SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CST Fri Nov 13 2020 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN PLAINS...OZARKS AND ARKLATEX... ...SUMMARY... Severe thunderstorms associated with wind damage and perhaps a tornado or two may occur across eastern Oklahoma and the Ozarks late this afternoon and evening. ...Eastern Oklahoma/Northwest Arkansas/Southern and Central Missouri... Southwest mid-level flow will be in place today from the southern Plains eastward into the Mississippi Valley ahead of the an upper-level trough moving through the High Plains. At the surface, a low will deepen across the central Plains as moisture advection occurs in the southern Plains. The surface low will move eastward into the lower Missouri Valley this afternoon with a cold front advancing southeastward across the central Plains and southern High Plains. Ahead of this front, surface dewpoints will increase into the lower to mid 60s F from northeast Texas into eastern Oklahoma and western Arkansas. In response, a pocket of moderate instability is forecast to develop across eastern Oklahoma by late afternoon. SBCAPE values are forecast to peak around 1500 J/kg. Increasing low-level convergence just ahead of the front will likely result in convective initiation along the northern end of the stronger instability late this afternoon. Discrete cell formation appears most likely during the one to two hours after initiation. This will be the most probable time for supercell development. Strong deep-layer shear, aided by the exit region of the mid-level jet, and ample low-level shear should be favorable for an isolated tornado threat with supercells. The tornado threat appears likely to be greatest along the western edge of the low-level jet from south-central Missouri southwestward into northwest Arkansas and far eastern Oklahoma. Due to a band of focused large-scale ascent, a squall-line is expected to organize and move east-southward across the Ozarks extending south-southwestward into the Arklatex. This is expected in the early to mid evening as the low-level jet markedly strengthens. Wind damage will be the primary threat along the leading edge of this line of strong to severe storms. The severe threat could continue into parts of eastern Missouri and east-central Arkansas late this evening. ..Squitieri/Broyles.. 11/14/2020
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