GaWx

12Z runs regarding the MDR AOI: --GFS/CMC/Icon all have this eventually as a H with GFS/CMC both recurving well E of Bermuda (Icon doesn’t go out far enough to tell) -JMA has this as a TD at 48 and a TS at 72. This is stronger than the two prior 12Z runs that each had it as only a TD. -Euro has a MH passing just SE of Bermuda -UKMET again has this as a TS. This is a bit further W than recent runs but it’s still aiming a bit E of Bermuda as of 168: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS FORECAST POSITION AT T+ 72 : 16.4N 47.4W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 17.09.2025 72 16.4N 47.4W 1006 40 0000UTC 18.09.2025 84 17.7N 48.8W 1006 42 1200UTC 18.09.2025 96 19.5N 52.1W 1006 44 0000UTC 19.09.2025 108 20.6N 54.3W 1006 40 1200UTC 19.09.2025 120 22.8N 55.1W 1006 44 0000UTC 20.09.2025 132 23.1N 57.0W 1005 43 1200UTC 20.09.2025 144 25.1N 57.7W 1003 46 0000UTC 21.09.2025 156 26.3N 58.6W 1001 49 1200UTC 21.09.2025 168 28.3N 59.3W 999 48

Though boring for tracking, I think it’s absolutely fascinating what’s been going on this Sept so far. The last time Sept had no TC this far into the month was way back in 1992! It had its first Sep TC on Sep 17th. If 2025 doesn’t get a TD+ by Sep 17th (going to be close because of many models progging the current E MDR AEW to become a TD near or just after that day; also have to make sure the low off NC doesn’t do the same), then 2025 would have the latest 1st Sep TC since 1939’s Sep 23rd! Any predictions on whether either the current MDR AEW or the low off of NC will reach TD status by Sept 17th?

Thanks, Snowman. 1. Agreed. I think it’s absolutely fascinating what’s been going on this peak season so far. The last time Sept had no TC this far into the month was way back in 1992! It had its first Sep TC on Sep 17th. If 2025 doesn’t get a TD+ by Sep 17th (going to be close because of many models progging the current E MDR AEW to become a TD near or just after that day; also have to make sure the low off of NC doesn’t become a TD), then 2025 would have the latest 1st Sep TC since 1939’s Sep 23rd! 2. But to clarify, predictions from reputable forecasters were for slightly to moderately above avg activity rather than hyperactive. Also, mine (which can be seen in the AmerWx Contest thread) was for only slightly above avg ACE of 139 as well as 14 NS, 9 H, and 3 MH: 2. Don, Chris, and myself found with our research over the last month and posted ITT that any correlation between ACE and NYC snowfall the following winter has been weak at best. So, it not being hyper doesn’t say much as regards NYC snowfall prognosis. The slight correlation at best means the chance this season of 35”+ there in 25-26 is decreased only a little by a not AN ACE season.

For 60% orange in MDR 0Z UKMET: TS in middle of ocean again NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 96 HOURS FORECAST POSITION AT T+ 96 : 16.4N 45.5W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 17.09.2025 96 16.4N 45.5W 1005 41 0000UTC 18.09.2025 108 17.6N 47.7W 1005 45 1200UTC 18.09.2025 120 19.7N 49.9W 1006 44 0000UTC 19.09.2025 132 20.6N 51.6W 1006 40 1200UTC 19.09.2025 144 21.4N 53.0W 1005 36 0000UTC 20.09.2025 156 22.5N 53.5W 1004 46 1200UTC 20.09.2025 168 22.9N 55.4W 1002 45

Followup: Today’s EW for weeks 2-4 has significantly more ACE than that of the last 6 runs and is the most active for that 3 week period yet with AN/active each week. Whereas the run from 2 days ago had 40 ACE for 9/15-10/12, this new run has 8+16+13.5+10.5=48. It also shows increased risk to the SE US/Gulf 10/6-12.

