***2005 Master Class Tour***

June 12, 2005 Northwestern Texas Tornadofest

We intercepted a classic cyclical tornadic supercell east of the dry line in Kent County, Texas early this evening. The first tornado and associated mesocyclone was truly beautiful!

Tour Leaders: David Gold and Bill Gargan

Tornadoes seen: 4

Number of supercells responsible for tornadoes: 1

Meteorological Synopsis and Summary

Fig. 1: Objectively analyzed 18Z June 12 surface map (dewpoint temperature in shading; standard plotted observations; surface pressure solid contours). Strong dry line evident over west Texas and the Texas panhandle.	Fig. 2: The 12Z June 12 Midland, TX sounding modified for a high temperature of 31.5C and dewpoint of 20C and using a virtual temperature correction in computing the lifted parcel ascent curve and CAPE/CIN.	Fig. 3: Subjectively analyzed 300 mb chart at 12Z June 12, indicating the strong digging upper-tropospheric trough approaching the southern Plains. Note the strong jet stream punching southeastward into west Texas in the base of the trough.

This day began in Plainview, TX, where we had the pleasure of meeting Jeff Passner, whom we encouraged to join us as we prepared the day's forecast. The challenge this day was to choose from among a myriad of possible "plays" east of a fairly strong dry line that was becoming established along the I-27 corridor by early afternoon (Fig 1). The boundary layer was particularly moist (Fig. 1, 2) over the entire region east of the dry line and therefore laden with lots of buoyant energy, as the modified 12Z MAF sounding revealed (Fig. 2). Thus, it was clear that significant severe convection was likely over the south plains and Texas panhandle once forcing along the dry line released the huge CAPE.As for precisely where to target, two general areas were evident: (1) downstream of a significant mesoscale dry line bulge along an outflow boundary extending roughly east-northeastward from the southeastern Texas panhandle north of Childress into western Oklahoma and (2) farther south east of the dry line east or southeast of Lubbock under the assumption that another dry line bulge would develop in response to downward mixing of stronger westerly momentum in the base of the approaching trough west of the dry line. Ultimately, our fears that storms in the northern target area would cross the outflow boundary and quickly become elevated/weaken forced us to keep the southern target in play, even with concerns that the cap might ultimately hold along the dry line further south. One more observation helped commit us once and for all to the southern play: the fact that early storms near Silverton decayed very rapidly while storms east-northeast of Lubbock - albeit not very impressive initially - continued to hold on for dear life and continue to work on the cap down there. We made the decision to head south to Matador where we observed a decent-looking striated updraft northwest of town. This storm soon weakened and we noticed on radar a north-south oriented broken line of storms developing and intensifying from south of Matador to south of Dickens, TX. The decision was made to quickly target the tail-end storm of this line. En route to the tail-end storm, we were delayed by the other two storms within the line, each of which was developing supercellular characteristics of its own - both from a radar representation and visually. A report of a cone tornado with the southern storm lit a fire under our backsides and we blew right past a respectable striated updraft just west of Dickens, making all haste to the now very significant supercell over northwestern Kent and extreme northeastern Garza Counties. The sight that greeted us is presented in the captions below.

Chase Summary with video captures

Having heard a reliable report of a significant tornado associated with the tail-end charlie storm, we blast right by this updraft visible to our west northwest of Dickens, TX.	Here's a screen shot (from the Baron Threatnet radar system) of the southern monster, along with the bottom half of the Dickens County storm.	On our way south along Hwy 70, we note a sky wild with shear funnels.	This is one of our first views (looking southwest from Hwy 208 just south of the Kent County line) of an ominous, block wall cloud beneath the base of the tail-end monster.
We continue driving southward until we get beyond the worst of the forward-flank precipitation, where we are greeted by this view of the enormous barrel-shaped updraft!	This updraft was simply amazing - what a striated barrel cloud. The low-level mesocyclone and associated wall cloud was full of fluid, smoky rotational motion. We knew this had more tornadoes up its sleeve!	A close in video capture of the wall cloud.	A slightly wider view of the entire low-level mesocyclone, including stubby tail cloud and bowl-shaped wall cloud.
Once again, I look back at these crummy video captures and lament not (1) tripoding the video camera and (2) shooting stills.	A classic back-lit cone tornado quickly takes shape beneath the wildly rotating wall cloud.	Cone becomes stouter. No violent motion here, but pretty strong rotation noted within the condensation funnel.	Cone fattens up. Thank GOD we went for the tail-end storm here!
Wow!	Now the tornado actually begins to weaken as it has reached its widest stage.	Truncated cone tornado; weakening still.	The original tornado has dissipated but the parent tornado cyclone remains intact and new vorticies form beneath.
Dirt is seen swirling beneath the wall cloud and a new tornado takes shape.	Tornadogenesis proceeds. Meanwhile, large hail stones begin falling at our location as the forward-flank downdraft encroaches on our position due to rightward propagation of the entire storm. We have to move south.	Having been forced to move about 1/2 mile southward from our previous viewing position (see previous images), we had sub-optimal lighting for the formation of a wedge tornado, seen above. This big dusty tornado was probably the strongest of the day.	A wide-angle shot of the wedge tornado and parent mesocyclone.
Same, except here I have managed to pick out a frame in which a cloud-to-ground lightning bolt flickers behind the tornado.	The updraft retains very impressive structure as it chugs east-northeastward over rural east-central Kent County southwest of Girard, TX.	A large multiple-vortex tornado forms southwest of Girard.	More multiple-vortex action.
Another vortex condenses within the larger-scale tornadic circulation.	Yet another wide-angle shot of the impressive updraft structure.	Great beaver tail streaming into the updraft along the forward flank northwest of Jayton.	We peer back into the storm's most mature occluded mesocyclone and see this cone tornado emerging from the rear-flank precipitation core.
Close-up shot of tornado #4.	Our final view of this graceful tornado just before we blast south to intercept a new tail-end storm.