Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
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034 ACUS01 KWNS 230105 SWODY1 SPC AC 230103 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0803 PM CDT Sat Jun 22 2024 Valid 230100Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST AND WESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible through this evening across parts of the Midwest, mainly posing a risk of damaging winds and a few tornadoes. Isolated damaging winds are possible over southern New England. ...01z Update Midwest... The primary severe risk through the next several hours across the upper Midwest remains with the cluster of supercells ongoing over southern WI. Strong low-level shear along the modified differential heating zone will continue to support the potential for a few tornadoes, especially with any supercells that are able to remain relatively discrete. Otherwise, ongoing upscale growth is expected to continue and one or more clusters/line segments appears likely to emerge and track southeast across the remainder of southeastern WI and northern IL. Damaging wind gusts and a couple of QLCS tornadoes appear likely into this evening. To the southwest of the WI cluster, additional storm development over central/southern IA, northern MO, and western IL has thus far been slow to organize along a weak cold front. Likely due to poor mid-level lapse rates, convection has slowly increased in coverage and intensity, and may continue to do so, as the front accelerates and outflow consolidates. Given relatively strong mid-level shear profiles (effective shear 40-45 kt) and sufficient buoyancy, one or more clusters of strong to severe storms may evolve and continue through this evening. Damaging gusts appear to be the most likely threat, though some hail and a brief tornado will remain possible. ...Southern New England... A cluster of severe storms has persisted across parts of upstate NY and eastern PA this evening ahead of broad troughing over the Great Lakes and southern Ontario. While buoyancy is expected to continue decreasing with nocturnal stabilization, a few of these storms may persist for a few more hours this evening. Increasing mid-level shear ahead of the consolidating shortwave trough farther west will support organized mutlicells or transient supercells capable of occasional damaging gusts and isolated hail. Additional, likely elevated, storms may develop overnight as low-level warm advection increases over portions of northern New England. ...Dakotas... Very isolated thunderstorms have developed within the post-frontal regime in the wake of the consolidating Great Lakes trough across the Dakotas. While buoyancy remains modest, relatively strong wind profiles suggest a storm or two may remain strong enough to produce isolated hail or damaging gusts into this evening. Have modified the existing MRGL to capture the remaining environment more conducive for hail and wind potential. A summary of remaining changes follows; MRGL was removed across portions of southwest FL and the Four Corners. Storms have decreased in coverage and waning buoyancy suggests the risk for a sustained severe threat is low. An occasional stronger storm may persist in southern CO for another hour or two, but the severe risk should continue to decrease near and after dark. ..Lyons.. 06/23/2024 $$