By the first signs of dawn with a blue tint to the sky, the Don River fully overtook the Parkway reclaiming its old flood basin

Pretty Impressive!

For reasons I'm not going to get into... I was stuck in the southbound DVP traffic with a bunch of other people. Now don't worry, when I took this photo I was stopped. In fact people were getting out of their cars and wandering about.

The Black Creek bursts over its banks flooding the roadway

A car is stalled and stranded after attempting to cross a flooded road

Today was one of those days, the morning was cloudy, foggy and cool, the forecast was for thunderstorms and depending on which model you wanted to believe it was bang or bust. The surface observations and meso-analysis data suggested a good amount of shear, low cloud levels thanks to the ample moisture, good visibility but limited energy. The whole forecast was basically based on surface observations and satellite data augmented by the meso scale RAP RTMA data which I like to use to sort of fill in the blanks. At the end of this set I'll get into some technical discussion about what made this storm special and why it did or did not do whatever it did. Anyway, the target was somewhere around Arthur and this storm fired up near Grand Bend along a surface trof riding under a mid level moisture plume. The storm quickly developed and tracked north but really looked like crap on radar, and I mean just CRAP! Dave Patrick and I who met up just north of Aurther raced north on hwy 6 as the storm came into view and were greeted by this rapidly developing wall cloud.

This was really one of those "wow, it going to probably drop a tornado soon, I feel like I'm in Oklahoma" moments. Usually structure this good in Southern Ontario means batten down the hatches and this was really a ground scraping wall cloud!

As the storm continued on, the strong 20km/h southerly inflow quickly turned to a gusty westerly flow as the rear flank downdraft kicked down and around. Look at the way the grass is leaning towards the bottom of the picture, it's leaning towards the right (east) since the photo was taken looking north. Dave was so impressed he was almost wandering around aimlessly in awe, video camera in hand forgetting to record!

The first really great chase day of the May season! I like to make photos interesting, and perspective is key! Just as Dave was pointing up at some of the rotating scud getting sucked in near the rear of the wall cloud I was able to snap this photo of him pointing! This was definitely one of the more awe inspiring weather moments I've had in Southern Ontario!

As the storm chugged along northeast from Mount Forest towards Shelburne it began to undercut itself since the RFD kick was so intense.

Despite this undercutting, the storm was actively cycling and working to produce a new wall cloud and again present another opportunity to produce an elusive Southern Ontario tornado.

Positioning ahead of the storm once again, this time just west of Shelburne in the wind farm area it was amazing to see the storm sucking up moisture and continuing to produce dangly things.

Getting closer to the storm it was doing some crazy stuff, it was neat to see the storm pull in and directly ingest what appeared to be fog from the surface. This really let's you see how a parcel of air get's into the storm and the path it takes. You can see how on the way up the air is twisting and coming in from an angle instead of going straight in and up.

Sadly, the storm was moving quickly and getting into a less chaser friendly area as it neared the edge of the Niagara Escarpment. A couple neat things happened, a combination of tree scud and pooled moisture that was overrun by the warm boundary or forced up the escarpment allowing up slope cooling created dense pools of fog which get sucked into the storm making for some cool skies. (no pun intended) Secondly, while out in what was essentially the middle of nowhere Dave and I ran into Todd Rittinger, or well we were parked and he ran into us! This is the second time I've run into another storm chaser in the field in Southern Ontario this year. It was a brief encounter but nice to meet Todd finally!

While we gave up and storm and watched it wander into the area north of Barrie (and eventually cottage country) I was intrigued by this weak "stuff" moving in from the west.

By 7:30AM it was already 18 degrees with a humidity of 94% making it feel like 20C with the humidex. Tower cumulus were already bubbling up in places as conditions only got hotter with the sun beating down.

Convection started going up early, two waves were forecast to move in from Michigan by both the Regional GEM and later the HRRR. Morning visible satellite images and even the radar data agreed well with the forecast showing both these waves very well in the visible satellite imagery. Also visible was a pre existing stationary boundary that was literally running right along highway 9 and eventually meeting with the Lake Ontario breeze. This boundary was in place since at least May 19th when weak storms fired off the leading edge and it was not washed out by the squall line May 20th since during the early morning hours of the 21st nocturnal convection fired along this same boundary. So by 12PM I was on the road and heading west towards Arthur to intercept the rapidly developing storms.

