4/30/09 FCST: TX, OK, KS

[Brett Roberts]

While flow may be somewhat marginal for tornadoes today (not to discount OFB interaction possibilities, of course), I really like the potential for excellent structure on any supercells that may develop in OK this afternoon. These days with high CAPE, low speed shear, but excellent directional shear (WNW or NW flow at 500 mb) seem to feature a higher-than-average likelihood of producing gorgeous, sculpted supercells. A couple recent examples that come to mind in this region include March 30 and June 16 of last year. Just a thought, for those in the area who enjoy good structure and still photography.

 

[tom hanlon]

Southern Indiana

I am heading for Southern Indiana to play the strange mix of dueling MCV's that we see on visual satellite.

Northern Illinois rotation is further east, Arkansas rotation further west, both heading east and lifting north.

Given some clearing the SPC is predicting some low top supercells.

This chase is close to home so I thought I would head out. The usual problems with convection this far east, too much moisture, too much rain, squall lines are to be expected.

So with the above warnings and potential for a messy indiana chase, I head out. The situation is complex, but MCV's are always an interesting dynamic. Plenty of moisture so if we get some sunshine things might happen.

This Indiana feels to me like it warrants another thread since it is a totally different situation that OK, but the rules say...
(7) There will not be more than one FCST thread, one NOW thread, one REPORTS thread, and one DISC thread for any one date. I

So.. here it is. Mod's can add Indiana to the subject of the thread, or pull this post, or leave it as an anomaly

--
Tom

 

[Brendon Lindsey]

I am agreeing with the recent posts. All the models are showing precip breaking out. And with that much instability, I would assume it could easily be supercelluar. Wow the 12z 12hrs out I believe was throwing 6000 Cape down in SW OK. Ha I didnt buy it... I am liking the lift. and the Rain Just east of I -35. I am going to make the trip to OKC and hope for the killer mothership picture that I have been waiting for. To tell you the truth I like beautiful structure rather than any wedge... Call me crazy, but one needs to know I am a photographer, just edging my way into videography...to take videography seriously I would need a whole extra paycheck every two weeks haha =)

 

[Chris Vagasky]

I would be taking a look at the Kingfisher/Garfield/Logan County intersection in NC Oklahoma.

Looking at the Mesonet, convergence seems to be maximizing in that area, SPC mesoanalysis seems to confirm. Looking at visible satellite, an agitated cloud field there, with some clearing in the area.

Monitoring Td trends, it appears that area is right at the east end of the moist axis, especially the axis of increasing moisture.

2000+ CAPE, and the outflow boundary there, could be something similar to the Lacey storm last May.

 

[nickgrillo]

I'm sitting here in El Reno, OK... RUC mesoanalysis has showed a significant decrease in surface-based and mixed-layer parcel CINH in the last few hours, and I'd expect that with continued insolation / diabatic surface heating, we could see initiation within the next 2-3 hours as the surface boundary sags south into OK. Given the ambient thermodynamic profiles -- supercells would be the main convective mode. I'm hoping we can see initiation before 00z. Assuming a supercell can latch onto an OFB, then I'd have to say a tornado would be HIGHLY likely.

 

[nickgrillo]

I'm heading north on US-270. RUC mesoanalysis shows the area of Tcu (just south of the outflow boundary) to be in a region of low LFC heights -- i.e. 1200-1400m AGL. However, boundary layer parcels are having a hard time reaching their LFC given the weak forcing along the outflow boundary. I hope something can go up within the next couple of hours...

 

[Jeff Snyder]

I'm sitting in Hennessey awaiting initiation which has thus far failed. I was about to leave, but it looks like there may (MAY) be some weak ascent aloft coming into the area, as some mid-level cloud cover has developed in the past 30-40 minutes near the area. The Cu thus far must not have been composed of surface parcels, as they've all been relatively flat and soft. There is a batch off to my ENE right now that looks a bit better, with increasing depth and some occassional pileus atop them . Then again, I'm not sure how much that means not that it's obvious that mid-level RH is nearly saturated neary (as evidenced by an uptick in mid-level cloud cover). The base of this particular batch of Cu is also a bit les flat, and it looks like it may be trying to pull in some surface air. I'm not very optimistic since we're past peak heating, but at least it's nice to see some condensation underneath what had been the ambient cloud bases (which thus far have been quite high -- certainly higher than would be expected from 10-15 F dewpoint depressions). Flow aloft is marginal near here, so I think any storm will need to interact with the OFB to have a chance of doing anything interesting (from a chasing perspective). I assume we aren't seeing enough surface convergence to push surface parcels to the LFC, and it probably doesn't help that earlier forecast soundings were showing poor lapse rates from the surface to nearly 700 mb (e.g. nearly moist adiabatic, similar to what we saw this past weekend, actually). *shrug*

 

[Jason Bolt]

Left split off the cell NW of OKC looks like its probably dropping some gorilla hail. Decent cell has blown up near Coffeyville KS over the last hour. Not warned atm but close to home so I might head out and get some lightning shots.