862  
FXUS63 KGRB 062341  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
641 PM CDT TUE JUN 6 2023  
 
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE  
   
SHORT TERM  
TONIGHT AND WEDNESDAY  
ISSUED AT 222 PM CDT TUE JUN 6 2023  
 
A COLD FRONT HAD SHIFTED WELL SOUTH OF THE FORECAST EARLY THIS  
AFTERNOON, AND HUDSON BAY HIGH PRESSURE WAS BUILDING INTO  
NORTHERN WI. SMOKY CONDITIONS HAD IMPROVED OVER GRB CWA, AT LEAST  
AT THE SURFACE, WHERE ALL OBSERVING SITES WERE REPORTING  
VISIBILITIES IN THE 7-10SM RANGE. PARTLY SUNNY SKIES WERE  
OBSERVED, ALONG WITH COOLER TEMPERATURES IN THE UPPER 60S AND  
70S.  
 
DRY WEATHER WILL PREVAIL TONIGHT AND WEDNESDAY, WITH SKIES  
BECOMING MOSTLY CLEAR LATER TONIGHT. AFTER A BIT OF A REPRIEVE  
TODAY, AN ELEVATED LAYER OF SMOKE IS EXPECTED TO ARRIVE IN NE WI  
OVERNIGHT, THEN OVERSPREAD THE REST OF THE FORECAST AREA ON  
WEDNESDAY. THERE ARE INDICATIONS THAT NEAR-SURFACE SMOKE MAY  
RETURN TO PARTS OF NORTHERN WI WEDNESDAY AFTERNOON.  
 
A VERY DRY AIR MASS AND DAYTIME MIXING WILL CAUSE DEW POINTS AND  
RELATIVE HUMIDITIES TO CRASH WEDNESDAY AFTERNOON. GIVEN THE DRY  
CONDITIONS OF THE PAST TWO WEEKS AND RELATIVE HUMIDITIES DROPPING  
INTO THE 15 TO 25 PERCENT RANGE, THERE WILL CONTINUED CONCERN FOR  
WILDFIRES, ESPECIALLY IN THE SANDY SOIL REGIONS OF NORTHERN WI.  
 
LOWS TONIGHT ARE EXPECTED TO MAINLY BE IN THE 40S ACROSS THE  
NORTH, AND AROUND 50 IN CENTRAL AND EAST CENTRAL WISCONSIN. HIGHS  
ON WEDNESDAY SHOULD BE IN THE 70S, WITH SOME 60S NEAR LAKE  
MICHIGAN.  
   
LONG TERM  
WEDNESDAY NIGHT THROUGH TUESDAY  
ISSUED AT 222 PM CDT TUE JUN 6 2023  
 
THE MAIN FORECAST CONCERN WILL BE PRECIPITATION CHANCES,  
ESPECIALLY FRIDAY NIGHT INTO SATURDAY.  
 
FOR MUCH OF THE WORK WEEK, THE FORECAST AREA WILL HAVE NORTHERLY  
FLOW ALOFT ON THE EAST SIDE OF A HIGH AMPLITUDE UPPER LEVEL  
RIDGE, WITH CANADIAN HIGH PRESSURE AT THE SURFACE. DRY AND  
COMFORTABLE CONDITIONS, INCLUDING LOW AFTERNOON RELATIVE HUMIDITY,  
CAN BE EXPECTED THROUGH AT LEAST THURSDAY NIGHT. HIGH  
TEMPERATURES WILL GENERALLY RANGE FROM 75 TO 80 DEGREES, EXCEPT  
NEAR LAKE MICHIGAN, WHERE PERSISTENT NE WINDS WILL KEEP  
TEMPERATURES COOLER. OVERNIGHT LOWS WILL BE IN THE 40S AND LOWER  
50S, THOUGH THE COLDER SPOTS IN NORTHERN WI WILL LIKELY DROP INTO  
THE 30S EARLY THURSDAY MORNING. WILL NEED TO MONITOR FOR POSSIBLE  
FROST HEADLINES THEN.  
 
