SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1107 AM CDT Wed Sep 15 2021 Valid 151630Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NEW ENGLAND...NEW YORK...AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms capable of damaging winds, severe hail and an isolated tornado or two are expected across the Northeast States and New England. An isolated tornado risk will also exist across parts of the middle Gulf Coast. ...Northeast... Water vapor imagery shows a low-amplitude and progressive upper trough moving across the Great Lakes region toward the northeast states. An associated cold front currently over parts of eastern OH/KY will sweep eastward today, providing the focus for numerous showers and thunderstorms. Relatively strong daytime heating is occurring ahead of the front, where dewpoints in the mid/upper 60s and afternoon temperatures in the 80s will yield MLCAPE values of 1000-2000 J/kg. Forecast soundings show deep and strong southwesterly flow, aiding in the organization and intensity of storms. Present indications are that primary severe threat will begin soon (refer to WW 501) and spread across parts of PA/NY and New England through the afternoon and early evening hours. Damaging winds will be the main threat with the line of storms, but severe hail is also possible given the favorable CAPE fields. A tornado or two is also possible - mainly over New England - where low level wind shear is forecast to be strongest. Storms should weaken after dark as they move into southern New England. ...Lower MS Valley... The remnant circulation of Nicholas is moving slowly eastward across southern LA. Scattered convection to the east of the low is in a region of moderate low-level vertical shear, with local VAD profiles indicating 0-3km SRH values of 150-250 m2/s2. This may be sufficient for a few rotating cells this afternoon and evening, posing a risk of a tornado or two. ..Hart.. 09/15/2021 Read more LIVE: spc.noaa.gov
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