Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 10 2023 08:51:43 AWUS01 KWNH 100851 FFGMPD MAZ000-NHZ000-VTZ000-CTZ000-NYZ000-101430- Mesoscale Precipitation Discussion 0686 NWS Weather Prediction Center College Park MD 450 AM EDT Mon Jul 10 2023 Areas affected...Eastern NY...VT...Western NH...Western MA...Western CT... Concerning...Heavy rainfall...Flash flooding possible Valid 100850Z - 101430Z SUMMARY...Deepening deformation zone, strong moisture flux convergence will support showers/thunderstorms with 1-1.5"/hr rates with training/repeating and localized totals of 2-4" by 14z posing likely flash flooding, especially in steeper terrain. Significant flooding is increasingly likely. DISCUSSION...Exiting shortwave/right entrance to 3H jet streak is lifting north into S Canada, but with larger scale shortwave further amplifying over S NY/PA swinging negative tilt into the left exit of another jet core crossing the Mid-Atlantic; resulting in very strong synotpic ascent/outflow channel. In the lower levels, a well defined inverted surface tough extends from a surface low near TBB through the eastern Hudson Valley crossing southern VT into NE VT, while RAP analysis and VWP network suggest 850-700 deformation zone is further west across Catskills into the eastern Adirondacks. Given orientation of the approaching shortwave, the deformation zone is expected to drift eastward, steepening the isentropes. Broad southeastly WAA with 1.75" total PWat will cross this boundary and rapidly ascend even with limited instability (150-350 J/kg of MUCAPE), perhaps aided a bit by orthogonal orographic ascent from the Berkshires into the Green Mtns. Prolonged ascent with embedded shallow cores will support 1-1.5"/hr rates and some slow northeast motions should allow for broad area of 2-4" with possible isolated 5" spots. This is likely to induce flash flooding and given steep terrain this could be significant in places from VT to W MA. Further south, near the surface low, the cyclone is starting to stack/increase in vertical depth, further acentuating the moisture flux convergence. Additionally the area of the S Hudson Valley and W CT can tap a bit of the deeper instability of 1000-1500 J/kg.=20 This may allow for short-term rates of 2-2.5"/hr and localized totals to 5" though the early morning. Similarly, flash flooding may be signficant in/near urban centers. This may be a problem over Ulster/Dutchess to Westchester county, NY that have already seen high totals late yesterday/early this morning, though trends appear to be a tad east of that axis, any overlap will maintain flooding conditions. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-qnZBRfCGQkTqvFnfJ_CPt-X3U0UeiHSHv5v5tywPtVj-it9qbQLAdNDGpje757BGM8J= NUauYweFms6LixNfz5o3snk$ for graphic product... ATTN...WFO...ALY...BOX...BTV...GYX...OKX... ATTN...RFC...NERFC...NWC... LAT...LON 44997137 44047154 42787218 41577293 41387361=20 41627423 42337434 43677392 44987349=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) .