Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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195 FXUS62 KMLB 170851 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 451 AM EDT Tue Sep 17 2024 ...New DISCUSSION, MARINE, HYDROLOGY... .DISCUSSION... Issued at 451 AM EDT Tue Sep 17 2024 Key Messages: - A marginal risk for isolated severe storms exists across all of east central Florida today. - Poor to hazardous boating and surf conditions continue today. - High astronomical tides will promote elevated water levels this week, and a Coastal Flood Advisory continues through at least tonight. Current-Tonight... High cloud cover is in place across much of east central Florida this morning while observing stations indicate localized areas of lower stratus. Patchy fog remains forecast across the interior, hinting at visibility reductions where clouds lower. A few showers continue in vicinity of Lake Okeechobee while lightning has remained over the local Atlantic waters. A weak surface boundary across the southern half of the peninsula gradually lifts northward late today into tonight. Aloft, a mid level shortwave swings across the area. Scattered diurnal showers and storms are forecast as surface heating and boundary interactions occur. Model soundings suggest steep low level lapse rates this afternoon which will be supportive of quick strengthening storm updrafts. An isolated marginal threat exists where updrafts can interact with dry air and shortwave energy aloft. However, it is worth noting some uncertainty in the forecast. Continued broken cloud cover and occasional light showers are forecast to continue across the south where the greatest moisture exists. This could delay or limit surface heating where CAMs generally suggest the greatest convective coverage should occur. An isolated severe storm which can develop will be capable of localized damaging wind gusts up to 60 mph, frequent lightning strikes, and torrential downpours. Westerly steering flow will push convective coverage back towards the coast late this afternoon and into the evening. Hazardous beach and coastal conditions continue today. Long period swells around 9-10 seconds will promote a a high risk of life threatening rip currents at all area beaches. Additionally, astronomical high tides will continue a minor coastal flood threat through at least this evening`s high tide cycle. High temperatures remain near seasonal in the upper 80s to low 90s. Peak heat index values are forecast between 98-105. Wednesday-Thursday... Mid level low pressure across the southeast U.S. becomes an open trough into Thursday. A surface boundary continues to lift northward Wednesday, shifting back southward across the area on Thursday. Local boundary interactions and pulses of shortwave energy aloft should support scattered afternoon and evening convection (40-50%) across much of east central Florida each day. Slightly higher coverage of showers and storms (~60%) is forecast across Okeechobee and the Treasure Coast in vicinity of higher moisture. Westward steering flow should allow inland convection to push back toward the coast each evening. Dry air aloft could promote isolated wind gusts up to 50 mph where stronger convective mixing can occur. Otherwise, hazards associated with isolated stronger storms include occasional to frequent lightning strikes and locally heavy downpours. Temperatures mostly in the low 90s Wednesday fall a few degrees cooler on Thursday, ranging the upper 80s to near 90. Peak heat index values are forecast between 98-103 degrees. Friday-Monday...A 500mb vorticity boundary slides southeastward across the state late week as mid level troughing moves offshore the eastern seaboard. A surface boundary settles across south Florida as high pressure builds across the southeast U.S. The greatest moisture remains southward late week into early next week. However, scattered PoPs remain in the forecast each day as sustained onshore flow develops. Seasonal temperatures are forecast each afternoon ranging the upper 80s to near 90. && .MARINE... Issued at 451 AM EDT Tue Sep 17 2024 Today-Tonight...Hazardous seas up to 7 ft offshore gradually subside through late morning, and a Small Craft Advisory remains in effect through 11 AM. Otherwise, small craft should exercise caution this morning for seas up to 6 ft across nearshore Brevard and the nearshore Treasure Coast. Seas become widely 4-5 ft late tonight. Winds remain light and variable, developing an onshore component near the coast as the sea breeze develops. Scattered offshore moving showers and storms are forecast into the afternoon and evening. An isolated severe storm will be possible, producing wind gusts up to 34 kts. Wednesday-Saturday...Seas continue to subside Wednesday becoming 3-4 ft. Winds remain light and variable before becoming onshore into late week. Scattered to numerous showers and scattered lightning storms are forecast through the period. && .HYDROLOGY... Issued at 451 AM EDT Tue Sep 17 2024 The Saint Johns River near Astor is forecast to remain in Moderate Flood stage (around 3.2-3.4 ft) through this week. The potential exists for small additional rises if locally heavy rainfall develops over the river basin. Southward, additional heavy rainfall across the Saint Johns River basin has caused a steady rise in river levels with the forecast point at Deland forecast to remain in Action Stage and the point at Sanford forecast to reach Action Stage today. Geneva Above Lake Harney is now forecast to remain just below Action Stage. Additional heavy rain could cause further rises, so interests along the river should monitor for forecast updates. && .AVIATION... (06Z TAFs) Issued at 120 AM EDT Tue Sep 17 2024 Will monitor for patchy fog/low stratus (low confidence) development overnight and early Tue morning, otherwise continued mainly VFR outside of afternoon/evening convection ~ MVFR CIGs/VSBYs. Should any fog/stratus develop, expect burn-off by around mid-morning. Some "Vicinity" wording in place for later convection and will accommodate TEMPO groups later on as necessary. Appears greatest convective coverage may be south of KMCO. Light/variable winds will transition onshore in the afternoon as the sea breeze develops and pushes well inland by late in the day. Storm steering flow today will be toward the ENE at 10-15 kts. && .PRELIMINARY POINT TEMPS/POPS... DAB 87 73 91 73 / 30 10 40 30 MCO 91 75 92 74 / 50 10 50 30 MLB 89 75 90 74 / 50 20 40 40 VRB 91 73 91 73 / 50 30 50 40 LEE 89 74 91 74 / 40 10 50 20 SFB 89 73 91 74 / 50 10 50 30 ORL 91 75 92 75 / 50 10 50 30 FPR 91 73 91 73 / 50 20 60 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until midnight EDT tonight for FLZ141-154- 159-164-347-447-647-747. AM...Small Craft Advisory until 11 AM EDT this morning for AMZ570-572- 575. && $$ DISCUSSION...Law AVIATION...Sedlock