A broken line of thunderstorms extends from Stephenville to Glen Rose to Hillsboro to Fairfield to Elkhart to Henderson to Carthage. The storms from Hillsboro to the Lousiana border are generally in the form of a solid squall line. They’re moving south/southeast at 45 to 50 MPH. Not all thunderstorms within the squall line are considered severe, but the most intense are producing damaging straight-line winds over 60 MPH and quarter size hail. From Hillsboro to Cleburne to Stephenville, we’ve seen a few severe hailers fire up over the last hour and a half. Those storms are on the western edge of the squall line and remain more cellular versus linear.

The cellular thunderstorms are capable of producing quarter to golf ball size hail and localized damaging wind gusts over 60 MPH. If these storms can grow upscale, they may pose an increased damaging wind threat by 3 AM. A lone severe thunderstorm quickly popped up over Killeen and produced ping-pong ball size hail at about 1:30 AM. That storm is now crossing Interstate 45 near Salado with a similar hail threat. Other showers and a few thunderstorms are firing up from Cameron to Rockdale to Lexington, but they’re not severe. All of the activity mentioned above is also moving southeast at 30 MPH.

Thunderstorms will continue to move south this morning quickly. The squall line itself will enter the Brazos Valley and East Texas by 3 AM. The most intense portions of the squall line will be severe, with damaging straight-line winds over 70 MPH and quarter size hail. Do note that isolated storms may arrive in the Brazos Valley before the squall line (such as the hailer near Salado). Storms should be approaching the Golden Triangle and Houston Metro in Southeast Texas by 4:30 to 5:30 AM – with some thunderstorms still capable of producing damaging winds and heavy rain. Some small hail may also be occurring, but we expect the hail threat to be lower.

The Storm Prediction Center issued a short-term discussion right as this post was being published. We’ve included it below.

Mesoscale Discussion 0500
NWS Storm Prediction Center Norman OK
0156 AM CDT Wed Apr 29 2020

Areas affected…East-central Texas…Louisiana

Concerning…Severe Thunderstorm Watch 154…155…

Valid 290656Z – 290900Z

The severe weather threat for Severe Thunderstorm Watch 154, 155
continues.

SUMMARY…A severe threat is likely to continue for several more
hours as a line of storms moves southeastward across WW 154 and WW
155. New weather watch issuance may be needed to the southeast of
the current watches.

DISCUSSION…A well-developed squall line is evident on radar from
north-central Texas arching east-northeastward across northwest
Arkansas into northwest Mississippi. The line of storms is located
on the northern edge of a moist airmass. Surface dewpoints are
highest in east-central Texas where the RAP is showing a moderately
unstable airmass. MLCAPE values are estimated to be in the 3000 to
4000 J/kg range across much of east-central Texas. For this reason,
the potential for wind damage and large hail will be greatest there
over the next few hours. Wind damage and hail will also be possible
eastward across northern Louisiana where low-level flow is stronger.
The severe threat should move southeastward to the edges of WW 154
and WW 155 by 10Z. If the intensity of the line can be sustained as
it approaches the edge of the weather watches, then a new weather
watch could need to be issued across parts of southeast Texas and
central Louisiana late tonight.