July 22nd

General Analysis:
Being the first true severe weather event many had been tracking it on the models for many days. The final 18 hour ETA run proved to be a challenging one. Much of southern and eastern Ontario had capes soaring well above 3000 and rh values above 80% with dew points making it feel like the upper 40's and in some spots the low 50's. A large series of low's had been strung across much of the central part of the country forming almost one large oval type low with a huge extended cold front dipping from southern Quebec right into mid Texas. Due to the shape and position of the many low cores a steady constant stream of excessively hot humid air was drawn north ward in a north easterly flow which allowed for small convective complexes to develop over some of the lakes but on a grand scale set the conditions for severe weather. With a heavily saturated capping inversion and sfc convergence from the front which was still well to the north it allowed storm develop well ahead of the cold front and far more complicated than expected.

	This chase was different than usual. This time I was heading out with Mark Rozitis. We were leaving close to 1PM when already storms had started to develop and it was raining outside. No sooner than we were off the chase essentially began. It actually started with some blinding rain and the loss of the wind shield wiper arm on the passenger side about 2km down the road. Well as soon as we got on the 400 we managed to get away from all the rain and were actually running into a much larger storm at severe criteria level.
	The sky is closing in. Oh no! Now I wont get to use my sun glasses LOL.
	We stopped in a gas station along 400 heading north. While Mark got ready to do some filming I decided to get a picture of this rising CB.
	The storm to our south which we had driven through was now back building and shifting directly north. You can see the rain core coming closer.
	Looking SE at the rest of the rain core heading our way.

	Some interesting scud was forming along the inflow banding created from the outflow that was a result of the rain core.
	As the the rain core got closer more and more scud debris could be seen as hot humid air was sucked upward.
	Well something interesting was certainly brewing on radar and there was a nice pocket of DBZ in excess of 60 nearby.
	We then proceeded farther up the 400 when the rain made it to the service station and messed up Mark's chance to film.
	He decided to pull over on the exit ramp from the 400 to King Rd and get some shots of the real dark cloud base.
	Some really interesting low clouds could be seen in the distance that looked almost as if they were dragging on the ground.
	A closer view of some of the streamer like clouds. (vidcap)
	We then noticed this amazing wall cloud which had developed a few minutes later to our west and was coming in our direction. The rotation became very distinct and scud debris was constantly getting sucked in. Radar also indicated a meso was developing.
	More footage of this giant rotating wall cloud. (vidcap)
	Looking SW into the SW flank of the storm an extended storm scale cold front could be seen created from outflow from this mother of a storm.
	The wall cloud came in and crept directly over our head. It also had this stream of scud directly in the center feeding into it.
	Looking NE into the storm with quite a bit of low scud activity developing along the outflow/inflow bands near the precip core.
	After that we proceeded east along King Road and had some moderate wind for a few seconds with extremely heavy rain falling all along. We also heard that someone reported a touchdown near hwy 9 and the 400 on the scanner. Mark deiced to keep going along King Road and eventually headed north on Younge Street in Aurora. Little did we know what we were going find.
	Many roads were also flooded (vidcap)
	A few trees had been reported down but little did we know what really did happen. I pointed out a down tree I saw at a gas station (Petro Canada I think). When we checked it out, it was a 100 year old Weeping Willow that had gotten demolished. Power was cut at the station and most of the street lights were out. The man who was running the station said that he first saw heavy rain and then the wind suddenly picked up. He then looked out the window and saw the tree falling and debris everywhere. When looking back at the radar loop it was indicative of a microburst and the damage was spread over a large area. One indication that it was a microburst was that the damage area was spread out over a circular area and that debris in all cases was pointed away from the center point of the burst.
	The radar officially confirmed it was a microburst. Where the 60+ DBZ area was had suddenly collapsed into a weak 45 DBZ area in only 4minutes indicating that there was a collapsing updraft or a possible downdraft collapse which had created the burst.
	Mark pulled into a Canadian Tire a few kilometers up the road that had power and he was able to replace the windshield wiper. While analyzing some stuff on the lab top I noticed some nice CB development off on the northern horizon.
	The most NE cell on radar which was part of the line was also visible.
	Heading west back towards the 400 on hwy I got a clear view of the monster cell developing. We were actually going to see if there was any damage from the reported touchdown.
	As it turns out we could not find any and the report was probably false. They were most likely seeing those long linear clouds near the ground that can be seen near the center of the 400 and King road picture (a few images up). So we then headed north once again.
	Some very nice TCU development was present.
	Although not rain producers or thunder producers yet they were nearing that point.
	Heading up some road towards them we were not sure if they would become storms in time before heading out over lake Simcoe. You can see that the convection is very deep giving the cloud a sharp jagged cut out apperance.
	As we neared and would eventually have to pass under them Mark decided it was best to unload his footage to Global from the Bell Box in Barrie because the storms were not really doing anything at all yet.
	Not long after sending the video throughout the Bell Box we were off again and encountered a wonderful line of TCU north of Barrie near Orillia.
	The line was getting progressively stronger.
	We drove a little farther north west and Mark got some video of the clouds going up. We waited for a bit but the line was not coming together as fast as I had hoped. The TCU to the left of the image was already producing rain but it did not look to go severe so we drove off.
	But before we drove off Mark got some nice footage of the lead TCU of the line going up through some weak banding rain from the TCU which was father west (in the pic above).
	Some more light rain falling.
	We reached hwy 11 and saw that the TCU we were watching had exploded into a massive CB and wondered if to head back after it but the problem was that the storm had already moved over Lake Simcoe and was to far from us.
	Here you can see the cell across the lake and it is at almost 65 DBZ.
	Heading south on hwy 11 we caught up to some storms going severe. The mess of cloud in the photo began to rotate as it got closer. The rain was actually wrapping around the developing meso and had us confused with storm direction for a short bit.
	The storm continued to develop and eventually the meso got close enough that rain which was wrapping around moved further east but the meso and developing wall cloud headed straight in our direction.
	As it got closer Mark got some nice video of it with all the rotation along the base clearly visible.
	Starting to organize itself and continue lower.
	You can see the northerly most wall of the wall cloud closets in the picture with the southerly most wall not to fast south of it. the wall cloud also has a very defined center point with steady inflow from all angles but mainly south west.
	You can see we were pretty deep in the storm.
	Later we headed back south to find more tree damage when another storm developed to our north.
	Mark decided to try and head north to catch up with the developing complex.
	They were looking fairly good on radar.
	Unfortunately we did not get there in time but we saw a nice shelf cloud starting to develop and some interesting cloud that was nearly touching the ground.
DAMAGE PHOTOS