I rolled some video around Grand Valley. The sky was getting dark and it was hot out, damn hot! The air was super sticky and muggy, there was a fairly strong southerly flow and the day had that Oklahoma feel to it, the feeling you get just as your waiting for a supercell to come into view. Of course, this was no supercell and the skies looked ominous but it was not like I was expecting anything crazy, which is very different from Oklahoma! I guess, the anticipation is really the feeling I'm describing.

As I was just going to punch through the first storms, things were getting a little messy, there was a lot of convection going up ahead of the main storm cell I was interested in. My gut told me to stop driving and wait, but the radar was screaming at me to keep going west so I listened to the radar.

So yeah, it started to pour, not overly hard and there was no wind or anything so the rain was more of a visibility hindrance I found then anything to worry about.

Just as I was outside of Arthur I saw a green flow directly in front of my and then a wall of scud quickly rising as it was being pushed up by outflow. I was not nearing one of the first stronger cells in the cluster ahead of the main storm. When I drove into it, the rain hit like a wall! There was some wind in the 50km/h range but it looked more severe than it was due to the rain falling so hard and banding into sheets. I heard a few dings from pea sized hail.

I kept pushing and punched into the main storm I was interested in intercepting. Just as I started to get into the core the storm blew itself out. The winds began to really gust hitting about 63 km/h at times but that was it, the highest gust was actually 63.7 km/h with the average around 50 - 55 km/h. You can see how the rain was just howling up the road towards me but again, it was not severe. It just looked more intense than it really was.

Again, anytime things are rocking and rolling video always takes presidence over still photos. Maybe I just have this opinion because I'm actually a videographer by trade?

Yep, the rain was just rolling through the fields!

After getting my fill of video and outflow wind I decided to keep driving towards the storms southern flank. I was getting dinged by random pieces of pea sized hail and then I had a couple dime sized stones hit me but they were few and far between. It felt like it was taking me forever to reach the southern flank of the storm but then suddenly clearing appeared ahead and I could see the definite boundary coming into view.

Today was one of those wait and see and hope and wish and drive type days. All the moisture, energy and instability was contained to southern and central Michigan as a warm front lifted north across much of the Northeast U.S and Southeastern Canada. Earlier in the week models had shown storms erupting across southwestern and southcentral Ontario around the dinner hour but as the forecast day drew closer, the incoming trough aloft slowed down and ushered in more capped air in the mid levels leaving the cooler less stable air farther west. This meant that here in Southern Ontario we were widely out of luck, but the HRRR did have one interesting card up its sleve. It showed the stuff in Michigan to eventually go linear and turn into an MCS (this was widely supported by the the mid and upper level wind fields). The MCS was then supposed to rapidly begin accelerating east across Lake Huron and blast into Southern Ontario with the nose of the forecast bow-echo to land somewhere around Teeswater which agreed well with the actual surface observations and radar data. My biggest fear was that the stable marine air over Lake Huron would kill the line of storms long before they had a chance to hit Canadian soil as is sometimes the case. I was concerned because they were going to be outpacing the more unstable air and moving into a more and more capped atmosphere. I tried to take a nap because I was tired and had to work overnight after the chase but the tornado action in Oklahoma kept me awake and then I watched as Moore was taken off the map again much like it had been on May 3rd 1999. It was horrific to watch but at the same time kept me glued to the live streams. After getting virtually no sleep, the HRRR forecast began to validate as the storms in Michgan began to line out and blast eastward. I jumped in the truck and took off. I spoke to fellow chaser Dave Patrick on the phone, he was farther west than I was and in good position. Looking at the radar I figured I had another hour or so before I would be into the squall line since it was only over central Lake Huron at about the time I was entering the Town of Lucknow. I immediately called Dave to see what was going on in front of me and he said it was blasting him with dirt and gustnadoes. I was sort of stunned since the storms were still so far away on radar, or at least that's where the precipitation was. I didn't notice it at the time, but if you look near the horizon you'll see a brown wall of dust just above it! I was so busy getting the graduated ND on the camera and aligning everything so perfectly I did not realize that the interior of my car was going to get pretty dusty soon.

