Let’s start off by saying we are expecting severe storms from Wednesday afternoon into the pre-dawn hours Thursday. That’s pretty much locked in unless something dramatic changes. This is April and severe storms in April are just a way of life in Texas. I’m well aware that there is increased sensitivity due to this past Saturday’s tornadoes in East Texas. We’re not forecasting a tornado outbreak at this point. A few tornadoes will certainly be possible, but giant hail looks to be the most common hazard.
Latest Severe Weather Outlook from the Storm Prediction Center
A level 3 risk of severe weather is in place for much of Central Texas, North Texas, and Northeast Texas. Georgetown, Waco, D/FW, Sherman, Paris, Texarkana, Tyler, and Fairfield are a few towns included. A level 2 risk – the standard risk level – includes East Texas, the Brazos Valley, South-Central Texas, and the Edwards Plateau. This outlook was issued by the Storm Prediction Center early this morning. The next outlook for Wednesday will be issued after midnight. Model trends have been to slow the system down, resulting in the dryline and associated severe weather risk beginning farther west. It is probable the risk levels will have to be expanded west in future updates.
Threats with Wednesday’s Storms
Very large to giant hail is expected with the strongest storms. Hail sizes approaching the size of a softball are possible. Not all storms will produce giant hail, but the atmosphere sure looks set to support really nasty hailers with the most intense supercells. A few tornadoes are possible and the risk for tornadoes will be monitored in the coming days as we get closer to Wednesday.
As usual, the highest corridor for any tornado threat will be from localized, mesoscale features that we simply can’t predict outside of 24-36 hours (sometimes even that is too far out). Tornadoes cannot be ruled out, but this also doesn’t look as favorable as this past Saturday.
Damaging straight-line winds are also a threat and could become a more widespread risk by Wednesday night as storms organize into a squall line. That squall line will move east late Wednesday night and into Thursday as a cold front pushes in. The level 2 risk of severe will likely continue eastward on Thursday).
Isolated to scattered thunderstorms will develop between 4 PM and 6 PM just east of a surface dryline – regardless of its west of Highway 281 or to the east. Those storms will quickly become severe and supercelluar. Very large to giant hail, localized damaging winds, and at least a low-end tornado threat are expected. Those discrete supercells may continue east/northeastward for several hours. Eventually, a line of thunderstorms is expected to form Wednesday evening. That line will move east Wednesday night and into Thursday across the eastern half of Texas. It’ll exit Texas to the east and continue producing severe weather all the way to the Atlantic seaboard. Damaging straight-line winds, hail, and brief tornadoes will be possible with that squall line.
What we know:
- Dewpoint values will be in the upper 60s to lower 70s across the eastern third of Texas, with mid-60s farther west along the dryline. Surface temperatures in the 80s to lower 90s will combine with that moisture to produce very high to extreme instability values.
- A strong upper-level storm system will help ‘lift’ or eliminate the cap by the late afternoon/early evening hours – allowing for thunderstorm development.
- That same upper-level storm system, combined with high moisture values, will allow the atmosphere to remain strongly unstable all night.
- The aforementioned extreme instability will allow for a very high threat of big hail – at least the size of baseballs, but probably larger, with the strongest storms.
What we don’t know:
- Low-level wind shear is somewhat uncertain. We may have a small weakness in the low-level wind profile that could help keep the tornado threat lower during the afternoon and early evening. If that weakness doesn’t develop we may see a slightly higher threat of tornadoes. Regardless, any discrete storms in place after 8 PM may have a higher threat of producing a few tornadoes as cloud bases lower and low-level wind shear increases (both a process that occurs near and after sunset)
- How far west will the dryline actually be by Wednesday afternoon? One model says the dryline may be in the western Big Country and into the eastern Texas Panhandle. Others are closer to Highway 281 in western North Texas south into the Hill Country. This is mainly applicable for the afternoon severe weather threat and will determine how far west that threat can develop. A line of storms will still move east Wednesday night into Thursday morning.
- The timeline for storms may need to be adjusted a few hours (either a bit earlier or a bit later). That’s to be expected when we’re still 2+ days away.
So yes, we’ll probably be dealing with a severe weather event on Wednesday. Some folks are going to see really big hail, some folks will have some wind damage, and we will probably be dealing with at least a low-end tornado threat. As usual, we’ll be able to become more specific on the timing, threats, and the highest threat corridors as we get closer. We’ll post the new severe weather outlook from the Storm Prediction Center early tomorrow morning once it is released.
SAFETY INFO: This is a great time to review your severe weather safety plan. Make sure your family knows how to get warnings, what to do and where to go if a dangerous storm is approaching, and a few items that should be handy. Click here for our full severe weather safety guide.