5/10/10 FCST: TX / OK / KS / CO/ MO

[Jason McKittrick]

Models are forecasting incredible moisture return. Nam indicates morning DPs in the upper 40's all the way south to the Red River, increasing into the 60's to near 70 by 7PM all the way into SC KS. With everything pointing toward an exceptional outbreak, I believe it is time to start looking for things that could limit this event.

I have been planning to chase Monday, however the target has slipped a little too far south for me to reach in one day. Given the potential, the lack of storms so far this year and the extended models hinting at a big fat ridge this becomes a tough decision.

It appears there will be enough of a cap to prevent early initiation, orientation of the shear vectors orthogonal to the boundary should guarantee supercell storm mode. I am concerned about two factors. As Jason Boggs mentioned yesterday storm speeds maybe a little fast, at least for my liking, and while I have never chased east of 81 it is my understanding that the terrain and road network in SE KS are less than ideal. Second the warm sector appears to be rather narrow limiting the amount of time the triple point storm (the storm closest to me) will have to mature before potentially crossing the warm front and becoming elevated.

Still time to hash out the details, pray that what ever does happen will not cause any fatalities.

 

[Jason Boggs]

Yeah, there are obviously still a lot of details to work out, but for some reason, my gut has been telling me all day to target south of I-40.

First off, forecast soundings don't show a stout cap in that region that I see. Second of all, I sometimes like targeting down the dryline away from the main source of energy. Storms are more discreet, and sometimes they're more photogenic because of the lack of other storms nearby. I guess to be honest, the main reason is...I want to try to stay away from the chaser rat race that will occur in north central OK and south central KS.

CAPE should be pushing 3500-4000 with Td in the mid 60's east of the dryline. I dont want to get caught too far south, so I'll more than likely start a few miles south/southeast of Weatherford, OK.

 

[Nathan Hoelting]

Still too early to know exactly what kind of cap we'll be dealing with in OK for Monday, but I wouldn't be suprised to see that MOD Risk area move a little further south towards I-40 Monday IMO. Have a hard time believing the forecast parameters will not be able to overcome even a moderately strong cap. I'll skip repeating all the well-publicized juicy details and just stick with calling them "totally tubular." For the time being, I like the Kingfisher OK area for a good starting point. Good road options in all directions depending on where the storms will fire With forecast storm motions, I just want to make sure I don't start too far west and get stuck trying to play catch up.

FWIW: I am more than a little biased to chasing a Souther Target since it is awful hard to chase Central/Southern KS and return to Amarillo w/o being a zombie when I head into work @ 6 am Tuesday.

 

[Russ Conlon]

06 NAM and GFS are in agreement now with placing dryline at Hwy 81 at 00Z. For the most part all the factors look pretty much in place. Surprised that SPC didn't come as far south as I-40 with the moderate risk on the Day 2 outlook. The area I had in mind still looks to be prime late tomorrow afternoon and evening. Chickasha extending north to Enid eastward to the point on the KS/OK border directly north of Ponca City SE to Cushing to Shawnee SW to Norman and then back to Chickasha, OK. Hodographs are insane from OKC metro to Stillwater to Ponca City. I figured I'll stay in close proximity to I-40 tomorrow with as many road options as possible. Target: Edmond, OK Good luck tomorrow everyone and stay safe.

 

[Jason Persoff]

The ETA forecast soundings look like a case study in severe storm climatology. Loaded gun soundings forecast up and down a line from Enid->Lawton at 00z with a dry punch pushing up from the TX PH. I am concerned that the forecast low is now progged to be a bit more north than originally thought resulting in less backing winds in OK (and more into KS). That said, I am most impressed with the the low-level hodographs throughout the region. Upper air seems to be a narrow area over the KS/OK borders north of Enid for initiation.

Putting it all together, I guess my target would be SW of ICT for initiation/intercept. Great road networks, terrific dynamics coming together. Sadly, this is also going to be a disaster in terms of long-tracked tornados over highly populated areas. Any boundary intersecting the dryline will provide for an amazing show.

This is the kind of day that almost makes me wish I could call in sick and jaunt out to the Plains...Alas...my colleagues would out me.

Stay safe all. I'll be in eager armchair positions after work tomorrow...

 

[Warren Faidley]

There are still some critical differences between the NAM and GFS re: target / risk areas for tomorrow. The O6 (5-09-10) NAM maintains the dryline near the TX Panhandle OK border at 18z through 21z with only a slight eastward push. The GFS shows a nice DL bulge into southern KS. Its a little hard to believe (NAM) that such a dynamic system would leave a stationary dryline for that long --- however, both the GFS and NAM seem to be pushing the surface low further north. This could really complicate matters.

