Severe Thunderstorm Watch may be issued:
Mesoscale Discussion 1801 NWS Storm Prediction Center Norman OK 0233 PM CST Sun Nov 15 2020 Areas affected...Portions of the Mid Atlantic into southern New England Concerning...Severe potential...Watch possible Valid 152033Z - 152300Z Probability of Watch Issuance...60 percent SUMMARY...The damaging wind threat will increase later this afternoon into the evening, in association with low-topped convection. Watch issuance will become increasingly probable later this afternoon once development of an organized squall line appears imminent. DISCUSSION...A cold front is expected to accelerate eastward through much of PA and adjacent portions of the Mid Atlantic and southern New England late this afternoon into the evening, as a powerful mid/upper-level trough moves from the Great Lakes into the Northeast. While a long-lived line of severe-wind producing thunderstorms will stay primarily northwest of the MCD area, one or more additional bands of convection are likely to develop along the front by late afternoon. While widespread cloudiness will limit heating across this region, continued low-level moist advection should support the development of weak buoyancy (SBCAPE of 100-200 J/kg) immediately in advance of the cold front. Despite the weak instability, strong low-level mass response in association with the front should support the development of a low-topped band of convection. Convection may produce little-to-no lightning, but very strong low-level flow (50-60 kt in the lowest 1km) will support a threat of damaging wind gusts. Given the potential for widespread 50+ mph wind gusts and at least widely scattered severe (60+ mph) gusts, severe thunderstorm watch issuance may be required later this afternoon.
9 views0 comments