GaWx

Watch off the E coast next week. Here’s a hint of that from 0Z Uk: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 150 HOURS FORECAST POSITION AT T+150 : 36.1N 70.8W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 25.09.2026 156 36.9N 69.7W 1000 47 0000UTC 26.09.2026 168 39.1N 67.9W 997 41

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AAM +3.9 & rising to very extreme levels. Should be off the chart on next runs:

Did you see this?

There may very well be a reduction in the # of storms due to GW because it has warmed the poles much more than the tropics. Because tropical systems bring heat out of the tropics to higher latitudes, it’s possible that the lower contrast means fewer storms albeit with perhaps stronger storms on average due to the warming oceans. Indeed, we’ve had stronger storms in the Atlantic basin with more cat 5 since 2016 per year than for the prior period. But OTOH, I do wonder if just having warmer oceans is enough to generate stronger storms. Isn’t it the contrast of the avg tropical ocean temp vs the avg global temp that matters most? The oceans in the tropical/subtropical regions are obviously warmer, but the rest of the globe is warmer, too. It used to be that ~79F was a crucial SST to support TCG. Is that crucial SST going to warm up due to GW? Your thoughts?

Follow-up: I emailed the 2 contacts who are listed at this CFSv2 site. Just minutes later, the site was updated! Here’s the brand new latest 10 day mean RONI forecast: as expected, the progged peak dropped even further to +2.8. Compare that to the +3.5 runs of late July. It appears it could even drop to +2.75 later this month based on the red vs blue lines:

I don’t know about “ever increasing disaster”, but you must know that there have been some bad seasons since including 2008, 2012, and most of 2016-24. 2016-24 was one of the worst 9 year periods for the SE US overall. Fortunately 2025 as well as 2026 so far have given us a much needed break, especially after the horrible 2024. But that’s less than 2 seasons.

Yesterday’s Euro Weeklies suggested a pretty active period in and near FL during the week of Sept 28-Oct 3rd. This suggests a recurving TC in that area is quite possible: This matches long-term climo well, which is at least close to the most active period for FL throughout the season: These 5 strong+ El Niño analogs with hits in FL during or near this active period shown on the Weeklies suggest to be wary especially in FL then although it’s interesting that these 5 were all 1902 and earlier as the subsequent 11 strong+ Ninos didn’t have a FL hit around then: 1902: 1899: 1896: 1888: 1877:

99L is now a cherry: 1. Eastern Subtropical Atlantic (AL99): Showers and thunderstorms have changed little in organization since this morning in association with an area of low pressure located several hundred miles southwest of the Azores. However, just a small increase in organization is likely to result in the formation of a tropical depression as soon as later today. The system is expected to move slowly over the next couple of days remaining southwest of the Azores, followed by a turn to the southwest by early next week, when environmental conditions are forecast to become less favorable for additional development. * Formation chance through 48 hours...high...70 percent. * Formation chance through 7 days...high...70 percent.

Is 99L going to be the first TC formation of the month? Edouard became a TC in August. When was the last Sept that didn’t have a TC formation by now? 2025 took til Sep 17th. 1976 didn’t have one that later became a TS til the TD that formed on 9/26 and that became TS Gloria on 9/27. And there was a ST storm on Sept 13th. So, that doesn’t count as a TC. However, 1976 also had 2 TCs that maxed out as only TDs early in Sep. in the satellite era. So, even if a TD is declared today, 2026 has already beaten 2025 for the latest 1st TC declared in Sept. during the satellite era. Now, if it becomes a TS, that would mean that 1976 would remain the season with the latest first named TS in Sept. in the satellite era, which is Sept 27th.

This CFSv2 seasonal prediction site, which includes the ENSO SSTa forecasts, hasn’t updated in over 4 days: https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml This is the most recent 10 day mean forecast for RONI: this has a peak at +2.9, compares to peaks of ~+3.5 on some runs from late July, and was suggesting further drops in the peak being likely on later 10 day means due to most of the blue lines being lower than the red ones:

12Z UKMET is at least the 2nd full run with it as a TD but the prior run didn’t do so until hour 36 (tomorrow at 8AM EDT) before dissipating it 48 hrs later; this run has it already doing that as of 2PM EDT today and then moving very little and never becoming a TS prior to dissipating at hour 96: GLOBAL MODEL DATA TIME 1200UTC 18.09.2026 NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 6 HOURS FORECAST POSITION AT T+ 6 : 31.9N 34.2W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 19.09.2026 12 32.2N 33.6W 1016 20 1200UTC 19.09.2026 24 32.7N 33.2W 1014 22 0000UTC 20.09.2026 36 33.1N 33.4W 1015 22 1200UTC 20.09.2026 48 33.8N 32.9W 1014 27 0000UTC 21.09.2026 60 35.0N 32.6W 1014 25 1200UTC 21.09.2026 72 34.5N 31.9W 1015 27 0000UTC 22.09.2026 84 33.5N 32.7W 1017 25 1200UTC 22.09.2026 96 CEASED TRACKING

The SOI has been negative for 37 days in a row.

The area near the Azores is now Invest 99L.

Something may be forming near the Azores: From 8AM TWO: Eastern Subtropical Atlantic: A trough of low pressure located several hundred miles southwest of the Azores is producing showers and thunderstorms that are showing some signs of organization. Environmental conditions appear marginally favorable for additional development over the next couple of days while the system moves slowly over the eastern portion of the Subtropical Atlantic. By early next week, environmental conditions are forecast to become less favorable for development. * Formation chance through 48 hours...low...20 percent. * Formation chance through 7 days...low...30 percent.