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

UPDATE
Issued at 900 PM EDT Fri May 16 2025

The forecast for east central Florida remains on track. An area of high pressure remains situated across the area, keeping skies mostly clear and conditions dry. After a warm day across east central Florida, temperatures have slowly started to fall back into the 80s this evening, with overnight lows forecast to fall into the upper 60s to low 70s.

PREVIOUS DISCUSSION
Issued at 358 PM EDT Fri May 16 2025

Currently-Saturday... Local radar imagery shows dry weather over east central Florida and GOES-16 satellite imagery shows mostly clear skies. High pressure (~1018mb) is situated over the eastern Gulf of America and the state of Florida. Temperatures are currently in the upper 80s to mid 90s with heat index values in the 90s to 100F degrees and dew points generally in the 60s to low 70s. Winds are from the east-southeast at 6-12mph with gusts to 20mph along the coast with the east coast sea breeze beginning to move inland and from the west-southwest at 6-12mph to the west of I-95.

Dry and hot weather is expected to continue this afternoon with above normal to record high temperatures. Dry and hot weather will continue Saturday afternoon with high pressure over Florida, as well as 500mb heights at around 591dm forecast over east central Florida into Saturday afternoon. ECMWF and NAEFS ensembles indicate afternoon temperatures in the 97.5th to maximum percentile for this time of year over east central Florida. Lows in the mid 60 to mid 70s are forecast. Above normal (~5-10F+) to record high temperatures in the low to mid 90s are forecast. There is a Moderate HeatRisk on Saturday. This level of heat affects most individuals sensitive to heat, especially those without adequate hydration. It is recommended that those who spend extended periods of time outside this afternoon and early evening to drink plenty of water, wear light-colored clothing, reduce time spent outdoors or stay in the shade, and take breaks in an air conditioned facility.

Sunday-Tuesday... High pressure over Florida on Sunday is expected to gradually shift east over the southwest Atlantic on Monday and Tuesday. Guidance shows 500mb heights over east central Florida around 588-591dm Sunday to Tuesday. Additionally, ECMWF and NAEFS ensembles indicate afternoon temperatures in the 90th to maximum percentile for this time of year over east central Florida. Dry weather is expected with high temperatures in the low to upper 90s and lows in generally the mid 60s to mid 70s. Heat index values between 98-106F degrees are forecast. There is a Moderate to Major HeatRisk Sunday to Monday, and a Moderate to Extreme HeatRisk Tuesday. A Major to Extreme HeatRisk affects anyone without effective cooling and/or hydration. More information on HeatRisk can be found at wpc.ncep.noaa.gov/heatrisk. Winds are forecast to increase from the east-southeast at 10-15mph with gusts to 20mph into each afternoon with the east coast sea breeze generally to the east of the Orlando metro with winds from the west-southwest at 5-10mph.

Wednesday-Thursday... High pressure is expected to weaken and shift southeast over the southwest Atlantic Wednesday and Thursday before a "cool" front is forecast to move east-southeast over east central Florida on Thursday. Global models show PWATs between 1.40-1.70" over east central Florida on Thursday.
Isolated showers (PoPs ~20%) and lightning storms are forecast ahead of the "cool" front Wednesday evening and into early Thursday morning generally along and to the north of I-4 as the aforementioned front moves south over northern Florida before moving over east central Florida into Thursday afternoon. Isolated to widely scattered showers (PoPS ~ 20-30%) and lightning are forecast to develop from the northwest to southeast over east central Florida Thursday morning and afternoon before showers and storms are expected to move offshore of the Treasure Coast into Thursday night. West-southwest winds at 10-15mph with gusts to 20-25mph are forecast. Above normal to record afternoon highs in the low to upper 90s are forecast on Wednesday and the upper 80s to mid 90s are forecast on Thursday. Heat index values between 98-106F degrees are forecast on Wednesday. There is a Moderate to Extreme HeatRisk on Wednesday and a Moderate HeatRisk on Thursday.
Lows in the upper 60s to mid 70s are forecast.

MARINE
Issued at 218 PM EDT Fri May 16 2025

Currently-Saturday.... Favorable boating conditions and dry weather are expected with high pressure (~1018mb) over Florida.
South-southeast winds at 6-14kts are expected to veer west- southwest tonight and back east-southeast into Saturday afternoon.
Seas to 1-3ft are expected.

Sunday-Tuesday... Favorable boating conditions and dry weather are expected with high pressure (~1017mb) over Florida expected to gradually shift southeast over the southwest Atlantic through Tuesday. West-southwest winds at 6-14kts are expected to back east-southeast into each afternoon and increase to 10-15kts on Tuesday. Seas to 1-3ft are expected.

AVIATION
(00Z TAFs)
Issued at 720 PM EDT Fri May 16 2025

VFR conditions anticipated tonight through tomorrow, with no rain chances forecast near the terminals. Variable winds tonight pick up out of the west-southwest at 5 to 10 knots tomorrow morning.
Along the coast from TIX southward, winds are forecast to become more onshore as the east coast sea breeze develops and moves inland during the afternoon hours.

FIRE WEATHER
Issued at 358 PM EDT Fri May 16 2025

Sensitive fire weather conditions are expected through mid week next week with soils expected to continue to dry out with no mentionable rain chances in the forecast through Tuesday. Minimum RH values between 30-35% over the interior are expected Saturday; however, winds will be relatively light, so conditions will not reach Red Flag criteria. Minimum RH values near 50% are forecast close to the coast south of Cape Canaveral. Minimum RH values between 35-40% are forecast generally over the interior Sunday and into early next week. Winds will turn onshore each afternoon at 10-15mph with gusts to 20mph behind the sea breeze, mainly east of the Orlando metro. Above normal to near record high temperatures are expected each day.

PRELIMINARY POINT TEMPS/POPS
DAB 69 96 70 96 / 0 0 0 0 MCO 72 96 73 96 / 0 0 0 10 MLB 72 92 73 92 / 0 0 0 10 VRB 71 93 72 93 / 0 10 0 10 LEE 70 94 71 94 / 0 0 0 0 SFB 70 97 71 97 / 0 0 0 10 ORL 73 96 73 96 / 0 0 0 10 FPR 70 92 71 92 / 0 10 0 10

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