Jul.10/2013 - Severe thunderstorms

[WayfaringStranger]

Severe thunderstorm warning for
Strathroy - Komoka - Western Middlesex CountyLondon - Parkhill - Eastern Middlesex County issued

[WayfaringStranger]

Severe thunderstorm warning for
Chatham-Kent - Rondeau Park Windsor - Leamington - Essex County - Rodney - Shedden - Western Elgin County ended

Severe thunderstorm warning for
Woodstock - Tillsonburg - Oxford County - Kitchener - Cambridge - Region of Waterloo issued

[obwan]

Doppler showing tornado signature on the storm north of Woodstock, nice hook on it as well

[DarkSky]

Watch up for my area (Niagara):

035 
 WWCN11 CWTO 101447
 SEVERE WEATHER BULLETIN
 ISSUED BY ENVIRONMENT CANADA
 AT 10:47 AM EDT WEDNESDAY 10 JULY 2013.
 ---------------------------------------------------------------------
 WATCHES/WARNINGS IN EFFECT FOR SOUTHERN ONTARIO...

SEVERE THUNDERSTORM WATCH FOR:
 =NEW= CITY OF TORONTO
 =NEW= WINDSOR - ESSEX - CHATHAM-KENT
 =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
 =NEW= HALTON - PEEL
 =NEW= YORK - DURHAM
 =NEW= HURON - PERTH
 =NEW= WATERLOO - WELLINGTON
 =NEW= DUFFERIN - INNISFIL
 =NEW= SAUGEEN SHORES - KINCARDINE - SOUTHERN BRUCE COUNTY
 =NEW= BRUCE PENINSULA - SAUBLE BEACH - TOBERMORY
 =NEW= HANOVER - DUNDALK - SOUTHERN GREY COUNTY
 =NEW= BARRIE - ORILLIA - MIDLAND
 =NEW= BELLEVILLE - QUINTE - NORTHUMBERLAND
 =NEW= KINGSTON - PRINCE EDWARD
 =NEW= PETERBOROUGH - KAWARTHA LAKES
 =NEW= STIRLING - TWEED - SOUTH FRONTENAC
 =NEW= BANCROFT - BON ECHO PARK
 =NEW= BROCKVILLE - LEEDS AND GRENVILLE
 =NEW= CITY OF OTTAWA
 =NEW= GATINEAU
 =NEW= PRESCOTT AND RUSSELL
 =NEW= CORNWALL - MORRISBURG
 =NEW= SMITHS FALLS - LANARK - SHARBOT LAKE
 =NEW= PARRY SOUND - MUSKOKA
 =NEW= HALIBURTON
 =NEW= RENFREW - PEMBROKE - BARRY'S BAY
 =NEW= ALGONQUIN.

      POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING
       ALONG A COLD FRONT.

      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.

---------------------------------------------------------------------
 ==DISCUSSION==
 A COLD FRONT WILL CROSS SOUTHERN ONTARIO FROM WEST TO EAST THIS
 AFTERNOON AND EVENING.  CONDITIONS AHEAD OF AND ALONG THE FRONT WILL
 BE FAVOURABLE FOR THE DEVELOPMENT OF SEVERE THUNDERSTORMS.
 WIND GUSTS TO 90 KM/H ARE POSSIBLE WITH THESE STORMS, AS WELL AS HAIL
 2 CM IN DIAMETER AND HEAVY DOWNPOURS UP TO 50 MM IN AN HOUR.

THE FRONT WILL AFFECT SOUTHWESTERN ONTARIO EARLY THIS AFTERNOON, THE
 GREATER TORONTO AREA AND SOUTH CENTRAL ONTARIO BY MID AFTERNOON, AND
 EASTERN ONTARIO LATE THIS AFTERNOON AND EARLY THIS EVENING.

ENVIRONMENT CANADA IS CLOSELY MONITORING THIS SITUATION AND WILL
 ISSUE FURTHER WATCHES AND WARNINGS AS NECESSARY.

