608  
FXUS63 KGRB 181137  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
637 AM CDT SAT AUG 18 2018  
 
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE  
   
SHORT TERM...TODAY...TONIGHT
 
AND SUNDAY  
ISSUED AT 320 AM CDT SAT AUG 18 2018  
 
INTERESTING THINGS GOING ON TODAY. WE HAVE LAKE EFFECT  
CLOUDS COVERING NORTHCENTRAL WISCONSIN FROM LAKE SUPERIOR, LOW  
CLOUDS FORMING OVER THE NORTHERN BAY DRIFTING OVER THE DOOR  
PENINSULA, AND SOME LAKE EFFECT CLOUDS DOWNWIND OF LAKE WINNEBAGO.  
THESE CLOUDS SHOULD MIX OUT BEFORE NOON. WE ALSO HAVE AN ELEVATED  
SMOKE LAYER FROM FIRES IN THE WESTERN UNITED STATES AND CANADA.  
THE SMOKE WILL MAKE THE SKY APPEAR HAZY OR GREY DESPITE SUNNY  
SKIES THIS AFTERNOON. TEMPERATURES TODAY WILL BE CLOSE TO NORMAL,  
WITH RELATIVE HUMIDITIES MORE COMFORTABLE THAN THE LAST WEEK OR  
TWO.  
 
SKIES SHOULD START OUT CLEAR THIS EVENING, WITH THE POTENTIAL FOR A  
BEAUTIFUL ORANGE OR RED SUNSET IF THE SMOKE IS STILL PRESENT. SOME  
GROUND FOG IS POSSIBLE LATE TONIGHT. LOWS WILL BE NEAR NORMAL.  
 
SUNDAY COULD START OUT WITH A BEAUTIFUL SUNRISE IF THE SMOKE IS  
STILL AROUND. IT WILL BE MOSTLY SUNNY AND A LITTLE BIT WARMER AND  
A LITTLE MORE HUMID. STILL A GOOD SUMMER DAY FOR OUTDOOR ACTIVITIES.  
   
LONG TERM
 
SUNDAY NIGHT THROUGH FRIDAY  
ISSUED AT 320 AM CDT SAT AUG 18 2018  
 
MAIN FOCUS OF THE LONG TERM REMAINS THE UNSETTLED WEATHER FROM  
MONDAY INTO TUESDAY AS AN UNSEASONABLY STRONG SYSTEM TRACKS ACROSS  
THE GREAT LAKES. THEN PRETTY QUIET LATE SUMMER CONDITIONS ARE ON  
TAP FOR MID-WEEK WITH ANOTHER COLD FRONT APPROACHING TOWARD NEXT  
WEEKEND. BELOW NORMAL TEMPS ARE EXPECTED ON TUESDAY BEHIND THE LOW  
PRESSURE SYSTEM. OTHERWISE, NEAR TO ABOVE NORMAL TEMPS LOOK TO BE  
THE RULE THROUGH THE PERIOD.  
 
MODELS HAVE COME INTO BETTER AGREEMENT FOR THE SYSTEM EARLY NEXT  
WEEK, WITH THE GFS GIVING IN AND TRENDING CLOSER TO THE ECMWF AND  
CANADIAN. EVEN THE GFS ENSEMBLES HAVE COME ON BOARD. EXPECT  
CHANCES FOR PRECIP TO INCREASE SLIGHTLY LATE SUNDAY NIGHT INTO  
MONDAY MORNING AS THE UPPER TROUGH APPROACHES FROM THE WEST AND A  
COLD FRONT SAGS SOUTH INTO NORTHERN WI. BUT THE MAIN SHOW WON'T  
ARRIVE UNTIL MONDAY AFTERNOON AND ESPECIALLY MONDAY NIGHT INTO  
EARLY TUESDAY AS SURFACE LOW PRESSURE STRENGTHENS AND TRACKS  
TOWARD SOUTHERN LAKE MICHIGAN BY AROUND 12Z TUESDAY. MODELS IN  
AGREEMENT SPREADING A WIDESPREAD AREA OF SHOWERS AND EMBEDDED  
STORMS ACROSS THE AREA, ESPECIALLY ACROSS EASTERN WI. IMPRESSED ON  
HOW MUCH THIS SYSTEM WRAPS UP ON THE CANADIAN (FOR MID-AUGUST  
STANDARDS AT LEAST) WHICH HAS A 996MB LOW OVER NORTHERN LAKE HURON  
BY TUESDAY AFTERNOON. BUT AM A LITTLE SKEPTICAL, AS THIS SYSTEM  
HAS VERY LITTLE TEMP CONTRAST/BAROCLINIC ZONE. IT DOES HAVE A  
COUPLED JET THOUGH, SO SOME DEEPENING IS REASONABLE, MORE IN LINE  
WITH THE ECMWF WHICH HAS A 1002MB LOW TUESDAY AFTERNOON OVER  
NORTHEAST LAKE HURON. AS LONG AS THE LOW TRACKS A LITTLE TO OUR  
SOUTH, NO SEVERE WEATHER IS EXPECTED AS THE WARM SECTOR (AND  
ASSOCIATED INSTABILITY AND WIND SHEAR) WOULD NOT MAKE IT FAR  
ENOUGH NORTH. THE CANADIAN IS THE ONLY MODEL THAT SHOWS THE WARM  
SECTOR MAKING A RUN AT MANITOWOC CO. MONDAY EVENING. TRENDS FOR A  
SLIGHT NORTHWARD SHIFT WILL NEED TO BE WATCHED, BUT FOR NOW, NO  
SEVERE WEATHER IS EXPECTED. STILL LOOKING LIKE THE HEAVY RAIN  
POTENTIAL WILL BE THE BIGGER STORY WITH THIS SYSTEM, ESPECIALLY  
FOR THE FOX VALLEY AND LAKESHORE. IT WILL BE A PRETTY QUICK  
MOVER, SO OVERALL FLOOD THREAT WILL BE LIMITED. HOWEVER, PWATS  
BETWEEN 1.3 AND 1.8 INCHES AND ANY BANDING/TRAINING OF  
SHOWERS/STORMS COULD LEAD TO LOCALIZED FLOODING ISSUES. ONE FINAL  
NOTE, THE CIPS ANALOGS SHOW THE HEAVIER RAIN FOCUSING TO OUR SOUTH  
(CLOSER TO THE GFS), SO THAT WILL BE SOMETHING TO WATCH AS WELL AS  
MODELS GET A BETTER GRASP OF THE FEATURES AS THEY NOW SHOULD ALL  
BE ONSHORE OF THE CONUS.  
 
