11PM Day 1 Convective Outlook for Friday, January 23. NO SEVERE THUNDERSTORM AREAS FORECAST
SUMMARY
Scattered weak thunderstorm activity is likely today into tonight across the Texas Big Bend region into central Texas.
Synopsis
Late-evening water-vapor imagery depicts increasing ascent across northern Mexico into the Southwest/Big Bend region of TX as an upper low off the southern CA coast begins to slowly shift east. At the surface, a cold front continues to push south across the Plains with modest moisture return ongoing along the TX Coastal Plain. Precipitation is expected to slowly increase from the Big Bend region northeastward into the southern Plains/Ozark Plateau through the day as isentropic ascent strengthens across central TX. Isolated to scattered thunderstorm development is anticipated along and north of the cold front as it impinges on a plume of returning moisture.
Big Bend Region to Central Texas
Moisture return of mid 50s to low 60s dewpoints along and south of the I-10 corridor and into the Big Bend region is expected by evening and should support a swath of 500-1000 J/kg MLCAPE. Scattered thunderstorm development is expected along the front across the Edwards Plateau by early evening, spreading east as the front pushes further into the unstable air mass. While a few storms may initially be surface-based, northeastward storm motions will quickly displace any deep convection onto the cool side of the boundary. Wind profiles are expected to strengthen through the day in response to the approaching upper wave, and could support effective shear values on the order of 40 knots. Despite this, a combination of modest buoyancy profiles (lifted indices generally -2 to -3 C), rapid undercutting by the front, and a propensity for storm interactions/upscale growth should largely mitigate the potential for severe convection.
A few CAM solutions, notably the 00z HRRR, hint at the potential for upscale growth of a surface-based convective cluster as it propagates eastward along the front with an attendant threat for damaging winds. While plausible given the aforementioned CAPE/shear parameter space, the lack of supporting signal in other CAM solutions and ensemble/calibrated guidance, along with unfavorable phasing with the diurnal cycle, suggest that this is a relatively low probability scenario.