SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 PM CDT Mon Oct 02 2023 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered severe storms should be most likely Tuesday from parts of west Texas into Nebraska. Large hail (some 2-3 inches), severe wind gusts, and a couple of tornadoes all appear possible. ...Synopsis... An upper trough will advance eastward across the Rockies and the adjacent Plains on Tuesday, with upper ridging persisting over much of the MS Valley and eastern states. The primary surface low is forecast to be located over the Dakotas at the start of the period Tuesday morning. It should develop northeastward through the day into central Canada, with an attendant cold front expected to advance east-southeastward over the northern/central Plains through Tuesday night. A weak secondary surface low should develop over western KS and shift northeastward towards south-central NE by Tuesday evening. A surface dryline should extend southward from this low across parts of the central/southern High Plains. ...Plains... At least isolated showers and thunderstorms may be ongoing Tuesday morning in a low-level warm advection regime. This activity is expected to remain generally sub-severe and weaken through the morning. In the wake of these thunderstorms, a narrow corridor of greater low-level moisture should exist along/east of the dryline and cold front. Surface dewpoints generally in the low to mid 60s appear most probable from parts of south-central NE southward into the southern Plains. Most guidance suggests that moderate to locally strong instability, with MLCAPE around 2000-2500 J/kg, will develop in tandem with daytime heating along/south of the front and east of the dryline. There is still some uncertainty in model guidance regarding the location of these surface features by late Tuesday afternoon, especially the eastward extent of the dryline across the southern/central Plains. Forcing for ascent associated with the upper trough and attendant 40-55 kt mid-level jet will likely encourage robust convective development by early Tuesday afternoon across western into northern KS and south-central NE. Deep-layer shear of 40-50 kt will easily support supercell structures initially with a threat for very large hail given favorable shear, steep mid-level lapse rates, and moderate to strong buoyancy. Some potential for a couple of tornadoes may also exist with this initially discrete development, as low-level shear appears favorable for updraft rotation. But, upscale growth along/near the cold front suggests the severe risk will probably transition to more of wind threat with time as thunderstorm clusters move quickly northeastward across central/eastern NE and vicinity. The potential for supercells with southward extent along the length of the dryline into the eastern OK/TX Panhandles, west TX, and western OK is less clear. Still, have maintained a Slight Risk across this area given a conditionally favorable environment. ..Gleason.. 10/02/2023
