891 FXUS62 KMFL 090603 AFDMFL Area Forecast Discussion National Weather Service Miami FL 203 AM EDT Sat Oct 9 2021 .AVIATION(06Z TAFS)... A lull in showers and storms could develop over the coming hours with most terminals improving back to VFR. Additional rounds of convection are possible by the afternoon spreading from west to east. Terminals impacted by convection could fall to IFR/LIFR at times. Short-fused AMDs will likely be needed. && .PREV DISCUSSION... (Issued 307 PM EDT Fri Oct 8 2021) SHORT TERM (Now through Saturday)... Moisture continues to move into South Florida ahead of a trough across the SE CONUS. A diurnal seabreeze convective pattern across the region today with higher overall coverage than previous days with the increased moisture. Initial development will be along sea breezes with additional development along outflow boundary interactions. Hi-res models continue to depict highest coverage over the interior and Gulf coast. Convection may linger into the later part of the evening for some areas. Main impacts will be lightning and heavy rainfall with the strongest storms. A mid-upper level trough will approach the region Saturday with a frontal boundary stalling to the north. South Florida will remain in the very moist warm sector tomorrow. Precipitable water values will be around 2 inches as moisture transport vectors continue to bring tropical moisture ahead of the front from the Caribbean and Gulf of Mexico. Diurnal heating will not be a problem tomorrow with temperatures rising into the upper 80s. This will lead to plenty of instability for convective development. Model soundings are depicting temperatures cooling aloft and increasing steep mid-level lapse rates. Meso and global models depict 500mb temps approaching -10C as well as mid level lapse rates around 6.5 C/km. Looking at all these factors, the potential for strong to even severe thunderstorms looks to exist on Saturdays. The primary concerns would be strong to damaging wind gusts and hail. Given the moisture profile as well, efficient rainfall with high rainfall rates may lead to localized flooding. Other hazards such as a tornadic potential will have to be monitored tomorrow as the event unfolds. Monitoring bulk shear values and the east coast seabreeze for SRH increasing right along the Atlantic coast. Overall, an active setup for scattered to numerous showers and thunderstorms with the potential for strong to potential severe storms tomorrow afternoon and evening across South Florida. LONG TERM (Saturday Night through Friday)... Later this weekend and into early next week an upper level low will close off and drift generally toward our region. This will allow for colder temperatures aloft, which should provide a source for a better thermodynamic profile through the weekend in regards to shower and t'storm chances. At the surface, the low level flow appears rather lackluster, which will lead to a slower moving sea breeze. With the relatively steep lapse rates aloft and a surface trigger thanks to the diurnal cycle, showers and storms will be common on Sunday, although some drier air in the mid level tries to work in across the northern tier Sunday and into Monday. The synoptics going through the week looks to be rather complicated. The aforementioned upper low is forecast to continue to drift southward into the western Caribbean through the remainder of the period. Across the Southeast US, a ridge begins to develop. The GFS and to some extent the ECMWF indicate the formation of a Rex Block over Florida during this timeframe. Although the synoptics are complex, the expectations here at the surface are rather simple...a continuation of wet season with model QPF signals in all the globals. Of course driven by the diurnal cycle, it appears the best rain chances will be across the southern tier (generally along and south of I-75/Alligator Alley) through out much of the upcoming workweek. These locations will have a better thermodynamics profile (cooler temperatures aloft) and perhaps slightly better moisture quality throughout the column. Temperatures should stick to climo, give or take a degree here or there depending on daily convection. MARINE... East to southeasterly wind flow with fairly benign marine conditions today, with isolated to scattered showers and thunderstorms possible. For this weekend, increasing coverage of showers and storms ahead of a frontal boundary that will stall north of the region. A 1 to 2 ft long period swell will also move into the Atlantic waters off South Florida on Saturday. BEACHES... A moderate rip current risk remains for the Palm Beaches today. Higher than normal astronomical tides (King Tides) could result in minor coastal flooding of vulnerable low-lying coastal areas during the times of high tide this week, though generally light winds and low surf heights should largely mitigate these concerns. An elevated risk of rip currents is possible for the east coast beaches this weekend as a small long period swell moves into the Atlantic waters. && .PRELIMINARY POINT TEMPS/POPS... Miami 73 87 73 87 / 50 50 30 40 West Kendall 70 88 71 89 / 40 50 30 40 Opa-Locka 72 88 73 88 / 50 50 30 40 Homestead 70 86 71 87 / 40 50 40 40 Fort Lauderdale 73 86 73 87 / 50 50 30 40 N Ft Lauderdale 73 87 74 87 / 50 50 30 40 Pembroke Pines 71 87 72 87 / 50 50 30 40 West Palm Beach 71 87 73 88 / 40 40 30 40 Boca Raton 72 87 73 87 / 50 50 30 40 Naples 72 87 72 87 / 20 30 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && $$ Aviation...RAG Visit us at weather.gov/miami Follow us on Facebook and Twitter at: www.facebook.com/nwsmiami www.twitter.com/nwsmiami