TEMPERATURES WILL INCREASE A BIT BY FRIDAY, AS WARMER AIR PUSHES  
INTO THE REGION AHEAD OF A COLD FRONT. THIS WILL BE SHORT-LIVED,  
AS THE COLD FRONT IS FORECAST TO MOVE THROUGH FRIDAY NIGHT INTO  
SATURDAY. THE FRONTAL PASSAGE AND ASSOCIATED SHORT-WAVE TROUGH  
WILL OFFER THE BEST POSSIBILITY FOR PRECIPITATION DURING THE  
EXTENDED FORECAST PERIOD. THE BEST CHANCE SHOULD OCCUR OVER C/EC  
WI SATURDAY AFTERNOON, AS INSTABILITY INCREASES TO AROUND 1000  
J/KG AND PWATS INCREASE TO 1-1.4 INCHES IN THE VICINITY OF THE  
FRONT, AND THE RRQ OF AN UPPER LEVEL JET PASSES THROUGH. WITH DEEP  
LAYER SHEAR OF 25 TO 35 KNOTS ANTICIPATED, WE WILL NEED TO  
MONITOR THE POTENTIAL FOR A FEW STRONG STORMS AS WELL. MOST OF  
THE PRECIPITATION SHOULD SHIFT SOUTH OF THE REGION SATURDAY  
NIGHT.  
 
THERE IS SOME UNCERTAINTY WITH THE FORECAST FOR THE END OF THE  
WEEKEND INTO EARLY NEXT WEEK. MODELS ALL CLOSE OFF AN UPPER LOW  
OVER THE WESTERN GREAT LAKES ON SUNDAY, BUT THE ECMWF IS SLOWER  
THAN THE GEM/GFS TO SHIFT IT TO THE EAST. DEPENDING ON THE  
POSITION/MOVEMENT OF THE UPPER LOW, PRECIPITATION CHANCES MAY NEED  
TO BE INCREASED, TEMPERATURES LOWERED SEVERAL DEGREES, AND WINDS  
INCREASED AT TIMES.  
 
   
AVIATION  
FOR 00Z TAF ISSUANCE  
ISSUED AT 640 PM CDT TUE JUN 6 2023  
 
SOME STRATOCUMULUS AROUND 5000-6000 FEET WILL CONTINUE INTO THIS  
EVENING ACROSS MAINLY CENTRAL WI, WITH OTHER HIGHER MID AND UPPER  
CLOUDS OVER THE ENTIRE AREA. THESE CLOUDS WILL SLOWLY EXIT FROM  
NORTHEAST TO SOUTHWEST OVERNIGHT. A SPRINKLE COULD CLIP AUW/CWA  
LATER TONIGHT, BUT WILL HAVE NO IMPACT TO CEILINGS.  
 
EAST TO NORTHEAST WINDS WILL CONTINUE, WITH ANY GUSTS DIMINISHING  
LATE THIS AFTERNOON AS THE BETTER MIXING ENDS NEAR SUNSET. WINDS  
WILL REMAIN LIGHT TONIGHT THEN INCREASE AGAIN WEDNESDAY, GUSTING  
UP 12-22 KTS, HIGHEST IN THE FOX VALLEY AND LAKE SHORE.  
 
WHILE A LITTLE SMOKE REMAINS ALOFT THIS EVENING, A THICKER AREA IS  
LURKING OVER LAKE SUPERIOR AND ONTARIO, SEEN NICELY ON THE GOES  
VISIBLE IMAGERY (PLUS YOU CAN SEE SOME VERY LARGE FIRES RAGING IN  
EASTERN ONTARIO AND WESTERN QUEBEC). RAP/HRRR DON'T FULLY AGREE  
ON WHERE THE AREA OF SMOKE WILL GO, BUT RAP SEEMS TO HAVE A BETTER  
HANDLE ON THINGS (LIKELY DO TO A BIGGER DOMAIN WHICH CAPTURES MORE  
OF THE CURRENT SMOKE), SO WILL FOLLOW IT. THIS BRINGS THE THICKER  
SMOKE BACK ACROSS MOST OF THE AREA INTO WEDNESDAY. IT LOOKS TO  
STAY MAINLY ALOFT, CREATING HAZY SKIES, BUT LITTLE IMPACT IN  
SURFACE CONDITIONS (VSBYS) IS EXPECTED FOR THIS TAF PERIOD. WHILE  
A 6SM IS POSSIBLE WHERE THE SMOKE IS THE THICKEST, NOT MUCH  
UPSTREAM SUPPORT FOR THE SMOKE MAKING IT DOWN TO THE SURFACE SO  
WILL KEEP P6SM FOR ALL SITES.  
 
   
GRB WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
SHORT TERM.....KIECKBUSCH  
LONG TERM......KIECKBUSCH  
AVIATION.......BERSCH  
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