The storm looked okay, it was far from producing anything impressive and the colours were pretty bland but I was still excited to see if there were any good winds on the leading edge. I was absolutely dieing to test a new Inspeed anemometer that I had purchased just for purposes like this!

As soon as the storm came within a good close view, I grabbed my video camera and began getting video. This is one of those things that makes far better video than it does a still photo. With the video you have motion, action and sound, with the still photo, all you really have is just a moment in time, which sometimes does little to illustrate what happens or is about to happen next. So video from this point on took priority!

This is just the coolest things! It was incredibly dry across much of Southern Ontario for a good part of May and a late planting season saw many farmers tilling their fields just days prior to this storm rolling in. The barren and dusty fields created an amazing display, it's not like seeing strong straight line winds or a tornado, it's more like a feeling of "that's just cool!" without actually shouting that out.

At about this time somewhere in the back of my mind I was thinking "it's getting close, that's a lot of dust, should I stay out and get hit, what about the camera and lens? Wait, my truck windows are rolled down!"

I managed to jump into the truck and get the windows and doors closed just as the wall of dust hit. I kept shooting video through the windshield with both the Canon XH-A1 and on my Sony Handycam I have mounted on the dash.

Like I said, this was the first time I had the ability to actually put the Inspeed Anemometer to the test, I was hoping and probably expecting stronger winds but the absolute highest gust I measured while on the hill, outside of Lucknow was 50.3 km/h, hardly a severe gust! Heck, you'd be lucky if that tipped over your trash can.

Now knowing the storms outflow was only moving at around 50km/h peak I knew I could keep pace and get back out in front of the storm for a second round. I actually had my camera at this point mounted to my window and was able to snap this shot while looking for somewhere to stop. The contrast was pretty cool!

The gustfront was spinning up all sorts of eddies glorified as gustnadoes. COOL!

The dust made visibility in places poor.

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.

The setup for storms was driven by a low scooting just north of Lake Erie and Ontario, the supercells in Southcentral and Southeastern Ontario formed along the warm front where a marine / lake breeze boundary interacted with the surface warm front and trigger storms

A weak elevated supercell in a low energy but moderate shear environment approaches Milton

The storm is now passing through Milton, you can see mid level clouds flowing into the storm from the Southeast (image looking west). It also presents a bit of a vaulted type structure with the usual lateral tilt of the updraft. Slight clearing between the "hail" region of the core and the heavier rain is visible just to the right of center. The biggest problem with this storm if any is the fact that it remained elevated with limited boundary layer interaction and hence produce virtually nothing as far as wind at the surface.

Inflow / outflow and rain as the storm passes overhead and looses some of its structure

Here a screenshot from PYKL3 (Android radar software) showing my location and a weak couplet appearing on the NWS Buffalo Nexrad radar.

Here's the Meso Analysis sounding for a point nearest the storm at the given time. You'll notice the storm is entirely elevated with very little cape and very low topped since the LFC/CCL EL is ~7km. lon=-79.813855 lat=43.555635

The hodograph data shows little in the way of dynamic shear, all the veering in this ground relative hodoraph is below any of the convective instability.

The storm relative hodograph shows a very different story, veering winds with supportive inflow exist well above the ground into the mid levels allowing the storm to still rotate (although very slowly) despite being elevated. This explains why this storm took on a supercellular structure.

Hard to believe that less than a week after the ice storm I was out chasing a large ragged bowing squall line with temperatures around 25 Celsius. April is really a month of extremes!

Storm motion with this bowing segment was 59 degrees (Northeast) at 57 knots (105 km/h) You'll see how the storm progressively bows as it progresses north along the line

Here's a quick screen grab from my tablet showing the radar at the end of my storm chase day. You'll notice the a large bowing segment heading off towards Uxbridge, that there is the storm which bowed out right over my head in Bolton/Caledon.

A smattering of ice pellets cover the roof of a home in Leaside, Toronto as the first wave of precipitation from the impending storm moves in

The low elevation of Leaside in Toronto allowed the snow up north to instead fall as ice pellets down in the city. The expected change over to rain was stunted as more cold air flooded in and mixing began to occur aloft.

