TC Koji Coastal Winds

📍 Wind observations snapshot (Bowen vs Hamilton Island vs Willis Island)

Bowen Airport AWS (coastal mainland)

• The strongest period of “average wind” (10-minute mean) was around 5:00 am, with ESE winds ~63 km/h and gusts to ~83 km/h.

• That’s right on the Cat 1 threshold for 10-minute winds (and it lines up with the feel on the ground: persistent strong onshore winds rather than a sharp “peak then drop”).

Hamilton Island Airport (more exposed / island setting)

• Hamilton Island recorded the highest gust of the two coastal sites, with gusts to ~117 km/h around 8:44–8:45 am, with 10-minute winds ~72 km/h at the time.

• The strongest average wind was later, with 10-minute winds peaking around ~83 km/h (gusts around ~109 km/h).

• These figures are still Cat 1 on the Australian scale for 10-minute winds, but clearly a very punchy Cat 1 with squally bursts.

Willis Island (open ocean / best “true intensity” sample)

• Willis Island is the standout for intensity evidence, showing 10-minute winds ~96 km/h with gusts to ~133 km/h (around early afternoon Saturday).

• That does fall in the Cat 2 range for 10-minute winds, and it’s the clearest surface-based hint that the system briefly reached Cat 2 strength offshore.

🌀 What it tells us about the system

This lines up with what we saw the whole way through: the system was messy and uneven, with strong squalls and bursts, but not a clean, consistent core as it approached the coast. It was initially expected to arrive as a Cat 2, but was later downgraded to a Cat 1 crossing, and the only strong “Cat 2-style” surface evidence in the data you’ve shown is Willis Island.

And yes — the BoM also factors in satellite and other observations, so land stations alone don’t tell the whole story — but they’re very useful for showing how patchy and lopsided the wind field was on the approach.

Ex-TC Koji winds explained (why some copped it more than others)

Ex-TC Koji tracked south along the coast, then drifted inland west to west-southwest. Even though it affected a big stretch of coast, the strongest winds weren’t evenly spread — they were focused on the more exposed and “strong side” of the system as it moved past.

 Quick timeline (simple version):

* Early: Koji pushed a southerly surge up the coast — that’s when Townsville saw its main burst of gusty weather.

* Later (as it slid further south / offshore): the tighter pressure gradient and squally rainbands lined up better for the Whitsundays + Mackay coast, so winds ramped up there.

* Then: once the centre moved inland, winds gradually eased on the coast, with the focus shifting inland with showers/rainbands.

Who copped the worst gusts (and why):

* Mackay / Sarina coast: closer to the stronger wind field and squally rainbands as Koji moved down the coast — more sustained gusty conditions.

* Hayman Island / exposed islands: often record higher gusts because they’re more exposed to open water winds (less land friction to slow the wind).

Why Townsville was relatively quiet (after the early burst):

Townsville sits in Cleveland Bay, with Magnetic Island + headlands breaking up the wind flow. So once the initial southerly surge passed, Townsville wasn’t as exposed to the “clean fetch” off the ocean like the more open coastline further south — meaning gusts were generally lower compared to places like the Whitsundays/Mackay.

Bottom line: Koji’s winds were very “location dependent” — exposure + which side of the system you were on mattered as much as distance to the centre.