Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jan 13 2024 04:26:15 AWUS01 KWNH 130426 FFGMPD MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-131023- Mesoscale Precipitation Discussion 0013 NWS Weather Prediction Center College Park MD 1124 PM EST Fri Jan 12 2024 Areas affected...Portions of the Northern Mid-Atlantic...Southeast NY/Long Island...Southern New England Concerning...Heavy rainfall...Flash flooding possible Valid 130423Z - 131023Z SUMMARY...Heavy rains overspreading the northern Mid-Atlantic, southeast NY/Long Island, and southern New England will be capable of causing areas of flooding given the very wet antecedent conditions including some areas of melting snow. DISCUSSION...A deep layer cyclone lifting from the OH Valley into the Great Lakes region will allow for a very strong northward surge of warm air and moisture up along the Eastern Seaboard overnight which will bring areas of heavy rainfall across coastal and interior areas of the northern Mid-Atlantic into southern New England. Already there is an impressive southerly low-level jet on the order of 60 to 70 kts nosing up across the Chesapeake Bay region northward through eastern PA/NJ and aiming for southeast NY and southern New England. Enhanced isentropic ascent associated with this coupled with very strong levels of moisture transport through the vertical column and a modest nose of elevated instability will favor a general increase in rainfall rates going through the overnight hours. IVT magnitudes are forecast to increase to as much as 1000 to 1250 kg/m/s in the 06Z to 09Z time frame across many of these areas, and especially toward northern NJ, southeast NY/Long Island and southern New England. The 00Z HREF guidance supports high probabilities (50% to 80%) of seeing rainfall rates increasing into the 0.50" to 0.75"/hour range along the I-95 corridor including the major metropolitan areas of Philadelphia and New York City. Some rainfall totals may reach as high as 1.5 to 2.5 inches by dawn where some of these heavier rainfall rates set up and locally train over the same area. Given the very wet antecedent conditions that are in place from recent heavy rainfall, and also areas of melting snow (especially the higher terrain of the Poconos, Catskills, and Berkshires), these rains may result in areas of flooding, and there will be some low-end urban flash flooding potential if some of these rates can approach or even very briefly exceed 1 inch/hour over the more sensitive metropolitan areas. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_YeiOjF2FG8JqJGe3AN0PQatHyw37NJft9m4p18azm8a1FbrXt04AItb1LVSjg_I77M6= hK93pSDVsyhwuA5_-U0LhsI$ for graphic product... ATTN...WFO...AKQ...ALY...BGM...BOX...CTP...LWX...OKX...PHI... ATTN...RFC...MARFC...NERFC...NWC... LAT...LON 42687280 42557186 42167127 41777128 41297149=20 40897212 40307337 39627404 37907525 38107643=20 39117683 40337690 41647634 42357515 42667410=20 =20=20=20=20=20=20=20=20=20=20=20=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) .