SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook RESENT 2 NWS Storm Prediction Center Norman OK 0341 PM CST Tue Feb 18 2025 Valid 182000Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA... ...SUMMARY... Isolated severe thunderstorms remain possible this evening across parts of southeast Texas, shifting across southern Louisiana tonight. Hail should be the primary hazard, but a brief tornado and occasional severe gusts may occur along the immediate Louisiana Coast. ...20Z Update... The previous forecast remains on track. Low-level warm-air and moisture advection are already underway across coastal portions of TX and LA, as indicated by 19Z mesoanalysis. Current thinking is that the low-level warm-air/moisture advection will continue to increase and boost elevated CAPE to 1000 J/kg along the coast with the approach of a mid-level impulse currently situated over NM. Elevated thunderstorms should develop later this evening. Mainly hail is expected given elongated hodographs. However, if any supercellular structure can materialize along the southeast LA coast and become rooted in the boundary layer tonight, a damaging gust or tornado cannot be ruled out. ..Squitieri.. 02/18/2025 .PREV DISCUSSION... /ISSUED 1029 AM CST Tue Feb 18 2025/ ...Southeast Texas into Southern Louisiana... Water-vapor imagery this morning shows a shortwave trough moving into northern AZ from the Great Basin. This upper feature will move east-southeast during the period reaching northern LA/southern AR by daybreak Wednesday. Surface analysis this morning delineates an arctic cold front from the Concho Valley northeastward into north TX. This boundary will continue to surge south-southeastward to the TX coast tonight. A modifying airmass over the northwest Gulf Basin will aid in destabilization this afternoon/evening over southeast TX. Thunderstorms should eventually form by this evening across parts of southeast TX as large-scale ascent increases. Forecast soundings continue to indicate this thunderstorm activity will likely remain elevated with around 1000 J/kg MUCAPE. This activity will spread eastward across portions of southern LA late this evening and overnight while posing mainly an isolated hail threat. The surface-based thunderstorm probabilities are greatest near the south-central and southeast LA coast. However, low-level lapse rates in a deep/saturated environment will be modest, likely limiting tornado potential. Nonetheless, if a couple of storms can become near-surface based in the coastal parishes, a risk for severe gusts may accompany the stronger storms.