6/12/09 NOW: OK/TX

[Darren Stephens]

Several warnings issued for North Central and NE Okla. Giant MCS moving in on those areas.

 

[Jeff House]

That MCS may achieve derecheo-like characteristics intermittently today. The derecheo checklist is far from being met at 500 mb, mainly due to lack of a decent shortwave. However 700 and 850 mb warm air advection is in progress, which is on the checklist. Also the airmass is extremely unstable and exceptionally humid. SPC upgrade to MDT is clearly justified. Enjoy the show but be safe and respect the wind.

 

[Michael O'Keeffe]

I agree with Jeff this storm is trucking along which is typically a characteristic of a derecho and just received a report of 85MPH winds near Tulsa and hail larger than 2" has also been reported near I35 in N Oklahoma. The SPC has issued an MD mentioning an upgrade to a moderate risk over Arkansas by the 1630z outlook and for good reason. I would also be watching those isolated cells developing along the boundary ahead of the MCS.

Edit: Supercell ahead of MCS has split and the right mover is riding the boundary.

 

[CZandbergen]

Northern end of the MCS has just gone warned east of Adair OK. Showing 55kts of shear.

 

[Darren Stephens]

Southern end of MCS near the Northern portions of McIntosh County is bulging quite a bit more. Persons in that area should pay close attention.

 

[Jeff Duda]

Gotta love this: PDS Severe Thunderstorm Watch issued for the area downstream of the bow echo.

 

[Robert Dewey]

Wow, that bow echo is extremely impressive. Both SR and base velocity at tilt 1 showing winds between 70-100knts. That'd be awesome to intercept, that's for sure.

 

[Chad Cowan]

That is a really impressive derecho. It's been consistently showing a LEWP/ mesovortex on the southern edge, just about 30 miles west of Little Rock, could probably use a Tor warning if it wraps in any more.

Any bets on how far this thing goes? I wouldn't be surprised to see a big blue smear on the SPC reports page all the way down to Florida.

 

[James Hammett]

Here's a power outage map but it's not working at the moment:

http://www.entergy-arkansas.com/outages/ar.aspx

Maybe too many people trying to get on Tornado warning now on the northern edge. Looking for webcams now.

 

[Larry J. Kosch]

Any Chasers in AR??

Hmmmm... I don't see any active chasers in AR on TVN??

I have heard from other chasers that they don't like to chase storms into AR for the following reasons: 1. Too many hills 2. Too many streams to cross and lakes to detour around. 3. Roads that seems to be going NOWHERE! 4. Did i mention hills??

Unless they have extended the Vortex2 project by one more day, guess this will be the last chance chase for them or any other chasers to do for this week. Sigh...

 

[J.B. Dixon]

Clearly recognizable TVS signature just SW of Vilonia, AR at this time on the leading edge of the bow. Reminds me a lot of Kansas City tornado/bow echo nocturnal incident last year. Looks to pass just south of Vilonia.

 

[James Hammett]

KTHV has live streaming coverage here:

http://www.thv2.com/

You can hear the wind/rain in the background. Webcams here:

http://www.instacam.com/search.asp?searchbox=ar&searchtype=state

 

[Robert Dewey]

That is a really impressive derecho. It's been consistently showing a LEWP/ mesovortex on the southern edge, just about 30 miles west of Little Rock, could probably use a Tor warning if it wraps in any more.

Any bets on how far this thing goes? I wouldn't be surprised to see a big blue smear on the SPC reports page all the way down to Florida.

I'm going to say central/eastern GA as the RUC shows decreasing shear down that way. Instability remains strong, however I do see a lot of storms developing rapidly in front of the system, which may act to slow down the cold pool.

 

[James Langford]

TX should please be added for this thread. An active area of cu is starting to show up W of the DFW metroplex. Huge amounts of CAPE and good flow are present. Primary concern will probably be large hail, but spc has issued a large tor watch box for the area. I'll be camping up near Pilot Point, and will be watching things very closely this evening.

 

[Dave Kaplow]

Very nice supercell in Jack County TX, just NW of DFW. A "developing tornado" already reported with this storm. So far I haven't found a live stream, but there have to be plenty of chasers on that cell.

Edit: SPC mesoanalysis is reporting CAPE over 7000 in that area now! Wow. I'm not sure I can remember ever seeing a storm actually go up in that kind of instability. The TX storms appear to backbuilding somewhat against the mean flow, they haven't budged much off the dryline since initiation. That can only help any tornado chances.