Tornado Tuesday Part II? It’s certainly a possibility. Talk about luck in that I have a half-day on Tuesday, so I’ll be able to chase a reasonable distance from home, and things are certainly starting to line up within a reasonable distance from home! The NAM is now within range, and I’m liking what I see.
A big trough will be digging through north central Mexico on Tuesday afternoon, resulting in 60 knot 500mb winds downstream in central and north Texas, extending into southern Oklahoma. At the surface, dew points will reach the low to mid 60’s thanks to a low-level jet from the south-southeast. Surface temperatures will be near 70 by mid-day. A dryline will set up in central Texas, with a bulge forecast just to the northwest of the Metroplex.
The NAM tends to be a bit bullish on dewpoints most of the time, and I’m a little concerned that we won’t really see 66 dews in Decatur as the above map indicates. Still, given the amount of shear in place as a result of the upper-level trough, there looks to be a decent tornado threat. CAPE is also forecast to reach 3000 J/kg in the area above the dryline bulge, which again, may be a bit optimistic, but given the shear, that much CAPE will not be required for supercell development. There may be a narrow window of opportunity before isolated cells merge into an MCS, though in this area north-northeast of the dryline bulge, more backed surface winds resulting in greater directional shear should be more favorable than the more unidirectional winds south along the dryline in the I-35 corridor in central Texas.
It’s too early to pick a target, but as of right now anywhere along the dryline bulge looks like the place to be. Here’s a sounding from near Decatur, TX at 3pm:
Definite S-curve in that hodograph, but the first 3 km look great, and I’ve seen 2 tornadoes in areas that had the S-curve in the past, including the Elmer, OK tornado last year (that was a big concern leading up to that chase). Time to start prepping and charging all of my equipment!