November 21, 2024 2000 UTC Day 1 Convective Outlook Updated: Thursday, November 21, 2024 19:44:17 UTC (Print version | | ) Stochastic to Categorical Outlook Conversion Table SPC AC 211944 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0144 PM CST Effective Thursday, November 21, 2024 212000Z – 221200Z …No severe thunderstorm areas forecast… …SUMMARY… No severe thunderstorms are expected into tonight. …Synopsis… A line of convective rain/show showers continues across the Appalachians, with occasional flashes of lightning. This condition will continue for several more hours and weaken in the late afternoon as the boundary layer cools and the low-level lapse rate weakens. Lightning is expected to remain offshore near the New England coast and near the northwest coast of the Pacific Ocean, so lightning lines have been removed from both areas. ..Bentley.. 11/21/2024 .PREV DISCUSSION… /ISSUED 1029 AM CST Thu Nov 21 2024/ …Synopsis… A deep mid-level cyclone characterized by a temperature of 500MB near -32℃ throughout this period, from the Great Lakes to the Mid-Atlantic. These colder mid-level temperatures and the associated elevation loss associated with the mid-level low will likely produce isolated lightning flashes buried in showers across the central Appalachians this afternoon. Along the southern New England coast, low-level warm advection north of an associated occluded surface low will also support isolated thunderstorms given the weak altitude instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible in the immediate coastal areas of Washington state. There, the uplifting forces in the jet stream’s left exit region overlap with moisture and weak instabilities in the deep troposphere. Click to Get WUUS01 PTSDY1 Product Note: Next 1 day outlook is scheduled for 0100Z. Top/Latest 2nd Day Outlook/Today’s Outlook/Forecast Products/Home
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