Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
169 ACUS03 KWNS 240730 SWODY3 SPC AC 240729 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA INTO NORTHERN NJ AND SOUTHEAST NY... ...SUMMARY... Scattered damaging winds are possible over parts of the Northeast and northern Mid Atlantic on Wednesday. ...Upper Ohio Valley into the Northeast/Mid Atlantic... A mid/upper-level shortwave trough is forecast to move from the upper Midwest toward the lower Great Lakes and Northeast on Wednesday. Rather moist low-level westerly flow will support potential for moderate diurnal destabilization from OH into parts of the Northeast and northern Mid Atlantic. Scattered thunderstorm development will be possible Wednesday afternoon along/ahead of a cold front across parts of OH/PA and southern NY, which will spread eastward into the evening. Strengthening flow in the 700-500 mb layer will support sufficient effective shear for storm organization, with potential for a few organized clusters and perhaps a couple of supercells. Damaging wind and perhaps isolated hail will be possible, along with some potential for a brief tornado if a supercell can be sustained. A Slight Risk has been added for parts of PA into southeast NY and northern NJ, where the most favorable overlap of instability, storm coverage, and strengthening low/midlevel flow is currently anticipated. Diurnal storm coverage becomes increasingly uncertain with southward extent, but at least an isolated severe threat could extend into parts of the Mid Atlantic during the late afternoon and evening. ...Lower Ohio Valley into the Ozarks vicinity... Uncertainty regarding storm potential and evolution is quite high from the lower Ohio Valley vicinity into the Ozarks. There is some potential for an MCS (or its remnant) to be ongoing at the start of the period. An outflow-influenced front will be draped somewhere across the region through the day, to the south of a reinforcing cold front that will move southward from the upper Midwest. Northwesterly mid/upper-level flow will be in place across the region, though the strength of the flow and any embedded shortwave troughs may also be influenced by antecedent convection and potential development of any MCVs. Some redevelopment of storms will be possible near the front and any remaining outflow boundaries. The northwesterly flow regime may provide sufficient effective shear for some storm organization, with one or more clusters possible with a threat of damaging wind and perhaps some hail. ...Southeast WY/northeast CO into central High Plains... Moist low-level southeasterly flow is expected on Wednesday from eastern CO/WY into the NE Panhandle, in the wake of a cold frontal passage. Moderate destabilization will be possible during the afternoon within this regime. While the region will initially be under the influence of an upper-level ridge over the southern Rockies, guidance suggests potential for a low-amplitude shortwave trough to crest the ridge from WY into western NY. This will support potential for at least isolated thunderstorm development. Midlevel flow may remain rather modest, but sufficient veering with height will support sufficient effective shear for storm organization, including some supercell potential with a threat of large hail and localized severe gusts. A strengthening nocturnal low-level jet could support some upscale growth, which could spread at least isolated severe-gust potential into parts of southwest NE and western KS. ..Dean.. 06/24/2024 $$