Seas six to seven feet Wednesday, two to three by Saturday

At 2:56 Tuesday afternoon the wave buoy about twelve miles east northeast of the St. Augustine Inlet was reading seas of 2.0 feet and a water temperature of 83.5 degrees. The National Weather Service forecast for that same stretch of water has it running six to seven feet by Wednesday afternoon, occasionally to nine. Both of those numbers are right, and they are not the same kind of number. One is what an instrument measured at a stated minute, and the other is what the Jacksonville forecast office expects the water to do tomorrow.

The small craft advisory is written off the second kind. It runs in the water from Fernandina Beach to St. Augustine until 5 a.m. Thursday, and in the water from St. Augustine to Flagler Beach until the same hour, having taken effect there at 6 Tuesday evening. A high rip current risk covers coastal Nassau, coastal Duval, coastal Flagler and both coastal St. Johns zones until 5 a.m. Friday.

The forecast issued at 2:25 Tuesday afternoon takes the seas back down before the weekend. From Fernandina Beach to St. Augustine it gives three to four feet Friday, occasionally to five, then two to three feet Saturday. From St. Augustine to Flagler Beach it gives the same three to four Friday and two to three Saturday. Surf at the beaches follows that curve, four to six feet Wednesday and Thursday, three to four Friday, two to three Saturday.

Three buoys, three seas, one afternoon

The three wave buoys on this run of coast were reading three different seas at the same hour on Tuesday, and the difference that matters to a boat is in the period rather than the height.

Off Fernandina Beach, station 41112 printed seas of 3.3 feet at a peak period of 4 seconds, with a water temperature of 85.5 degrees. Its wave summary gives a wind wave of 3.3 feet at 4.2 seconds out of the northeast, riding over a swell of 0.3 feet at 10.5 seconds out of the east.

Off the inlet, station 41117 printed 2.0 feet at a peak period of 3 seconds and 83.5 degrees. That was built of a wind wave of 2.0 feet at 3.3 seconds from the east northeast, over that same easterly ten and a half second swell. Off Ponce Inlet in Volusia County, station 41070 printed 1.6 feet at a peak period of 9 seconds and 83.5 degrees.

The National Data Buoy Center publishes all of those in feet and Fahrenheit itself, converted from its own metric rows, and it rounds a wave height to the tenth of a metre before it converts. A four second wind wave and a nine second swell of the same height are not the same ride out of an inlet, and that is most of what separated Fernandina Beach from Ponce Inlet on Tuesday afternoon.

There is no buoy on the outer shelf off this county. Past 41117 at about twelve miles, what exists for a boat running to the ledges is the twenty to sixty nautical mile zone forecast, and a zone forecast is a forecast. That product put the west wall of the Gulf Stream 53 nautical miles east of St. Augustine Beach as of midnight Tuesday UTC, 64 miles east southeast of Jacksonville Beach and 50 miles east of Flagler Beach, derived from the NCEP Global RTOFS model rather than measured anywhere.

The water temperature, and where nobody takes one

The gauge at the Mayport Bar Pilots Dock read 84.2 degrees at 3:30 Tuesday afternoon, and NOAA publishes that reading in Fahrenheit rather than in Celsius. That is river mouth water in the St. Johns, about thirty miles north of the inlet. The surf zone forecast issued at 11 a.m. gives the water at the beaches only as a band, 80 to 85, and it gives the wind as northeast at 15 to 20 mph. The pier station at St. Augustine Beach had that wind out of 60 degrees true at 3 p.m., which is northeast.

Nobody publishes an observed water temperature in the St. Augustine Inlet, in the Matanzas, or at St. Augustine Beach. NOAA’s index of the stations that report one carries three between Ponce Inlet and the Georgia line, and all three of them sit in the St. Johns River at Jacksonville: Mayport at the Bar Pilots Dock, Dames Point and Jacksonville University. The station at St. Augustine Beach, 8720587, was established in May 1992 and removed in August 2004, its sensor list comes back empty, and it publishes no water temperature at all. The nearest observed readings to the inlet are the buoy twelve miles out and the gauge thirty miles north, and on Tuesday afternoon those two sat about seven tenths of a degree apart.

The tides this weekend

All heights in feet above mean lower low water, as NOAA publishes them. Times are Eastern Daylight.

Those are predictions, published above mean lower low water, which is the average of the lower of each day’s two low waters across the years 1983 through 2001. A prediction is harmonic arithmetic about the sun and the moon. It carries no wind, no rain and no surge. It is not a forecast.

