Administrators NorthGeorgiaWX Posted August 2 Administrators Posted August 2 SPC 0600Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Fri Aug 02 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING ACROSS PARTS OF EASTERN GEORGIA...SOUTH CAROLINA...MUCH OF NORTH CAROLINA...CENTRAL AND EASTERN VIRGINIA/MARYLAND...DELAWARE...SOUTHEASTERN PENNSYLVANIA...NEW JERSEY...SOUTHEASTERN NEW YORK...SOUTHWESTERN CONNECTICUT...WESTERN LONG ISLAND...AND NORTHWESTERN WISCONSIN...MUCH OF CENTRAL/SOUTHERN MINNESOTA...EASTERN SOUTH DAKOTA AND ADJACENT SOUTHEASTERN NORTH DAKOTA... ...SUMMARY... Scattered strong thunderstorms accompanied by potentially damaging wind gusts may impact the Southeastern Piedmont and adjacent portions of the coastal plain into northern Mid Atlantic Saturday afternoon and evening. Other widely scattered strong to severe thunderstorms are possible across parts of the Upper Midwest into adjacent portions of the northern Great Plains late Saturday afternoon and evening. ...Synopsis... Models continue to indicate that mid-level flow across the northern mid-latitudes will undergo at least some amplification through this period. By Saturday night, this is forecast to include a building ridge across the northeastern Pacific through Alaska and adjacent portions of northwestern Canada. Downstream, flow across the Minnesota international border vicinity through the upper Great Lakes may trend broadly cyclonic, to the southwest of a significant deep-layer cyclone slowly progressing across the eastern shores of Hudson Bay into northern Quebec. In lower latitudes, a weak short wave perturbation may suppress ridging across the northern Intermountain Region. Otherwise, ridging appears likely to remain prominent across much of the West into the Great Plains, with an embedded high becoming centered over the Four Corners states. As downstream ridging across the subtropical western Atlantic builds northwestward toward the Mid Atlantic coast, troughing between the ridges is forecast to become increasingly sheared across the southern Appalachians through southern New England. At the same time, a tropical perturbation emerging from the Caribbean vicinity may begin impacting the Florida Straits and southern Florida Peninsula late Saturday into Saturday night. Beneath this regime, some lower/mid-tropospheric drying appears likely to continue spreading southward through the southeastern Great Plains and lower Mississippi Valley, with seasonably high moisture content (including a plume of precipitable water in excess of 2 inches) largely confined to the southeast of the southern Appalachians through the New England coast. However, lingering low-level moisture beneath an east-southeastward advecting plume of warm elevated-mixed layer air may contribute large potential instability ahead of a cold front advancing southward through the northern Great Plains and Upper Midwest. ...Mid/Southern Atlantic Seaboard... Although the approaching mid-level trough is forecast to become increasingly sheared and weaken, the height gradient between the troughing and the downstream building ridge may maintain modest south-southwesterly mid-level flow (on the order of 20-30 kt) to the lee of the Appalachians on Saturday. Beneath this regime, within the lee surface troughing, a moist boundary-layer including 70 F+ dew points appears likely to contribute to large CAPE in excess of 2000-3000 J/kg with daytime heating. Given weak mid-level inhibition, it appears that this will support considerable thunderstorm development, with strongest storms posing a risk for producing damaging wind gusts, aided by heavy precipitation loading and downward mixing of momentum. ...Northern Great Plains/Upper Midwest... Convective development appears likely to largely hinge on one or two subtle perturbations progressing through northwesterly flow near the base/southwestern flank of the large-scale mid-level troughing. Substantive spread exists among the various model output, including the convection allowing guidance. While it appears that thunderstorm development may remain isolated to widely scattered in coverage, shear beneath the northwesterly mid-level regime will be sufficient for supercells and one or two widely scattered upscale growing clusters with potential to produce strong wind gusts may not be out of the question Saturday evening. ...Florida... Beneath a warm mid-level environment, models (NAM in particular) suggest that precipitation preceding the developing tropical perturbation may stabilize the boundary layer across much of the interior peninsula Saturday through Saturday night. While trends will need to continue to be monitored, the risk for severe weather through this period currently appears low. ..Kerr.. 08/02/2024 Read more View the full article Quote
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