I had made a post back on 4/18/11 discussing the historical perspective on April '11 Severe weather and where it falls in the history books. Current updated April Tornado reports are at 491! Tuesday's outbreak across Missouri and Illinois definitely added to the total and there were a few nasty tornadoes to boot. In that Monday post I had mentioned 4 future severe weather events. I wanted to put a post up for tomorrows event for those curious and any one thinking of chasing. I unfortunately will not be able to chase tomorrow due to work and I have a marathon to run the next morning. So no pics/vids from my end. Besides, I am holding out for Monday (Severe Weather Event #3), but that post will come on Sunday. Seeing as tomorrow is a bit complicated and given I've been putting all this attention towards the potential breaking of the single monthly total for "tor" reports, I am just going to focus on tornado hot spots for tomorrow, so no in depth Synoptic and Mesoscale setup. Only the "Go Zone".
The Go Zone:
There looks to be two favored areas for tornadoes tomorrow. The first area is along the warm front, cold front, sfc low triple point across NC Missouri/SW Illinois. Here strongest upper level forcing will move over area of maximized CAPE, enhanced shear, and > mid 60s tds. Any elevated storms that go surface based near or along the warm front will be aided by backed flow with time and will undoubtedly be rotating as right movers will be favored. Closer to the cold front across east central missori, surface based convection in the warm sector will happen a little bit later and will be aided by 850mb-700mb confluence region across central Missouri. Convection should start out as discrete storms and ultimately grow upscale as boundary layer flow/properties are modified by down drafts/gust fronts. I'd favor SW Illinois as prime spot for tornadoes from discrete sfc based cells.
The second area, which is a little harder to make out in the model data appears to be across Southcentral/eastern OK into North Central Texas. The southwest portion of the Cold Front associated with larger system will stall out into a quasi stationary front. To the South of this frontal area dewpoints should reach the mid to upper 60s all the way South and West as the dryline in West Texas. This front will extend SW to Northcentral Texas where it will meet up with a secondary surface low. Here backed upslope flow at the surface from thermally induced heat low will aid in 0-1km and 0-3km enhanced helicity values. Surface based Storms that form along and south of the quasi stationary front will have sufficient CAPE > 3500 J/KG and enhanced low level shear to make up for lack of stronger mid level flow. Farther to the South along the Texas dryline a few supercells may be possible before/jsut after sunset. There a greater chance for Large Hail exists, but given backed flow at the surface and very large cape values, could see a "tor".
Should be an interesting day. I am extremely excited to see how it all shakes out. If a few things shift over the next 12hrs, these Go Zones could be total busts, lol. All in the fun though.
Fearless Fantasy Forecast: o/u 15.5 Tornado Reports
Dan aka Squall Line
P.S. It's been way too quiet on this blog recently, what gives??? I'm about ready to propose we rename this blog,"Where the Squall Line meets Convergence and Helicity"
Graduate School...that's what gives
ReplyDeleteCome on Zach, this is where you finally get to apply all that theoretical crap into real world situations, ;) , besides your Advisor is quite the Severe Weather guru herself. If I would have been smart enough to start something like this blog back when I was still in my first year of grad school, I'd probably be working at SPC, lol or taken another year to graduate (if that's even possible). Consider this blog Conceptual Model Fiber...
ReplyDeleteStudy hard buddy, lol
I'm having a hard time getting a handle on this forecast. Part of that is due to only looking at the model data for about 5 minutes. But it seems the NAM and GFS want to put down a lot of precip in the favored target zone near the warm front in MO/IL in the morning and during the day. (Maybe related to the departing right-entrance region of a jet max?) I don't think this means tomorrow is a bust, but it might be a slightly complex situation for the chaser. Sometimes I find this situation might result in a delay in the real action/initiation at a later time if there is too much stabilization/subsidence behind an earlier MCS (although there's no reason to think the lift associated with the cold front couldn't compensate for any resulting capping inversion say near just E of St. Joseph and areas S to S-SW). Other times I find this situation does put down a raging tornadic supercell near the warm front with its excellent low-level shear profiles making the cold front convection of secondary concern, but if there's a lot of morning/midday convection, it's often hard to know well ahead of time where that sweet spot of instability will set up along the warm front to support such a storm. But maybe the convection will clear out early enough and leave behind an E-W boundary oriented with storm motion and to allow for some further destabilization. The 4 km WRF, despite ample morning convection, initiates convection along the cold front from N central MO, S,SWrd and keeps some discrete cells along the warm front into IL starting from 21-22 Z, onward. So, with all that said, I also like the warm front target in north-central MO to W IL, maybe not too far ahead of the cold front, just to hedge my bet.
ReplyDeleteI'm going to go just slightly lower on the total tornado count at 7 reports, but I'm definitely not confident in that number. If there's adequate sunshine in the warm sector along the warm front tomorrow, I think it will be a very good chase day and my number may be too conservative.
Wow, sorry for all the rambling.
Seems convection moved the region of interest southward. SPC agrees with the shift in target.
ReplyDeleteyeah, true that...hoping my secondary Go Zone holds up (thinking it will based on HRRR, 12z model guidance). Boy what I wouldnt give to get out to Somewhere South of Columbia, MO this afternoon around 21-22Z! Convection is going to explode and remain discrete for a couple of hours...freaking race and work.
ReplyDeleteAgree! I'm starting to think my tornado count forecast is going to be too low. Seems like there's been plenty of destabilization in regions that still have adequate shear.
ReplyDeleteOh, and that morning MCS appears to have helped set up a favorable boundary, if anything, in central MO. With good CAPE/weaker cap already set up along this boundary.
ReplyDeleteHats off to Squall Line. You completely dominated this forecast! Both go zones verified, and your total count may even be a tad conservative when all is said and done, but is pretty close either way. Nice work!
ReplyDeleteI haven't looked into details in the STL impact yet, but that sounds like a significant story developing.
Nice job on the Go Zones! The STL tornado sounds pretty bad, unfortunately. It sounds like the airport took almost a direct hit. Part of the roof of a concourse was blown off, many of the windows were blown in, a shuttle van was lifted on top of the ledge of a parking ramp, etc. A commuter jet was even lifted and moved about 20 feet! The airport is now closed for cleanup, as well as, unfortunately, treatment of injuries (probably due to debris/glass flying around, I'm guessing). Cantore and Forbes were covering it for The Weather Channel and were actually doing a pretty good job of covering it, explaining the radar very well, pointing out different features (hook echo, tornado vortex signatures with velocity, debris ball, etc) that the general public might not know about and putting it into easy to understand terms. A rare win for the Weather Channel haha!
ReplyDeletehttp://twitpic.com/4o8pd2 Likely see a lot more footage like this in the next 24hrs. I'll go back to being MIA...taking a 3 day break from weather maps.
ReplyDeletehttp://twitpic.com/4o8ehz http://twitpic.com/4o8324
ReplyDeleteA couple pictures of the shuttle van on the ledge of the parking ramp. It is literally suspended on the ledge - none of the wheels are on the ground. It had to have been lifted up and dropped onto the ledge by the tornado. Another point made by Cantore - they don't normally keep these shuttle vans on the top level of the parking garage. It may have been lifted up from a parking lot on the ground and deposited up there. Curious to see just how much damage there is there, sounds like it was a strong tornado.
Whats real scarry is this coming severe wx week's setup...day after day after day. A lot of bad is going to come from this. And you can bet ill be out a few days.
ReplyDelete