PDA

View Full Version : Jul.24, 1999 - tornadic supercell chase


DarkSky
08-28-2009, 06:52 PM
(videos of our chase of this storm is in the videos section)

The Weather Network posted watches & warnings all day long:
http://www.ontariostorms.com/1999/july/24/twn01.jpghttp://www.ontariostorms.com/1999/july/24/twn02.jpghttp://www.ontariostorms.com/1999/july/24/twn03.jpg


Still photos! These images were taken on Lakeshore Rd, Niagara-on-the-Lake, around 8:20pm, facing East.

DarkSky
08-28-2009, 06:53 PM
The day started off with Environment Canada releasing severe thunderstorm watches for almost all of Ontario. In fact, the entire province WAS under a severe t-storm warning except for the Niagara and Toronto areas. CAPE values were over 3400 in some places, and lifted indexes down to -10 ! (Click here for CAPE image map (http://www.ontariostorms.com/1999/july/24/cape01.gif) , and Click here for Lifted Index map (http://www.ontariostorms.com/1999/july/24/lifted01.gif) ) As the afternoon came, these watches were upgraded to severe thunderstorm warnings, and these warnings were soon upgraded to tornado warnings in many places. Doppler showed cells exploding violently from the Windsor area, as well as the Georgian Bay area. Click here for doppler image (http://www.ontariostorms.com/1999/july/24/rad_buf_1926.gif) and Click here for radar summary (6:45pm) (http://www.ontariostorms.com/1999/july/24/buffalo_summary_1845.gif) and Click here for 7:29pm lightning map. (http://www.ontariostorms.com/1999/july/24/lightning_1929.gif) Eventually Environment Canada issued a severe t-storm watch for Niagara, which was soon upgraded to a severe t-storm warning, which was then upgraded to a tornado warning. The times of issues are listed here for Niagara:
7:07pm - severe thunderstorm watch
7:14pm - severe thunderstorm warning
7:30pm - tornado warning
The clouds built up quickly staring around 7:15pm, and by 8pm there was significant cloud-to-cloud (CC) lightning cloud-to-ground (CC) lightning, and the odd anvil crawler. Thunder was minimal. I grabbed all my gear together and packed it into the car. I filmed the cloud formations from within my house as the built up over the lake, producing many cloud lowerings, and 3 funnel clouds (one of which I managed to get on tape).
My friend Jeff and his fiancee called me on his cell phone around 8pm to tell me of the cloud build-up around Hamilton (he was on the QEW on his way back to St. Kitts). He arrived at my place around 8:20 and we headed straight out to Niagara on the Lake (NOTL). Classic supercell was fully developed as it hit land in NOTL and it began to cross straight over us. We weren't 10 minutes into the chase when we were caught in the strongest microburst I've ever been in as we were forced to come to a dead stop on Lakeshore Rd in NOTL. It came out of absolutely no precipitation, and got to the point where there was 0 visibility, the wind/rain was so intense I had to turn the car into the wind for fear of it rolling. Lots of debris in the air and being whipped across the street. All cars came to a dead halt in the middle of the street except for one or two who panicked and tried to push forward to shelter, only to drive on and off of the shoulders as they couldn't see where they were going.
The microburst lasted about 3 minutes, and after it subsided we head back to St. Kitts and found a large tree (measured to be 14" in diameter at the base where it snapped) that had fallen and taken out the power lines, which were strewn across the street (Cindy Dr., off Arthur St.). As soon as we stopped to get it on video the Fire Dept. rounded the corner and blocked off the street. We head back to the rural areas of NOTL and got some great lightning footage.

