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000 ACUS01 KWNS 191944 SWODY1 SPC AC 191943 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0243 PM CDT Mon Apr 19 2021 Valid 192000Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL FLORIDA PENINSULA... ...SUMMARY... Isolated severe thunderstorms remain possible through early tomorrow morning across parts of the central and southern Florida Peninsula. ...20Z Update... Minor changes have been made to the Day 1 Outlook. The northeast extent of the Marginal across the central FL Peninsula was trimmed, and severe probabilities across the Mid Atlantic were removed given convective overturning of earlier storms. Thunder probabilities were also removed from the Hudson Valley into New England as relatively shallower convection, driven by boundary-layer mixing, has struggled to support lightning flashes during peak heating. Otherwise, the rest of the forecast remains on track, with a gradual increase in thunderstorms and corresponding risk of severe hail, a damaging gust, or brief tornado expected across the west-central FL peninsula later tonight. ..Squitieri/Smith.. 04/19/2021 .PREV DISCUSSION... /ISSUED 1133 AM CDT Mon Apr 19 2021/ ...Central/southern Florida Peninsula... A corridor of convection continues to focus along a convectively reinforced boundary across the south-central Peninsula/Lake Okeechobee vicinity at midday. Destabilization through the afternoon will likely be maximized to the south of the lingering midday convection (where low/mid-level winds trend weaker), although some measure of air mass recovery could occur a bit north into more of the central Peninsula in closer proximity to the synoptic front. Additional cloud breaks/heating may allow for some renewed development/reinvigoration of storms this afternoon with a couple of downbursts and/or marginally severe hail a possibility. A lull in deep convection is expected this evening into the overnight as low-level winds become quite weak and convergence wanes. However, in response to the upstream shortwave trough approaching the northwest Gulf of Mexico, extensive convection is anticipated to form late tonight across the eastern Gulf. Some of this convection may reach the west-central/southwest Florida Peninsula early Tuesday with some increase in severe risk. ...Eastern North Carolina/far southeast Virginia... Ahead of a low-amplitude shortwave trough crossing the Appalachians, a modestly moist (around 60F surface dewpoints) and weakly unstable warm sector resides across the region at midday in advance of a weak front/surface trough. Thunderstorms will continue to develop across the region through early afternoon before the warm sector shifts offshore by late afternoon (likely by 21Z/5pm EDT). As low-level lapse rates further steepen early this afternoon, instability may be sufficient in the presence of long/semi-straight hodographs (atop a near-surface easterly component) to allow for some strong/locally severe thunderstorms capable of hail and/or wind gusts. $$