SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0136 PM CST Sun Nov 29 2020 Valid 292000Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST LA INTO SOUTHWEST GA THROUGH THIS EVENING...AND ACROSS THE EASTERN CAROLINAS LATE TONIGHT... ...SUMMARY... Thunderstorms may produce a few tornadoes and damaging wind gusts through tonight, from parts of the central Gulf Coast to the eastern Carolinas. ...20z Update... The only changes with the 20z update were to trim severe and general thunderstorm probabilities across southwest MS into parts of southeast LA. These changes are based on the current position of the surface cold front across southeast MS to near Lake Pontchartrain and southeast from there into the northern Gulf of Mexico. Otherwise, the ongoing forecast remains on track. At least a narrow window of opportunity will exist this evening into tonight across the FL Panhandle into southwest GA for a few damaging gusts and possibly a tornado or two. Later tonight into early Monday morning, the severe threat will increase toward the eastern Carolinas ahead of the cold front. A couple of tornadoes may accompany these storms overnight. ..Leitman.. 11/29/2020 .PREV DISCUSSION... /ISSUED 1022 AM CST Sun Nov 29 2020/ ...LA to GA/FL... Morning water vapor loop shows a significant shortwave trough moving across OK/AR, with an associated 80kt mid-level jet max rotating into LA/MS. This feature is resulting in cyclogenesis off the LA coast, with a warm front extending eastward from the low roughly along the Gulf coast of MS/AL/FL. The surface low and warm front will move slightly inland this afternoon and evening, with moist/unstable air overspreading the coastal counties of this region. Forecast soundings show ample low-level and deep-layer shear, favorable for a few supercells and the risk of isolated tornadoes or damaging wind gusts. Activity will move into southwest GA after dark, where a slightly more stable environment should result in a weakening trend of the storms. ...Eastern NC... As the aforementioned upper system moves eastward, significant intensification of the southerly low-level jet is forecast to occur over the Carolinas/VA. This will result in a corridor of rapid destabilization after midnight over parts of eastern NC as dewpoints rise into the mid/upper 60s. Vertical shear will be quite strong, and 12z CAM solutions suggest a few rotating storms may develop. There is a risk of a few tornadoes overnight in this region.
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