SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Wed Nov 05 2025 Valid 051300Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST AND OREGON/NORTHERN CALIFORNIA COASTS... ...SUMMARY... Isolated severe thunderstorms are possible through the day along the western Oregon and far northern California coastal region. Strong, potentially damaging wind gusts may accompany the stronger showers or low-topped thunderstorms that develop over parts of the Northeast. ...Northeast/southern New England... A trough will steadily amplify southeastward today over the Great Lakes and Ontario/Quebec, reaching coastal New England tonight. A considerably strengthening deep-layer wind field will accompany this trough, accentuated by 80+ kt mid-level winds late today. A surface low will steady deepen (approaching 1 mb/hr tonight) as it races eastward across the lower Great Lakes toward coastal New England tonight in tandem with a cold front. Near-frontal/warm sector moisture will be meager, and surface-based buoyancy will also be limited. Even so, modest diurnal heating/destabilization could influence somewhat more stout low-topped convection into late afternoon, and sustain into the evening given the magnitude of the forcing for ascent/large-scale mass response. Around 40-60 kt of west-southwesterly flow within the lowest 1-2 km AGL will be present from roughly central Pennsylvania to southern New England. As such, any stronger showers (or perhaps short-lived low-topped thunderstorms) that can develop may encourage sufficient downward momentum transport for a few strong, potentially damaging wind gusts during the afternoon and evening. ...Northern California and Oregon Coasts... As the mid-level trough overspreads the northern California/Oregon coast this morning and a cold front moves inland, cooler temperatures aloft will foster steep mid-level lapse rates atop a maritime airmass, resulting in a couple hundred J/kg MLCAPE. Through the afternoon, rapidly strengthening winds with height will be in place, resulting in enlarged but mostly straight/elongated hodographs. Any thunderstorms that manage to develop will be capable of isolated strong to severe wind gusts. Forecast soundings do show some low-level curvature closer to the coast, with 150-250 m2/s2 effective SRH. As such, if a sustained, land-falling low-topped supercell can develop, a brief tornado could occur. ..Guyer/Kerr.. 11/05/2025