MEDIA

Warnings

WWCN13 CWTO 221826 
SEVERE WEATHER BULLETIN 
ISSUED BY ENVIRONMENT CANADA 
AT 2:26 PM EDT MONDAY 22 JULY 2002. 
--------------------------------------------------------------------- 
WATCHES/WARNINGS IN EFFECT FOR SOUTHERN ONTARIO...

SEVERE THUNDERSTORM WARNING FOR: 
=NEW= OXFORD COUNTY 
=NEW= REGIONAL MUNICIPALITY OF WATERLOO 
=NEW= BRANT COUNTY 
      TORONTO 
      HAMILTON 
      REGIONAL MUNICIPALITY OF HALTON 
      REGIONAL MUNICIPALITY OF PEEL 
      REGIONAL MUNICIPALITY OF YORK 
      REGIONAL MUNICIPALITY OF DURHAM 
      WELLINGTON COUNTY.

      THE LINE OF SEVERE THUNDERSTORMS IN THE EXTREME SOUTHWESTERN 
      PART OF THE HAVE DIMINISHED IN INTENSITY BELOW SEVERE CRITERIA.

      HOWEVER THERE IS A LINE OF SEVERE THUNDERSTORMS FROM INGERSOLL 
      TO LAKE SCUGOG SIGHTED ON WEATHER RADAR AT 2.10 PM. THE LINE IS 
      MOVING SOUTHEASTWARD AT 20 KM/H.

      DAMAGING WINDS TORRENTIAL DOWNPOURS AND LARGE HAIL ARE THE MAIN 
      THREAT FROM THESE STORMS. THERE IS THE POSSIBILITY OF A BRIEF 
      TORNADO WITH THESE STORMS.

      THIS IS A WARNING THAT SEVERE THUNDERSTORMS ARE IMMINENT OR 
      OCCURRING IN THESE REGIONS. REMEMBER SOME SEVERE THUNDERSTORMS 
      PRODUCE TORNADOES..LISTEN FOR UPDATED WARNINGS. EMERGENCY 
      MEASURES ONTARIO RECOMMENDS TAKING COVER IMMEDIATELY WHEN 
      THREATENING WEATHER APPROACHES.

