Administrators NorthGeorgiaWX Posted October 29 Administrators Posted October 29 SPC 1730Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1240 PM CDT Tue Oct 29 2024 Valid 301200Z - 311200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHWESTERN MISSOURI...EASTERN KANSAS...AND NORTHEASTERN OKLAHOMA... ...SUMMARY... Strong/severe thunderstorms, capable of producing large hail, damaging wind gusts, and a few tornadoes, are expected on Wednesday across central portions of the country -- particularly from the middle Missouri Valley area southward to North Texas. ...Synopsis... An upper trough initially aligned across the interior West will progress east-northeastward out of the Rockies and into the Plains during the afternoon and evening, and then will continue onward toward/into the Mid- and Upper-Mississippi Valley area overnight. At the surface, a cold front will initially extend northeast-to-southwest across the central U.S. -- from the Lake Superior vicinity southwestward to southeastern New Mexico and Far West Texas. This front will make only gradual eastward progress initially, as a frontal wave develops in the southeastern Kansas vicinity and then shifts quickly northeastward along the baroclinic zone through the day -- to a position near Topeka around sunset. From there, as the low deepens and progresses toward Wisconsin, the trailing cold front will begin to surge more quickly eastward/southeastward, and should extend across central Illinois, southeastern Missouri, Arkansas, to central Texas by Thursday morning. ...Mid-Mississippi/Mid-Missouri Valleys across northeastern Texas... As the advancing upper system shifts out of the Rockies and across the High Plains through the day, large-scale ascent -- focused near the cold front -- will gradually increase. Ahead of the front, a moist (60s dewpoints) airmass will be in place along/ahead of the front across the central/southern Plains, and should spread northward across Iowa and into Wisconsin through the day. This, combined with daytime heating and modestly steep lapse rates aloft, will allow gradual/steady destabilization to occur through the morning and afternoon hours. Initial storm development is forecast by mid to late morning, in the eastern Nebraska/northeastern Kansas/western Iowa vicinity, and then expanding northeastward toward the upper Mississippi Valley, and southward across eastern Kansas, through the afternoon. In addition to the amply unstable environment that will be evolving (mixed-layer CAPE in the 1000 to 1500 J/kg range), increasingly favorable shear will also evolve with time. This will occur as mid-level southwesterly flow associated with the advancing upper system spreads eastward across the central Plains, atop low-level southerly flow near/ahead of the forecast track of the frontal low. The resulting wind field -- veering favorably and increasing in speed with height through the lowest half of the troposphere -- will support supercells. It appears that convection should remain at least somewhat cellular through the daylight hours from the Topeka/Kansas City vicinity southward, which would correspond with risk for a few tornadoes, along with large hail and damaging wind potential. Farther to the northeast, across Iowa and into Wisconsin, risk should remain lower, given lesser instability. Overall, storms should gradually grow upscale linearly, and will shift eastward with time across Iowa and into Missouri -- and eventually Illinois overnight, accompanied by at least limited severe risk into the overnight hours. Farther south into Oklahoma and Texas, storm development should occur later, likely not until after dark. Still, with the thermodynamic and kinematic environment favoring rotating storms, the all-hazards severe risk should expand southward across Oklahoma and into northern and possibly central Texas. With time, storms should grow upscale linearly across this region as well, after the initial/primarily cellular mode. Like areas farther north, at least some severe risk should continue overnight, spreading eastward into Arkansas and East Texas with time. ..Goss.. 10/29/2024 Read more View the full article Quote
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