Commuters in Brampton near hwy 50 & Queen St get on a Zoom bus as heavy wet snow falls. The snow was not expected, a combination of colder air flooding in and additional mixing aloft meant that the precipitation, which was supposed to remain as ice pellets eventually changing to rain fell almost entirely as snow with the first wave of precipitation.

A "surprise" winter storm blankets Langstaff Rd just west of hwy 27 with a coating of wet snow. This unusual late season storm left many municipalities unprepared to treat the icy road surfaces and commence plowing operations. The snow also created an additional forecast element not forseen, with a fresh blanket on the ground it meant that temperatures were able to remain cooler longer and this would aid in the freezing rain process which would begin with the second wave of precipitation much later in the day towards evening.

Normally at this time of the year the first spring sprouts are shooting out of the ground, but that seems unlikely given the fresh coating of snow.

This was the radar image at the time showing just where the snow, ice pellets, freezing rain and normal rain sat. You can see the blues and purples (snow) effecting the GTA and areas eastward while much of the Hamilton, Halton and western portions of Mississauga were seeing a good mix of ice pellets (orange). Further south, along the QEW on the south shore of Lake Ontario most of the precipitation was falling as rain (green) and to the west a pocket of freezing rain (pink) had developed over Kitchener, Waterloo, Guelph and other surrounding communities due to cold air damming at the surface.

As I started my missing late at nigh to find freezing rain as the second wave of precipitation moved in ice accretion was rapidly building. Here, a road sign stands frozen near Caledon.

The streets of Orangeville required a pair of well sharpened skates.

A driver heads west along an ice covered Broadway in downtown Orangeville

Glazed city streets

Looking at this photo it sure does not look like April 1st, and no this is not an April fool's joke I've concocted, it's a not a joke at all! Mother nature decided that we've not had enough winter this year and it seems even with balmy days between they are simply teasers. (There has been no Photoshop work done to this photo, it was taken purely using a Cokin graduated tobacco coloured filter)

My car (not visible but right of the frame) was actually partially blocking a lane. It was all fine and dandy since there was no traffic and this snow was low drifting stuff. Then just as a few cars came into view the wind started blasting and the drifting snow became a low visible wall of white a few feet tall. It was more than tall enough to shroud my car from any unsuspecting drivers so I made haste and got out of here as quickly as I could!

I'm not sure if the municipalities or province for that matter still has any salt in reserves. Whatever the case, this highway was just glazed over! I almost wiped out just stepping foot outside of my car! April 1st huh? Sure feels like I'm north of the Arctic Circle, not north of Orangeville.

This is the 0 visibility stuff blowing where I was parked. Yeah, not a good idea!

There were tons of little snow devils (vorticity pockets known correctly as eddies) dancing around in the fields. Unfortunately, what looked cool to my eye looked like crap to my camera. But for the record, you can see the winds and squalls made things nasty in these exposed places.

Here are some of the cellular convective snow squalls heading southeast into the Greater Toronto Area (I'm looking southwest). Some of the tops on these squalls must have been pretty high but I did not see any lightning returns on any of my services. (Again no Photoshop, just that Cokin Tobacco filter)

Yeah, the car was clean! I decided after the fact this was a bad idea, seeing as I was actually getting dirty! Note to self, don't unnecessarily go out of the way to drive through snow squalls when the car is clean!

No rainbows here, but the convective lake effect snow bands were so cellular in nature that you could literally be under a clear sky above while all around you snow is pouring down.

Just to illustrate the point.

This was highway 10 just north of Mono, as you can see this looks it typically does in the period between late November and early March. It sure is cruel to have it look like this in April, it's simply not funny!

Ever so slowly

Didn't need a sign to figure that out

Traffic creeps along highway 7 near Martin Grove Rd in Woodbridge

This homeward bound Honda with summer tires was heading nowhere quickly

This Mazada 3 driver attempts to make it home on a residential street

Vehicles struggle to make it up the Woodbridge Ave hill near Kipling.

