Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jul 27 2023 18:42:25 AWUS01 KWNH 271842 FFGMPD FLZ000-280000- Mesoscale Precipitation Discussion 0797 NWS Weather Prediction Center College Park MD 241 PM EDT Thu Jul 27 2023 Areas affected...Eastern and Southeastern Peninsular Florida... Concerning...Heavy rainfall...Flash flooding possible Valid 271840Z - 280000Z SUMMARY...Very slow moving, highly efficient thunderstorms near tropical wave. Rates up to 3"/hr possible and spots of 3-5" may result in rapid inundation flooding in urban corridor. DISCUSSION...GOES-E Visible loop denotes closing low to mid-level circulation just north-east of Cape Canaveral at the apex of the deeper tropical wave that drops south-southwest toward Everglades City. This leaves much of the east and southeast urban corridor under strong moisture flux with 2.3-2.5" total PWAT axis along the coast. Weakening convergence convection over the Northwest Bahamas has allow for increased southeasterly flow/fetch across this moisture axis; while clearing skies as increase low level heating for middle to upper 80s temps creating a highly unstable environment. Given the placement of the axis, convergence is fairly deep to support surface based convection with sufficient flux for deep moisture loading to updrafts. Additionally, proximity to the deeper tropical wave reduces mean cell motions enough to be slow enough to maintain clearer updrafts before becoming outflow dominant. Hourly rain rates of 3"/hr are possible particularly across SE FL where inflow may be strongest from the southeast. Spots of 3-5" are possible as the updrafts continue to expand and potentially form broader updrafts on older colliding outflows. Given upstream inflow is going to be enhanced by frictional convergence, there is a higher probability for cells to reside across the urban areas along the I-95 corridor, particularly south of St.Lucie/Martin counties. Further north, northeasterly return flow along the northwest edge of the deeper mid-level cyclone is more confluent and may be more persistent, with best convergence along the southern edge, perhaps developing within clearer skies/increasingly more unstable area of S Brevard/Indian River counties with even slower forward propagation given closer proximity to the deep layer trof axis and limited steering flow. All considered, rapid inundation flooding is considered possible within the urban areas seeing these most intense rainfall rates.=20=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5BYxGiA6JfdOqW7s7_2x2EJ33sHP1YJhiK4kDmcLRXRQiZzLiwrukXTvcvVhC8Ytd5Pv= QPRIg-CiRGjYHHFZH-emY4w$ for graphic product... ATTN...WFO...JAX...KEY...MFL...MLB... ATTN...RFC...SERFC...NWC... LAT...LON 30098127 29528073 28438038 28098032 26627990=20 25588003 25208020 24848067 25348124 26348089=20 27058077 27778096 28288108 28988142 29588173=20 29958164=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) .