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TheForecast Post

A chronicle of American weather and climate  ·  Wednesday, 16 September 2026

Weather Trader Tropics MILEPOST 1018

August 25, 2026 Tuesday Evening Tropics

Time running out for Invest 96L to become a tropical depression before conditions degrade. Then another window may open in 7-10 days near Bahamas.

What the month did

August 2026 was the warmest August in the 132-year national record (1895–2026), at 75.6°F against a 1991–2020 normal of 73.1°F (+2.5°F).

August 2026 was the 22nd-driest August in the 132-year national record (1895–2026), at 2.3in against a 1991–2020 normal of 2.7in (-0.4in).

NOAA/NCEI Climate at a Glance, contiguous United States. This is the observed record for the month, not a score of anything said in this piece — the forecast ledger begins 2026-08-17 and cannot reach earlier posts.

Invest 96L has not become much better organized but could still become a tropical cyclone in the next day or two (70% chance) before encountering even more hostile conditions in the western half of the Main Development Region.

As we have observed over the past several weeks, tropical waves look VERY healthy and ambitious/eager to “catch fire” but then “blow a tire” or poof out after encounter very dry (Saharan) air layers, dust, and vertical wind shear. Invest 96L is yet another example.

So far so good for this rather large circulation. In any other non-El Niño summer, we’d probably be seeing a hurricane in the next few days. But, this isn’t happening as the tropical wave will probably struggle until it escapes the MDR in 5 days.

The track is fair straightforward with a WNW turn into the Southwest Atlantic north of Hispaniola in 7-days.

Headlines Tuesday Evening in the Tropics

  • Tropical wave in Eastern Atlantic has not become a tropical depression, yet. NHC at 70% chance as it continues over the very warm waters of the eastern Main Development Region.

  • Invest 95L isn’t going to develop — ran out of time.

  • Typhoon Saudel (17W) in the Western Pacific still going at 80-knots (Cat 2) but the inner-core is less organized. Expect landfall in China as a strong tropical storm by this weekend.

  • In the Eastern Pacific, Tropical Storm Iselle (09E) did not become a hurricane, and has completely decoupled from its convection. Tropical Storm Julio was also absorbed into the circulation, and both are pretty much toast.

Sea Surface Temperatures across the Atlantic Basin (28°C — very warm = red)

Atlantic IR Satellite Loop

Robust convection with 96L — so it’s not going to take much more organization to become a tropical depression or storm — briefly. We will watch scatterometer passes in the coming 12-24 hours for indications of a sustained low-level circulation with westerly winds … and 35-knots.

You can see more Satellite Imagery at Squall Cloud —> LINK

Atlantic Tropical Outlook

Invest 95L is out of time, and moving into the colder North Atlantic — not the tropics. Invest 96L up to 70% chance of development. Plenty of time to watch it.

Atlantic Basin Tropical Spaghetti Next 15-days

Tracks from 51-member ensemble of AIFS-18z show limited development down the road assuming 96L survives in the Western Atlantic. The A.I. ensembles were most bullish over the past few days, and then just dipped out on 96L.

ECMWF Ensemble 12z full-physics tracks next 15-days

I’d count about a dozen (~25%) tracks that survive into the Western Atlantic and then blow up into a (major) hurricane. Still worth watching, but nothing is happening for several days. We’ll watch the MDR and Invest 96L and know more by this weekend.

Google Deep Mind 18z Ensemble Tracks

The FNv3 ensembles (18z) have really stepped back from their previous days’ excitement, but still a handful — 10 members so ~20% chance of development way down the road into early September. We can dial down the concern until these ensemble tracks fire back up. We hope they don’t!


ECMWF HRES | Precipitable Water | Atlantic Tropics Next 6-days

ECMWF 18z may have a TD/TS briefly into the weekend, but then loses the circulation thereafter. Atlantic is very hostile to tropical waves that would otherwise become strong hurricanes in a non-El Niño summer.

Flagship model: ECMWF AIFS 18z —> Integrated Vapor Transport next 12-days

Plenty of tropical waves — but none catch fire. Just along for the ride in the trade winds flow!

Some dust over the next 5-days … as another plume comes off the continent.

Equatorial Africa — Another tropical wave coming off Africa into Wednesday.

Eastern Pacific Tropics

Iselle really fell apart in the past 6-hours … you can look closely and see the circulation of former Tropical Storm Julio merge into the convection of Iselle.

Two more storms — a small one + hurricane in the next 6-days.

More storms on the way … maybe another one in the 6-10 day time frame a bit further east of the hurricane (Karina or Lowell).

Western Pacific Tropics | Typhoon Saudel

Typhoon Saudel nearing China in a few days but will weaken.

Still has an intense inner-core and eye.

Not expecting much else in the coming days as a large monsoon gyre forms east of the Philippines.


Global Tropical Cyclones for more ACE information, as well as my original climatlas.com/tropical site now with the beautiful Interstate Highway theme and full of interesting content!

Forecast Eagle maps explorer under construction.

Also, Forecast Canada with some beautiful Arctic views.

Satellite imagery from Squall Cloud, and soon Radar Imager from Forecast dBZ.

Maps sourced from weathermodels.com designed and innovated by yours truly! Please subscribe there for real-time access to the newest maps, charts from all of the weather models including ECMWF and AIFS, and NOAA GFS/GEFS, HRRR/RRFS and Blend of Models (NBM). NOAA WPC and SPC for fronts/convective outlooks. Our own content is now sourced from hottestsince.com and weather.city and celsius.earth, and squall.cloud and weather.football and global-tropical-cyclones.com and precipitation.earth

My Atlantic Hurricane Season Forecast (2026)

From April 7, 2026: Atlantic Seasonal Hurricane Forecast: (11/5/2)

9-13 Named Storms (11 most likely)
4-7 Hurricanes (5 or 6 most likely)
1-3 Major Hurricanes (2 most likely)
Accumulated Cyclone Energy: 75-85 (well below normal)

NOAA 2026 Atlantic Hurricane Season Forecast

More details in Thursday, May 21, 2026 Tropical Update

Milepost
1018 · laid 2026-08-26T01:41:16.542000Z
Source
https://weather.substack.com/p/august-25-2026-tuesday-evening-tropics
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c9ca926718cbb7d225980ea6c4a90c230fe21a004365917f739e90b3130e8b84
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