Every marine advisory written for this coast expires at 5 a.m. Thursday, and red snapper season opens the next morning.

On the bottom where the fish are, the forecast falls from 8 to 10 feet on Wednesday to 5 to 6 feet on Friday. That is a real improvement and it is still not a calm day.

The weather does not end there. The advisories stop on Thursday because the northeast blow stops on Thursday, and the weekend behind it is a separate system arriving from the other direction. The low driving that one was given a 70 percent chance of becoming a tropical depression on Monday morning, against 30 percent for the two days in front of it.

So the season opens into a narrow window between one piece of weather and another, and the better day in that window is Friday.

What is posted now

All of these were issued at 12:37 Monday afternoon by the Jacksonville office. This morning they stopped short of St. Augustine. They do not now.

Advisory Water or beach From Until
Small craft advisory Fernandina to St. Augustine, out 20 and 20 to 60 nm Tue 8 a.m. Tue 5 p.m.
Gale watch Fernandina to St. Augustine, out 20 and 20 to 60 nm Tue 5 p.m. Thu 5 a.m.
Small craft advisory St. Augustine to Flagler, out 20 and 20 to 60 nm Tue 5 p.m. Thu 5 a.m.
Coastal flood advisory Northeast Florida beaches Tue noon Thu 5 a.m.
High rip current risk The same beaches Tue afternoon late Wed night

The coastal flood advisory is for tidal flooding and not rainfall flooding, and the service says what it means at ground level: flooding of lots, parks and roads, with only isolated road closures expected. That is the minor end of the scale and it is driven by water piling against the coast under a prolonged northeast wind rather than by anything falling out of the sky.

On the rip currents the forecast and the discussion do not quite agree, and the difference matters to anyone standing on sand. The formal headline runs Tuesday afternoon through late Wednesday night. The forecaster’s own discussion says dangerous high surf and deadly rip currents are expected “from Tuesday through the end of next week.” Read the longer one.

Friday, which is opening day

The season runs Oct. 9 to 22 in state and federal water both, one fish per person per day, no minimum size, inside a ten-fish aggregate snapper bag. Those rules have not moved.

Red snapper on this coast are caught past the twenty-mile line, so the number that decides Friday is the forecast for the water from 20 to 60 nautical miles out, not the one for the beach.

Fernandina to St. Augustine, 20 to 60 nm St. Augustine to Flagler, 20 to 60 nm
Wednesday northeast 25 to 30 kt, seas 8 to 10 ft, occasionally 13 northeast 20 to 25 kt, seas 8 to 9 ft, occasionally 11
Thursday northeast 15 to 20 kt, seas 6 to 8 ft, subsiding to 5 to 6 northeast 15 to 20 kt, seas 5 to 7 ft, occasionally 9
Friday east around 20 kt, seas 5 to 6 ft, occasionally 8 east 15 to 20 kt, seas 4 to 6 ft, occasionally 8

That is the improvement, and it is a real one. It is also five to six feet with occasional eights on the bottom that holds the fish, and showers are likely through the day with a slight chance of thunderstorms.

At the beach, Friday reads surf 4 to 5 feet and northeast wind around 15 miles an hour. For comparison the buoy twelve miles off the inlet was reading a foot and a half at four o’clock Monday afternoon, on a ten-second period, over water at 82 degrees.

Saturday and Sunday are a different question

The northeast flow does not simply end. It decreases through Friday and then, in the forecaster’s words, shifts onshore this weekend.

What turns it is a surface low forming over the northwest Gulf, which moves to the Gulf coast and lifts the stalled front back north through here on Saturday and clear of the area on Sunday. The discussion expects widespread rain both days with the potential for heavy amounts, and lists strengthening winds and increasing rain and thunderstorm chances as a headline for the weekend.

That low is the one the National Hurricane Center is watching. Its 8 a.m. outlook Monday put formation at 30 percent through 48 hours and 70 percent through seven days, which it files as high, and said a tropical depression is likely to form during the middle or latter part of the week before turning northward.

Seventy percent is not a forecast track and nothing in it says where such a system would go. It does say that the weather arriving here on Saturday is being organised by something the Hurricane Center has given a name to on a map.

What that leaves

A fourteen-day season, and the two weekend days at the front of it are the two with the most rain and the least settled wind.

Friday is the day the fourteen days begin, and on the current forecast it is also the best fishing weather of the three. A boat that waits for the weekend to be over has eleven days left, which is most of the season, and by then the wind will have been onshore for two days and the water will need time to clear.

The season closes Oct. 22. The next coastal waters forecast comes out before dawn Tuesday, and the hurricane center updates its outlook at 2 a.m., 8 a.m., 2 p.m. and 8 p.m.