Marine Weather and Tide Forecast for Sebastian, FL

DISCUSSION
Issued at 400 PM EDT Wed Jul 15 2026

Currently-Tonight... Current KMLB radar imagery shows dry weather across east central Florida. GOES-16 satellite imagery and local observations indicate mostly clear skies across east central Florida. Analysis charts show a mid/upper level high over the Gulf with a mid level trough over the western Atlantic. Temperatures are currently in the upper 80s to low 90s with dew points in the low to upper 70s. Heat index values are in the upper 90s to around 104F degrees.

Scattered east-southeast moving showers (30-50% chance) and lightning storms are forecast to develop this afternoon and evening hours before showers and lightning storms diminish and push offshore of the Treasure Coast by around 10PM. This morning's 15Z XMR sounding shows MUCAPE pf 2,433 J/kg, DCAPE at 594 J/kg 0-6km shear at 11kts, a PWAT value of 1.71", and a 500mb temperature of -6C which suggests that the potential for a strong to marginally severe storm is low and isn't high compared to previous days. Low temperatures in the low to upper 70s are forecast with mostly clear skies.

Thursday-Friday... Moisture is expected to increase areawide on Thursday with PWAT values between 2.0"-2.5". Guidance shows MLCAPE up to 1,500-3,000 J/kg, 0-6km shear up to 20-30kts enhanced by the local sea breeze, as well as conditionally to absolutely unstable lapse rates. Additionally, guidance shows PVA pivoting across east central Florida during the afternoon and evening hours which will enhance lift for strong to marginally severe storms to develop. Scattered to numerous showers (30-70% chance)
and lightning storms are forecast to develop in the afternoon and evening as collisions occur between sea breezes and outflow from previous storms. A similar forecast is expected on Friday with slightly higher probability of precipitation. The main hazards will be frequent lightning, wind gusts up to 40-60 mph (< 5% chance to 60mph), and heavy rainfall (1-3"+ in 30 to 60 minutes with the potential to result in minor flooding of roadways and low lying areas). Afternoon highs in the low to mid 90s with heat index values between 100F-107F are forecast with lows in the low to upper 70s. A Moderate to Major HeatRisk exists on Thursday. A Major HeatRisk affects anyone without adequate cooling and hydration.

Saturday-Tuesday (modified previous discussion)... Deterministic guidance has gone back and forth on the potential development of a tropical disturbance in the eastern Gulf and the state of Florida Saturday into Sunday. Conditions will be favorable for development if it occurs with the GFS and ECMWF showing relatively low deep layer shear, as well as current SSTs at 30C+.
Additionally, the LREF ensembles are all in good agreement on a pattern favorable for a tropical disturbance to develop in the eastern Gulf. However, there is currently a 20% (low) chance of development. Regardless, a trough is expected to remain in place across the Florida peninsula through the weekend and into next week. The surface high will respond by shifting southward with the ridge axis forecast to stay south of central Florida through the extended period. Persistent west to southwest flow is forecast locally, resulting in moisture advection from the Gulf towards east central Florida. Rain and storm chances are forecast to remain high as a direct result with a return of scattered to numerous shower and lightning storm coverage anticipated each afternoon from Saturday through Tuesday. Convection will be primarily driven by the west coast sea breeze pushing across the peninsula, with the sea breeze collision favored across the eastern peninsula each afternoon. Activity will then push offshore, diminishing across the local Atlantic waters through the overnight hours. In addition to showers and storms, the usual Florida heat will persist, with near to slightly above normal highs forecast in the low to mid 90s. Humid conditions will support peak heat indices exceeding 100F areawide, with a low chance of nearing Heat Advisory criteria in some spots through the extended period. Will continue to closely monitor trends.

MARINE
Issued at 400 PM EDT Wed Jul 15 2026

Currently-Sunday (previous discussion)... Generally favorable boating conditions are forecast across the local Atlantic waters.
Broad surface high pressure will remain situated just south of the local waters, allowing for persistent west to southwest flow overnight and into the morning hours, with the east coast sea breeze causing winds to become more southerly during the afternoons. Wind speeds are forecast to remain below 15 knots through the remainder of this week and into the weekend. Seas remain between 1 to 3 feet.

Rain and storms will be possible each afternoon into the evening and overnight hours as activity from the peninsula pushes offshore. Coverage of showers and storms will increase Thursday onward as moisture increases across the local Atlantic waters.
Storm hazards with convection will include cloud-to-water lightning strikes, wind gusts in excess of 34 knots, brief heavy downpours, and locally higher seas near convection.

AVIATION
(00Z TAFs)
Issued at 733 PM EDT Wed Jul 15 2026

Unusually dry for a July evening, with only a few showers near SFB and DAB prior to 0Z. Have maintained VCSH mention there and at TIX through around 1Z. Otherwise, dry conditions look to prevail through tonight, as winds become light and offshore. Scattered showers and storms are forecast Thursday, beginning over the interior around 18-19Z, before spreading towards the coast on W winds around 8-10 kts. A sea breeze collision at the coast could lead to some VIS/CIG impacts at coastal terminals, but have left out any TEMPOs or PROB30s, for now. W winds prevail, but an east coast sea breeze looks to develop in the afternoon east of I-95.

PRELIMINARY POINT TEMPS/POPS
DAB 75 91 75 91 / 20 70 20 70 MCO 76 93 77 93 / 10 60 30 70 MLB 76 92 77 91 / 20 60 30 70 VRB 74 93 75 92 / 20 50 30 70 LEE 77 92 77 91 / 10 60 30 70 SFB 77 93 77 93 / 10 70 20 70 ORL 77 93 77 92 / 10 60 30 70 FPR 74 93 74 92 / 20 50 30 70

MLB WATCHES/WARNINGS/ADVISORIES
FL...None.
AM...None.