SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Sat Jul 31 2021 Valid 311200Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE TENNESSEE AND MIDDLE MISSISSIPPI VALLEY INTO SOUTHERN KANSAS AS WELL AS WISCONSIN AND THE COASTAL CAROLINAS... ...SUMMARY... Severe storms with damaging gusts will be possible today, mainly across a portion of central and southern Missouri into the western portion of the Tennessee Valley. Other strong storms will be possible over Wisconsin and the coastal Carolinas. ...Central and southern Missouri into western Tennessee and Kentucky... The eastern U.S. synoptic upper trough will amplify today contributing to a belt of slightly stronger winds aloft over the middle MS and TN Valley areas. Meanwhile a cold front will move southward through central into southern KS, while a stationary front persists from northeast KS to southern MO and western TN. With rich low-level moisture in place, the atmosphere south of the boundaries will become moderately unstable with 1500-2500 J/kg MLCAPE likely. It is probable that an MCS will be in progress across central/northern MO by 12Z today. Some threat for strong to damaging wind gusts might still exist, but this activity may weaken as it continues southeast during the morning. Additional storms are expected to develop along the trailing outflow boundary/front merger across central MO and spread southeast into the moderately unstable warm sector during the afternoon. A belt of up to 35 kt northwesterly mid-level winds will reside across this region with modest effective bulk shear supporting mostly multicells. Storms may evolve into line segments with potential for a few damaging wind gusts across a portion of southern MO and possibly into western TN/KY during the afternoon and evening. Considerable uncertainty remains regarding evolution of morning storms which precludes a categorical upgrade to SLGT at this time. ...Wisconsin... A shortwave trough embedded within the broader, amplifying upper trough will move southeast into the upper Great Lakes during the afternoon accompanied by a cold front. Up to 1000-1500 J/kg MLCAPE is expected in the pre-frontal warm sector, but mid-level lapse rates will remain marginal. Thunderstorms will likely develop along the cold front and spread southeast through central WI. Northwest flow aloft with modest vertical shear will support multicells, but some storms might produce locally strong wind gusts and small hail before weakening during the evening. ...Coastal Carolinas... Multicell storms are expected to develop along a stalled front near the coastal Carolinas within a weakly sheared and moderately unstable environment during the afternoon. A few of the storms might produce strong to severe downburst winds before weakening during the early evening. ..Dial/Moore.. 07/31/2021
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