SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 PM CST Wed Dec 30 2020 Valid 310100Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE TEXAS COASTAL PLAIN... ...SUMMARY... A few locally strong wind gusts, some hail and a brief tornado remain possible along a portion of the Texas Coastal Plain tonight. ...Texas Coastal Plain... This evening a slow-moving cold front extends from northern LA into the TX Coastal Plain. A moist boundary layer with mid to upper 60s F dewpoints has advected inland through the pre-frontal warm sector with 00Z RAOB data and objective analysis indicating MLCAPE from 800 to 1000 J/kg. A pronounced mid-level inversion (near 700 mb) was indicated on the 00Z CRP RAOB data. So far most surface-based storms have been developing along a pre-frontal convergence band extending from the western Gulf into the central TX coastal area near Palacios. Hodograph size in the 0-2 km layer remains modest with 150-200 m2/s2 storm relative helicity. Weak to modest winds are evident between 850 and 700 mb. However, effective bulk shear from 35-45 kt is sufficient for some updrafts to develop weak rotation. A somewhat greater chance for a couple of organized storms is expected later tonight as deep forcing for ascent attending the vigorous shortwave trough over northern Mexico intercepts the warm sector across the southern and central TX coastal regions. Low-mid level wind speeds and vertical shear will also undergo some increase with the approach of the shortwave trough. Some erosion of the mid-level inversion is also expected, and additional storms will likely develop along and just ahead of the southward-advancing cold front. A few organized storms including a couple of supercells are possible as the environment becomes more favorable. However, the warm sector will diminish in size as the cold front approaches the coast. Tendency will be for more robust updrafts to be undercut by this boundary which should provide a limiting factor for a more widespread/robust severe threat. ..Dial.. 12/31/2020
There’s more click here.