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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Saturday, March 25, 2023

SPC Mar 25, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Sat Mar 25 2023 Valid 251200Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE LOWER GREAT LAKES INTO THE MID-ATLANTIC STATES...AND FOR PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated severe thunderstorms are possible from the Lower Great Lakes into parts of the Mid-Atlantic states. A separate area of potential isolated severe thunderstorms will encompass parts of the Southeast. ...Synopsis... A potent mid-level trough over the middle MS Valley early this morning will move northeast and evolve into a closed mid-level low over the central Great Lakes by early evening. A belt of intense west-southwest mid-level flow will extend from the southern U.S. into the Mid-Atlantic states/Northeast. At the surface, a cyclone initially over northeast IN will develop north-northeast and deepen, reaching Lake Huron by late afternoon/early evening, and then subsequently weaken/occlude tonight. A surface front will sweep east across the OH Valley and into the Lower Great Lakes during the day, with the trailing portion of the boundary moving through a large part of the Southeast but stalling and becoming draped over the central Gulf Coast. ...Lower Great Lakes into the Mid-Atlantic states... In wake of some early day clouds, diurnal heating and a narrow plume of lower 50s F dewpoints ahead of the front over the upper OH Valley will act to weakly destabilize the boundary layer (200-400 J/kg MLCAPE). Strong large-scale forcing for ascent --due in part to strong, differential cyclonic vorticity advection-- will promote isolated to scattered thunderstorms from the lower Great Lakes to perhaps as far south as WV/VA/MD. Strong low-level shear profiles and cold mid-level temps may yield a low-topped supercell risk from eastern OH into western PA and perhaps western NY. Other strong to locally severe storms may develop during peak heating farther south/southeast and yield a marginal wind-damage threat. This activity will likely subside by early evening coincident with the loss of heating. ...Southeast... A band of showers/thunderstorms will likely be ongoing early this morning across parts of GA into the southern Appalachians. A lingering strong to locally severe risk may accompany this activity before weakening by late morning. Models show a reservoir of seasonably rich low-level moisture and relatively steep mid-level lapse rates across AL/GA into SC. Although much of the large-scale forcing for ascent will be displaced to the north of the region, neutral mid-level heights and the heating of a moist boundary layer becoming moderately unstable may favor isolated thunderstorms redeveloping during the afternoon. If residual morning convection re-intensifies or additional afternoon storms develop, the presence of strong deep-layer shear will favor storm organization and a severe risk. Models vary considerably on the placement/coverage of storms in this overall weakly forced setup. Nonetheless, at least an isolated risk for all hazards seems warranted. This potential storm activity will likely weaken by early evening. ..Smith/Weinman.. 03/25/2023 Read more CHECK UPDATE ZOOM GRAPHIC