323  
WWCN11 CWTO 130341  
YELLOW WATCH - SEVERE THUNDERSTORM  
FOR SOUTHERN ONTARIO  
UPDATED BY ENVIRONMENT CANADA  
AT 11:41 P.M. EDT WEDNESDAY 12 AUGUST 2026.  
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YELLOW LEVEL WATCH - SEVERE THUNDERSTORM - FOR:  
BROCKVILLE - LEEDS AND GRENVILLE  
CORNWALL - MORRISBURG.  
 
YELLOW LEVEL WATCH - SEVERE THUNDERSTORM - ENDED FOR:  
CITY OF OTTAWA  
PRESCOTT AND RUSSELL  
SMITHS FALLS - PERTH - EASTERN LANARK COUNTY.  
 
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IMPACT LEVEL: MODERATE  
FORECAST CONFIDENCE: HIGH  
 
==DISCUSSION==  
 
CONDITIONS ARE FAVOURABLE FOR THE DEVELOPMENT OF SEVERE  
THUNDERSTORMS THAT MAY BE CAPABLE OF PRODUCING STRONG WIND GUSTS,  
LARGE HAIL AND HEAVY RAIN.  
 
WHAT:  
WIND GUSTS NEAR 90 KM/H.  
QUARTER SIZED HAIL.  
HEAVY RAIN.  
 
WHEN:  
THIS EVENING.  
 
WHEN THUNDER ROARS, GO INDOORS(EXCLAMATION MARK) LIGHTNING KILLS AND  
INJURES CANADIANS EVERY YEAR. SECURE LOOSE OBJECTS.  
 
HEAVY RAIN CAN CAUSE FLASH FLOODING AND SIGNIFICANT REDUCTIONS TO  
VISIBILITY.  
 
STRONG WIND GUSTS CAN DAMAGE TREES, BUILDINGS AND OVERTURN VEHICLES.  
 
SEVERE THUNDERSTORM WATCHES ARE ISSUED WHEN CONDITIONS ARE  
FAVOURABLE FOR THE DEVELOPMENT OF THUNDERSTORMS CAPABLE OF PRODUCING  
DAMAGING HAIL, WIND OR RAIN.  
 
EMERGENCY MANAGEMENT ONTARIO RECOMMENDS THAT YOU TAKE COVER  
IMMEDIATELY IF THREATENING WEATHER APPROACHES.  
 
PLEASE CONTINUE TO MONITOR ALERTS AND FORECASTS ISSUED BY  
ENVIRONMENT CANADA.  
 
TO REPORT SEVERE WEATHER IN ONTARIO, SEND AN EMAIL TO  
ONSTORM(AT)EC.GC.CA OR POST REPORTS ON SOCIAL MEDIA USING  
(HASH)ONSTORM.  
 
FOR MORE INFORMATION:  
HTTPS://WWW.ONTARIO.CA/PAGE/BE-PREPARED-EMERGENCY.  
 
HTTP://WEATHER.GC.CA  
 
END/OSPC  
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