ZCZC SPCSWOMCD ALL ACUS11 KWNS 141929 SPC MCD 141929 NYZ000-PAZ000-WVZ000-OHZ000-142130- Mesoscale Discussion 0435 NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Apr 14 2024 Areas affected...portions of central/eastern Ohio into Pennsylvania Concerning...Severe potential...Watch likely Valid 141929Z - 142130Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms are expected to develop by 4-5 pm EDT. Damaging gusts and isolated large hail will the the main hazards with this activity as storms track south-southeast through the evening. A severe thunderstorm watch will likely by needed in the next 1-2 hours. DISCUSSION...Boundary-layer moisture has gradually increased through the day across the Upper Ohio Valley into northeast PA, with surface dewpoints now in the mid 40s to low 50s F. Strong heating beneath steep lapse rates is supporting weak destabilization. Deepening cumulus has been noted over Lake Erie into western NY the past hour or so, indicating increasing ascent is overspreading the region. The expectation is that this activity will continue to deepen and potentially become more surface-based with time as it shifts southward into OH/PA over the next few hours. Initial cells will likely quickly develop into linear segments given unidirectional flow, which is also parallel to a south/southeastward-advancing surface cold front. Given steep low-level lapse rates and modest boundary-layer moisture, damaging gusts are expected. Furthermore, steep midlevel lapse rates and cold temperatures aloft will support isolated large hail, especially with any convection that remains cellular/semi-discrete. Some improvement of low-level shear is expected with time, resulting in somewhat enlarged low-level hodographs. This may support a tornado or two, but marginal low-level moisture will limit the overall tornado risk. ..Leitman/Smith.. 04/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...BGM...CTP...PBZ...RLX...CLE...ILN... LAT...LON 40768277 41258110 41947686 42107557 41887519 41547500 41027539 40697604 40377712 39857919 39768057 39748213 39978271 40358292 40638290 40768277 NNNN