Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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854 FXUS62 KMLB 251950 CCA AFDMLB Area Forecast Discussion...CORRECTED National Weather Service Melbourne FL 350 PM EDT Sat May 25 2024 ...New DISCUSSION, MARINE, FIRE WEATHER... .DISCUSSION... Issued at 252 PM EDT Sat May 25 2024 Key Messages: - Heat concerns continue through the holiday weekend, with highs in the 90s and peak heat indices over 100. - Afternoon storms will be possible today, with frequent lightning strikes, gusty winds, heavy downpours, and small hail the primary concerns with any storms that develop. Rest of Today-Tonight...Lightning storms didn`t waste any time getting started this afternoon, with a strong to severe storm developing in Indian River County a little ahead of schedule. The 15Z XMR sounding is looking a bit spicy, with over 2,000 J/kg of SBCAPE, over 1,200 J/kg of DCAPE, a 6.8 C/km 0-3km lapse rate, and 40-50 kts of unidirectional bulk shear. Despite 500mb temperatures warming to between -7C and -8C, the IRC storm has managed to punch up over 50kft with a significant enough hail core to produce three-body scatter spikes on radar, prompting a severe thunderstorm warning. Sidelobe contamination is making it difficult to get reliable velocities, but gusts 45-55 mph are likely, and locally damaging gusts to 60 mph are possible. The abundance of low level boundaries has led to somewhat erratic storm motion, and given all that convergence, a brief spinup can`t be ruled out. Activity should increase over the next couple hours, becoming isolated to scattered as the sea breezes collide. As long as storms keep moving the risk for flooding will be limited, but depending on how boundaries becoming oriented, back building storms that could lead to locally minor flooding remain possible. As for the rest of the forecast, hot. Temperatures have pushed into the U80s-M90s, and should climb a few more degrees over the next hour to the M-U90s inland and U80s-L90s along the coastal corridor, before starting the muggy crawl back down to around 70 tonight. Winds becoming light and variable overnight. Sunday-Monday...The mid-level ridge axis extending from Mexico across the Gulf and into the southeastern US is shunted south over Florida through Monday afternoon, as a broad trough swings across the CONUS. Increasing subsidence from the ridge and weak high pressure draped across Florida from the western Atlantic will cause afternoon highs to soar into the 90s both days for just about everyone except a few lucky spots on the barrier islands holding short in the U80s, pushing into the U90s across the interior, while the usually hotter parts of Okeechobee and southern Osceola counties flirt with 100 on Monday. Peak afternoon heat indices will reach between 96-103 Sunday, and 99-104 Monday (down a bit from previous forecast thanks to slightly lower dew points, but will need to see if this trend holds). Speaking of moisture, while PWATs 1.4-1.6" will be similar to today, higher temperatures will result in lower relative humidity, and increasing mid-level temperatures will reduce instability, knocking rain and storm chances down to just 20 pct from the Treasure Coast to Lake Okeechobee. With the surface ridge to our south, prevailing westerly flow will slow inland progression of the east coast sea breeze while accelerating the west coast sea breeze (which will also help crank those highs up), resulting in an mostly uneventful collision near or or just east of the Orlando Metro area Sunday, then a little further east Monday as the westerly flow finds a few extra miles per hour but remains near or below 10 mph. Tuesday-Friday (Modified Previous Discussion)...Mid-level troughing will dig into the southeastern US on Tuesday into Wednesday, pushing a weak frontal boundary into Florida. The boundary will likely stall across central Florida, keeping a sufficient band of moisture present locally through the remainder of the forecast period. Diurnal afternoon convection is forecast to return across east central Florida and continue through the remainder of the period. The east coast sea breeze will prompt development of isolated showers and storms as it moves inland, with the sea breeze collision across the peninsula leading to an increase in shower and storm coverage each afternoon. The highest rain chances are forecast on Tuesday afternoon, with PoPs 30 to 50 percent. Wednesday through Friday, rain chances diminish slightly to around 20 to 40 percent. Shower and storm chances decrease each evening into the overnight hours. Heat will continue to be a concern through the long term as temperatures each afternoon continue to climb into the 90s. Heat indices will continue to reach over 100 Tuesday and Wednesday, falling to 95 to 100 Thursday and Friday. Overnight lows will remain in the upper 60s to mid 70s. && .MARINE... Issued at 252 PM EDT Sat May 25 2024 Rest of Today-Sunday...Favorable winds and seas today, but isolated to scattered lightning storms are expected to push offshore late this afternoon and evening, working eastward across the waters through the early overnight. Some of these storms could become strong, capable of gusty winds over 35 kts and locally higher seas. Generally favorable boating conditions Sunday, with just a few showers and storms possible across the Treasure Coast waters. The ridge axis of weak, broad high pressure will remain south of the local Atlantic waters, producing light SW-WSW in the overnight and morning, becoming calm and variable at times, that back to SE-ESE at 10-15 kts in the afternoon after the sea breeze develops. Seas 1-3 ft. Monday-Wednesday Modified Previous Discussion)...Generally favorable boating conditions will continue into the middle of next week. West-southwest winds will become south-southeast each afternoon as the east coast sea breeze develops, with wind speeds 5 to 10 knots increasing to 10 to 15 knots each afternoon through the period. Seas are forecast to remain between 1 to 3 feet. Monday, drier air present across the Florida peninsula will continue to limit rain and storm chances, with any development that does occur likely remaining south of the Cape. Rain chances increase again on Tuesday and Wednesday across the local Atlantic waters as a weak front stalls across or just north of the waters, with showers and storms that develop across the Florida peninsula moving offshore into the late afternoon and early evening hours. Activity will diminish into the overnight hours. && .FIRE WEATHER... Issued at 252 PM EDT Sat May 25 2024 Warm temperatures across the Florida peninsula will persist through the weekend and into the beginning of next week, leading to sensitive fire weather concerns. Across the interior, minimum RH values between 35 to 45 percent are forecast each afternoon through at least Thursday. Winds are forecast to remain below 15 mph through the period. Lightning storm development will be possible today and again Tuesday through Thursday along the sea breeze. && .AVIATION... (18Z TAFs) Issued at 128 PM EDT Sat May 25 2024 Winds 5-10 KT this afternoon with winds SW across the interior, and onshore along the coast. The east coast sea breeze has formed and is beginning to push inland. Isolated showers have developed near MCO this afternoon, so have started VCSH a little earlier than previous TAF packages. The sea breeze collision is still expected to occur near MCO/ISM around 21Z. Have kept VCSH/VCTS for the rest of the terminal starting at 19Z. TEMPOs for TSRA impacts at MLB- SUA from 20-24Z. Brief MVFR/IFR conditions possible in stronger storms. Showers and storms should clear by 00-02Z. VFR conditions outside of convection through the TAF period. Winds will become light and variable overnight before speeds increase to around 5-10 KT and winds become SW across the interior and onshore along the coast by mid-morning. && .PRELIMINARY POINT TEMPS/POPS... DAB 71 93 72 94 / 20 10 0 10 MCO 72 97 73 97 / 10 10 0 10 MLB 73 90 74 93 / 30 10 10 10 VRB 71 92 73 94 / 30 10 10 20 LEE 73 95 74 94 / 10 10 0 10 SFB 72 96 74 96 / 10 10 0 10 ORL 73 96 75 97 / 10 10 0 10 FPR 71 92 72 95 / 30 20 10 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ DISCUSSION...Haley AVIATION...Watson