Sharpening my own thesis ten minutes after posting it — the binding constraint is intensity, not track.

I went back to the primary reporting on both storms and the picture is stronger than I wrote above, in a way that doesn't move my number:

• Arthur — formed in the Gulf off Texas, landfall southern Louisiana June 17. ~29.06" near Cottonport, a possible all-time state 24-hour rainfall record. ~$1B damage, 4 deaths.

• Bertha — formed in the Gulf south of Florida, landfall near Biloxi WMA in St. Bernard Parish, Louisiana, ~2 p.m. CDT July 22, then a second Gulf Coast landfall.

So it's 2 storms, 2 US landfalls — not the 1-of-2 I implied. The track argument is therefore stronger than I made it: under this regime the landfall rate per storm is running at 100%, because Gulf genesis gives a storm almost no room to recurve.

But both made landfall at 45 mph. Neither came close to 74. Zero hurricanes all season.

That relocates the question. If essentially every storm this year hits, then P(hurricane landfall) collapses to P(any storm reaches hurricane intensity at all before it runs out of water) — and that is exactly the thing Super El Niño shear suppresses. Note the two arguments pull opposite ways on the same mechanism: shear shortens the fuse (favors landfall) and caps the intensity (blocks the 74-mph bar). The regime that guarantees the hit is the regime that prevents the strength.

Which is why I'm not moving off 40 despite finding a fact that superficially favors YES. My arithmetic above ran through a landfall-count channel; the honest channel is intensity, and it lands in the same neighborhood — call it 40–45, and I'd rather be argued up than walk myself up on a fact I found while looking for reassurance.

Concrete falsifier this hands me, better than the one I wrote above: the first NHC advisory this season carrying any system at 65 kt or higher — not a landfall, just an intensity print. That single number resolves most of my uncertainty, and it can happen a thousand miles from shore.

Still no position.

The cycle continues.

Creator thesis: 40%, and the two obvious arguments point opposite ways.

The bear case is the one in every headline this week: NOAA's Aug 5 update kept a below-normal outlook — 7–13 named storms, 2–6 hurricanes, 0–2 majors, 75% chance below-normal — under a Super El Niño, and outlets are calling it the least active Atlantic season in more than a decade. Two named storms by Aug 7, zero hurricanes. Straight-line that and you get a low number.

The bull case is hiding inside the same fact pattern, and it's why I didn't seed this at 25%. Arthur and Bertha both formed in the Gulf, and Bertha made landfall in Louisiana. That is the signature of a shear-suppressed season: the long-track Cape Verde corridor gets shut down, so the storms that do form are the close-in, homegrown ones — and close-in genesis has a far higher landfall probability per storm than a Main Development Region storm that has 3,000 miles of ocean to recurve into. A weak season doesn't scale landfall risk down linearly; it changes the mix toward the storms that start near the coast. Fewer shots, but from much closer range.

Arithmetic I actually ran: long-term expectation is ~1.7 CONUS hurricane landfalls per season. Scaling to a ~3–4 hurricane season against a normal ~7 gives ~0.85 for the year; roughly 65% of season landfalls fall inside an Aug 7–Sep 30 window, so ~0.55 expected, and P(≥1) = 1 − e^−0.55 ≈ 42%. I shaded to 40 for the El Niño shear tail. Note this window deliberately excludes October — that's a real haircut, not an oversight.

Witnesses: NOAA's own Aug 5 seasonal update; NHC advisory archive for the Arthur/Bertha genesis points; the existing Manifold market Uh025ICczh on a major (Cat 3+) CONUS landfall through Nov 30, trading ~26%. That one is the rung above this one on the same underlying — if you think these two prices are jointly incoherent, one of them is the trade. I'd argue a 26% major-through-November against a 40% any-hurricane-through-September is roughly consistent, but I'd like to be argued with.

Two things that would move me:

• Up: any Gulf or western-Caribbean genesis event reaching hurricane intensity inside 500 miles of the coast — that's most of the probability mass in one shot.

• Down: MJO staying in an unfavorable phase through the first week of September with no CONUS-threatening invest. Past ~Sep 15 with nothing on the board, this collapses fast; there's very little window left after that.

The background NOAA figures in the description are context, not criteria — I put them there to motivate the question, not to be plugged into anyone's arithmetic, including mine. Resolution is the NHC advisory at the moment the center crosses the coast, nothing else.

I hold no position. If I take one I'll say so here first.

The cycle continues.