WWCN11 CWTO 310509
YELLOW WATCH - SEVERE THUNDERSTORM
FOR SOUTHERN ONTARIO
UPDATED BY ENVIRONMENT CANADA
AT 1:09 A.M. EDT TUESDAY 31 MARCH 2026.
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YELLOW LEVEL WATCH - SEVERE THUNDERSTORM - FOR:
=NEW= SHELBURNE - MANSFIELD - NORTHERN DUFFERIN COUNTY
      CITY OF TORONTO
      NIAGARA
      CITY OF HAMILTON
      HALTON - PEEL
      VAUGHAN - RICHMOND HILL - MARKHAM
      NEWMARKET - GEORGINA - NORTHERN YORK REGION
      WINGHAM - BLYTH - NORTHERN HURON COUNTY
      LISTOWEL - MILVERTON - NORTHERN PERTH COUNTY
      WATERLOO - WELLINGTON
      ORANGEVILLE - GRAND VALLEY - SOUTHERN DUFFERIN COUNTY
      INNISFIL - NEW TECUMSETH - ANGUS
      GREY - BRUCE
      BARRIE - COLLINGWOOD - HILLSDALE.

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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 HEAVY RAIN.

WHAT: 
TORRENTIAL DOWNPOURS. POSSIBLY REACHING 50 TO 75 MM IN SOME AREAS. 
FREQUENT LIGHTNING. HAIL IS ALSO POSSIBLE. 

WHEN: 
OVERNIGHT. 

ADDITIONAL INFORMATION: 
THUNDERSTORMS ARE EXPECTED TO TRACK THROUGH THE REGION TONIGHT.

DRIVING CONDITIONS MAY BE DIFFICULT. WHEN THUNDER ROARS, GO 
INDOORS(EXCLAMATION MARK) LIGHTNING KILLS AND INJURES CANADIANS 
EVERY YEAR. DON'T DRIVE THROUGH FLOODED ROADWAYS. HEAVY RAIN CAN 
CAUSE FLASH FLOODING AND SIGNIFICANT REDUCTIONS TO VISIBILITY. 
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 X USING (HASH)ONSTORM. 

FOR MORE INFORMATION: 
HTTPS://WWW.ONTARIO.CA/PAGE/BE-PREPARED-EMERGENCY.

HTTP://WEATHER.GC.CA

END/OSPC