DarkSky
08-28-2009, 06:54 PM
July 24th, 1999 - Tornadic supercell thunderstorm
2 cloud-to-cloud (CC) lightning shots as the storm begins to build:
http://www.ontariostorms.com/1999/july/24/vidcap01.jpghttp://www.ontariostorms.com/1999/july/24/vidcap02.jpg

Cloud lowerings produce a possible funnel start (these shots taken from inside my house):
http://www.ontariostorms.com/1999/july/24/vidcap04.jpghttp://www.ontariostorms.com/1999/july/24/vidcap05.jpg
http://www.ontariostorms.com/1999/july/24/vidcap06.jpghttp://www.ontariostorms.com/1999/july/24/vidcap07.jpg

DarkSky
08-28-2009, 06:54 PM
The chase begins... Cloud formations over Lake Ontario (St. Catharines):
http://www.ontariostorms.com/1999/july/24/vidcap08.jpghttp://www.ontariostorms.com/1999/july/24/vidcap09.jpg
Mesocyclone builds up as we enter rural Niagara-on-the-Lake:
http://www.ontariostorms.com/1999/july/24/vidcap10.jpghttp://www.ontariostorms.com/1999/july/24/vidcap11.jpg
http://www.ontariostorms.com/1999/july/24/vidcap12.jpghttp://www.ontariostorms.com/1999/july/24/vidcap13.jpg
Lower bands under the meso:
http://www.ontariostorms.com/1999/july/24/vidcap14.jpg
In the middle of the microburst (Lakeshore Rd., NOTL, ~8:30pm). Judging by how fast the debris and 'packets' of rain were travelling and comparing them to the speed of a car, I estimated wind speeds here at over 100km/hr (anemometer is next :^) We could see leaves and branches in the air everywhere... Newspaper reported that around the same time of this microburst a tornado cut a 50m swath through grape vineyards about 1 mile away from us, pulling the grape wires clean from their supports).
For a movie file (with sound) of this, CLICK HERE! (http://www.ontariostorms.com/movies/1999-jul24-05.asf) (RealVideo format)
http://www.ontariostorms.com/1999/july/24/vidcap15.jpghttp://www.ontariostorms.com/1999/july/24/vidcap16.jpg
Tree (measured the next day at 11" trunk diameter) snapped at base (St. Catharines) knocked power line down across the street. We actually got there the same time the Fire Dept. arrived!
http://www.ontariostorms.com/1999/july/24/vidcap17.jpghttp://www.ontariostorms.com/1999/july/24/vidcap18.jpg

DarkSky
08-28-2009, 06:55 PM
Lightning shots from Niagara-on-the-Lake (lots of anvil crawlers) :
http://www.ontariostorms.com/1999/july/24/vidcap19.jpg http://www.ontariostorms.com/1999/july/24/vidcap20.jpg http://www.ontariostorms.com/1999/july/24/vidcap21.jpg
http://www.ontariostorms.com/1999/july/24/vidcap22.jpg http://www.ontariostorms.com/1999/july/24/vidcap23.jpg http://www.ontariostorms.com/1999/july/24/vidcap24.jpg
http://www.ontariostorms.com/1999/july/24/vidcap25.jpg http://www.ontariostorms.com/1999/july/24/vidcap26.jpg http://www.ontariostorms.com/1999/july/24/vidcap27.jpg

DarkSky
08-28-2009, 06:55 PM
http://www.ontariostorms.com/1999/july/24/vidcap28.jpg http://www.ontariostorms.com/1999/july/24/vidcap29.jpg http://www.ontariostorms.com/1999/july/24/vidcap30.jpg
http://www.ontariostorms.com/1999/july/24/vidcap31.jpg http://www.ontariostorms.com/1999/july/24/vidcap32.jpg http://www.ontariostorms.com/1999/july/24/vidcap33.jpg
http://www.ontariostorms.com/1999/july/24/vidcap34.jpg http://www.ontariostorms.com/1999/july/24/vidcap35.jpg
Here's me taking a picture of a very photogenic meso that was crossing the lake from Burlington:
http://www.ontariostorms.com/1999/july/24/vidcap36.jpg

Itchy
03-05-2010, 02:20 PM
I am really hoping a supercell tracks east just north of London this year, swear it's some of the best chasing country and road network