Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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675 FXUS62 KMLB 191859 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 259 PM EDT Thu Sep 19 2024 ...New DISCUSSION, MARINE, HYDROLOGY... .DISCUSSION... Issued at 255 PM EDT Thu Sep 19 2024 Key Messages: - Showers and storms continue through mid evening, decreasing rain chances as a front settles south of the area this weekend - High astronomical tides promote minor coastal flooding into this weekend, particularly during late morning high tides - A medium chance for tropical development next week remains in the northwest Caribbean and Gulf of Mexico Now-Tonight...An earlier start to showers and lightning storms is under way this afternoon. Activity is generally moving to the east around 15 mph, and the highest coverage of rain so far extends from Lake Okeechobee to the Treasure Coast. Coverage of showers and storms is expected to continue increasing this afternoon through early evening, before activity gradually dissipates by mid to late evening. RAP analysis shows 1000-2000 J/kg of MLCAPE areawide with very weak mid level lapse rates. Despite slightly more supportive 500mb temps around -6C to -7C, updrafts will struggle to maintain any formidable strength. Additionally, PW are lower across the northern half of the area (1.5-1.6"), compared to values around 1.9- 2.0" over locations from Osceola and southern Brevard southward. All of this is to say, the environment is supportive of brief heavy downpours, gusty winds up to 45 mph, and occasional lightning strikes. Even a brief funnel cloud along boundary collisions cannot be ruled out. However, stronger activity will likely be held back by the limiting environmental conditions today. As rain winds down later this evening, temperatures will retreat from the 80s to the mid 70s overnight. Sky conditions are expected to improve west to east, and similar to the past couple of mornings, some patchy fog is possible over northern Lake and Volusia counties into Friday morning. A reminder that a high risk of rip currents remains at the Volusia and northern Brevard County beaches, along with a moderate risk of rip currents at the southern Brevard County and Treasure Coast beaches through tonight. Additionally, a Coastal Flood Advisory continues with minor flooding of low-lying areas along the shoreline possible, especially around times of high tide (10 PM tonight). Friday-Saturday...Coastal flooding concerns increase around times of high tide, especially the mid morning high tides, late this week into the weekend. A Coastal Flood Advisory remains in effect through Saturday afternoon, and it is possible that this will need to be extended further into the weekend. Some flooding of low-lying areas along the shoreline, potentially leading to instances of road closures, is possible. A weak surface boundary settles well south of the area on Friday, allowing drier northerly flow to overspread north central Florida. This forecast reflects a shift to the drier weekend pattern, beginning Friday afternoon, with 15-25 PoP north and 30-40 PoP from Melbourne south to Lake O and the Treasure Coast. Slightly higher moisture in these locations will allow for a little better coverage of showers and a few lightning storms. Similarly on Saturday, 15-25 PoP is in place for much east central Florida, as weaker marine showers approach the coast and any development along the inland-moving sea breeze stays rather isolated. Temperatures both days will top out in the upper 80s to low 90s, but with lower humidity, heat index values are expected to remain below the 100 degree mark. Overnight lows return to the low 70s inland to the mid 70s along the coast. Sunday-Wednesday...As upper ridging builds east over the Gulf Coast and southeast U.S. late weekend into early next week, a lot of questions remain regarding our next chance at widespread measurable rainfall. Monday and Tuesday look to be the driest with only 15-20 PoP, and depending on what happens across the northwest Caribbean early to mid week (if anything), we will stay in a drier pattern until deeper, southerly moisture makes a return to the state. As outlined by the National Hurricane Center, a medium chance for tropical cyclone development in the next 7 days over the northwest Caribbean and south-central Gulf of Mexico. Models continue to waver on a myriad of solutions, so for now, continue to monitor the latest forecasts. Highs each day into next week are forecast to remain near or slightly above mid-September normals, with lows around typical values (low 70s) for this time of year. && .MARINE... Issued at 255 PM EDT Thu Sep 19 2024 Now-Tonight...Seas will continue to fall into tonight, around 2-4 ft, as onshore flow becomes light and variable through daybreak Friday. Scattered showers and lightning storms will continue to push over the waters through the evening and may last through the early overnight period. Locally higher wind gusts and seas are possible as a result of this activity. Friday-Monday...Generally favorable conditions are forecast through the weekend with poor boating conditions potentially returning by Sunday or early next week. Persistent northeasterly winds will increase each day with the highest gusts 15-20 kt in the afternoon and evening hours. Seas 2-3 ft thru Saturday, increasing to 3-5 ft Sunday-Monday. && .HYDROLOGY... Issued at 255 PM EDT Thu Sep 19 2024 The Saint Johns River at Astor is forecast to remain in Moderate Flood stage through at least the upcoming weekend. The potential exists for small additional rises if locally heavy rainfall develops over the river basin. Farther upstream, the Saint Johns at Deland and Sanford will remain near or slightly above Action Stage. && .AVIATION... (18Z TAFs) Issued at 130 PM EDT Thu Sep 19 2024 Increasing shower and storm coverage is forecast through the remainder of this afternoon and into the evening hours as the east coast sea breeze moves inland and collides with the west coast sea breeze. Activity has already started across the Treasure Coast terminals, with TEMPOs between 18-21Z. Guidance is hinting at a later collision across the interior terminals, so have started TEMPOs later, between 22-01Z. The TEMPOs are for VIS and CIG reductions to MVFR due to TSRA, though drops to IFR cannot be ruled out. Will continue to monitor and amend as needed. Activity will linger into the evening as activity gradually moves offshore, with conditions improving after 00Z. VFR conditions are forecast through the overnight hours with winds becoming light and variable. Winds pick back up out of the NE after 15Z between 5 to 10 knots. && .PRELIMINARY POINT TEMPS/POPS... DAB 73 88 74 88 / 10 20 10 30 MCO 74 90 74 90 / 30 20 0 30 MLB 74 88 74 88 / 30 30 10 20 VRB 73 89 74 89 / 30 40 10 20 LEE 74 90 73 90 / 20 20 0 20 SFB 73 89 73 89 / 20 20 0 30 ORL 74 90 74 90 / 30 20 0 30 FPR 72 88 73 89 / 30 40 10 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 2 PM EDT Saturday for FLZ141-154- 159-164-347-447-647-747. AM...None. && $$ DISCUSSION...Schaper AVIATION...Tollefsen