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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Sunday, May 30, 2021

SPC May 30, 2021 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0243 PM CDT Sun May 30 2021 Valid 302000Z - 311200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS REGION... ...SUMMARY... Scattered severe hail and wind, along with a few tornadoes are possible across the southern High Plains. These hazards are expected to peak during the late afternoon and evening. No changes were required at 20Z. Storms are now forming over New Mexico, and are expected to expand in coverage and intensity throughout the day as they develop toward the Texas Panhandle and South Plains. Initial development may contain large hail and a couple tornadoes before storms merge this evening at which time damaging wind threat will increase. ..Jewell.. 05/30/2021 .PREV DISCUSSION... /ISSUED 1132 AM CDT Sun May 30 2021/ ...Southern High Plains region... A complex setup is evident this morning, with ongoing convection underway, along with varying degrees of cloud cover over the region that will affect destabilization potential in some areas. With that said, a persistent feed of low-level moisture being provided by southeasterly upslope flow, beneath steep lapse rates aloft, will result in substantial destabilization in tandem with afternoon heating, with generally 1000 to 2000 J/kg mixed-layer CAPE expected to evolve away from areas of persistent ongoing storms/cloud cover. As the upper trough gradually advances across the Southwest, large-scale ascent focused at the surface near various convective boundaries, as well as upslope-induced ascent in favored areas, will result in an increase in convective coverage by early afternoon, as storms develop across the area. Initial, cellular convection will be capable of producing large hail and locally damaging winds, with a tornado or two also possible given favorably increasing/veering flow with height through the lower troposphere. With time, storms are expected to merge/grow upscale into multiple eastward/southeastward-moving clusters, accompanied by continued risk for damaging winds. Storms will likely persist into the overnight hours -- particularly across the Texas South Plains and Panhandle area -- though severe risk should gradually diminish overnight. ...Central and southern Florida... Moderate CAPE development this afternoon -- resulting from diurnal heating of a moist boundary layer, and slight mid-level cooling associated with the passing of the southern fringe of the eastern U.S. trough -- is expected to yield scattered to widespread storm development across central and southern Florida. Storms will likely develop near both a west- and east-coast sea-breeze boundary, with storms possibly merging over interior portions of the peninsula by late afternoon. While flow aloft will remain fairly weak, a few stronger storms -- particularly near storm mergers -- may be capable of producing gusty/locally damaging winds, and possibly marginal hail, into the evening hours. ...Central and northern Minnesota vicinity... Afternoon heating of a modestly moist (upper 40s to low 50s dewpoints) pre-frontal warm sector is expected to yield around 500 J/kg mixed-layer CAPE during the afternoon/early evening. With large scale ascent provided by the slowly advancing upper system, and focused at the surface near both the primary cold front (now draped from far northwestern Minnesota into eastern North Dakota), and a pre-frontal convergence axis (now indicated from north central to west central Minnesota), expect isolated afternoon storm development to occur, within one or more broken bands. While modest thermodynamics should limit storm coverage/intensity, veering/increasing flow with height to westerly at 30 to 40 kt will contribute to sufficient shear for organized updrafts. As such, a few strong storms -- or perhaps a linearly organized storm cluster -- will likely become capable of producing marginally severe hail and/or wind locally. Any severe risk will diminish into the evening as diurnal cooling commences. Read more LIVE: