SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 AM CST Fri Dec 11 2020 Valid 111300Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS EAST TX...FAR SOUTHEAST OK...SOUTHWEST TO CENTRAL AR...WESTERN LA... ...SUMMARY... Very isolated damaging winds are possible across a portion of the South-Central States mainly this evening, with a brief tornado also possible in southeast Texas. ...South-Central States... Primary changes this outlook are to reduce the spatial extent of the Marginal Risk, as well as add low tornado probabilities over southeast TX. Overall severe weather setup will be constrained by weak to moderate mid-level lapse rates and marginal boundary-layer moisture. Modified boundary-layer moisture return from the western Gulf should yield mid 50s dew points as far north as eastern OK to central AR with mid 60s dew points remaining confined close to the coast. Ongoing belt of elevated showers supported by 700-mb warm theta-e advection from the Ozark to the Edwards Plateau should shift east through the day. In the wake of this swath during the late afternoon to early evening, renewed convective development may occur along the surface front near the southeast OK/northeast TX border and farther south in southeast TX within pre-frontal confluence. These corridors will be supported by more favorable mid-level lapse rates which should yield a plume of weak MLCAPE around 250-750 J/kg across east TX. Deep-layer shear will be sufficient for organized convection which may include the development of one or more clusters/line segments that would likely become rooted atop near-neutral boundary-layer lapse rates with eastern extent in AR/LA. Enlarged low-level hodographs may have narrow spatial overlap with weak surface-based buoyancy across southeast TX and yield a couple transient supercell structures with low probability of a brief tornado. Otherwise, a few strong gusts capable of very isolated damaging winds appear possible. ..Grams/Goss.. 12/11/2020
There’s more click here.