Two vehicles face the wrong way on highway 401 in Toronto after colliding as part of a larger 5 car collision

My poor electric snow thrower had a hard time cutting through this 30 inch deep snow drift

This was one of hundreds of accidents that occurred along highway 401 in Toronto during the morning rush hour. Heavy snow and poor conditions made this morning a rush-hour from hell

Several hours after the snow stopped falling I began the task of diggin out

Weak towering cumulus clouds congealed to form a weak rain shower. This "storm" never amounted to anything.

New storms formed as a wave of activity pushed into the Windsor area. Storms formed near Oil Springs and expanded northward. This one cell formed ahead of the mess over London and had some brief interesting characteristics. This was taken near Arva looking south.

After the London storm was eaten by the more dominant storms to the west I headed north and watched as a meso-triple point (storm scale feature) came together just west of Ilderton.

An isolated cell formed north of the main body of the storm system just north of Ilderton and popped out a lowering

There was some major convergence & forcing between the two storms, cloud motions intesified and stuff was happening at 10's of meters per second.

This was a huge outflow scud bomb shelf thingy facing towards the inflow from the south

This was all inflow and there was violent mixing above my head with a sharp temperature increase outside of the car as inflow winds overcome any outflow.

What may have been a brief wall cloud or inflow/shelf feature formed and I shot video since photos would not do it justice. After the main action started to press east of my location I snapped this photo of a tail cloud. There was some major inflow action along it.

After the storm(s) lost their structure I punched back through what was a rainy core and emerged on the east side of the complex near St.Mary's

This was a crappy ragged shelf cloud, it looked cool (I guess all clouds look cool to me) but it posed zero threat,

This wide shot gives an idea of perspective with regards to the size and scope of the flooding.

Persistent local rains in excess of 50mm created localized flash flooding. These vehicles in Concord (Vaughan) became flood victims.

Illuminated by the not too distant city lights, a massive shelf cloud comes into view as it bares down on Milton

The shelf/roll cloud slowly getting closer

As the MCS moved towards Milton around 1:50AM a shelf cloud & roll cloud developed

The 8AM surface map paiting the setup for the day. The MCS visible over WI/MI would later be the trigger point for the convection

The meso NAM bufkit data looked alright, there was plenty of energy to be had and while support was no great there was enough instability to kick off some good storms

The real-time MESO analysis RAP soundings around the time storms started to fire up

This was the first storm of the day, it formed in a triple point convergence zone between lake breeze boundaries and an outflow wave from the MCS which was now crossing Georgian Bay

Here's the storm a little later on in life

Just after this photo Mark Robinson and I bailed and left the Innisfil storm to go chase storm which were forming to our immediate west

A shelf cloud on the leading edge of the MCS outflow near Beeton, ON

Here is the shelf cloud approaching

This is pretty self explanatory. It was neat to see dust and other small debris blowing, winds were kicking up into the mid 50's with maybe an isolated gust as high as 60.

Tower going up on the western flank of what remained of the outflow in Vaughan

Mark Robinson and I spent the better part of the afternoon waiting for initiation which never came. We agreed it was a bust and went our ways. Just as I started east along hwy 9 towards the 400 a developing tower to my north with faint echoes on radar caught my attention.

This is how I planned to document what was quickly turning into a bust, beautiful crepuscular rays in Orangeville

Surprised I was! What started as a faint echo over Georgian Bay quickly grew and morphed into a beautiful mothership of a supercell which I intercepted near Baxter, ON.

Words can't describe what was going through my mind! The structure was unreal, and winds were south-easterly veering to southerly before a dry but still warm RFD kicked passed.

The storm did briefly produce a well defined wall cloud, but more impressive was the notched out RFD cut at the back of the storm

Easily the best structure of the year so far in Ontario. I can't believe there was no significant severe weather. It was a great storm!

Here is the 9PM meso-analysis sounding for the nearest airport effected by the supercell, by this time the supercell was passing through Baxter and south of Borden

Here is the 8PM meso-analysis sounding for the nearest airport effected by the supercell

As the day went on the RAP model consistently increased the amount of surface energy present with shear and tornado indices increasing

This was the first RAP model I really dug deep into. Numerous key shear elements were coming together to make the day "interesting"

Here's the core literally falling out of the storm over Milverton looking west from Poole

Near stationary storm near Poole, Ontario