SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 AM CST Tue Dec 24 2024 Valid 241300Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL...EAST...AND SOUTHEAST TEXAS... ...SUMMARY... Isolated to widely scattered strong to severe thunderstorms capable of large hail and damaging gusts are possible late this afternoon into the overnight. ...Central and eastern TX... Water-vapor imagery early this morning shows an upper trough digging southeastward over the southern High Plains. This upper feature is expected to reach eastern TX and the western Gulf of Mexico by early Wednesday morning. In the low levels, morning analysis indicates an inverted trough extending from central TX northeastward into the Arklatex. A cold front over north TX extending southwestward into west-central TX will gradually move southeastward during the period and become a focus for showers/storms. Southeasterly low-level flow ahead of the front will maintain an adequately moist fetch from the western Gulf (upper 50s to lower 60s dewpoints). Some heating during the day and mid-level cold-air advection will likely yield moderate destabilization (750-1500 J/kg MLCAPE) from near I-20 in northeast TX southwestward into the TX Triangle. The relatively cold mid levels will promote hail growth with the stronger updrafts that maintain a cellular mode, but a transition to linear is expected given the frontal forcing and modest high-level flow promoting updraft seeding from adjacent storm activity by early evening. A locally higher risk for large hail may ultimately focus near the I-35 corridor from San Antonio northward through Waco. A gradual emphasis towards damaging wind potential is expected during the evening/overnight as storm coverage increases coincident with a more pervasive linear mode. Elsewhere, a progressive and powerful upper trough will move from the eastern Pacific and into the UT/AZ vicinity by late tonight. Isolated low-topped thunderstorms may occur in association with cold mid-level temperatures overspreading CA into the southern Great Basin. Scant instability will tend to limit storm vigor and overall coverage of thunderstorm activity. ..Smith/Grams.. 12/24/2024