Severe Weather Returns & Threatens South Midweek

Severe Weather Returns & Threatens South Midweek

There is a slight risk of severe thunderstorms from parts of central Texas in the evening and into southeast Texas overnight Wednesday (12/26/2018)

Scattered severe thunderstorms are possible Wednesday over portions of central Texas during the evening and moving into southeast Texas overnight.

(Additional: Winter Storm Eboni Taking Aim; Midwest Possible Blizzard Conditions )


Categorical Outlook

Post Christmas Severe Weather

Probability of Severe Weather


Simulated Products

Supercell Composite 

Significant Tornado

Simulated RADAR Reflectivity 

 

…TX Panhandle/far western OK into northwest TX…

A seemingly conditional risk for severe thunderstorms will probably unfold beginning by the early-mid afternoon through the evening over this region. Strong low-level moisture transport will occur to the southeast of a deepening surface low, in a warm sector with an increasingly narrow moist/unstable airmass with northwest extent, from western north-central TX northwestward into the eastern TX Panhandle. Despite boundary-layer dewpoints only in the mid to upper 50s, very cool 500mb temperatures (-17 to -18 degrees C) may yield SBCAPE in the 250-750 J/kg range. However, strong DCVA (and 120m/12hr 500mb height falls over the South Plains between 12z-00z) may promote an early convective initiation (CI) during the morning over West TX. The early CI scenario is possible and would have deleterious effects on the development of buoyancy. As it stands currently, a marginal risk for severe gusts and perhaps a tornado seem to be a sufficient highlight. But…if the early CI scenario does not occur and a brief window (1-2 hour) of cloud breaks and heating can occur, a greater risk for supercells with an attendant tornado/wind risk would develop.

…Central into eastern TX…

A moist airmass, characterized by lower to middle 60s degree F dewpoints, will gradually destabilize during the day as stronger deep-layer forcing for ascent remains to the west and northwest of the region. Strong south-southeasterly low-level winds veering to the southwest in the mid levels will result in a wind profile supporting thunderstorm organization. By the late afternoon/early evening, thunderstorms are forecast to develop over the Concho Valley with thunderstorm coverage expected to increase as this activity moves into richer low-level moisture near I-35. Severe gusts and the possibility for a few tornadoes may accompany a band of thunderstorms as it grows upscale and moves east reaching the Upper Coast of TX during the midnight-6am CST period. Farther north over northeast TX, weaker instability may result in a lower risk for wind damage as thunderstorms move through the area overnight.

…Further Details…

A lower-latitude, mid-level shortwave trough will eject east into the central-southern High Plains from the southern Rockies with a closed mid-level circulation evolving Wednesday night over southwest KS. A broad belt of strong, cyclonic mid-level flow will overspread a destabilizing moist sector located over TX/OK. In the low levels, a surface cyclone will develop northeastward from the TX/NM border across the TX/OK Panhandles and into north-central KS by early Thursday morning. A north-south dryline is forecast from the eastern TX Panhandle into southwest TX and a Pacific cold front will overtake the aforementioned boundary and accelerate east across much of central TX late.

 

Stay Weather Alert and Weather Aware!