SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0138 PM CST Wed Nov 11 2020 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER WESTERN PORTIONS OF THE FLORIDA PENINSULA... ...SUMMARY... A few tornadoes are possible across parts of Florida mainly northeast through southeast of the center of Hurricane Eta. ...20Z Update... ...FL... As discussed in recently issued MCD 1971, convection within one of the outer bands of Hurricane Eta has undergone some strengthening, primarily from the western FL Keys northeastward into the southwestern portion of the FL Peninsula. Lightning data confirms this strengthening, with the cells about 20-30 miles north-northwest of MTH show appreciable lightning density. Temperatures have warmed into the low/mid 80s and mesoanalysis indicates about 1000-1500 J/kg of MLCAPE. However, contrasting these thermodynamic improvements are the weakening kinematic fields. The 18Z sounding from MFL indicates 0-1 km storm-relative helicity around 170 m2/s2, down from 220+ m2/s2 on the 12Z sounding. Even so, this parameter space remains adequate for a few stronger storms capable of producing locally strong wind gusts and perhaps a brief tornado or two. The 2% tornado risk was expanded eastward to account for this band of storms. A 5% wind area was also added to portions of central/south FL. ...NC/VA... No changes needed to this portion of the outlook. Damaging wind gusts still appear possible within any of the stronger cells. ..Mosier.. 11/11/2020 .PREV DISCUSSION... /ISSUED 1022 AM CST Wed Nov 11 2020/ ...FL... Hurricane Eta is moving slowly northward across the eastern Gulf of Mexico, with outer bands affecting the western coast of the FL Peninsula. A few of the convective elements in these bands have shown indications of weak low-level rotation. Local VAD profiles and forecast soundings show ample low-level shear for a risk of a few spin-ups this afternoon. However, CAM solutions suggest that coverage of more discrete cells will be sparse. Nevertheless, will maintain the ongoing forecast with no changes. ...NC/VA... Water vapor imagery shows a subtle shortwave trough over middle TN/northern AL moving across the southern Appalachians. This feature will begin to affect parts of VA/NC later this afternoon with slightly strengthening low/mid level winds and vertical shear. Scattered thunderstorms are expected to affect this region through the day, with the increasing shear likely resulting in a few weakly rotating storms. Forecast hodographs are not particularly favorable for tornadoes, but one or two of the storms could become sufficiently organized to produce locally gusty/damaging winds.
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