SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1017 AM CST Wed Dec 03 2025 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER TX GULF COAST INTO FAR SOUTHWEST LOUISIANA... ...SUMMARY... Thunderstorms will be possible this evening into tonight across the western Gulf Coast states. Severe storms are not expected. ...Synopsis... A mid-level wave traversing the Four Corners region as of mid-morning is forecast to move eastward into the southern Plains through early Thursday morning. West/southwesterly mid-level flow will steadily increase to around 50-60 knots as the wave approaches, which will help advect a plume of modestly steep (7 to 7.5 C/km) lapse rates out of northern Mexico towards the TX/LA Gulf Coast region through tonight. At the surface, a weak surface low noted off the south TX coast will gradually intensify and lift northward towards the LA coast as broad-scale ascent ahead of the upper wave increases later tonight. The combination of increasing ascent and steepening lapse rates will support isolated to scattered thunderstorms tonight into early Thursday morning for much of the TX Coastal Plain and central to southern LA. ...Upper TX Gulf Coast to far southwest LA... Isolated to scattered thunderstorms are expected to develop along the upper TX Gulf Coast around 02-04 UTC tonight as warm advection atop a residual frontal boundary increases. Forecast consensus is that the surface low will remain off the coast through the forecast period, which will limit the potential for surface-based convection. However, strong moistening/ascent within the 925-850 mb layer will likely support a narrow swath of deep convection along the TX coast where MUCAPE may exceed 1000 J/kg. Within this zone, buoyancy profiles should be deep enough to realize the favorable kinematic environment, which will be characterized by elongated hodographs and effective shear of around 50 knots. Destructive storm interactions/modes will likely modulate the overall longevity of any particular cell, but the sufficient thermodynamic/kinematic environment may support a few brief strong/severe storms capable of small to severe hail. ..Moore.. 12/03/2025
