SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CST Fri Dec 04 2020 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FAR EASTERN NC... ...SUMMARY... A tornado or two and isolated severe wind gusts will be possible across far eastern North Carolina, centered on 11 PM to 3 AM EST. ...Carolinas to southeast VA... A shortwave trough over the Mid-South will amplify and become negatively tilted as it reaches the Lower Mid-Atlantic Coast towards 12Z/Saturday. Cyclogenesis will occur during the latter half of the period across the Carolina Piedmont into southeast VA. Given the presence of predominately 30s and 40s surface dew points across much of the region at present and the timing of cyclogenesis, surface-based instability will likely be confined to eastern NC overnight. Nevertheless, intensifying deep-layer forcing for ascent may yield a narrow corridor of low-topped convection by late evening near the track of the surface low amid meager buoyancy (MUCAPE around 100 J/kg). As this spreads east into the weakly destabilizing air mass of eastern NC, isolated severe wind gusts appear possible. Otherwise, warm conveyor convection should increase overnight, mainly across far eastern NC east of the US-17 corridor. Here, enlarged low-level hodographs coincident with lower 60s surface dew points will foster potential for a couple supercells capable of producing tornadoes and severe wind gusts. ...FL Panhandle... Have maintained low probabilities for a risk of locally damaging winds from midday to late afternoon. Showers have been ongoing near the southwest AL/FL Panhandle border within the warm conveyor region ahead of an impinging cold front. The surface warm front remains just offshore, except across the Apalachicola vicinity. This boundary should gradually advance north during the day, yielding surface-based instability across the southern portion of the Panhandle. Amid weak tropospheric lapse rates, adequate deep-layer shear may exist for transient mid-level updraft rotation within convective clusters near the coast until they diminish towards sunset. ..Grams/Goss.. 12/04/2020
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