395  
FXUS63 KGRB 090353  
AFDGRB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREEN BAY WI  
1053 PM CDT TUE JUL 8 2025  
 
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE  
   
KEY MESSAGES
 
 
- SHOWERS/STORMS LIKELY (60-80% CHANCE) LATE FRIDAY INTO  
SATURDAY. CONFIDENCE IN SEVERE STORMS IS LOW, BUT LOCALLY HEAVY  
RAIN MAY OCCUR.  
 

 
   
DISCUSSION
 
 
ISSUED AT 213 PM CDT TUE JUL 8 2025  
 
SCATTERED STORMS THROUGH THIS EVENING...  
 
BROAD MID-LEVEL TROUGH WILL PASS ACROSS THE NORTHERN GREAT LAKES  
THIS AFTERNOON INTO EARLY EVENING. OVERALL, LIMITED SYNOPTIC FORCING  
AND MODEST LOW-LEVEL CONVERGENCE SHOULD TEND TO KEEP CONVECTION  
ISOLATED TO SCATTERED AND FAIRLY DISORGANIZED, WITH THE HIGHER  
CHANCES ALONG THE WI/MI BORDER. MID-LEVEL LAPSE RATES SHOULD BE  
RATHER WEAK, BUT RAP/SPC MESOANALYSIS SUGGEST MLCAPE REACHING  
1000-1500 J/KG ACROSS EASTERN WISCONSIN THIS AFTERNOON. WITH  
30-40 KTS OF EFFECTIVE BULK SHEAR, HAIL OR GUSTY WINDS COULD NOT  
BE RULED OUT WITH ANY MORE PERSISTENT CORES, ESPECIALLY ACROSS  
FAR NORTHEAST WISCONSIN WHERE TEMPS ALOFT ARE COOLER AND FORCING  
FROM THE SHORTWAVE MAY BE A BIT STRONGER, BUT THE OVERALL  
THREAT LOOKS QUITE LIMITED. SPC DID ADD A MARGINAL (LEVEL 1 OF  
5) RISK FOR SEVERE STORMS FOR A SMALL AREA OF NORTHEAST  
WISCONSIN TO ACCOUNT FOR THIS RISK. STORMS MAY PERSIST INTO THE  
EVENING BEFORE DIMINISHING AS INSTABILITY WANES.  
 
MID WEEK INTO EARLY NEXT WEEK...  
 
SURFACE RIDGING WILL PROVIDE DRY WEATHER FOR THE MID-WEEK PERIOD.  
THE NEXT PERIOD OF FOCUS FOR MORE IMPACTFUL WEATHER COMES FRIDAY  
INTO SATURDAY AS A SHORTWAVE TROUGH EMERGING FROM THE CENTRAL  
ROCKIES INTERACTS WITH A BROADER TROUGH APPROACHING FROM THE  
NORTHERN PLAINS. RICH MOISTURE WILL BE ADVECTED NORTHWARD IN ADVANCE  
OF THIS SYSTEM WITH PRECIPITABLE WATER VALUES FORECAST TO EXCEED THE  
90TH PERCENTILE RELATIVE TO CLIMO, BASED ON THE NAEFS. ALTHOUGH  
SYNOPTIC AND MESOSCALE DETAILS REMAIN UNCLEAR, THE ENVIRONMENT  
WOULD SUPPORT THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. RIGHT  
NOW, THE NBM SHOWS THE FOOTPRINT OF HIGHEST PROBABILITIES FOR AT  
LEAST 1" OF RAIN DURING THIS TIME (30-50%) ACROSS PARTS OF  
MINNESOTA AND WESTERN WISCONSIN. THE DEGREE OF DESTABILIZATION  
REMAINS UNCLEAR ON FRIDAY, AND WITH RELATIVELY WEAK DEEP LAYER  
WIND SHEAR EXPECTED, THE OVERALL SEVERE WEATHER THREAT LOOKS  
RATHER LOW FOR NOW, WITH THE VARIOUS MACHINE-LEARNING OUTPUTS  
SHOWING GENERAL 5-15% PROBABILITIES FOR SEVERE WEATHER ACROSS  
THE AREA ON FRIDAY. THE TIMING OF THE WAVE COULD IMPACT  
RAIN/STORM CHANCES HEADING THROUGH SATURDAY.  
 
OTHERWISE, A TYPICAL MID-JULY WEATHER PATTERN WILL CONTINUE LATE  
THIS WEEKEND INTO EARLY NEXT WEEK WITH QUASI-ZONAL FLOW ACROSS THE  
NORTHERN TIER OF STATES AND ANY SHOWERS/STORMS TIED TO LOWER  
PREDICTABILITY SHORTWAVE TROUGHS. NO CLEAR PRECIPITATION SIGNAL IS  
EVIDENT AT THIS TIME.  
 
TEMPS GENERALLY LOOK SEASONABLE OVER THE NEXT WEEK WITH A SLOW CLIMB  
FOR MID TO LATE WEEK ALONG WITH INCREASING HUMIDITY LEVELS LATE THIS  
WEEK.  
 

 
   
AVIATION
 
FOR 06Z TAF ISSUANCE  
ISSUED AT 1052 PM CDT TUE JUL 8 2025  
 
PATCHY FOG IS POSSIBLE AFTER MIDNIGHT MAINLY OVER NORTH-CENTRAL WI  
AND NEAR LAKE MICHIGAN. HAVE INCLUDED MENTIONS OF VSBY REDUCTIONS  
AT RHI AND MTW. OTHERWISE, SCT-BKN IFR/MVFR STRATUS WILL SETTLE  
ACROSS ALL BUT CENTRAL WI. THE LOWER CIGS LIFT ON WEDNESDAY MORNING,  
BUT COULD STILL REMAIN MVFR FOX VALLEY TO THE LAKESHORE. BY AFTERNOON,  
ALL TERMINALS WILL SEE SCATTERED VFR CU. WINDS WILL BE LIGHT THROUGH  
THE ENTIRE TAF PERIOD.  
 

 
   
GRB WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
DISCUSSION.....JM  
AVIATION.......JLA  
 
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