Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 30 2023 18:17:43 AWUS01 KWNH 301817 FFGMPD NJZ000-DEZ000-MDZ000-VAZ000-NCZ000-010015- Mesoscale Precipitation Discussion 0217 NWS Weather Prediction Center College Park MD 216 PM EDT Sun Apr 30 2023 Areas affected...Portions of the Mid-Atlantic Coastal Plain Concerning...Heavy rainfall...Flash flooding possible Valid 301815Z - 010015Z SUMMARY...Additional rounds of heavy showers and thunderstorms arriving across the coastal plain of the Mid-Atlantic coupled with relatively moist/wet antecedent conditions may result in some instances of flash flooding. DISCUSSION...The latest surface analysis shows multiple waves of low pressure riding northeast up along a frontal zone draped across the coastal plain of the Mid-Atlantic along with corresponding shortwave support aloft. The lead wave is advancing across the Hampton Roads area of southeast VA currently with a relatively concentrated, but somewhat progressive axis of convection exiting toward the lower Delmarva. Meanwhile, a second and more dominant wave of low pressure with stronger forcing/energy aloft is getting ready to exit eastern SC and lift up across eastern NC. Radar imagery is showing a gradually expanding area of convection with the more dominant southerly wave and this energy should favor an expansion and redevelopment of convection off to the northeast across areas of central to northeast NC, and into southeast VA going through the mid to late-afternoon hours. In fact, the latest hires model guidance shows this energy taking on a negative tilt as it lifts up across the Mid-Atlantic coastal plain this afternoon, and the strong DPVA/forcing associated with this coupled with instability recovery and favorable shear profiles in the wake of the lead wave should favor rather widespread convection with heavy rainfall rates. The 12Z HREF guidance shows high probabilities for seeing 1 to 2 inch/hour rainfall rates impacting areas of central to northeast NC and southeast VA in particular with some potential for additional rainfall amounts of 2 to 4 inches. The NAM-Conest actually supports isolated 5 to 6 inches of rain given some concerns for locally training convective cells along the aforementioned front. A combination of both the lead wave and the dominant secondary wave will also eventually impact areas of the Delmarva and southern NJ late this afternoon and into the early evening hours. Additional rainfall amounts here may also reach as much as 2 to 3 inches with locally higher amounts. Given the already moist/wet antecedent conditions and expectation of seeing additional rounds of convection over the next few hours, there should be a threat of seeing some instances of flash flooding. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_XKU5sgUxzYGWFap0upcisqgj2B-Ks7I_Jo8kQhVEU7Asgv6bqCgavKo5V3poAt9NpKd= 2AeNDv0Btx0ItLhgNdcHPrQ$ for graphic product... ATTN...WFO...AKQ...LWX...MHX...PHI...RAH... ATTN...RFC...MARFC...SERFC...NWC... LAT...LON 39917481 39887417 39467418 38507497 37717536=20 36037623 35337734 35257844 35887885 37027768=20 38197674 39197579=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) .