Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Nov 16 2023 19:31:21 AWUS01 KWNH 161931 FFGMPD FLZ000-170100- Mesoscale Precipitation Discussion 1175 NWS Weather Prediction Center College Park MD 230 PM EST Thu Nov 16 2023 Areas affected...Central East Coast & Central Florida... Concerning...Heavy rainfall...Flash flooding possible Valid 161930Z - 170100Z SUMMARY...Prolonged moderate rain with occasional embedded slower moving convection capable of 2"+/hr pose low end flooding concerns particularly in proximity to urban centers. Localized spots of 3-4" are possible through 00z.=20 DISCUSSION...GOES-E Visible imagery depicts the remnant surface low of the MCC just SW of Grand Bahama, continuing northeastward toward the island. While the warm conveyor belt has shifted east of Abaco, moisture returns through the sharp gradient from the the boundary layer through 500mb. This aids very strong gradient driven low level easterly flow of 25-35kts from the northern Space Coast through the northern Treasure Coast of eastern FL, with enhanced mid-level moisture flux providing 1.75-1.9" total PWats, mainly in the 850-500mb layer. VWP and RAP analysis depicts the 700-500 mb trof axis is swinging through the western coast of FL, extending toward AMX in Southeast Florida increasing deep layer moisture flux intersecting with this trof axis. Combined with weak but sufficient 300-250mb divergence across central Florida to the Space Coast at the diffluent region of the 90kt speed max over the Florida Straits is providing increased dynamics for vertical ascent over the next few hours. Currently, cloud cover has limited best insolation for increased temperatures, but given proximity to the warmer Gulf stream, coastal temps aid modest instability nearing 1000 J/kg.=20=20 As such, the light and broad shield precipitation is starting to denote some cumuliform/vertical development across S Brevard and N Volusia coastal areas. Available moisture and near 80-90% RH through the cloud depth, should allow for efficient rainfall production and as the depths of the clouds increase with time rates should increase to 1.5-2"/hr by 21z. In the high shear environment, shield precipitation has been fast moving to the west, but as the 700mb wave continues east, weak southerly flow in the layer will reduce forward speed and help to increase rainfall duration. Additionally, redevelopment/back-building environment supported by frictional convergence near the coast line should help to further redevelop localized convection that may (but not certainly) repteat through areas. As such, scattered but localized totals of 3-4" total (maybe even higher with strongest cells) may induce some rapid rise/slow run-off flooding concerns through the evening/early overnight period.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7BD-7se-N7T2wI7B7tMdb0IZuXBSPLSP82skg2_8_5T8bbwP46P130ZDjmt_GXx4Ic7K= TsKYqVDUtWp8oEwCPRvvpZ0$ for graphic product... ATTN...WFO...JAX...MLB...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 29538113 29048084 28778066 28528048 28268052=20 28018047 27558029 27298061 27348110 27868170=20 28408205 28798214 29218201 29438169=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) .