144
WWCN11 CWTO 121603
YELLOW WATCH - SEVERE THUNDERSTORM
FOR SOUTHERN ONTARIO
ISSUED BY ENVIRONMENT CANADA
AT 12:03 P.M. EDT WEDNESDAY 12 AUGUST 2026.
---------------------------------------------------------------------
YELLOW LEVEL WATCH - SEVERE THUNDERSTORM - FOR:
=NEW= SARNIA - LAMBTON
=NEW= ELGIN
=NEW= LONDON - MIDDLESEX
=NEW= SIMCOE - DELHI - NORFOLK
=NEW= DUNNVILLE - CALEDONIA - HALDIMAND
=NEW= OXFORD - BRANT
=NEW= NIAGARA
=NEW= CITY OF HAMILTON.
---------------------------------------------------------------------
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 100 KM/H.
TOONIE SIZED HAIL.
HEAVY RAIN IN EXCESS OF 40 MM.
WHEN:
THIS AFTERNOON INTO THIS EVENING.
ADDITIONAL INFORMATION:
THE HIGHEST RAINFALL AMOUNTS ARE EXPECTED FOR AREAS THAT RECEIVE
MULTIPLE THUNDERSTORMS.
LOCAL UTILITY OUTAGES ARE POSSIBLE. FAST-MOVING AND RAPIDLY RISING
WATER CAN SWEEP VEHICLES AWAY AND DAMAGE INFRASTRUCTURE. WHEN
THUNDER ROARS, GO INDOORS(EXCLAMATION MARK) LIGHTNING KILLS AND
INJURES CANADIANS EVERY YEAR. SECURE LOOSE OBJECTS.
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page