Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 20 2024 18:22:41 AWUS01 KWNH 201822 FFGMPD MDZ000-VAZ000-NCZ000-210000- Mesoscale Precipitation Discussion 0671 NWS Weather Prediction Center College Park MD 221 PM EDT Sat Jul 20 2024 Areas affected...Southeast Virginia...Southern Delmarva Peninsula...Northeast North Carolina... Concerning...Heavy rainfall...Flash flooding possible Valid 201820Z - 210000Z SUMMARY...Continued flash flooding risk for slow moving, efficient warm-cloud process tropical showers/thunderstorms. Proximity to earlier morning flooding increases the potential for possible flash flooding again this afternoon. DISCUSSION...A very moist, modestly unstable environment remains across the coastal plain of southeast VA/northeast NC. Total PWats remain 2-2.25" along a speed convergence axis across SE VA into the southern Delmarva, with 15kts slowing and backing toward cyclonic enhancement near a weak surface to boundary layer wave near OFP/FCI. Aloft a shearing southern stream shortwave exists across south-central VA, further shearing toward the northeast.=20 This feature is demarcated well by shallow convection/curved arcs noted in GOES-E visible imagery and RADAR mosaic.=20 RAP analysis supports 1000-1500 MLCAPE which is fairly robust given the deep moisture profiles/moist adiabatic lapse rates.=20 Deep warm cloud layer up through 13-14Kft will support efficient rainfall production with the 15-20kts of southwesterly flow increased by local updraft strength. Best forced cells have been along/just downstream of the DPVA, but still remain weak though parameters appear sufficient; so localized enhancement may not take much to reach those 2"/hr rates that are possible given the CAPE/moisture. Further downstream, local frictional convergence along bays/inlets appear to be effective on stronger cells with slow/zero cell motions...due to the maintained/stationary low level convergence, and can be an additional potential method for localized heavy rainfall totals contributing to flash flooding.=20=20 Cell motions may allow for additional localized 2-3" totals, the proximity to urban centers across the lower Neck and Norfolk metro area will pose a higher probability for increased runoff as well as, areas that were affected earlier this morning, though soil conditions. Localized flash flooding may still be possible even with the trailing edge of the upper-level shortwave may align for short-term repeating into the evening hours across northeast NC.=20 Here, recent rains have brought soil saturation to slightly above average at 55-60% per NASA SPoRT LIS products.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_meZIOFqG3Q9hDh1cJd21wBfqdy-fKpbAAogIohNdjSelEjbO-JecDDOxPKXCNqwYcsN= NdPIHx-iEJpmFLkXgVyoR2s$ for graphic product... ATTN...WFO...AKQ...MHX...RAH... ATTN...RFC...MARFC...SERFC...NWC... LAT...LON 38137519 37627544 36917575 35957574 35477833=20 35517930 35947937 36557855 36927828 37857765=20 37977639=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) .