severe thunderstorm WARNING now in effect for Windsor, and extends NE through London&Waterloo and into Barrie.

Here's the latest from Environment Canada

WWCN11 CWTO 212149
SEVERE WEATHER BULLETIN
ISSUED BY ENVIRONMENT CANADA
AT 5:49 PM EDT THURSDAY 21 JUNE 2012.
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WATCHES/WARNINGS IN EFFECT FOR SOUTHERN ONTARIO...

SEVERE THUNDERSTORM WARNING FOR:
=NEW= WINDSOR - ESSEX - CHATHAM-KENT
SARNIA - LAMBTON
LONDON - MIDDLESEX
WOODSTOCK - TILLSONBURG - OXFORD COUNTY
CALEDON
GODERICH - BLUEWATER - SOUTHERN HURON COUNTY
STRATFORD - MITCHELL - SOUTHERN PERTH COUNTY
LISTOWEL - MILVERTON - NORTHERN PERTH COUNTY
WATERLOO - WELLINGTON
DUFFERIN - INNISFIL
BARRIE - ORILLIA - MIDLAND.

SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP AND REDEVELOP OVER
THE WARNING AREAS UNTIL 8:00 PM EDT. THESE STORMS MAY PRODUCE
LARGE HAIL, DAMAGING WINDS OR HEAVY RAINFALL. REMEMBER THAT
SOME SEVERE THUNDERSTORMS CAN ALSO PRODUCE TORNADOES.

EMERGENCY MANAGEMENT ONTARIO RECOMMENDS TAKING COVER
IMMEDIATELY WHEN THREATENING WEATHER APPROACHES.

SEVERE THUNDERSTORM WATCH FOR:
CITY OF TORONTO
WINDSOR - ESSEX - CHATHAM-KENT
SARNIA - LAMBTON
ELGIN
LONDON - MIDDLESEX
WOODSTOCK - TILLSONBURG - OXFORD COUNTY
HALTON HILLS - MILTON
MISSISSAUGA - BRAMPTON
CALEDON
YORK - DURHAM
STRATFORD - MITCHELL - SOUTHERN PERTH COUNTY
LISTOWEL - MILVERTON - NORTHERN PERTH COUNTY
WATERLOO - WELLINGTON
DUFFERIN - INNISFIL
BARRIE - ORILLIA - MIDLAND
PETERBOROUGH - KAWARTHA LAKES
BANCROFT - BON ECHO PARK
HALIBURTON - MINDEN - SOUTHERN HALIBURTON COUNTY.

CONDITIONS ARE FAVOURABLE FOR STRONG THUNDERSTORMS TO DEVELOP
THIS EVENING. SOME OF THESE STORMS COULD REACH SEVERE LEVEL
WITH TORRENTIAL DOWNPOURS, LARGE HAIL AND DAMAGING WINDS.

THIS IS AN ALERT TO THE POTENTIAL DEVELOPMENT OF SEVERE
THUNDERSTORMS WITH LARGE HAIL, DAMAGING WINDS OR HEAVY
RAINFALL..MONITOR WEATHER CONDITIONS AND LISTEN FOR UPDATED
BULLETINS.