We've been Meso'd Mesoscale Precipitation Discussion 0841 NWS Weather Prediction Center College Park MD 631 PM EDT Thu Aug 08 2024 Areas affected...Portions of the Mid-Atlantic... Concerning...Heavy rainfall...Flash flooding possible Valid 082230Z - 090400Z SUMMARY...Back-building efficient tropical showers. Banded streaks of enhanced rainfall and flash flooding likely to continue through early overnight period. DISCUSSION...Regional RADAR depicts a tightening mid-level deformation/FGEN zone highlighted by the more dense stratiform shield extending from the Blue Ridge across central MD toward the Delaware River Valley. CIRA LPW and 850-700mb RH analysis suggests the core of the warm conveyor belt is directed from the Outer Banks directly up the Chesapeake Bay. It is at this intersection that the strongest deep layer moisture convergence is analyzed and 22z surface streamlines veer slightly through the Delmarva peninsula to enhanced surface moisture convergence. This has resulted in prolonged training event across N DE with 5"+ rainfall has already fallen; the wave and deformation zone is lifting slowly into SE PA, but given strong intersection convergence with the deformation zone broader ascent and a favorable back-building environment still will remain with very slow northward progress over the next few hours. Combine this with frictional convergence affects and additional convective bands may start to develop across N MD and maintain across W MD/E WV as well. A wedge of weak to modest instability (500-1000+ J/kg) is forecast to maintain given advection off the warmer eastern Atlantic through the evening. The core of 2.25-2.5" TPW in the warm conveyor belt will continue to be advected on 40-50kts of 850mb flow, so efficient flux convergence will continue to support shallow tropical warm core convection capable of 2-3"/hr rates. As such, narrow streets of 3-5" remain possible. The MPD area also aligns with lowered FFG due to recent Predecessor Rainfall Event (PRE) in the last couple of days. Hourly FFG values less than 1.5" stretch much of the area of concern with 3-6hr FFG not much higher at 2.5-3" with exception of Northern VA/southern MD and S NJ. As such, focused bands of flash flooding are likely though given the bands will be relatively narrow and widely scattered. Sent from my SM-G970U using Tapatalk