REFER TO YOUR LOCAL PUBLIC FORECAST FOR FURTHER DETAILS.

END/OSPC

[DarkSky]

Warning now for St. Catharines - sky has become very dark.

St. Catharines - Grimsby - Northern Niagara Region
 5:22 PM EDT Wednesday 10 July 2013
 Severe thunderstorm warning for  
St. Catharines - Grimsby - Northern Niagara Region issued

 At 5:25 PM EDT, meteorologists are tracking a line of severe  thunderstorms capable of producing large hail, damaging winds and heavy  downpours. The line extends from about 10 km west of Milton to just  southwest of London and is moving southeastward at about 50 km/h. There  is also another thunderstorm ahead of the line to the west of St  Catharines. Hail with diameter 2 to 4 cm and wind gusts to 110 km/h are  possible with these thunderstorms, as well as heavy downpours giving up  to 50 mm of rain in less than one hour. There is also a slight risk of a  tornado.

Emergency Management Ontario recommends that you take cover immediately, if threatening weather approaches.

Strong wind gusts and hail can damage property and cause injuries.  Local downpours can cause flash floods.

Go  indoors and move away from windows and skylights. Avoid areas of the  building that could be affected by falling debris such as tree limbs.   Stay on the lower floor of your home or building and if the storm is  particularly severe go to the basement.

Avoid driving through water on roads.  Even shallow fast moving water across a road can sweep a vehicle away.

Remember, severe thunderstorms can produce tornadoes.

In Canada, lightning kills up to 10 people every year. Remember, when thunder roars, go indoors.

For more information:
http://www.emergencymanagementontario.ca/english/beprepared/beprepared.html

[WayfaringStranger]

Warning up for my area now. So far only a little bit of thunder, but it appears to be rolling my way.

Pickering - Oshawa - Southern Durham Region
5:38 PM EDT Wednesday 10 July 2013
Severe thunderstorm warning for
Pickering - Oshawa - Southern Durham Region continued
At 5:35 pm EDT, meteorologists are tracking a severe thunderstorm capable of producing large hail, damaging winds and heavy downpours in the northeast end of Oshawa and moving eastward at about 50 km/h.

Emergency Management Ontario recommends that you take cover immediately, if threatening weather approaches.

[DarkSky]

I was going to post a nice time-lapse video I made of the storm approaching and rolling through, but my power keeps going out. I was 1hr into encoding the video from about 8GB of 1080p footage and the power went out. I rebooted and it went out again. I'm not even going to try again until tomorrow.

[Itchy]

On way back from Kitchener after the storm rolled through I noticed some fields with corn around 4 feet high had flattened patches straight line wind style. I forget what kind of wind speeds you need to flatten corn.

[davefootball123]

Was on the St Marys/Tavistock/Embro Supercell today. Saw damaging winds of around 100km/h and some quarter sized hail toward the beginning. Dropped south a touch out of the reported golfball sized hail as I was in my parents car :-/ Winds were unreal. Lots of damage with trees down on powerlines and corn fields flattened. Anyone have any EC/NWS radar images from the storm? Was also some decent rotation with the storm too. Just wanted to add something, downed power line started a fire near Hickson.

[tice23]

Just got home after a lengthy drive to Burlington and area. I just missed the main action by about 45 mins, if i just got off work a little earlier...

Either way i took some pictures of the super cell as it was fizzling out over lake ontario which i will post in the next week when i have more time. What i did see was evidence of a possible small downburst by Lakeshore and Walkers Line in Burlington. A mature relatively healty tree had large limbs broken (approx 10-15cm diameter). And a swath of about 400m wide was scattered with fresh twigs and leaves. by the time i was in the area the city had their street sweepers out so it was hard to say how it looked right afterwards, but if it was enough to warrant a clean up crew and snap some branches it must have been half decent.

As for radar imagery: EC should be easy to get the historical base reflectivity right away, as for doppler the NOAA has a few days delay before they make it available and then I will have to compile their data, I would say sunday I will post a video of the radar and dopplar side by side if i have it ready.