AS THE SYSTEM DEPARTS ON TUESDAY, LOOK FOR THE MAJORITY OF THE  
SHOWER ACTIVITY TO END IN THE MORNING, WITH ONLY A FEW SHOWERS  
POSSIBLE ACROSS EASTERN WI IN THE AFTERNOON AS COLD AIR ADVECTION  
AND ANOTHER SHORTWAVE PUSHES ACROSS THE REGION. DRIER AIR PUSHING  
INTO THE AREA AND SUBSIDENCE BEHIND THE DEPARTING LOW SHOULD  
LIMIT OVERALL COVERAGE. WINDS WILL CRANK UP AS THE SYSTEM DEPARTS  
AS WELL. JUST HOW STRONG THE WINDS WILL BE AND HOW MUCH MIXING  
OCCURS TO BRING DOWN THE WINDS IS STILL IN QUESTION. MODELS RANGE  
FROM 20 TO 40 KTS AT 850MB, ALL DEPENDENT ON HOW WRAPPED UP THE  
SYSTEM BECOMES. MIDDLE OF THE ROAD APPROACH SEEMS REASONABLE,  
WHICH WOULD BRING GUSTS IN THE 20 TO 30 MPH RANGE FOR MOST  
LOCATIONS ON TUESDAY, POSSIBLY HIGHER OVER FAR EASTERN WI AND OVER  
THE BAY AND LAKE. TUESDAY WILL BE THE COOLEST DAY OF THE PERIOD,  
WITH HIGHS IN THE UPPER 60S TO MIDDLE 70S (COOLEST NORTH). IF  
CLOUDS/PRECIP STICK AROUND A LITTLE LONGER THAN FORECAST, MOST  
SPOTS COULD STRUGGLE TO GET OUT OF THE 60S (A FALL PREVIEW FOR  
SOME).  
 
QUIET WEATHER RETURNS TO THE AREA WEDNESDAY AND THURSDAY AS A  
SPRAWLING AREA OF SURFACE HIGH PRESSURE BUILDS EAST INTO THE GREAT  
LAKES REGION. A SHORTWAVE COULD BRUSH THE AREA ON WEDNESDAY,  
POSSIBLY BRINGING SOME CLOUDS TO THE AREA, BUT IT LOOKS TO STAY  
DRY. TEMPS SHOULD REBOUND NICELY, ESPECIALLY ON THURSDAY. THE NEXT  
WEATHER MAKER WILL APPROACH FROM THE WEST VERY LATE IN THE WEEK.  

 
   
AVIATION
 
FOR 12Z TAF ISSUANCE  
ISSUED AT 636 AM CDT SAT AUG 18 2018  
 
LOTS OF LOW CLOUDS AROUND THIS MORNING FROM A VARIETY OF PLACES.  
LAKE EFFECT CLOUDS WITH CEILINGS OF 400 TO 1300 FEET COVERED MUCH  
OF NORTHCENTRAL WISCONSIN AT 12Z. CLOUDS WITH BASES OF 1000 TO  
1500 FEET WERE FORMING OVER THE BAY AND DRIFTING OVER THE DOOR  
PENINSULA. THESE CLOUDS SHOULD SLOWLY DISSIPATE A FEW HOURS AFTER  
SUNRISE AND BE PRETTY MUCH GONE BY 18Z. GOOD FLYING WEATHER IS  
EXPECTED THIS AFTERNOON THROUGH MIDNIGHT. GROUND FOG IS POSSIBLE  
AGAIN LATE TONIGHT.  
 

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM.....RDM  
LONG TERM......BERSCH  
AVIATION.......RDM  
 
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