Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Oct 07 2024 03:14:01 AWUS01 KWNH 070313 FFGMPD FLZ000-070900- Mesoscale Precipitation Discussion 1092 NWS Weather Prediction Center College Park MD 1113 PM EDT Sun Oct 06 2024 Areas affected...Southern Peninsular Florida and the Upper Keys... Concerning...Heavy rainfall...Flash flooding possible Valid 070315Z - 070900Z SUMMARY...Approaching surface frontal wave with bands of warm advective tropical showers/thunderstorms capable of 2-2.5"/hr rates and spots of 3-5" totals along the coasts may pose localized urban rapid inundation flooding through overnight hours. DISCUSSION...GOES-E 3.9um SWIR depicts a few boundary layer swirls of Cu and TCu across the eastern Gulf of Mexico (main one near 25.8N 85.5W) with the frontal/convergence boundary extending eastward to just offshore of S Sarasota county before paralleling the SW Coast through the central Keys. VWP and RADAR mosaic suggests a 925-850mb wave in proximity of Naples, pressing eastward. This is spurring an increase in low level southwesterly flow and warm advection from the Florida Channel and enhancing convergence with new deepening convection through the central Keys starting to arch northeastward. Relative maxima in low level instability and available moisture along/ahead of this band are running about 2000-2500 J/kg SBCAPE and 1.05-1.25" per CIRA LPW values. This will allow for solid low level moisture loading for intense tropical rain showers and be capable of an easy 2-3"/hr rain rate, but translation/duration will be critical to pose flooding problems. As the aforementioned wave crosses southern FL, WAA and southwesterly flow is expected to lift north and replace the band. Deeper layer (700-500mb) flow appears to suggest weak ridging to delay or allow the wave to pivot across the Everglades while the band lifts north. This will bring stronger cells along/through areas of Miami-Dade with those high rates through the next few hours. There is potential the band will slow and increase duration near the pivoting wave over the urban corridor and present increasing duration of heavier rainfall totals with 3-5".=20 HREF probability of 40-80% of 3" and 30-50% of 5" remains across the southern tip and up the east coast to Palm Beach county.=20=20 Given a secondary boundary/theta-e gradient is also connected to a prior wave/WAA exists resulting in localized frictional convergence across Broward county lifting north potentially adding to/expanding the risk area of potential 3-5" totals by 09z. Given proximity to urban/flat and some already saturated areas, rapid inundation flooding may occur locally with these cells through the overnight period and is considered possible. Along the SW FL coast... The potential for excessive rainfall/higher totals, is diminished slightly compared to the SE FL coast as cells are more likely to reside along/just offshore through the overnight period. However, there remains solid convergence along the southeast angled frontal zone to support similar cells from Manatee to Lee/Charlotte county and with limited cell motions, so though the cells are likely to remain just offshore, there remains some potential for 2-2.5"/hr rates but could result in slightly higher overall totals if they sneak ashore.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9_7cGQdvrEw7ej5aqDEy8Z5IxL-XzFWS6mFU4daM6-UoumjKkf6Lm_uXSparPF6aTtcP= 87H0kDMJREFSlW_QoFuAcN4$ for graphic product... ATTN...WFO...KEY...MFL...MLB...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 27228016 26577992 25867999 25218020 24738081=20 24798129 25718143 25828178 26208193 26538231=20 26988253 27178260 27198225 26408162 26028113=20 26028075 26568050 27178040=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) .