SEVERE THUNDERSTORM WATCH FOR: 
      TORONTO 
      WINDSOR-ESSEX-CHATHAM-KENT 
      ELGIN 
      SARNIA-LAMBTON 
      LONDON-MIDDLESEX-OXFORD 
      BRANT-HALDIMAND-NORFOLK 
      NIAGARA 
      HAMILTON 
      WATERLOO-WELLINGTON-DUFFERIN 
      HALTON-PEEL 
      YORK-DURHAM 
      HURON-PERTH 
      BARRIE-HURONIA-SIMCOE COUNTY.

      THE HOT HUMID AIR MASS OVER SOUTHERN ONTARIO HAS GIVEN RISE TO 
      IDEAL CONDITIONS FOR THE FORMATION OF THUNDERSTORMS. 
      WEATHER DATA FROM THIS MORNING INDICATED THAT SOME OF THESE 
      THUNDERSTORMS MAY REACH SEVERE LIMITS THIS AFTERNOON.

      THIS IS AN ALERT TO THE POTENTIAL DEVELOPMENT OF SEVERE 
      THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.

      MONITOR WEATHER CONDITIONS..LISTEN FOR UPDATED STATEMENTS. 
      IF THREATENING WEATHER APPROACHES TAKE IMMEDIATE SAFETY 
      PRECAUTIONS.

--------------------------------------------------------------------- 
WATCHES/WARNINGS ENDED FOR SOUTHERN ONTARIO...

SEVERE THUNDERSTORM WARNING ENDED FOR: 
      ESSEX COUNTY 
      CHATHAM-KENT 
      LAMBTON COUNTY.

--------------------------------------------------------------------- 
==DISCUSSION== 
THE HOT AND HAZY CONDITIONS OVER SOUTHERN ONTARIO ARE A RESULT OF 
SOUTHWESTERLY WINDS FROM THE AMERICAN MIDWEST.  THUNDERSTORMS HAVE 
DEVELOPED IN THIS AIR MASS ON PREVIOUS DAYS AND SOME OF THE STORMS 
HAVE PRODUCED DAMAGING CONDITIONS.  THE STORMS THAT WILL DEVELOP OVER 
ONTARIO TODAY WILL HAVE THE POTENTIAL FOR LARGE HAIL..DAMAGING WINDS 
AND TORRENTIAL DOWNPOURS.

PLEASE REFER TO THE LATEST PUBLIC FORECASTS FOR FURTHER DETAILS.

END/ELB

WUCN13 CWTO 222354 
SEVERE THUNDERSTORM WARNING 
ISSUED BY ENVIRONMENT CANADA 
AT 7:54 PM EDT MONDAY 22 JULY 2002. 
--------------------------------------------------------------------- 
SEVERE THUNDERSTORM WARNING FOR: 
=NEW= SIMCOE COUNTY.

      A LINE OF SEVERE THUNDERSTORMS APPROACHING LAKE SIMCOE FROM THE 
      NORTHWEST...

--------------------------------------------------------------------- 
==DISCUSSION== 
AT 7:45 RADAR INDICATES A LINE A LINE OF SEVERE THUNDERSTORMS 
APPROACHING LAKE SIMCOE FROM THE NORTHWEST.  THUNDERSTORMS ARE 
EXPECTED TO REACH BARRIE NEAR 8 PM AND END BY 9 PM.  WIND GUSTS TO 
100 KM/H ARE LIKELY.

THIS IS A WARNING THAT SEVERE THUNDERSTORMS ARE IMMINENT OR OCCURRING 
IN THESE REGIONS.  REMEMBER SOME SEVERE THUNDERSTORMS PRODUCE 
TORNADOES..LISTEN FOR UPDATED WARNINGS.  EMERGENCY MEASURES ONTARIO 
RECOMMENDS TAKING COVER IMMEDIATELY WHEN THREATENING WEATHER 
APPROACHES.

NOTE..A SUMMARY OF ALL WARNINGS AND WATCHES FOR SOUTHERN ONTARIO IS 
AVAILABLE IN THE WWCN13 CWTO BULLETIN ISSUED IMMEDIATELY FOLLOWING 
THIS BULLETIN.

END/..


Winds directly out of the SW feeding into storms on SW flank.	Skew-t showing general conditions	General stability of the atmosphere was fairly stable.

BRN showing possible supercells changing to multicells.	Skew-t showing cape in excess of 3000 and anvil tops of 45,000ft with 7000ft overshoot	A large convergence zone was created by the cold front as it slowly moved southeast.