Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 12 2024 05:24:31 AWUS01 KWNH 120524 FFGMPD NYZ000-PAZ000-MDZ000-VAZ000-WVZ000-121100- Mesoscale Precipitation Discussion 0154 NWS Weather Prediction Center College Park MD 123 AM EDT Fri Apr 12 2024 Areas affected...Western NY...Western to Central PA... Adj Northwest MD...Far Eastern WV... Concerning...Heavy rainfall...Flash flooding possible Valid 120530Z - 121100Z SUMMARY...Some threat for flash flooding continues overnight due to training storms across complex terrain, though overall coverage and magnitude will be diminishing with time. DISCUSSION...GOES-E WV shows a potent southern stream shortwave lifting north across S West Virginia at this time being kicked from the base of the larger scale polar trough lifting out of the Cumberland Plateau (ahead of the undercutting jet in the Tennessee Valley). So combined with the stronger DPVA along/ahead of the wave, broadening diffluence across the Allegheny Plateau and steepening mid-level lapse rates with CAA aloft keeps an environment for scattered thunderstorms. While much of the temperature/dewpoint depressions have fallen to near zero; modest moisture of upper 50s and low 60s have streamed northward through the terrain, with CIRA LPW denoting very anomalous moisture in the sfc-850 and modest 850-700mb layers still advecting across central PA into south-central Upstate NY with providing ample moisture flux to any ongoing lingering convection. At this time, profiles still support some 200-300 J/kg of MUCAPE to allow for some vertical development to maintain/weaken slowly in the region of continued best ascent. Rates of up to .75" are possible with smaller convective elements, but more likely .25-.5"/hr rates will remain with those remaining cells...so duration is going to remain key for any potential flash flooding downstream into W NY, central PA.=20 Given the terrain of central PA remains favorably oriented to deep layer steering (near parallel) and low level flow still suggests some orthogonal easterly component along/ahead of the shortwave; there remains some potential for training. As such, high-res CAMs and last WoFS runs suggested a few stripes of 1-2" totals remain especially across along and east of the track of the mid-level shortwave (which appears to be crossing W PA)...placing best potential from Bedford to Potter counties.=20 Though this is not very much rainfall; however, given recent saturated ground conditions (200-300% of normal in last 2 weeks) across complex/steep terrain; FFG values are well below normal and within range of exceedance given 1-2" potential. As such, cannot rule out a spot or two of flash flooding through the overnight hours and flash flooding is considered possible...even as the overall trend of intensity and coverage continues to diminish. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7jXQVJfWl2XnGcVR7c9MU4bLeyWC8FkjrlBvNvv984Ox4yYvRP9PFPsp_g5hcU_kFGf1= GOXJAhP3qjsIRbUAT3s9mGM$ for graphic product... ATTN...WFO...BGM...BUF...CLE...CTP...LWX...PBZ... ATTN...RFC...MARFC...NERFC...OHRFC...NWC... LAT...LON 43147858 43017775 42597727 41847683 40587658=20 39577682 39297850 40357926 41637968 42427946=20 42987905=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .