SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Wed Apr 03 2024 Valid 032000Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC/CHESAPEAKE BAY REGION...AND CENTRAL PORTIONS OF THE FLORIDA PENINSULA... ...SUMMARY... Storms capable of producing a couple of tornadoes and damaging gusts will continue this afternoon across eastern Virginia and vicinity, and across central Florida. ...Discussion... Current outlook areas and reasoning remain valid for the remainder of the afternoon, thus not requiring any major changes for this update. The only adjustments have been to tweak areal delineations to reflect current convective evolution, and to remove the 5% tornado probability across Florida (reducing the probability to 2%, for ongoing convection). ..Goss.. 04/03/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Wed Apr 03 2024/ ...Eastern VA/northern NC area this afternoon... A deep midlevel low near southern Lake MI will drift southeastward through early Thursday, while embedded speed maxima rotate northeastward through the southeastern periphery of the midlevel low (GA/north FL to VA). Secondary surface cyclogenesis is expected along a baroclinic zone across VA today, and this cyclone will move just off the Mid-Atlantic coast by early tonight. Along and southeast of the cyclone track, a moistening warm sector is expected from NC into VA, where destabilization will become sufficient for additional thunderstorm development by midday. The warm sector will be characterized very strong deep-layer shear/long hodographs, and sufficient low-level curvature/SRH for right-moving supercells capable of producing a couple of tornadoes, damaging gusts of 60-70 mph, and isolated large hail of 1-1.5 inches in diameter this afternoon. ...North/central FL this afternoon... A pre-frontal band of thunderstorms will continue to spread southeastward through the afternoon from north toward central FL. 50+ kt midlevel flow will be maintained through the afternoon as the warm sector gradually destabilizes as temperatures warm into the upper 70s/lower 80s with boundary-layer dewpoints near 70 F. This will maintain the storms through the afternoon, with the potential for a few damaging gusts of 60-70 mph with embedded line segments, and potentially a couple of tornadoes with embedded circulations and/or supercells that form just ahead of the main line of storms. Storm intensity is expected to wane by this evening/tonight as the storms move from central toward south FL. ...Southeast OR/ID this afternoon/evening... A midlevel trough will continue to amplify/dig southward near the Pacific Northwest coast. East of the trough, a gradual increase in midlevel flow from the southwest is expected through this evening, as well as a gradual increase in ascent along the deep-layer baroclinic zone from eastern OR into ID. Surface heating/mixing and modest low-midlevel moisture will contribute to inverted-V profiles with weak buoyancy along the baroclinic zone, and sufficient deep-layer vertical shear for some organized storms. The net result should be a few cells/small clusters capable of producing isolated strong-severe outflow gusts (50-60 mph) and marginally severe hail (0.75-1 inch diameter hail) for a few hours later this afternoon/evening.
