Marine Weather and Tide Forecast for Port St. Lucie, FL

DISCUSSION
Issued at 154 AM EDT Wed Aug 5 2026

-----------Synoptic Overview-----------

A pattern change is underway for the Florida Peninsula. The weak upper low over the Southern Appalachians is weakening and slowly lifting northward, as was expected. Meanwhile, the Bermuda high over the W Atlantic is continuing to strengthen, with H5 heights already rising above normal over Florida this morning. Over the next 36 hours, the core of the 598 dam H5 anticyclone will become anchored off the Outer Banks. In tandem, surface high pressure will retreat northward, its axis passing over Central Florida today on its way to the I-20 corridor by Thursday afternoon.
Boundary layer flow will quickly shift to the SE today before backing to the east beginning Thursday. In this regime, total moisture (PWATs) will decrease slightly, approaching normal for early August.

An inverted trough was initialized this evening north of the U.S. Virgin Islands. It is moving quickly westward beneath the sprawling high to its north. Considerable disagreement still exists regarding the sharpness of this trough once it reaches Florida by Friday, with EPS members sharper and GEFS members weaker. Still, a batch of rich moisture is expected to accompany this feature as it moves through the area through at least early Saturday.

Cluster analysis of the 04/12Z grand ensemble exhibited strong agreement in the upper-air pattern late this weekend and early next week. A mid-latitude polar jet streak flattens the ridge over the W Atlantic, shunting its axis southward toward Florida as it expands westward over the Gulf. By Sunday and Monday, H85 temperatures nudge slightly above normal while total moisture decreases to near seasonal averages. The ridge is forecast to remain in place through at least the middle of next week. There remains some hint of a Saharan Air Layer (SAL) beyond Tuesday, which may lower moisture values below normal at the tail end of the forecast period.

-------Sensible Weather & Impacts-------

Today - Thursday...

Lingering showers finally diminished over interior, and mainly dry conditions are expected early this morning. As southeasterly flow begins in earnest, a few showers may approach the coast later in the morning. A diffuse Atlantic sea breeze should march inland this afternoon, sparking at least scattered showers and storms (30-50% coast, 50-70% interior). Some of the guidance suggests that cloud cover will linger over the I-4 corridor today, limiting the strongest instability to the interior south of Orlando. Any activity should diminish after sunset, with only low shower chances overnight, especially on the Treasure Coast.

As winds turn solidly onshore on Thursday, a few showers or storms may move ashore on the coast in the morning before the focus pushes inland and toward the west coast late in the afternoon. Overall, rain chances range from 50-60% at the coast to 60-75% over the interior.

Should any stronger storms form, they would be capable of producing the usual summer hazards: frequent lightning, gusty winds up to around 50 mph, and torrential rainfall of 2-4" in a short period.

High temperatures should reach the upper 80s to low 90s each day, with peak heat indices near or just above 100.

Friday - Saturday...

Easterly winds increase as the trough pushes near or over Florida to end the work week. This will bring a surge of additional moisture into the area, likely sparking bands of showers and storms on Friday. Coastal showers in the morning should be enhanced by the wave, then the focus of storms drifts inland by afternoon. Overall, 60-80% coverage is forecast on Friday. While a sharper trough would pose at least a low risk of excessive rainfall, it is still too early to determine how organized this feature will be. Statistical guidance shows only a 5% chance of 2"+ of rainfall between Friday morning and Saturday night.

The moisture surge slowly lifts northward on Saturday, with some drying noted in the mid-levels, especially southeast of Orlando late in the day. Deviated somewhat from NBM rain chances, which looked too high given the pattern. Went with rain chances just above climatology, from 40-50% along the coast up to 60-70% elsewhere.

Seasonably hot and muggy conditions persist, with heat indices from 100-105, warmest on Saturday. Surf is still forecast to become choppy at our beaches by Friday, likely increasing the risk of life-threatening rip currents.

Sunday - Next Week...

With Central Florida fully influenced by a sprawling area of high pressure, the daily sea breeze circulation will become the focus for afternoon and evening showers and storms. Coverage should lessen each day as we move into next week, courtesy of some drier air aloft approaching the state from the east. With less storm coverage, temperatures should turn hotter. Widespread low/mid 90s are forecast. Seasonably high dew points may allow heat indices to nudge closer to 105-108 degrees.

MARINE
Issued at 154 AM EDT Wed Aug 5 2026

High pressure will move over the local Atlantic waters today before lifting north of the area on Thursday. Onshore flow will develop, with a diffuse sea breeze pushing inland each afternoon. Winds freshen slightly on Friday as a trough passes over the waters. Briefly poor boating conditions may occur with this feature, especially in the Gulf Stream. After this disturbance passes, high pressure is expected to remain in place through early next week.

SE winds up to 10 kt today, becoming E at 10-15 kt on Thursday. E winds freshen to 15-18 kt in the Gulf Stream early Friday, before settling slightly out of the SE by the weekend (10-15 kt). Seas 1-3 ft through Thursday, building to 3-5 ft on Friday. Seas generally 2-4 ft this weekend.

AVIATION
(12Z TAFs)
Issued at 658 AM EDT Wed Aug 5 2026

Mainly VFR outside of showers and storms today. May see some initial showers or a storm push onshore near KSUA toward mid to late morning. Otherwise, scattered showers and storms are forecast to develop with the inland moving east coast sea breeze this afternoon and evening, with greatest coverage focused inland west of I-95. Tempo IFR/MVFR conditions will occur with any of this activity. Have PROB30 and TEMPO groups for MVFR TSRA impacts continuing for all sites, with three hour windows around 18/19Z-21/22Z at the coast, except 16-19Z at KSUA, and 20-23Z for inland TAF sites, including KMCO. Isolated strong storms will be possible today. As convection diminishes into the evening, some areas of light debris cloud rainfall may persist through midnight, then will see a return of isolated onshore moving showers along the coast overnight.

Southeast winds around 5 knots this morning become easterly around 8-10 knots behind the inland moving east coast sea breeze in the afternoon. Winds then diminish after sunset, becoming 5 knots or less.

PRELIMINARY POINT TEMPS/POPS
DAB 88 76 89 77 / 30 10 50 10 MCO 90 75 91 76 / 50 20 60 10 MLB 88 77 89 78 / 30 20 50 20 VRB 88 77 89 77 / 40 30 60 40 LEE 89 76 90 76 / 50 30 60 10 SFB 90 76 92 77 / 40 20 60 10 ORL 90 76 91 77 / 50 20 60 10 FPR 88 76 89 77 / 50 30 60 40

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