Marine Weather and Tide Forecast for Altamonte Springs, FL

DISCUSSION
Issued at 250 PM EDT Sat Jul 11 2026

Through Tonight...Deep layer high pressure remains overhead across the Florida peninsula this afternoon, with shower and storm activity already firing up along the west coast sea breeze. The east coast sea breeze has developed and is actively pushing inland, with an eventual sea breeze collision across the central peninsula anticipated to lead to the highest coverage today. CAM guidance continues to favor the greatest coverage near and north of the I-4 corridor, but isolated to scattered activity will continue to be possible across most of east central Florida as the sea breeze moves inland. SPC has added northern portions of east central Florida in a Marginal Risk (1/5) for severe storms this afternoon. Plentiful surface instability via daytime heating and steep low-level lapse rates will support storm development, with frequent lightning strikes, wind gusts to 60 mph, and heavy downpours all possible with the strongest activity. Small hail cannot be ruled out given 500mb temperatures of -8C to -7C overhead. Anticipate shower and storm activity diminishing by midnight, with mostly dry conditions then prevailing through the overnight hours along with light southwesterly winds.

A Heat Advisory remains in effect across all of east central Florida through 7 PM for peak heat indices of 105-110F. Afternoon highs remain on track to reach the mid 90s, with some spots across the north forecast to reach the upper 90s. Overnight lows are forecast to fall into the 70s, with conditions remaining muggy areawide.

Sunday-Monday...Mid-level and surface high pressure remains in place across the Florida peninsula through the remainder of this weekend and into Monday, with the ridge axis forecast to generally stay draped across central Florida. Southwesterly flow will continue to advect moisture towards east central Florida, with PWATs forecast to range between 1.7-2" areawide. The west coast sea breeze will develop and quickly move inland, while the east coast sea breeze will struggle to develop and, if it does manage to develop, remain pinned closer to the east coast. As the west coast sea breeze pushes eastward, shower and storm coverage is forecast to increase along and ahead of it, with coverage increasing as the sea breeze collision occurs across east central Florida (PoPs 30-50%). This pattern is forecast to occur both Sunday and Monday afternoons, with activity pushing offshore across the local Atlantic waters into the late evening and overnight hours. Any storms that develop will be capable of producing frequent lightning strikes, wind gusts to 55 mph, and heavy downpours.

Afternoon temperatures are forecast to remain in the mid 90s both Sunday and Monday afternoons, which is still above normal but not quite as warm as the last few days. Peak heat indices are forecast to still exceed 100F, but there is less confidence in reaching Heat Advisory criteria. The guidance will be monitored closely. Preventative actions to avoid heat illness should continue to be taken by residents and visitors spending extended periods of time outdoors.

Tuesday-Friday...Mid-level troughing will be draped across the southeastern US into the middle of next week, providing mid-level support for a stalling boundary just north of the Florida peninsula. The surface high will weaken across the Florida peninsula, with the ridge axis shifting southward. While this set- up would typically lead to increasing moisture across the local area, there is guidance suggesting another wave of Saharan dust drifting towards the Florida peninsula, which would help to limit shower and storm development through mid to late next week. The GFS has keyed in on this drier solution, causing NBM PoPs to trend downward (20-40%). The Euro, however, continues to favor a wetter solution across the Florida peninsula. Would not be surprised to see some fluctuations in PoPs through the extended period over the next few days as the guidance continues to key in on how the pattern will evolve. For now, have stuck with NBM guidance as a good middle road, with 20-40% chances Tuesday and Friday and 20% chances Wednesday and Thursday. Temperatures are forecast to remain above normal through next week with highs in the mid to upper 90s and lows in the mid to upper 70s.

MARINE
Issued at 250 PM EDT Sat Jul 11 2026

Favorable boating conditions are forecast to continue through this weekend and into next week as broad high pressure remains in place across the local Atlantic waters. South to southwest winds at 5 to 10 knots during the overnight and morning hours will become more southeasterly at 10 to 15 knots each afternoon as the east coast sea breeze develops. Seas are forecast to remain between 1 to 3 feet through the period.

Isolated to scattered showers and storms will be possible at times across the local Atlantic waters through the forecast period. The best rain and storm chances are forecast on Sunday and Monday, primarily across the nearshore waters as activity moves offshore into the late evening and overnight hours.

AVIATION
(06Z TAFs)
Issued at 140 AM EDT Sun Jul 12 2026

VFR conditions outside of convection at ECFL terminals through the TAF period. Light SW-WSW/VRB winds overnight pick up to 5-10 kts from the WSW in the late morning. Offshore flow will slow development/inland progression of the east coast sea breeze, shifting winds onshore (SE-E) along the coast after 18Z. TS are forecast to develop on the quick moving west coast sea breeze after 18Z (possibly as early as 16Z) and gradually increase in coverage while pushing east. ISO TS may develop on the nearly pinned east coast sea breeze INVOF of the coastal terminals after 18Z. TS forecast to become SCT-NUM leading up to and along the sea breeze collision after 20Z west of the I-95 corridor. Added TEMPOs for TS impacts at KMCO and most other TAFs from KMLB-KISM north, and PROB30 along the Treasure Coast where chances are a little lower. Some uncertainty in timing, and can't rule out TS impacts an hour or two sooner than forecast in the TAFs. Will continue to evaluate. TS/SH diminish or move offshore after 00Z, but impacts could linger as late as 04Z. Quiet again overnight after convection dies off and winds become light S-SW/VRB.

PRELIMINARY POINT TEMPS/POPS
DAB 93 76 93 76 / 60 10 50 0 MCO 95 77 97 76 / 50 20 20 0 MLB 93 77 94 77 / 50 30 30 10 VRB 94 77 96 76 / 50 20 30 10 LEE 93 78 94 78 / 40 10 30 10 SFB 94 77 95 77 / 60 20 30 0 ORL 94 77 95 77 / 60 20 20 0 FPR 94 76 96 75 / 40 20 20 10

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