SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0157 PM CST Fri Dec 04 2020 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NORTH CAROLINA... ...SUMMARY... A tornado or two and isolated severe wind gusts will be possible across eastern North Carolina, mainly from late evening into the overnight. Otherwise, a couple of strong wind gusts remain possible over a portion of the Florida Panhandle and southwest Georgia this afternoon. ...20Z Update... Only change this outlook update cycle was to shift low severe probabilities northward into southwest Georgia. A semi-organized band of showers/embedded thunderstorms has evolved and surface temperatures have warmed to near 70F with some low 60s F surface dewpoints, exceeding some earlier guidance in both regards. Reference Mesoscale Discussion 1832 for additional short-term details. ..Guyer.. 12/04/2020 .PREV DISCUSSION... /ISSUED 1028 AM CST Fri Dec 04 2020/ ...Eastern North Carolina... A vigorous shortwave trough situated across AR and western TN will transition to a negatively tilted wave as it continues through the southern Appalachians late this afternoon and into the Carolinas tonight. In response to the strong forcing for ascent attending this feature, a surface low will deepen as it moves from SC this evening to off the southeast VA coast late tonight. By mid evening this low will be situated near the central SC/NC border with trailing cold front extending southwestward through the central FL Panhandle. A warm front/coastal boundary should advance inland through a portion of eastern NC with dewpoints rising to around 60F in the warm sector contributing to weak instability with 500-1000 J/kg MLCAPE. Farther west across central NC, instability will remain meager (100-200 J/kg MUCAPE). However, given the strength of mesoscale forcing along the portion of the cold front near the surface low track, some potential will exist for a narrow line of low-topped convection to develop this evening. This activity will be embedded within a strong kinematic environment with 50 kt flow just above the surface, suggesting some of the convection could produce strong to damaging wind gusts. Farther east in the warm sector across eastern NC, greater instability and strong vertical shear profiles will support potential for a few supercells and bowing segments with an attendant threat for a couple of tornadoes and isolated damaging wind overnight. ...Florida Panhandle... As of late morning a warm front was situated near the coast of the FL Panhandle with a cold front moving through the western Panhandle into the central Gulf. As the small warm sector develops northward, weak instability with 400-800 J/kg MLCAPE will evolve inland. The convection currently developing along the warm conveyor belt may undergo some intensification this afternoon as the boundary layer destabilizes. Vertical wind profiles are supportive of a couple of rotating updrafts and bowing segments. The deeper forcing for ascent will remain north of this region which combined with the modest thermodynamic environment should remain limiting factors for a more robust severe threat.
There’s more click here.