Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
607 ACUS03 KWNS 120729 SWODY3 SPC AC 120729 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Wed Jun 12 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND NORTHEAST... ...SUMMARY... Scattered severe storms with large hail and severe wind gusts will be possible from Friday afternoon into the overnight period across parts of the central Plains. Thunderstorms associated with severe wind gusts will also be possible in parts of the Northeast. ...Central Plains... An upper-level ridge is forecast to move eastward into the central and northern Plains on Friday. Behind the ridge, a northwest-to-southeast corridor of moderate instability will likely be in place by afternoon. Model forecasts are in good agreement that scattered thunderstorms will develop Friday afternoon to the west of the ridge axis from far northeast Colorado and far northern Kansas into central Nebraska. These storms are forecast to move east-northeastward across Nebraska and could impact southeastern South Dakota during the late evening or overnight period. MCS development will be possible across parts of the central Plains. Strong instability appears likely to develop by afternoon from northern Kansas into western Nebraska, where model consensus has MLCAPE peaking in the 3000 to 4000 J/kg range. Forecast soundings near the instability axis for North Platte, NE at 00Z/Saturday have substantial amount of directional shear in the low-levels, with 0-6 km shear near 50 knots. This should support severe storm development during the late afternoon. Supercells with isolated large hail will be possible. However, temperatures near 700 mb are very warm, and generally above 12C. This could temper the hail threat some. Severe wind gusts will also be possible, especially if an cluster can organize, or if a linear MCS can develop during the evening. ...Northeast... An upper-level trough is forecast to move eastward into the Northeast on Friday, as a cold front moves southeastward across the region. Surface dewpoints ahead of the front are forecast to be in the mid 60s F, which will result in a narrow corridor of instability in the central and northern Appalachians. As surface temperatures warm, thunderstorms will likely form in the higher terrain around midday, with several small clusters moving eastward into the lower elevations during the afternoon. There is some disagreement concerning how much instability will develop across the northeast on Friday. More aggressive solutions suggest that moderate instability could be in place ahead of the front by mid afternoon. Forecast soundings that show moderate instability, have veered winds and steep lapse rates at low-levels, and moderate to strong deep-layer shear. These soundings would support a severe threat with either large hail or wind damage possible. The severe threat would be concentrated near and after peak heating as instability maximizes during the late afternoon. ..Broyles.. 06/12/2024 $$