Hopefully it ends up a complete dud! A dud is so overdue. Boring for tracking is a small price to pay for a safe season. But too early to know yet for sure, of course, as it takes only one and late seasons have gotten worse. Besides the good for insurers, it would obviously be even better for insureds that have suffered so much in recent years in the US and abroad like in 2024, 2022, and 2016-21. Euro Weeklies have been suggesting back to near the 20 year active avg starting ~9/22 and into mid Oct.

Storm Number Storm Name Typea Datesb (UTC) Max. Winds (kt) Min. Pressure (mb) Accumulated Cyclone Energyc (x104 kt2) Direct Deathsd U.S. Damagee ($million) Tropical Cyclone Report Status 1 Alberto TS 19 Jun–20 Jun 45 992 0.8 2 125 Final 2 Beryl MH 28 Jun–09 Jul 145 932 34.5 35 7,200 Final 3 Chris TS 30 Jun–01 Jul 40 1005 0.1 5 0 Final 4 Debby HU 03 Aug–08 Aug 70 979 4.9 12 2,500 Final 5 Ernesto HU 12 Aug–20 Aug 85 967 14.4 3 0 Final 6 Francine HU 09 Sep–12 Sep 90 972 4.8 0 1,300 Final 7 Gordon TS 11 Sep–17 Sep 40 1004 1.3 0 0 Final 8 Eight PTC 15 Sep–17 Sep 50 1004 0.0 Final 9 Helene MH 24 Sep–27 Sep 120 939 7.0 176 78,700 Final 10 Isaac HU 25 Sep–30 Sep 90 963 7.9 0 0 Final 11 Joyce TS 27 Sep–30 Sep 45 1001 1.7 0 0 Final 12 Kirk MH 29 Sep–07 Oct 130 928 23.7 0 0 Final 13 Leslie HU 02 Oct–12 Oct 90 970 16.1 0 0 Final 14 Milton MH 05 Oct–10 Oct 155 895 22.5 15 34,300 Final 15 Nadine TS 19 Oct–20 Oct 50 1002 0.7 7 0 Final 16 Oscar HU 19 Oct–22 Oct 75 984 4.5 8 0 Final 17 Patty TS 01 Nov–04 Nov 55 982 2.3 0 0 Final 18 Rafael MH 04 Nov–10 Nov 105 954 12.3 2 0 Final 19 Sara TS 14 Nov–18 Nov 45 997 2.0 9 0 Final Yep, very active JJ, BN AS, very active ON.

I thought it was a warm NE Pac that had some correlation to a cold E US winter rather than a warm N Pac overall, which is what I believe is the current case.

Hey Liberty, 2024 came in less active than, for example, the initial forecasts from CSU. But the season was still solidly above avg and it was a horrific season for the SE US: 2024 North Atlantic Summary Named Storms (vs 1991-2020 Normal) Hurricanes (vs 1991-2020 Normal) Major Hurricanes (vs 1991-2020 Normal) Total ACE (x104 kt2) (% Difference of 1991-2020 Normal) Total Direct Deaths Total U.S. Damagee ($million) 18 (+4) 11 (+4) 5 (+2) 161.5 (+32% ) 274 124,125

I agree about today’s warmth. Today’s mid 80s felt pretty decent due to a nice NE breeze and dewpoints in the low 60s. It was nice enough to get me to do an impromptu walk at the park. In stark contrast to your area due to over double the normal Aug rains and plentiful rains May-July overall, our water tables are getting a much needed break with the mainly dry (only 0.9” MTD).

Hey Liberty, In addition from what I’ve read, extreme cold has killed many more than extreme heat has although that balance could eventually even up and then reverse well into the future if GW continues that long. More significantly as I recently posted about, increased CO2 has helped lead to increased crop sizes via 3 main ways: -longer avg growing seasons -ability to grow crops in higher latitudes that couldn’t sustain them before -CO2 fertilization effect since CO2 is like plant food So it isn’t all bad by any means and an increased food supply for animals is a biggie and not just for farmers!