NOAA publishes the great diurnal range at St. Augustine Beach as 5.15 feet, which is the average distance from the lower low water up to the higher high. The highest water predicted at that station across the three days is 4.75 feet, on Friday afternoon. Every high tide it predicts there lands under that average, and on each of the three days the afternoon high is the higher of the two. NOAA prints these to the thousandth of a foot, on a shoreline the tide itself moves, and a tenth of a foot is as much as anyone should hold them to.

For a reader setting a tide height against a survey or an elevation certificate, NAVD88 sits 3.13 feet above mean lower low water at St. Augustine Beach and 2.99 feet above it at Mayport, on the same 1983 to 2001 epoch. NOAA publishes the two datums and not the subtraction between them. A predicted tide height is a number for a boat, not a number for a doorstep.

What is being caught

Florida Sportsman published its Northeast Florida forecast on Sept. 10, written by Captain Roger Bump, who covers the coast from Fernandina Beach to Flagler Beach including Jacksonville and Saint Augustine.

That report puts eleven kingfish caught in a single day off the Jacksonville Beach pier in the week before it ran. It has kingfish holding in good numbers at the spots it names as the red tops, the Southeast hole and the Nassau buoy. It has tarpon and bull redfish schooling at most of the inlets, taking live or dead mullet fished on the bottom, and it advises a live mullet under a float where tarpon are working the surface.

Offshore the same report is flatter, and it quotes a Fernandina charter captain, David Dry, saying “We are in a lull!” It gives the bottom fishing as limited to triggerfish, mutton snapper and vermilion snapper, with the best bottom starting at 120 feet or 40 miles from shore. It puts water temperatures still in the 80s with no cooling in sight for at least another two weeks.

Inshore, Bump wrote that the tides were running high in the afternoons that weekend and put tailing redfish in the flooded grass as the thing to go and look for. He recommends pieces of dead shrimp dragged slowly on the bottom along grass lines and pilings for croaker, black drum, flounder and redfish. He reports that a client recently caught a slot redfish of more than ten pounds doing exactly that.

No state or federal agency publishes a catch report for this coast.

What is open, and what closes

The Florida Fish and Wildlife Conservation Commission manages redfish, seatrout and snook here as one northeast region, running from the Florida and Georgia border south to Lytle Avenue and the South Causeway in New Smyrna Beach. The region takes in the St. Johns River and its tributaries. South of that line the rules change, and red drum in the Indian River Lagoon region is catch and release only.

Inside the northeast region, red drum is open all year at not less than 18 and no more than 27 inches total length, one fish per person per day and four per vessel. Spotted seatrout is open all year at not less than 15 and no more than 19 inches, with nothing over 19 inches kept, three fish per person per day. Snook is 28 to 32 inches and one fish per person per day, closed Dec. 15 to Jan. 31 and again June 1 to Aug. 31, which leaves it open now. Tarpon is a catch and release fishery, and one over 40 inches has to stay in the water unless the angler is holding one of the tags the state sells for a record attempt.

Offshore, gag grouper in Atlantic waters is given as open May 1 to Aug. 1, and a notice on the same page records the executive order that closed recreational harvest of Atlantic gag on Aug. 2. Red, scamp, yellowfin and yellowmouth grouper are open May 1 through Dec. 31 at 20 inches total length, up to three per person inside the three grouper aggregate, and black grouper runs the same season at 24 inches. Atlantic red snapper is open in state waters and closed in federal waters, at 20 inches total length and two per person, and Atlantic state waters reach from the shore out to three miles.

The three fish Bump names on the bottom are all open. Vermilion snapper is open all year at 12 inches and five per person. Mutton snapper runs at 18 inches and five per person inside the ten snapper aggregate. Gray triggerfish is 12 inches fork length and ten per person. King mackerel is open all year at 24 inches fork length, two per harvester.

Two things shut inside the next seven weeks. Flounder closes on Oct. 15 and stays closed through Nov. 30 statewide, and until then it is 14 inches total length and five per person. Hogfish in Atlantic state waters is open May 1 through Oct. 31 at 16 inches fork length and one per harvester, so the last day for it is Oct. 31.

Anyone fishing for shark from the beach needs the shore based shark fishing permit and the Shark-Smart course that goes with it, and both are renewed every year. FWC prints that on its shark page.

Saturday’s high water at St. Augustine Beach is predicted for 3:18 in the afternoon, and the low before it for 8:51 in the morning.