Storm Chase 4/8/11 And a Close Encunter to... Something...

 Would I call this a successful chase? 

Yes

Were amazing storms witnessed?

Yes

How about the photography? Was it good?

For me? errr... No... not really. 

Was it fun?

Yes

Were we almost killed because we were dumb enough to drive underneath the base of a massive tornadic supercell at 11:00pm?

Probably not but can't say with any certainty... and not all the facts are in.     o_0

Chased with James Langford, Justin Terveen, and Colin Miller. 


This was probably one of the more unique chases I have had thus far. And I think it was one of the more educational... and that is not necessarily a good thing.

So, we had a target picked basically northwest of Oklahoma City. Dry Line was expected to push east in the late afternoon with an impulse in the upper flow expected to help erode the cap.  There would be strong surface heating making this easier and dew points were generally well into the sixties... especially east of I 35. One thing we were lacking some what was low level shear and helicity, but there was a nice boundary (warm front) along the Oklahoma/Kansas boarder that would come into play and provide some of those ingredients late in the period.

In reality we had not completely settled on northwest of Oklahoma City. Any where along the dry line was fare game as far as we could tell and the dry line stretched from Kansas to Texas through Oklahoma... way to much area to target obviously. So, what did we do? We sat in Norman at a McDonalds and leached there Wi-Fi. We took a look at the HRRR and what did we see? A massive cluster of supercells firing basically between I 44 and I 40. The biggest developed near Lawton paralleled I 44 and moved just south of OKC. So, thinking the HRRR was onto something we decided we would stay south of Oklahoma City and wait for this monster to emerge from near Chickasha.

 Since we didn't want to have to cross OKC (I am sick of typing Oklahoma City... such a waste of space ya know) in rush hour traffic we decided that it would be best to stick to one side or the other. And since the HRRR wanted to play a joke on all the chasers dumb enough to believe it we decided to stay south of OKC.

While the HRRR was not wrong in the type of storms it developed nor there areal coverage, it was wrong in there placement. The HRRR turned out to be about 150 miles to far south... go figure.

By 4pm-ish (or perhaps a little later) towers began to build west of Oklahoma City and the El-Reno area. We decided to head west and possibly make the turn south towards Chickasha. We noticed on Radar scope that chasers were packed along I 40 and north of there. We then also noticed as we headed west towards the Union City area that reflectivity was beginning to show up north west of El-Reno. We also noticed towers exploding over head and especially north west. It was becoming clear that the action was going to be further north than originally thought. We decided to take highway 81 north through El-Reno and see if we couldn't catch the developing convection.

Unfortunately it was about 30 - 40 miles to our northwest and moving north-northeast at about 40mph. (At least initially). Another tower exploded just to our west as we got lost and wandered around El-Reno looking for the stupid SR 81. This tower fell apart and the convection well to our northwest was exploding into a massive supercell. We decided to chase it as we didn't know if it would be the only one worth chasing or not.

As we raced towards Hennessey another storm developed way west of us and since we were not crazy about the idea of trying to race the first supercell down along with all the rest of the storm chasers in Oklahoma we decided to target the west cell. This was both a good choice and kind of a bad one.

First, we were in a much better position on the the western cell and could catch it much more easily. The bad news was that for some reason (probably due to lower helicity and or lower moisture content) this storm took forever to organize.

We chased it while the first supercell (now off to our northeast) continued to look amazing from a distance. And our storm (near Fairview)... well... didn't seem to have any organization. It split multiple times and these "left splits" were more intense than the "right split" we stayed with. We even core punched it due to its weakness. We drove all around underneath it looking for any tail-tell signs of  mesocyclone development. But none-emerged... until sunset.

At that point we had almost given up. We had found a storm and it looked kind of neat. It had dime size hail that had pelted our car, and it had given us something nice, at least, to look at. But our expectations had been so much more. (At least mine). BUT... as we let the storm drift to our north so that we could shoot what we could in the fading sunlight, an obvious change began to take place in this disorganized cluster of storms.

One of the predominate ones was an inflow band coming straight into the storm from the east. Another, the lowering of the cloud base (possibly due to a combination of surface temperatures cooling along with more moist air advection). Those wonderful little anvil crawlers (or anvil zits as we like to call them) started to really show up in the fading light.

We moved north with it to find a closer place to shoot photos hoping for lighting shots as the light faded. It was here that the most dramatic change in the storm occurred.

 A large wall cloud developed. And compared to the rest of the storm base it was practically hugging the ground. What we were watching was the development of a strong mesocyclone that would produce at least one tornado (confirmed by another chaser's pictures).

The interesting thing is this storm continued to have a multi-cellular characteristic while at the same time developing strong supercellular characteristics. This lead to multiple mesocyclones in fairly close proximity to each other. This showed up on radar as more of a line of supercells merged together in a line running east to west, moving to the east. Each with its own little hook area, and each had its own wall cloud visually. 

