Monday, October 25, 2010

Convection at dusk last night / tonight's wind

Went out on a "chase" yesterday that ended with a post-sunset intercept of some sub-severe convection near Bloomington, IL. Things looked decent for a couple supercells yesterday evening, but it was unclear if things would go before dark. Being a weekend, I decided to go for it since I was already in the target area of central IL. I left Champaign around 3 PM and made it to my Springfield target where I met up with Jarrod Cook, Mark Sefried and Mike Brady. We shot the breeze for an hour or so before the sun started getting lower on the horizon. Cells began popping up right at sunset, and were lining up along the drive home so we hit the road. I figured if anything went nuts I could easily pull off and shoot lightning photos.

Just as the last little bits of twilight were fading away a cell to my west started to organize, and began spitting out frequent enough lightning that I decided to pull off at the Hudson, IL exit along Interstate 39. I shot this little broken line of storms for probably an hour before they lost their photogenic appearance. With the remaining twilight behind the storms, a nearly full moon front lighting them, and city lights giving off a red glow and the lightning provided by the storms it was a photographer's dream. It's situations like that which almost make the camera operators job easy. All I had to do at that point was set up the camera and keep shooting.

The next 24 hours look very interesting in this region. It's not an ideal tornado chasing setup, but my meteorological senses are getting tingly all over for several reasons. The extreme storm system is expected to bomb out over the Minnesota and Canada border sometime tomorrow with a forecast low of 960 mb, which would rank it among the strongest in recorded history in this area. That alone will cause gradient surface winds of the likes that we have not seen in years. Surface gusts could hit 60-70 mph tomorrow afternoon in Wisconsin and northern Illinois as the dry slot wraps around the system, behind the cold front.

The cold front is another story, as it may bring with it a fast moving round of severe weather. I'd like to get excited about the tornado prospects, as I do think there will be a few tornadoes in central/northern Illinois into Indiana tomorrow, likely early in the morning. However, even if tornadoes do occur, almost everything is against one actually seeing it unless you are unlucky enough to actually be hit. The storms could very well pass through this area very near, or even just before sunrise which would obviously cause any tornado to be hidden by darkness. I don't expect a lot of lightning with the storms, so while night chasing in general is dangerous enough due to your inability to see the tornado, any tornado that strikes before sunrise tomorrow will be almost undetectable aside from radar, which will be hard enough in itself. Then, you add storm motions. Let's say an embedded supercell does begin producing tornadoes. You better be directly in the path of that thing right as it produces, because once it passes you up, at 60 mph the storm has passed you up and your chase is over. Then, you add the embedded nature of the tornado. See my video from the August 19 2009 tornado near Rochester, IL. Let's say you DO get near an in progress tornado. Congratulations, you've passed most odds. Now, can you see it?
The odds are any tornado that occurs tomorrow will not only be fighting daylight, and moving at 60 mph, but it will likely be partially or entirely obscured by rain. The best case scenario, is that isolated/scattered supercells form along confluence bands ahead of the main squall line and you're able to catch a view of one of those potentially classic supercells. However, I think this is a pretty unlikely scenario tomorrow unless some changes take place to the overall synoptic setup. If we end up with supercells ahead of the main squall line, we need to start talking historic tornado outbreak. I'm personally not ready to do that, but the overall "we've never seen anything like this" nature of the storm has my senses tingling, and my interest peaked.

Then, once the squall line of doom passes the area, the dry slot wraps around and we spend a good 12 hours in insane surface winds. We'll probably be seeing sustained winds above 40 mph for a couple hours, and I won't be shocked at all to see an 80 mph wind gust somewhere in Wisconsin or northern Illinois tomorrow afternoon.

I'm not planning a chase, per say at this moment. However, I'll be watching the event closely and will intercept whatever does occur that I feel I can do so safely, and with a potential reward. I'm not in to driving a ton of miles on a Tuesday for video of sideways rain, but should I feel my odds of photographing a tornado, or perhaps insane winds is decent, I have not put away the chase gear after last night's storm.

Flickr set with higher quality images:

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