SPC AC 061623 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Jun 06 2023 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN SEVERAL AREAS WITHIN THE CONUS... ...SUMMARY... Isolated severe thunderstorms with threats of damaging winds and large hail will be possible through this evening across several portions of the country: the South Carolina vicinity, the Northeast, northern California to northern Utah/southern Idaho, New Mexico/Texas Trans-Pecos, and south Florida. ...SC Vicinity... A plume of moderate buoyancy with MLCAPE of 1000-2000 J/kg centered on north GA will shift east into SC later this afternoon. Isolated to scattered thunderstorms will develop along and just ahead of a weak surface trough shifting slowly south across NC to upstate SC. The region will lie within the gradient of weak to moderate mid-level northwesterlies, well to the southwest of a deep upper low over the Canadian Maritimes. While low-level flow will remain weak and veered to the west-southwest, 15-25 kt effective bulk shear should support some multicell clustering and a threat for isolated damaging winds and severe hail. ...Northeast... A secondary mid-level impulse embedded within the larger-scale trough on the backside of the deep upper low over the Canadian Maritimes should aid in isolated to scattered higher-based convection. MLCAPE will remain weak owing to surface dew points only in the mid 40s to around 50 F. But moderate speed shear through the cloud-bearing layer should foster small to marginally severe hail growth in the deeper cores. This combined with an inverted-v thermodynamic profile will support a threat for locally damaging winds. Refer to the SPC Fire Weather Outlook for additional information. ...Northern CA to northern UT/southern ID... An upper low will wobble over the San Joaquin Valley through tonight. A belt of modest buoyancy with MLCAPE of 600-1200 J/kg should develop at peak heating within a largely west/east-oriented arc across northern CA to northern UT/southern ID. Scattered thunderstorms are expected within this buoyancy plume by late afternoon. While moderate mid-level flow will generally be displaced to the south, 20-30 kt southeasterlies around 500 mb will support some multicell clustering and a primary threat of isolated severe wind gusts. Small to marginally severe hail will also be possible in deeper updrafts. ...NM and the TX Trans-Pecos... Downstream of the CA upper low, scattered thunderstorms will develop within a modest buoyancy plume characterized by MLCAPE of 700-1400 J/kg. The bulk of stronger mid-level flow should remain displaced west of the buoyancy/higher PW plume in AZ, as a low-amplitude mid-level ridge tries to hold over central NM. As such, convection will likely struggle to initially organize with sporadic severe gusts and small hail being the main threats. Somewhat greater effective shear should occur from the TX Trans-Pecos to the Raton Mesa during the early evening, where isolated marginally severe storms may occur. ...South FL... Morning convection along the southeast FL coast has yielded outflow that has pushed inland over the Everglades. Later afternoon convection will probably be focused along this boundary into southwest FL. While a 50-kt speed max at 500 mb was sampled in the 12Z Miami sounding, guidance is consistent with weakening mid-level winds through the afternoon. It still should remain sufficient for a transient cell or two with mid-level rotation, and supportive of a brief threat for severe wind/hail. ..Grams/Thornton.. 06/06/2023 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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