And many on you tube and elsewhere are calling for a cold E US winter? Does that jibe with the warmest N Pacific on record?

UKMET (12Z) again has the lemon as a TS in the MDR. It develops it 18 hours later. Unlike last run, this one has it already recurving out of the MDR way out in the middle of nowhere: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 120 HOURS FORECAST POSITION AT T+120 : 18.5N 45.0W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 17.09.2025 120 18.5N 45.0W 1006 39 0000UTC 18.09.2025 132 19.9N 46.2W 1006 39 1200UTC 18.09.2025 144 22.6N 48.3W 1006 43 0000UTC 19.09.2025 156 24.3N 50.8W 1006 36 1200UTC 19.09.2025 168 25.2N 52.2W 1005 41 ————- Also, this run doesn’t have the 2nd TC that the prior run had.

And JB has been talking like there’s been significant cooling that he attributes to reduced undersea seismic activity. But in this case (Sept 1-10) it’s ~0.2C cooler than 2 years that were a whopping 0.4 warmer than the prior year. Imagine how 2025 would stick out like a warm thumb had 2023 and 2024 not been on the graph! Edit: Aside: I still have to wonder why there was that 0.4C spike up and whether or not that undersea volcanic explosion bringing tons of H2O into the atmosphere had something to do with it. It’s awfully coincidental timing!

For the first time, the UK has a TC (actually a TS) behind the current lemon in the far E MDR moving WNW: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 108 HOURS FORECAST POSITION AT T+108 : 11.9N 16.7W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 16.09.2025 108 11.9N 16.7W 1008 35 0000UTC 17.09.2025 120 13.3N 19.7W 1008 29 1200UTC 17.09.2025 132 14.7N 23.2W 1008 28 0000UTC 18.09.2025 144 15.8N 26.7W 1009 32 1200UTC 18.09.2025 156 16.6N 29.8W 1010 27 0000UTC 19.09.2025 168

0Z UKMET for E MDR lemon: again has a TS in the MDR moving mainly WNW though it turns W after 156:NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 90 HOURSFORECAST POSITION AT T+ 90 : 13.7N 36.1WLEAD CENTRAL MAXIMUM WINDVERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)-------------- ---- -------- ------------- -------------0000UTC 16.09.2025 96 14.2N 37.0W 1008 291200UTC 16.09.2025 108 15.8N 38.9W 1006 370000UTC 17.09.2025 120 17.0N 41.9W 1006 381200UTC 17.09.2025 132 17.6N 43.1W 1006 410000UTC 18.09.2025 144 18.7N 44.9W 1006 431200UTC 18.09.2025 156 20.0N 46.7W 1006 430000UTC 19.09.2025 168 19.9N 48.8W 1007 39

I thought it was too early when we discussed this a couple of weeks ago and it’s still obviously far from a done deal, but the chances of your bold prediction verifying are certainly increasing as the quiet continues. Like they’ve been showing almost every day for over a week and although they don’t get to above the active avg ACE like they showed 2 weeks ago, the Euro Weeklies still end the below avg ACE starting with the week that begins Sept 22nd. It rises to near the 20 year active avg then and that lasts for the 3 weeks going through Oct 12th. It still has the most active week of the next 4 to be 9/22-28 (with ~13.5 ACE) and the 2nd most active being 9/29-10/5. It’s projecting ~40 ACE 9/15-10/12. That would bring total ACE up to ~80. That would keep season to date ACE well below the active era’s avg of ~103 as of then.

Like they’ve been showing almost every day for over a week and although they don’t get to above the active avg ACE like they showed 2 weeks ago, the Euro Weeklies still end the below avg ACE starting with the week that begins Sept 22nd. It rises to near the 20 year active avg then and that lasts for the 3 weeks going through Oct 12th. It still has the most active week of the next 4 to be 9/22-28 (with ~13.5 ACE) and the 2nd most active being 9/29-10/5. It’s projecting ~40 ACE 9/15-10/12. That would bring total ACE up to ~80. That would keep season to date ACE well below the active era’s avg of ~103 as of then.

