SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Aug 03 2023 Valid 031200Z - 041200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF NORTHEAST CO...SOUTHWEST NE...NORTHWEST KS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM MIDDLE TN INTO NORTH AL/NORTHWEST GA...AND ALSO ACROSS PARTS OF NORTHERN NY... ...SUMMARY... Scattered severe thunderstorms are possible over the central High Plains this afternoon and evening, with gusts in the 60-80 mph range possible. Storms capable of damaging gusts will also be possible across parts of the Tennessee Valley, Southeast, and upper Great Lakes region. ...Central High Plains vicinity... A mid/upper-level trough will move from the Intermountain West into parts of the central/northern Plains later today. As this occurs, moderate midlevel westerly flow will overspread moist low-level easterly flow over portions of the central High Plains. This will result in a favorably sheared and moderately unstable environment by late afternoon. Supercells will be possible with initial scattered thunderstorm development, with an attendant threat of hail and isolated severe gusts. Evolution into an outflow-driven storm cluster is expected by early/mid evening, which could result in an increasing risk of 60-80 mph gusts spreading eastward with time. The greatest threat for an organized, severe-wind producing cluster still appears to be from northeast CO into southwest NE and northwest KS, where an Enhanced Risk is maintained with this outlook. ...Parts of the TN Valley/Southeast... A well-organized MCS that is ongoing early this morning near the lower OH Valley is expected to move southeastward into parts of the TN Valley and Southeast later today. Uncertainty remains regarding the severity of this MCS with time, but some damaging-wind risk may persist into parts of middle TN and northern AL/GA through the morning. Additional development will be possible this afternoon near and to the cool side of the remnant outflow, possibly aided by a convectively enhanced midlevel shortwave trough that will move through the region this afternoon and evening. Low/midlevel flow will be sufficient to support at least a localized damaging-wind risk with any redevelopment during the afternoon/evening, though the bulk of convection may remain somewhat elevated to the cool side of the outflow boundary. ...Parts of lower MI into NY... A seasonably deep upper trough will move across parts of Ontario/Quebec today, with the southern extension of this trough impinging upon a rather moist environment from parts of MI into the upper Great Lakes region. There remains some uncertainty regarding the potential for early convection to disrupt destabilization across parts of NY/VT, but in general, MLCAPE of 1000-1500 J/kg (locally greater) is expected by late afternoon from lower MI into the upper Great Lakes region, as effective shear increases into the 30-40 kt range. Storm coverage may be relatively isolated through the afternoon, but an organized cluster that initially develops across eastern Ontario may move into northern NY by early evening, with a threat of damaging gusts and perhaps isolated hail. Isolated storm development will also be possible as far west as eastern lower MI, where a conditional risk for hail and damaging gusts will be present with any sustained storms during the afternoon and evening. ...Eastern KS into western MO... While a relative minimum in storm coverage is possible from eastern KS into western MO, some CAM guidance suggests that storms may develop in association with an MCV sometime during the afternoon or early evening, which would pose a conditional hail/wind risk. The organized cluster that is forecast to develop across the central High Plains may also propagate as far as eastern KS by early Friday morning, with an isolated severe-wind threat. ..Dean/Bentley.. 08/03/2023
