Subj : MESO: Mesoscale Discussion 1517 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jul 13 2023 15:59:29 ACUS11 KWNS 131559 SWOMCD SPC MCD 131558=20 VTZ000-NYZ000-PAZ000-131800- Mesoscale Discussion 1517 NWS Storm Prediction Center Norman OK 1058 AM CDT Thu Jul 13 2023 Areas affected...Portions of NY...VT...and far northern PA Concerning...Severe potential...Watch likely=20 Valid 131558Z - 131800Z Probability of Watch Issuance...95 percent SUMMARY...The threat for damaging winds, hail, and perhaps a couple of tornadoes will increase this afternoon. Watch issuance is likely. Parts of this area will be upgraded to Enhanced Risk (for severe wind gusts) with the 1630Z Day 1 Convective Outlook. DISCUSSION...Airmass destabilization is rapidly occurring across NY and vicinity as ample daytime heating has already warmed surface temperatures mostly into upper 70s and 80s. A rather moist low-level airmass is also present based on recent surface dewpoint observations and area 12Z soundings. Further heating of this moist airmass will likely lead to the development of around 1500-2000 J/kg MLCAPE along/ahead of a cold front. This front, coupled with large-scale ascent associated with a shortwave trough ejecting across the Northeast and southern Quebec, will likely foster robust thunderstorm development within the next couple of hours as parcels reach their LFCs. Recent VWPs from KENX and KCXX show a veering and strengthening wind profile with height through mid levels, with around 30-35 kt of deep-layer shear. This should provide sufficient updraft organization to support a mix of cellular and linear modes. Convection developing along the cold front is already beginning to show signs of deepening in far western NY. This trend should continue over the next couple of hours as the front moves eastward across NY. As low-level lapse rates become steep, scattered to numerous damaging downdraft winds will be a concern with any clusters/lines that can become established. Convection that remains at least semi-discrete will pose a threat for hail. The presence of a seasonably strong (25-35+ kt) southerly low-level jet across much of NY and vicinity will also provide sufficient 0-1 km SRH to support some threat for a couple of tornadoes, both with supercells and line-embedded vorticies. Recent (12Z) high-resolution guidance suggests that a mainly linear mode should dominate. Given the increased potential for scattered to numerous damaging/severe winds this afternoon, parts of central/eastern NY and VT will be upgraded to Enhanced Risk with the 1630Z Day 1 Convective Outlook. ...Gleason/Bunting.. 07/13/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6SV_xljua-K_1CRjmUfjqtvOp9kaNdNNCmntBj3qXzmj9NMfZF06QZ-ZzCUNVHEs1AgdzQvTq= SCQca9ddx60zpA8aiA$ for graphic product... ATTN...WFO...BTV...ALY...BGM...BUF... LAT...LON 42537728 44437586 45027494 44977225 44437204 43357271 42747328 41647453 41907645 42537728=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .