ZCZC SPCSWOMCD ALL ACUS11 KWNS 071639 SPC MCD 071639 NYZ000-PAZ000-071845- Mesoscale Discussion 1880 NWS Storm Prediction Center Norman OK 1139 AM CDT Mon Aug 07 2023 Areas affected...portions of western New York into northern and central Pennsylvania Concerning...Severe potential...Watch likely Valid 071639Z - 071845Z Probability of Watch Issuance...80 percent SUMMARY...The severe threat is increasing across portions of western NY into northern and central PA. Several to potentially numerous damaging gusts are likely and at least a couple of tornadoes are also possible. A WW issuance will be needed in the next hour or two. DISCUSSION...Clearing skies are evident to the east of a surface low, now centered over Ontario, with surface temperatures already exceeding 80 F amid a developing cumulus field. Though mid-level lapse rates are relatively mediocre (i.e. 6 C/km), mid to upper 60s F surface dewpoints, in tandem with the warm surface temperatures, is contributing to 2000 J/kg of tall/thin SBCAPE/MUCAPE (shown via 16Z mesoanalysis). Furthermore, gradually veering low-level flow, along with strong speed shear (driven by an approaching upper-level jet) supports modestly cured but elongated hodographs as shown by regional forecast soundings. Given strong forcing for ascent by an approaching vigorous shortwave, multicells/supercells that manage to form should quickly merge into a squall line/QLCS. Several to potentially numerous damaging gusts are expected to accompany all modes of convection. At least a couple of tornadoes cannot be ruled out, either with supercell structures or leading-line system-scale mesovortices within the QLCS. A WW issuance will be needed in the next hour or two to address the impending severe threat. ..Squitieri/Guyer.. 08/07/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BGM...BUF...CTP...PBZ... LAT...LON 42077627 41287684 41057721 40967783 41057826 41367898 42357841 43267778 43407717 43307650 42987612 42567614 42077627 NNNN