015

A WARM AND RELATIVELY QUIET PERIOD WILL BE PRESENT ACROSS THE REGION
FOR MUCH OF NEXT WEEK...AS UPPER TROUGHING PERSISTS OVER THE WEST
COAST...AND RIDGING BUILDS EAST OF THE MISSISSIPPI RIVER.  THE LONE
SYSTEM TO CONTEND WITH CONTINUES TO TAKE PLACE DURING THE FRIDAY
THROUGH SATURDAY PERIOD.  THE OPERATIONAL MODELS CONTINUE TO HAVE
DIFFICULTY RESOLVING THE TRACK/TIMING OF SHORTWAVE AND SURFACE LOW
DURING THIS PERIOD.  THE ECMWF NOW SHOWS THE FARTHEST NORTH TRACK
WHILE THE GFS IS NOW THE FARTHEST SOUTH...WHICH IS A REVERSAL OF THE
SOLUTIONS LAST NITE AT THIS TIME.  WILL TRY TO MITIGATE THE
DIFFERENCES BY BLENDING THE TWO SOLUTIONS...WHICH IS RELATIVELY
CLOSE TO THE 00Z NAM.

FRIDAY NIGHT THROUGH SATURDAY NIGHT...LOW PRESSURE WILL SLOWLY BE
MOVING TO THE EAST OVER EASTERN IOWA TO SOUTHWEST WISCONSIN FRIDAY
NIGHT.  AHEAD OF THE LOW...STRONG MID-LEVEL FGEN ON THE NOSE OF A 30-
40 KT LLJ AND PWATS UPWARDS OF 1.75 INCHES WILL GENERATE AN AREA OF
SHOWERS AND STORMS OVER CENTRAL AND NORTHEAST WI THROUGH THE NIGHT.
THOUGH LACK OF INSTABILITY WILL PROHIBIT SEVERE STORMS FROM
DEVELOPING...THE SLOW MOVEMENT OF THE SYSTEM COMBINED WITH STRONG
FORCING/HIGH PWATS WILL MAKE LOCALLY HEAVY RAINFALL A DECENT THREAT.
MOST NUMERICAL GUIDANCE GENERATES A SWATH OF QPF IN EXCESS OF 2
INCHES.  BEST GUESS FOR THE HEAVY RAIN PLACEMENT IS OVER CENTRAL AND
EAST-CENTRAL WISCONSIN BUT MODEL SPREAD MAKES THIS A RELATIVELY LOW
CONFIDENCE FORECAST. WILL ADD THE THREAT TO THE HWO.

HEAVY RAINFALL MAY LINGER OVER NORTHEAST WI SATURDAY MORNING BEFORE
PULLING OUT DURING THE AFTERNOON.  WITH THE ANTICIPATED
RAINFALL...SATURDAYS HIGHS COULD BE COOLER THAN CURRENTLY
FORECASTED...AND WILL DROP TEMPS A FEW DEGREES.  BECOMING MOSTLY
CLEAR AND CALM FOR SATURDAY NIGHT.  THE RAINFALL AND LIGHT WINDS MAY
LEAD TO FOG DEVELOPMENT.  WILL ADD TO THE FORECAST.

REST OF THE FORECAST...WARMER AIR WILL GRADUALLY BUILD OVER THE
WESTERN GREAT LAKES SUNDAY AND MONDAY AS MID-LEVEL HEIGHTS INCREASE
OVER THE REGION.  WITH ANY SEMBLANCE OF A FRONT WELL OFF TO OUR
WEST...NEXT WEEK SHOULD SEE ABOVE NORMAL TEMPERATURES AND DRY
CONDITIONS.  THE LONGER NIGHTS COMBINED WITH HIGHER DEWPOINTS WILL
LIKELY LEAD TO GROUND FOG SOME NIGHTS.  HIGHS MAINLY IN THE 80S AND
LOWS IN THE 60S.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1026 PM CDT WED AUG 26 2015

THE MAIN AVIATION FCST ISSUE WL BE FOG FORMATION TONIGHT. WITH
CLR SKIES AND LGT WINDS...TEMPS ALREADY APPROACHING DWPTS IN MOST
AREAS. EXPECT SOME SIG FOG /POSSIBLY DENSE/ AT LEAST AT RHI AND
CWA. THE MAIN QUESTION REMAINS HOW PERSISTENT AND WIDESPREAD IT WL
BE. FCST REASONING HAS NOT CHANGED...SO DO NOT ANTICIPATE ANY SIG
CHGS WITH THE 06Z TAFS.
&&

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

$$

SHORT TERM.....KURIMSKI
LONG TERM......MPC
AVIATION.......SKOWRONSKI


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