SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1141 PM CST Tue Dec 15 2020 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NORTH CAROLINA... ...SUMMARY... A few strong to severe thunderstorms are expected across parts of coastal North Carolina and the Gulf coastal areas of the northern Florida Peninsula. ...Southeast... Strong mid-level height falls will spread across the southern/central Appalachians later today as a 100kt 500mb speed max translates across northern GA into western NC. This feature is currently located over the lower MS Valley, and in response a weak surface low is expected to approach the FL Panhandle by mid day. A brief opportunity for strong/locally severe storms will be noted with the Gulf-moisture surge as weak buoyancy spreads inland ahead of the initial surface low. Strengthening wind fields and near-surface based instability suggest some threat for damaging winds, and perhaps a tornado with any supercells. Of more concern will be the Atlantic-moisture surge expected across coastal NC. Latest model guidance suggests a surface low will develop off the SC Coast early then lift north into eastern NC by 18z. Very strong wind fields will result in shear profiles favorable for supercells and possible tornadoes. NAM forecast sounding for HAT at 21z exhibits ~1200 J/kg SBCAPE just prior to low-level flow veering to the southwest. While the storm mode will likely be multi-faceted, with clusters and possible line segments, supercells along with some tornado threat will be noted, especially across the Outer Banks where buoyancy will be greatest. ..Darrow/Cook.. 12/16/2020
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