Pros: Dynamic system as discussed ad nauseam. Main storm mode should be CL with rapid supercell development and tornado production. Early AM storm activity may lay down boundaries, including boundaries for western and southern DL storms, possibly making up for some loss of low level surface shear away from the main surface low. I would not be surprised to see a violent supercell somewhere W / SW of the current Day 2 moderate risk area, or the area to be moved a little further SW later today.

Cons: Relatively small area of obvious maximum risk – ATM. Surface low position. The Mad Max chase mode will be in full swing. (I've been getting emails from the media all over the world wanting to cover this event as its been hyped to death). With the regular groups of chasers, tours, VORTEX, media and the mass of locals (who have been primed like race horses in gates for the last few days), it will be crazy. CIN, rain cooled air, cloud cover, LCL's (further S / SW), an early wave / subsidence (the usual monkey wrenches) also have to be considered in some areas.

Storm speed could be >40 kts. This will lead to a lot of frustrated locals and others trying to keep up with the storms. It will also make chasing a lot more dangerous, especially if (when) the storms move east of I-35, or into the evening hours.

Target: Initial 1-40 / e.g., Shamrock -- to be adjusted as the forecast jells.

Good luck to all – stay safe.

W.

 

[Chad Ringley]

Biting on this one and flying up from Houston, leaving tonight.

12z NAM appears to be a little more realistic with the DL, pushing it east from far western Oklahoma at 21z to just west of the I-35 corridor at 00z. The entire area from just west of the I-35/160 JCT in South Central KS southward to Lawton appear interesting, with cap erosion occuring in multiple locations (even south of I-40 now in the 12z NAM).

Like the hodograph curvature farther north; might be the only place the near surface flow can keep a little backed. Wouldn't be surprised if there's a monster cell to the south of I-40 as everyone has mentioned.

Kind of reminds me of 29 May 2004; two distinct plays..a big beast of an HP all by itself near I-40 in OK and cyclic classics in SC KS where the flow remained slightly backed.

The other part that reminds me of 29 May 2004 is the hype and circus nature of it all, particuarly on the HP beast down along I-40. I expect a similiar situation tomorrow (though that was exacerbated a bit since it was Memorial Day weekend).

 

[Warren Faidley]

Biting on this one and flying up from Houston, leaving tonight.

Kind of reminds me of 29 May 2004; two distinct plays..a big beast of an HP all by itself near I-40 in OK and cyclic classics in SC KS where the flow remained slightly backed.

The other part that reminds me of 29 May 2004 is the hype and circus nature of it all, particuarly on the HP beast down along I-40. I expect a similiar situation tomorrow (though that was exacerbated a bit since it was Memorial Day weekend).

I think you nailed it with the storm mode and 5-29-2004 reference.... hodographs further S / SW have lost a lot of curvature and signaling hybrid or HP mode. Looks like it will be a "get on it early" day the further S / SW you chase.

W.

 

[Chris Sokol]

Alright...I managed to get somebody to cover my shift in the ER tomorrow, so it looks like game on for me. At this stage I am thinking of heading to the Clinton/Weatherford area early to stage...gives me numerous options for target adjustment as necessary. There is a little voice inside me that keeps trying to steer me to Mangum/Altus area initially, but so far I have not seen enough data to convince me of that path. But...there is a lot of time (and model runs) between now and tomorrow.

 

[Chris C Sanner]

I don't think discussing the impacts is really necessary at this point, because there is no reason to re-hash what everyone else and their dog is saying. I, however, have some serious problems with this setup from a chaseability standpoint...and they are things I'm thinking a lot aren't taking into account given the W. Oklahoma targets by many:

-Storms will be moving fast, 45mph+
-If the models are right, the dryline will be just 40 - 70 miles from I-35 at the time of initiation, and that's if you are south of 40.
-Put those two together, and the bulk of chasing Monday will be done in unfavorable terrain with relatively poor road options.

This will likely cause many to pull their hair out as storms fade into the horizon -- or worse, as you try to find a vantage point through the trees that isn't already taken by hordes of chasers. Posted a couple of forecasts now on the blog with a bit more information on my thinking...but I definitely don't like that aspect of Monday's setup even though long track tornadoes are a given if tornadoes occur because of fast storm motions.

More detailed forecasts:
http://www.supercellhunting.com/

 

[John Farley]

Wonder if anyone else is noticing the lack of QPF forecast along the dryline by this morning's runs of both the GFS and NAM? And what others might make of this? The NAM does seem to break out quite a bit between 0z and 3z, but along the warm front in SE KS, not along the dryline. Perhaps this tendency is enhanced by the potential for outflow boundaries from early a.m. convection to sharpen the warm front? That area is closer to home for me, but southeast Kansas is not very good chase territory.

