SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0632 AM CST Mon Dec 21 2020 Valid 211300Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...Synopsis/Discussion... A progressive upper-air pattern will continue this period, with ridging shifting eastward from the Great Basin/inland Pacific Northwest, across the central/northern Rockies to the Great Plains. A well-defined trough -- initially located from southern WV across GA to the northeastern Gulf -- will eject offshore from the Atlantic Coast, while a stronger perturbation now over the upper Mississippi Valley region amplifies and digs southeastward. A broad area of cyclonic flow around a synoptic-scale trough should result over the coastal Mid-Atlantic and New England by the end of the period. At the surface, a cold front -- initially drawn from the Atlantic across central/southwestern FL Peninsula to the eastern Gulf -- will proceed southeastward past the peninsula by 00Z. Isolated thunder may occur the next few hours in the prefrontal belt of precip and embedded convection, before the regime weakens amidst lessening low-level convergence, and shifts southeastward out of the area. Weakening deep shear and modest lapse rates/buoyancy should preclude a severe threat. Elsewhere over the CONUS, the air mass will be to dry and/or stable for thunderstorms. ..Edwards.. 12/21/2020
There’s more click here.