Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
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620 ACUS01 KWNS 201614 SWODY1 SPC AC 201612 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Thu Jun 20 2024 Valid 201630Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains. ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. ..Hart/Lyons/Halbert.. 06/20/2024 $$