Surface analysis 12Z Wed May 15 2013
As night turns to day slowly, the morning rays of sunshine reveal showers produced by elevated thunderstorms moving in along a warm front.
Here's a radar shot showing the first target storm as it tracked southeast from Shelburne.
You can see it is the dominant storm cell in the line. At around this time I'm making my way east on the 407 to head north on the 404 for an intercept.
This was one of the few dominant storm cells approaching me from the west.
I raced north along highway 404 and stopped on Stouffville Rd just east of the highway. The thunder and lightning was nearly continuous as the storm moved ever closer. It seemed far more intense than it really was.
The storm cell was still highly elevated, it produced some small pea sized hail and heavy rain. There was virtually no wind at the surface.
You can see the back side of the storm as it passes, this particular shot was taken looking Southeast.
Here's my position relative to the storm to give you a better idea of what I was seeing.
Fresh towering cumulus going up to my immediate west along a turbulent zone of convergence and mixing aloft near the leading edge of the prior convection.
This was the second storm cell which later spiked on radar.
When this photo was taken it was still in its infancy but at this point the surface warm front was getting closer and it was later in the day so boundary layer mixing was increasing. This allowed the storm to mix down further and at least appear to be getting closer to the ground.
A little while later the same storm seen in the previous image is now east of me and beginning to hit 65dbz on the radar. You can see the rain shafts from the storm directly in front of the power lines.
Here's the radar showing how intense the storm actually appeared on radar despite its benign appearance visually.
This is a stylized image of the storm as it continues eastward. I've used a graduated neutral density filter to darken the sky and create this vibrant image. At this point the storm was hitting 68 dBz and producing some small hail. A warning for Durham Region was issued, and this storm eventually made its way out over Lake Ontario.
I tried to keep pace with the storm but gave up, it was moving at well over 80 km/h.
Here's a quick analysis of the surface showing the warm front and the storms well ahead of it near the green line.
FYI - I know the occluded front is backwards, I drew as if it was a cold front by mistake