National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KGRB 110300
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1000 PM CDT THU JUL 10 2014

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 310 PM CDT THU JUL 10 2014

FAIR WEATHER CUMULUS DEVELOPED LATE THIS MORNING AND CONTINUED THIS
AFTERNOON AWAY FROM THE BAY AND LAKE. WEAK BOUNDARY ACROSS SOUTHWEST
WISCONSIN...PLUS DAYTIME HEATING TRIGGERED AN ISOLATED SHOWER JUST
SOUTH OF WOOD COUNTY. SINCE SOME OF THE MODELS WERE SHOWING ISOLATED
CONVECTION THIS AFTERNOON...ADDED ISOLATED SHOWERS TO PORTIONS OF OUR
SOUTHWEST COUNTIES FOR THE REST OF THE AFTERNOON.

THE FORECAST REMAINS MUDDLED ON TIMING OF THE PRECIPITATION LATE
TONIGHT AND FRIDAY. MOST OF THE 12Z MODELS HAVE DELAYED THE TIMING
OF THE ARRIVAL OF THE PRECIPITATION. HOWEVER...LATER HRR MODEL
INDICATED PRECIPITATION MOVING INTO WESTERN WISCONSIN AROUND 06Z
DUE WEAK SHORTWAVE MOVING THROUGH THE MEAN FLOW. THINK SOME OF THE
PRECIPITATION WILL MAKE IT INTO OUR WESTERN COUNTIES VERY LATE
TONIGHT OR MORE LIKELY FRIDAY MORNING. ONCE THIS SHORTWAVE PASSES
THE REGION...NOT MUCH IN AN UPPER LEVEL TRIGGER FOR THINGS TO GET
GOING FRIDAY AFTERNOON. HOWEVER...DAYTIME HEATING PRODUCED CAPES
APPROXIMATELY AROUND 1000-1500 J/KG. THINK THERE WILL BE SOME
DIURNALLY DRIVEN CONVECTION.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 310 PM CDT THU JUL 10 2014

EARLY IN THE EXTENDED THE UPPER FLOW OVER THE WESTERN GREAT LAKES
STARTS OUT RATHER FLAT...THEN IMPRESSIVE CLOSED UPPER LOW DROPS
SOUTHWARD OVER THE AREA BY EARLY IN THE WORK WEAK. DURING THIS
PATTERN EVOLUTION...EXPECT SEVERAL OPPORTUNITIES FOR PRECIPITATION
WITH A GRADUAL DOWNTURN IN TEMPERATURES WITH READINGS FALLING WELL
BELOW NORMAL BY TUESDAY. MODELS STRUGGLING WITH THE DETAILS OF
THIS EVOLUTION...THUS FORECAST CONFIDENCE IS LOW.

FORECAST FOR FRIDAY NIGHT INTO SATURDAY NO SLAM DUNK WITH
INITIALLY FLAT UPPER-LEVEL FLOW AND EMBEDDED GENERALLY WEAK
IMPULSES TRAVERSING THE WESTERN GREAT LAKES. STILL PLENTY OF MODEL
DIFFERENCE ON DETAILS OF CONVECTIVE EVOLUTION AHEAD OF APPROACHING
FRONTAL BOUNDARY. FIRST NOTABLE DISTURBANCE WORKS ACROSS THE AREA
FRIDAY NIGHT. OVERALL CONSENSUS OF THE MODEL GUIDANCE SEEM TO
SUGGEST TWO PRIMARY AREAS OF FOCUS FOR PRECIPITATION ACROSS NORTHERN
WISCONSIN CLOSER TO THE STRONGER UPPER-LEVEL FORCING...AND OVER
SOUTHERN WISCONSIN NEAR STRONGER INSTABILITY AND DEEPER MOISTURE.
KEPT HIGH CHANCE POPS OVER ENTIRE FORECAST AREA FRIDAY NIGHT GIVEN
UNCERTAINTY IN TIMING AND EVOLUTION OF CONVECTIVE ACTIVITY AHEAD
OF THE APPROACHING FRONT. INSTABILITY AND FORCING NOT PARTICULARLY
IMPRESSIVE THUS CHOSE TO GO WITH ISOLATED THUNDER FRIDAY NIGHT
INTO SATURDAY MORNING. INITIAL COLD FRONT LOOKS LIKE IT WILL NOW
SURGE SOUTHEAST OF THE FORECAST AREA SOMETIME SUNDAY MORNING THUS
ADJUSTED POPS ACCORDINGLY WITH HIGHEST CHANCES OVER THE SOUTHEAST
PORTION OF THE FORECAST AREA.

AS UPPER LOW CONTINUES TO DROP SOUTHWARD SUNDAY INTO SUNDAY
EVENING...SECONDARY COLD FRONT PUSHES SOUTHEASTWARD WITH ANOTHER
CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS. AGAIN STILL MUCH
UNCERTAINTY ON TIMING OF THE FRONT...THUS CONTINUED THEME OF BROAD
BRUSH POPS ON SUNDAY WITH ACTIVITY GENERALLY SCATTERED IN
NATURE. SOME POTENTIAL DOES EXIST FOR SOME OF THE STORMS TO BE STRONG
SUNDAY AFTERNOON BUT AGAIN MUCH WILL DEPEND ON HOW MUCH
INSULATION CAN BE REALIZED.

BY MONDAY NIGHT AND TUESDAY...UPPER-LOW SETTLES OVER THE FORECAST
AREA. SOME OF THE GUIDANCE SUGGESTS FAIRLY ROBUST AREA OF
PRECIPITATION TO DEVELOP OVER EAST CENTRAL WISCONSIN...BUT NOT SOLD
ON THIS JUST YET. WILL NEED TO KEEP ON EYE ON THIS. ROBUST CAA
AND VERY BRISK NORTHERLY WINDS LATER ON MONDAY AND TUESDAY WILL
MAKE FOR QUITE COOL CONDITIONS FOR THE MIDDLE OF JULY.

UPPER-LOW SHOULD BEGIN TO LOOSE ITS GRIP LATE TUESDAY INTO
WEDNESDAY WITH SOME MODERATION IN TEMPERATURES BY WEDNESDAY.
HOWEVER TEMPERATURES WILL STILL BY WELL BELOW NORMAL.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 959 PM CDT THU JUL 10 2014

MID TO HIGH LEVEL BUT STILL VFR CLOUDS WILL SPREAD
FROM WEST TO EAST OVER THE REGION OVERNIGHT. A FEW LIGHT SHOWERS
MAY PASS OVER NORTH CENTRAL WISCONSIN OVERNIGHT AS AN UPPER
DISTURBANCE TRACKS OVER NORTHERN MINNESOTA AND THE WESTERN GREAT
LAKES AND WEAK WARM FRONT LIFTS NORTH OVER THE STATE. LAKE
MICHIGAN FOG DEVELOPED THE PREVIOUS NIGHT AND WILL BE POSSIBLE
AGAIN FOR MTW AFTER 09Z. SCATTERED SHOWERS MAY WORK INTO PARTS OF
CENTRAL AND NORTH CENTRAL WISCONSIN FRIDAY AFTERNOON HOWEVER VFR
CONDITIONS SHOULD CONTINUE TO PREVAIL.
&&

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

$$

SHORT TERM.....ECKBERG
LONG TERM......ESB
AVIATION.......TDH