Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
993 ACUS02 KWNS 211722 SWODY2 SPC AC 211721 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast Friday. Severe storms are not expected. ...Synopsis... Amplified mid-level flow is likely over much of the CONUS Friday, with a deep upper low off the East Coast and a similarly deep trough off the West Coast. Between the two lows, a shortwave ridge will slowly migrate eastward over the central Plains. At the surface, a low and trailing cold front will steadily move offshore through the day over the East. High pressure and offshore flow are likely over the central CONUS. While along the West Coast, a pronounced low and onshore flow will continue. As the upper trough continues to shift eastward, cool and stable offshore flow should limit buoyancy and deep convection over the eastern 2/3rds of the CONUS. The only exception to this could be brief, low-topped storms near Cape Cod. A few deeper convective elements embedded within broad stratiform could produce sporadic lightning before stronger offshore flow shifts any lingering buoyancy completely offshore by midday. Across the Pacific Northwest, continuous onshore flow is likely as the cold core of the upper trough (-28 to -30 C 500 mb temps) moves onshore late in the day and overnight. Scattered low-topped convection will be most likely over the ocean overnight, but a few thunderstorms with sporadic lightning could move inland. With very weak MUCAPE (100-200 J/kg) any stronger updrafts will likely be brief. Strong deep-layer shear could briefly overlap with the buoyancy supporting a sporadic strong wind gust near the coast. However, the transient nature of the updrafts should keep the severe risk negligible. ..Lyons.. 11/21/2024 $$