Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Oct 07 2023 04:45:06 AWUS01 KWNH 070445 FFGMPD NYZ000-PAZ000-071043- Mesoscale Precipitation Discussion 1135 NWS Weather Prediction Center College Park MD 1244 AM EDT Sat Oct 07 2023 Areas affected...southern and eastern New York State, portions of central Pennsylvania Concerning...Heavy rainfall...Flash flooding possible Valid 070443Z - 071043Z Summary...A band of deep convection has stalled over central/northeastern New York State, with spots of rain rates beginning to appraoch flash flood guidance thresholds on an isolated basis. These trends are expected to continue through at least 10Z this morning, posing an isolated flash flood risk. Discussion...Recent radar mosaic imagery highlights a focused band of deepening convection extending from near Saranac Lake, NY south-southwestward through Rome, Binghamton, to northwest of Harrisburg, PA. The convection was focused along a stalling pre-frontal trough, with deep moist convergence maximized along that boundary owing to modest low-level easterly flow across much of NY and PA. Thermodynamic profiles support continued development of convection along this axis, with 250-750 J/kg MUCAPE, weak/negligible convective inhibition, and 1.3 inch PW values all supporting efficient rain rates. Additionally, flow aloft was largely parallel to the initiating trough, allowing for training and areas of both 1) 1 inch/hr rain rates especially in central NY and 2) 3-hourly rain rates approaching 2-2.5 inches.=20 The three-hourly rain rates were approaching 3-hourly FFG thresholds (in the 2-3 inch range), suggesting potential for flash flooding beneath the current band in the short term. The overall flash flood scenario is not expected to change much over the next 3-6 hours, suggesting a continued flash flood threat through at least 10Z. The surface trough (and attendant convection) will only make slow eastward progress across the discussion area, with convergence remaining maximized along it.=20 Weak low-level warm advection and mid 60s F dewpoints will help to maintain instability ahead of the storms while flow aloft continues to support training. Flash flood potential should generally be isolated, but remain most likely where training bands of convection can persist over any local area for more than an hour. A secondary risk for training/isolated flash flood potential will also exist where convection can develop well out ahead of the front and result in prolonged heavy rainfall potential through 10Z as well. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4T7Ga6l_9kkk1hnx9Vq3Xm-X4Mne9S1aSHzZC_3HljrUU1_LymcEZ9i6kew1csz9vEIQ= nJmEIgP2ANoKwx3XCBUWiaQ$ for graphic product... ATTN...WFO...ALY...BGM...BTV...BUF...CTP...OKX...PHI... ATTN...RFC...MARFC...NERFC...NWC... LAT...LON 45067391 44037350 41737421 40837564 40647630=20 41157717 43407606 44957503=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) .