The first was large and showed sings of increasing organization the entire time we watched it.

  

 While we watched this wall cloud pass off to our north another formed to our northwest and fallowed the same path as the first. It also steadily increased in impressiveness as it passed to our north.

Here both wall clouds can be seen, with the first being the hardest and off to the right. 

While these images were not all that great it made the trip worthwhile to see this. We soon decided to call it a night and head back to I 35 to begin the return trip home. However, the moment we left it and started heading back east on highway 412 a tornado warning was issued for the storm. The lead rotation had dominated and began to wrap up a nice hook on radar. Since it was going to cross I 35 not too far to the north of 412 we decided to go ahead and race it to I 35. This would've been a lot easier if the town of Enid had not been in the way... but you can't have everything.

Once we reached I 35 we shot straight north towards the storm with the thought that we would at least try for some lightning again. 

We stopped at some truck stop or gas station along I 35 and tried to shoot some of the anvil lightning which was insanely frequent. But a mid-level cloud band was already rotating around the storm and overhead blocking our view of the bolts. 

Here is where the story gets interesting.

I have tried to pay careful attention to this part as it will probably impact how we handle night time events in the future.

At this point the tornado warning had been allowed to expire and we decided to head up towards the storm base again just to see if anything was going on. The point was not to get close to anything, but to simply see if any structure could be viewed in the downdraft/updraft interface.

We drove up under the storm base trying to maintain what we thought would be a safe distance. I figured that since we were experiencing decent outflow winds and that the main area of rotation remained a few miles to the north we were fine. There were lowerings all under the storm base... but none of these I was too worried about as most of them were just scud, or outflow clouds.

But, as we were looking for an exit to pull off the highway onto in order to watch the main area of rotation to the north, Colin announces that he sees a funnel due west or west-northwest of us. Hmmmm... I look out that way and can't see anything. Since I was on the east side of the vehicle I really can't see what he sees. James also sees something and pulls the vehicle over. Colin then reports that whatever he has seen has lifted for the most part but a lowering was still present. 

I stick my head out of the window to get a view over the car to the west. I don't see anything that made me overly suspicious. There were several lowerings on the horizon... none of which looked especially menacing or organized.  Colin insisted that whatever he saw was still present and that we needed to find a way to turn around. This would be difficult since the nearest exit (the only one we had seen for miles) was about 1/4 of a mile up the road. Colin and James didn't know if we could make it there before the lowering passed over the general area. 

While the debate as to what to do was taking place I finally began to notice what Colin had, but at first it still didn't impress me. But then the lowering began to take on an obvious wall cloud shape. There even looked to be an RFD cut immediately to the south of it. The outflow we were experiencing was from this down draft area and it was picking up speed. The wall cloud also was not moving but remaining in a fixed position under the storm base (another sign of very suspicious activity). James, after attempting to snap a few pictures of the wall/funnel cloud (to help us get a better idea of  what it looked like) decided that staying put was not safe... nor would trying to cross the medium to make a u-turn (both illegal and would likely get us stuck... with the latter reason carrying the most weight in the present situation). 

We made the drive up to the exit and as we approached a strong wind shift was noted. First we had winds out of the west coming out of the downdraft immediatly to our left. Then we had winds whip around to the east and get fairly strong. This coincided so well with what I had seen above that I was now fully convinced that we had indeed witnessed and driven through a circulation of some kind. Once we got flipped around on the highway the lowering was already either on or just east of the road. Since the lightning remained to the west and north the lowering was front lit and therefore completely invisible. I believe we gave it a minute or two before we headed straight back south on I 35 to begin the long journey home. 

Once the storm had crossed I 35 it went tornado warned again and became an absolute monster. It developed a very large and impressive circulation on radar. The towns of Tonkawa and Ponca City were pounded during the time we had spent under the storm with one report of 94 mph winds and baseball size hail in the general area to our north. 

It really was a blast all around and am very glad we made the trip into Oklahoma. But we did make a number of mistakes and only have God to thank that a full blown tornado didn't make minced meat out of us on I 35. 

Preparing to chase on 4/8/2011

This is certanly not the best set up I have ever seen but it is one which we will be chasing nonetheless.

Models are forecasting a decent capping inversion to be in place during the early afternoon, but erode it away in places along a dry line running through Central Oklahoma. The most recent run of the NAM has actully pushed the dry line further east before stalling it in the evening. The seems to me to indicate some possible lift along it.

Dry Line position by 7pm can be clearly seen here.

CIN looks to be weakest near and north of Oklahoma City. But is weak all along the dry line.

There does appear to be some kind of disturbance moving through at 7pm in the 500mb level.

From what I can understand most think that this will not be much of an event. But given the strength and amount of deep layer shear Supercell storms would be likely if convection can develop. I think we will be targeting Ardmore Oklahoma to start with and then see where to move from there.