SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Dec 10 2024 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE EASTERN NC VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible across many of the East Coast States. The most probable area for a few tornadoes and damaging winds is centered on eastern North Carolina during Wednesday afternoon. ...Synopsis... A longwave trough will extend from south-central Canada to the northern Gulf Coast on Wednesday morning. A vigorous shortwave impulse embedded within the basal portion of the trough will rapidly advance into the Mid-Atlantic States by early evening and pivot north to the St. Lawrence Valley Wednesday night. This will yield an increasingly negative tilt to the broad trough, with associated intensification of deep-layer flow fields and surface cyclogenesis. ...Eastern NC vicinity... A plume of mid 60s surface dew points are expected to advect north across parts of the eastern Carolinas into southeast VA by Wednesday afternoon. Boundary-layer destabilization should be tempered by preceding weak convection within the warm conveyor and pervasive cloudiness limiting insolation. Still, consensus of guidance suggests the relatively warmest surface temperatures should occur across eastern NC. Amid weak lapse rates, buoyancy should remain meager to around 500 J/kg along the coast. Even so, favorable timing of the synoptic evolution with respect to the diurnal heating cycle should yield a strongly forced convective line along the progressive cold front. Some guidance suggests a pre-frontal band of surface-based storms might separately develop in low-level confluence over coastal NC and the Outer Banks. At least a few embedded supercells are plausible, yielding a tornado and wind threat. The progressive nature of the front suggests the tornado threat may be more sporadic with shorter-lived circulations embedded in the line until it shifts offshore. ...Eastern Gulf/South Atlantic Coasts... Deep convection should be ongoing across parts of the FL Panhandle into south GA at 12Z Wednesday. Despite the time of day, the northern periphery of rich eastern Gulf moisture in conjunction with enhanced low-level hodograph curvature will support a localized tornado/wind threat through midday. Some potential may persist into the afternoon over parts of the north/central FL Peninsula but low-level winds will become more veered with time as the shortwave trough rapidly advances away from this region. The northern extent of the threat into GA/SC will be predicated on the degree of surface-based destabilization, which appears to be a relative min in the Southeast. ...Northeast... Primary thunderstorm activity should be in the form of sporadic lightning flashes amid scant elevated buoyancy within the low-level warm conveyor. Some CAM guidance does suggest a low-topped convective line may develop along the eastward-surging cold front during the afternoon/evening. Surface-based instability may remain negligible and lightning production appears unlikely. But with intensifying wind fields, potential remains for strong surface gusts capable of tree damage. ..Grams.. 12/10/2024