Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 26 2023 18:26:43 AWUS01 KWNH 261826 FFGMPD MAZ000-NHZ000-VTZ000-NYZ000-270015- Mesoscale Precipitation Discussion 0590 NWS Weather Prediction Center College Park MD 225 PM EDT Mon Jun 26 2023 Areas affected...New England Concerning...Heavy rainfall...Flash flooding possible Valid 261825Z - 270015Z SUMMARY...Heavy thunderstorms containing 2"/hr rainfall rates may result in areas of flash flooding this afternoon. DISCUSSION...Doppler Radar showed scatted thunderstorms across interior New England tracking NNE this afternoon. The region resides ahead of the mean 250-500mb trough axis to the southwest, placing favorable upper level divergence overhead this afternoon. There is also a potent 500mb vorticity maximum making its way through northern VA and act as a trigger for thunderstorms in ther northern Mid-Atlantic. Mean 850-300mb flow is out of the SSW, which may direct ongoing storms unfolding near the Catskills and eastern PA towards the region later this afternoon. There is a steady stream of southerly 850mb moisture flux being directed north into the northern Appalachians and along a frontal boundary positioned over NH and northern VT. PWATs are forecast to reach at least 1.5" and may even top 1.75" in the Hudson Valley and Champlain Valley. The warm front has lifted north into southeast Canada and the warm sector has steadily destabilized. 3-hr MLCAPE change ranges between 200-400 J/kg from the western half of VT to northern NY with values topping 1,000 J/kg in most areas. The atmospheric column is also quite saturated, as evidence by the 80-90% RH values within the 1000-500mb layer. Warm cloud layers are likely to be 10,000' in depth in some areas, providing storms with the tools to maintain efficient warm rain processes. While much of the region can use the rain, these are still storms containing almost tropical-like characteristics in areas that are not as adept to handling 2"/hr rainfall rates. In fact, 1-hr FFGs are as low as 1.0-1.5" and many areas are below 2"/hr. The steady SSW flow through the depth of the column will also support possible backbuilding convection, especially in favored upslope areas and as evidence by upshear Corfidi vectors <10 knots. There is the potential for flash flooding this afternoon with urbanized communities and low-lying/poor drainage areas most at-risk. Mullinax ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7YWO_Yc2EtN7Zmnhrr9D_wTtCduTttYY4P3D83j87xwkYDOPbkFE9TkbAts5bYJ0BCLr= Hshk84ACk_77nNOwS5z_oJY$ for graphic product... ATTN...WFO...ALY...BOX...BTV...GYX... ATTN...RFC...NERFC...NWC... LAT...LON 45137339 45127225 45137155 44467157 43847155=20 42597130 42557214 43057323 43277489 44147488=20 44857439=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) .