So, I'm still up in the air on whether to chase this one. Positives are the great dynamics, of course, but from a chase standpoint, storm motion (if in fact the cap is broken), terrain, and hordes of chasers could make it quite difficult. And as always, there's the issue of just how far I want to drive and the relative weight of distance driven vs. potential for a successful chase.

 

[John Hudson]

The Mad Max chase mode will be in full swing. (I've been getting emails from the media all over the world wanting to cover this event as its been hyped to death). With the regular groups of chasers, tours, VORTEX, media and the mass of locals (who have been primed like race horses in gates for the last few days), it will be crazy. CIN, rain cooled air, cloud cover, LCL's (further S / SW), an early wave / subsidence (the usual monkey wrenches) also have to be considered in some areas.

Storm speed could be >40 kts. This will lead to a lot of frustrated locals and others trying to keep up with the storms. It will also make chasing a lot more dangerous, especially if (when) the storms move east of I-35, or into the evening hours.

My thoughts exactly. While I'm still mulling over whether to chase this event, I'm thinking about how much and how long it's been on the radar, and how much of an "idiot magnet" its going to be (please know I'm only talking about the usual suspects here). Things are going to get Darwinian out there real fast.

Between that and the relatively fast storm motions, I'm almost certain that traffic accidents are going to be just about as common as storm damage.


John
VE4 JTH

 

[Mikey Gribble]

southeast Kansas isn't too bad of chase country. Its nothing like the chasers heaven that south central Kansas is, but its still relatively good when compared to some other places in the plains. The square mile grids kind of break down and are more skitish, but the terrain stays really flat for the most part.

I think we are looking at around 35 to maybe 40kts (total guess btw). That 80kt mid level jet certainly isn't helping us out with storm motions. Here is a map with storm motion vectors on it, but IMO you can't trust any of the products out there that show storm motions. They show different things all the time and I haven't found one yet that is consistently accurate. For example Bunkers is showing 50kts over the northern part of Oklahoma, while this other product from the NAM svr wx graphics page is showing more like 35kts.


IMO Bunkers is usually about 10kts fast. I am really hoping that we can keep it under 40kts with any mature storm. That is right at the upper end of what you can hope to keep up with in my experience. There has to be decent roads and you better bring your track shoes.
Days like tomorrow make you appreciate the slow moving late May tornadic storms where you can get out of your car for ten minutes and the updraft is still right in front of you. We'll be lucky to get out of the car at all tomorrow.

Well the tornado threat is there and has been discussed in full as Chris mentioned. The only thing that I don't like much is 850mb winds veering slightly. That isn't much of a concern for me when you consider that slightly veering 850mb winds isn't uncommon with some of the higher end tornado outbreaks in the past. I was looking back at the May 4, 2003 outbreak the other day because of how the setups are the same and it is seriously amazing how similiar they are. Everything across the board is pretty much right in line with what is expected tomorrow. The shear profiles are almost identical, temps and dewpoints are very close to the same, I haven't seen a CAPE map for the 4th but it should be close to the same. They are extremely similiar. here is a link to the archived data from that event http://w1.spc.woc.noaa.gov/exper/archive/events/030504/index.html

 

[Trey Thee]

Guys there are definitely a few negatives with this system, but they are relatively small and somewhat insignificant when looking at the entire dynamic environment. At least thats my opinion. I've never once seen a completely perfect setup...

We may now position ourselves at I35 as opposed to Enid based on the new data. Also I believe NE OK is firmly in play. I noticed some trends beginning with the 12z's yesterday that I mentioned to my buddy those trends remained intact. So there are three large metro areas that are no within the broad svr potential.

An additional concern I have that we haven't discussed a lot is the large hail potential. We could see some big hailers with this system and given the broad area of svr potential tomorrow there could be significant impacts from hail in OKC/Wichita/Tulsa...hope everyone has insurance

 

[Jeff Piotrowski]

Monday Chase Targets

The 12Z 4KM show lots of morning convection across central and NE OK/SE KS before 18Z. This will leave a boundary at 18Z from FSM-PNC area.

All Models are further NW with primary surface low IE Goodland at 18Z tracking toward Salina at 0Z. The DL at 21Z will run from HYS-GBR-END-FSI. Storms will fire around 19Z near Hays SE toward OK/KS border by 21Z.

The more significant tornados will developed on the boundary/DL intersection over SC-KS/NC-OK around 22Z time frame.