SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0644 AM CST Thu Dec 25 2025 Valid 251300Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE CALIFORNIA COAST AND PORTIONS OF THE CENTRAL VALLEY... ...SUMMARY... An isolated risk for severe gusts and localized wind damage, and perhaps a brief tornado will be possible today along much of the California Coast and portions of the Central Valley. ... California ... Water-vapor imagery early this morning shows a mid-level low over the eastern Pacific and a negative-tilt shortwave trough moving northward along the northern CA and OR coast. An upstream mid-level speed max and associated vorticity max will move cyclonically through the base of the eastern Pacific low/trough and approach San Francisco Bay and northern CA this evening and subsequently move into eastern OR by early Friday morning. Strong to locally severe thunderstorms mainly capable of a severe-wind hazard will potentially continue on an isolated basis this morning from the Central Valley/central coast and perhaps include portions of southern CA. The low CAPE/high shear environment will potentially support strong/locally severe convection contingent on sufficient updraft development. Forecast low-level hodographs will remain sufficiently enlarged to yield a low risk for a brief tornado across much of the Marginal Risk (level 1 of 5) area. By this afternoon, model guidance indicates low-level flow will weaken before re-intensifying towards evening in association with the arrival of the next speed max. A mix of linear bands and cellular convective structures may continue to pose an intermittent risk for isolated damaging gusts and perhaps a brief tornado into tonight. ..Smith/Weinman.. 12/25/2025
