Area Forecast Discussion
Issued by NWS Miami, FL
Issued by NWS Miami, FL
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145 FXUS62 KMFL 182329 AFDMFL Area Forecast Discussion National Weather Service Miami FL 729 PM EDT Wed Sep 18 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 722 PM EDT Wed Sep 18 2024 Fairly widespread thunderstorms have developed over SEFL this afternoon, with a few more robust cores necessitating the issuance of SVRs and SMWs. In general outflow boundaries from this earlier convection will continue to propagate towards the Interior which should support convective initiation through at least the 10PM- midnight time frame (after which point convection should generally wane overland into early Thursday morning). That being said increasing BL stabilization after sunset should prevent cores from being as intense as those observed earlier this afternoon. && .SHORT TERM... (Rest of today through Thursday) Issued at 210 PM EDT Wed Sep 18 2024 A trough of low pressure over the southeastern United States is keeping an unsettled pattern over much of Florida today and Thursday. With the trough axis generally east of southern Florida, some relatively cooler air has moved in aloft allowing for somewhat steeper lapse rates compared to previous days. Precipitable water values have dipped below 2 inches but there is still plenty of atmospheric moisture around to allow any slow- moving storms that may form today to be efficient rainfall producers. There is also the potential for some strong to locally damaging wind gusts with the more vigorous convection that may develop today. The westerly component to the wind flow is just present enough to pin the Atlantic sea breeze near the coast offering a focus for convection this afternoon and again on Thursday. Repeated rainfall could lead to localized saturation which will need to be monitored as moisture recovery in the coming days could build into an increasing risk of urban flooding from excessive rainfall. Temperatures will reach the lower 90s again on Thursday afternoon and heat index values should reach the 100 to 106 range. && .LONG TERM... (Thursday night through next Tuesday) Issued at 210 PM EDT Wed Sep 18 2024 By the end of the work week and into the upcoming weekend, upper level troughing will continue to dig southward into the eastern Gulf of Mexico and over South Florida, maintaining west-north westerly flow over the region aloft. Meanwhile a persistent plume of deep tropical moisture remains in place over the region as a diffuse stationary frontal boundary meanders through this period. The presence of cooler upper level temperatures (-6 to -7C @ 500 mb) and a pocket of divergence aloft may act to enhance convective coverage and intensity at times, though most convective will be driven by localized convergence maxima owing to mesoscale processes (sea- breeze and outflow boundary collisions). Expect bouts of periodic heavy rainfall to continue, particularly in the afternoon when instability and low-level convergence is maximized. Heavy rainfall that persists for a prolonged duration over urban areas may result in the usual localized flooding concerns. By Sunday and into early next week, a dominant/expansive ridge of high pressure will emanate from the TX/Mexico region and increase geopotential heights across South Florida. This may be commensurate with a wedge of drier air advecting towards the region through this same period (simultaneously), though there exists uncertainty regarding the southward extent of this drier air-mass. For now, it appears that strong upper ridging coupled with a lack of moisture should allow for rainfall totals that are below climatological norms through this period. Temperatures through this period will hover around seasonal norms through this period. Afternoon high temperatures should reach the upper 80s to low 90, while dew points reach the mid to upper 70s through the early part of the weekend. Heat Advisories may be necessary during portions of this period, although that will be contingent on the rainfall and cloud coverage for any given afternoon. Towards the end of the weekend and into early next week, dew-points may drop a few degrees, although less cloud coverage and rainfall could allow for more oppressive temperatures through this period. The National Hurricane Center continues to monitor an area of low pressure in the western Caribbean Sea with a 20% chance of tropical development over the next seven days. Readers are reminded that a lot can change in the 7-10 day time-frame, especially with the genesis and evolution of tropical systems. While the general pattern for tropical development appears to be favorable, it remains far too early to identify a potential track. In simplest terms, while deterministic model solutions will vary from run to run, it is very important to take them with several grains of salt. Ensemble model plots (EPS and GEFS) may provide a slightly clearer picture of what may unfold, however it is still quite early. Regardless of what transpires, this is an important reminder that we are in the midst of the peak of hurricane season. Although the climatological peak of the Atlantic hurricane season is on September 10th, the stretch of late September into the first half of October is the climatological peak for hurricane landfalls in South Florida. Remain weather aware, check hurricane supplies, and most importantly, be sure to receive information from reliable sources such as the National Hurricane Center, NWS Miami, and local and national broadcast media sources. && .AVIATION... (00Z TAFS) Issued at 722 PM EDT Wed Sep 18 2024 Generally VFR conditions will prevail through the overnight period, although a rogue thunderstorm will remain possible near the east coast terminals through about 02-03Z. Numerous thunderstorms can be expected again near the east coast terminals on Thursday afternoon. Winds will generally be light and variable through Thursday morning, perhaps trending light W-NW by mid-late morning. && .MARINE... Issued at 210 PM EDT Wed Sep 18 2024 Generally light winds will prevail across the area through most of this week as a weak surface boundary remains just to the north of the area. Scattered showers and thunderstorms will be possible each day through the period and could lead to locally higher winds and seas. && .BEACHES... Issued at 210 PM EDT Wed Sep 18 2024 Minor to moderate coastal flooding will continue during periods of high tide due to astronomically higher tides associated with the full moon phase. Elevated tides will continue on both coasts of South Florida through the end of the work-week. Upcoming High Tide Times: * Naples: 1:46 PM Wed, 1:52 AM Thu, 2:38 PM Thu * Lake Worth: 9:01 PM Wed, 9:31 AM Thu, 9:49 PM Thu * Port Everglades: 9:19 PM Wed, 9:50 AM Thu, 10:07 PM Thu * Virginia Key: 10:04 PM Wed, 10:36 AM Thu, 10:51 PM Thu Decreasing northerly swell will result in a lingering elevated risk of rip currents for the Palm Beaches with a decreasing risk along the Broward and Miami-Dade beaches in the coming days. && .PRELIMINARY POINT TEMPS/POPS... Miami 77 90 75 89 / 60 70 50 60 West Kendall 74 90 74 90 / 60 70 50 60 Opa-Locka 77 91 75 90 / 60 70 50 60 Homestead 76 90 75 89 / 60 70 50 60 Fort Lauderdale 77 89 75 88 / 50 70 50 50 N Ft Lauderdale 77 90 76 89 / 50 70 50 50 Pembroke Pines 77 92 76 91 / 60 70 50 60 West Palm Beach 75 91 75 90 / 40 70 50 50 Boca Raton 76 92 75 90 / 50 70 50 50 Naples 78 90 76 90 / 30 50 30 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 2 PM EDT Friday for FLZ069-075-168- 172>174. High Rip Current Risk until 8 PM EDT this evening for FLZ168. AM...None. GM...None. && $$ SHORT TERM...RAG LONG TERM....Hadi AVIATION...Carr