SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1008 AM CST Fri Dec 25 2020 Valid 251630Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms is negligible through early Saturday. ...Southwest OR and northwest CA... A shortwave trough will move inland across the Pacific Northwest this evening through tonight. Cooling mid-level temperatures and steepening low to mid-level lapse rates will support scant buoyancy west of the surface cold front. Scattered low-topped convection within this onshore flow regime may yield isolated lightning flashes after 00Z through tonight. Small hail is possible in the deeper updrafts with moderate speed shear in a nearly unidirectional southwesterly wind profile, which may result in effective bulk values approaching 30 kts. ...Southern ME... A narrow low-topped convective line recently weakened across eastern MA as low-level convergence has diminished along this leading cold front while focusing back west in eastern NY along a trailing frontal surge. Nevertheless, guidance still indicates scant elevated buoyancy from parcels rooted between 850-700 mb may persist within the warm conveyor region and yield a threat for very isolated lightning flashes through about 21Z. ..Grams.. 12/25/2020
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