12Z UKMET: another run with an MDR TS (this one moving WNW) from this wave: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 84 HOURS FORECAST POSITION AT T+ 84 : 12.7N 32.7W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 15.09.2025 84 12.7N 32.7W 1010 27 1200UTC 15.09.2025 96 13.7N 35.4W 1008 29 0000UTC 16.09.2025 108 13.9N 37.7W 1006 28 1200UTC 16.09.2025 120 15.2N 39.8W 1005 38 0000UTC 17.09.2025 132 17.1N 41.3W 1004 40 1200UTC 17.09.2025 144 18.6N 43.3W 1003 42 0000UTC 18.09.2025 156 20.4N 44.8W 1003 45 1200UTC 18.09.2025 168 21.3N 46.7W 1003 41

Another UKMET run (0Z) with an MDR TS headed for an early recurve:NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 66 HOURSFORECAST POSITION AT T+ 66 : 11.2N 26.1WLEAD CENTRAL MAXIMUM WINDVERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)-------------- ---- -------- ------------- -------------0000UTC 14.09.2025 72 11.7N 26.9W 1009 281200UTC 14.09.2025 84 13.1N 30.4W 1008 300000UTC 15.09.2025 96 13.2N 32.8W 1007 301200UTC 15.09.2025 108 14.4N 35.6W 1006 310000UTC 16.09.2025 120 15.7N 37.7W 1005 351200UTC 16.09.2025 132 16.8N 39.8W 1004 410000UTC 17.09.2025 144 18.8N 40.8W 1003 451200UTC 17.09.2025 156 19.9N 42.2W 1002 440000UTC 18.09.2025 168 21.1N 43.3W 1002 46

The last 2 Euro Weeklies runs, though not getting back to very active levels like they had for late this month at least as of yet, have suggested 9/22-28 to be the most active week ACEwise of the upcoming weeks with 9/29-10/4 being the 2nd most active.

I as one in a vulnerable location that was pretty heavily affected by two storms last year and in a region (SE) that was badly affected by several devastating hurricanes last year am enjoying this boring for tracking but thankfully safe period. I look at the secondary peak more as a regional peak of origin in/near the W Caribbean. That area of genesis peaks for the season the last week in September through mid October. Likely due to CC, this secondary peak is getting more intense and later. The bad thing about it is that: -many of these storms get very strong due especially to the lingering warmth in the W Caribbean and S Gulf -a very high % of these unfortunately make landfall in one or more locations due to the geography of that region. A lot of luck is needed to avoid that. -Due to these reasons, there have been a number of storms with horrific effects from this region during this timeframe and even well into November. Some examples of the even later storms include Eta of 2020, Iota of 2020, Paloma of 2008, Noel of 2007, Michelle of 2001, Mitch of 1998, Joan of 1988, and the 1932 Cuban hurricane among others. Also, Lenny of 1999 and Rafael of 2024 weren’t anything to sneeze at. And Sandy of 2012 originated down there late in October.

Like the 0Z run had (I didn’t post it), the 12Z UKMET continues with the MDR TS, very likely headed for a recurve in the middle of the ocean: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 114 HOURS FORECAST POSITION AT T+114 : 13.3N 34.5W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 15.09.2025 120 14.2N 35.3W 1008 28 0000UTC 16.09.2025 132 15.1N 38.9W 1007 30 1200UTC 16.09.2025 144 16.7N 41.0W 1006 36 0000UTC 17.09.2025 156 17.7N 42.9W 1005 41 1200UTC 17.09.2025 168 19.2N 45.2W 1003 44

Snowman, thanks. Do you have a link to a table of monthly IOD history?