2007 Chase Season - The Sequal

UPDATE 2115z: Not too excited about hurrying up to get out there. Blue box just went up. Storms are lining up and becoming outflow dominant quickly in the NW TX PH. It seems much less likely now that we'll see any isolated cells and thus the tornado threat is pretty much nill. It's still possible, but a very slim chance at best. Surface analysis shows a N/S convergence zone just E of AMA with the dryline off to the west. Convergence overall is weak and 21z surface plots aren't sharpening up as much as hoped. As existing storms continue moving further east into the panhandles, they should encounter better moisture and strong LLJ, so some impressive storm structure is still likely...worhty of a local chase. :-) Headed out in about 30 minutes. Will update later on Tailchaster (link to right).

UPDATE 1815z: I'm shifting my target to the NE TX PH....around Pampa/Borger. Better mid level winds are there as well as better insolation has been up there. The RUC continues to suggest a narrow area of strong SRH will exist in this area as well. Dewpoints are already in the lower 60's and continuing to advet into this area. A tongue of 2000 CAPE is nosing up into this area as a result. Pronounced dry punhc now evident on latest surface analysis taking aim on the N TX PH into the OK PH. Pretty much an easy target. Will depart in a couple of hours.

It feels good to once again intently peruse data in anticipation of a good chase day! :-) I hate these long intermissions.

As usual, I'll try not to regurgitate another good SPC discussion. The only thing I'll stress are weak winds from 300mb on up. It is a perfect formula for outflow dominant HP supercells. But, it's also a setup for some really great structure. The tornado threat is conditional on storm type and motion. I agree with the 2% risk.

However, what is abit odd to me is that the 200-300mb flow is southerly and up to 40-50 knots. With mid level winds westerly and relatively strong sfc-850mb flow, it certainly makes me think that there will be adequate anvil-level ventilation as a result of the southerly flow at that level. Plus, latest RUC shows CAPE developing up towards 3000j/kg over the E PH and extreme S OK. We have a perfect setup today for deviant moving cells with SE movement. In fact, I'm betting on it.

What's more, the RUC is forecasting very strong dryline convergence which should remain stationary beyond 00Z. With strong CAPE and 30 knot mid level flow atop strong low level flow, we also have an excellent setup for a cell to root on the dryline and stay there with a slow S/SE drift.

With SE low level flow forecast, any cells exhibiting this type of deviant or quasi-stationary movement will have very favorable SRH as well as good ventilation resulting in more HP/classic hybrids...at least within the first couple of hours of initiation. If we can maintain more isolated cells, then a couple of tornadoes should be had today pretty easily. The question is how strong the cap will be today versus the strong dryline convergence. It could certainly go either way imo...from a couple of isolated cells to a large areal cluster of storms. The latter solution would spell disaster for chasers given the vertical profiles. So, cross your fingers for a strong cap. :-)

One other thing to note is the forecast track of a weak impulse traversing the E TX PH by 21z into NW OK. It is weak, but I'm not sure how much if any subsidence it would create across the dryline. My gut instinct tells me that it will only increase the cap abit more and storms will still erupt. But, it could also work against stronger updrafts keeping everything strongly HP. Not that this will affect my decision to chase today...just something interesting to watch.

I'm happy to sit here in Amarillo and work away until the hour of initiation approaches. I expect to make an E or SE jog on 40/287 where the RUC has the dryline setup...but not too far. However, the 12z NAM keeps the dryline further west towards the NM border. I usually side with the RUC, but the NAM might have the right idea. I'll compromise for now and say I-27. Still, Amarillo is a great place to sit and wait.

There are signs of initiation starting up by 21z, so I'll be prepared to bolt out of here. I'll update later this afternoon. I also will be running my live blog again too since I got my new cellular card antenna adapter. Click on the Tailcaster link over there on the right.