GaWx

2022 was odd in that it ironically had the 10th highest Sept ACE of the current active era with way over the active era Sept avg ACE, but it also had the 3rd lowest ACE for Aug/Oct combined of the last 60 years behind only the super El Niños of 1997 and 1982.

Now 60/90: is the long drought about to be broken? Keep in mind though that 91L also made it to 60/90 along with strong model support and surprisingly never developed: Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 PM EDT Mon Sep 15 2025 For the North Atlantic...Caribbean Sea and the Gulf of America: 1. Central Tropical Atlantic (AL92): A broad area of low pressure is located about midway between the Windward Islands and the coast of west Africa. This system is showing signs of organization, and is expected to move through a favorable environment for further development. A tropical depression or tropical storm is likely to form by the middle to latter part of this week while the system moves west-northwestward at 10 to 15 mph over the central tropical Atlantic. * Formation chance through 48 hours...medium...60 percent. * Formation chance through 7 days...high...90 percent. Forecaster Pasch

12Z UKMET: again has a followup MDR TC to Invest 92L (0Z actually had 2 followups): NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 156 HOURS FORECAST POSITION AT T+156 : 15.9N 37.2W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 22.09.2025 156 15.9N 37.2W 1012 31 1200UTC 22.09.2025 168 16.7N 39.4W 1011 32

12Z JMA completed (fwiw): Although the 72 hour map had it recurving NW seemingly way out in safe recurve land, it then turned W through 144 getting it to 21N, 62W (similar to Icon). Then it does a recurve WNW and then NW ending at 25N, 70W.

Tropical Weather Outlook NWS National Hurricane Center Miami FL Issued by the NWS Weather Prediction Center College Park MD 200 PM EDT Mon Sep 15 2025 For the North Atlantic...Caribbean Sea and the Gulf of America: Central Tropical Atlantic (AL92): A broad area of low pressure has formed roughly midway between the Windward Islands and the coast of west Africa. This system has become better organized since yesterday and is expected to move through a favorable environment for further development. A tropical depression or tropical storm is likely to form by the middle to latter part of this week as the system moves west-northwestward at 10 to 15 mph over the central tropical Atlantic. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 7 days...high...90 percent. $$ Forecaster Blake/Putnam

12Z runs: -GFS/CMC favoring an H but well E of Bermuda -Euro is very close to but just NE of Bermuda with an H -Icon is well to the SW of those other 3 and it’s fate is still unknown at 180 with it a TS S of Bermuda just starting a NW recurve -12Z JMA out to 72 so far: TC moving NW way out there -12Z UKMET like prior run threatens Bermuda with this run aimed only a little E of there: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS FORECAST POSITION AT T+ 54 : 17.5N 46.9W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 18.09.2025 60 18.3N 47.8W 1007 41 1200UTC 18.09.2025 72 20.5N 50.5W 1007 43 0000UTC 19.09.2025 84 21.3N 53.4W 1007 41 1200UTC 19.09.2025 96 22.5N 55.5W 1007 31 0000UTC 20.09.2025 108 23.3N 57.0W 1007 32 1200UTC 20.09.2025 120 25.2N 58.1W 1007 38 0000UTC 21.09.2025 132 26.6N 58.4W 1004 44 1200UTC 21.09.2025 144 27.7N 60.4W 1002 41 0000UTC 22.09.2025 156 29.0N 61.7W 999 49 1200UTC 22.09.2025 168 30.6N 62.4W 995 51

Bastardi is mad that this isn’t being highlighted in the NHC TWOs so far. Remember the recent no name system that hit SE NC with extreme flooding along with TS force sustained winds? JB is still mad about that and I don’t blame him.

The thing is that the season started with significantly warmer subtropical than tropical SSTs in the absolute sense, an uncommon setup. That’s evidently added to unusual tropical stability. After that, we added an unusual E US mean upper trough since August, which itself may be a separate factor negative for development. However, neither of those will likely carry over to W Caribbean season as a negative for future development. Plus we have Invest 92L now, which prior to 12Z runs had strong support for TCG.

I suppose it wouldn’t be impossible for this to be designated a TD or even a TS. Bastardi is mad that the NHC hasn’t highlighted this yet.

-Invest 92L has significant ACE potential (10-15+) with much of this coming from the subtropics -The active Euro Weeklies for 9/22-10/12 show absolutely no resemblance to the relative quiet of the season overall to this point

I sincerely hope it does end up <100. I’ve been directly significantly affected by 5 TS/H since 2016 and the US, overall, has been hit very hard. However, the two most recent Euro Weeklies means generate ~50 ACE over the next 4 weeks vs the 2005-24 avg of 40. If that were to verify, we’d be ~90 as of Oct. 12th with a high chance of reaching 100 by season’s end. For more details, folks can go to the Atlantic tropical thread if interested. *Edit: I forgot to mention the favorable for TCG MJO consensus forecast dominating at least for the rest of Sept

One possibility (not proven AFAIK) is that the recent unusually deep E US upper trough pattern correlates somewhat with relatively inactive Atlantic. If so, it seems to me that that would likely be a significant contributing factor. Unfortunately though, that extra level of protection may not carry over to the late season climo favored W Caribbean centered area of genesis, which for US threat potential starts to dominate next week. What’s got me a little worried is: -the last 2 days of Euro Weeklies have 120-150% of the active 2005-24 avg ACE starting next wk for 3 wks, which adds to ~42 ACE 9/22-10/12 -The good news is that a large portion of the 9/22-28 ACE is being generated by the current MDR AOI, which appears based on great op/ens agreement to be an easy safe recurver from us -But there’s some activity during that week in W Car/Gulf -Though some of the 9/29-10/12 activity is well out in the Atlantic and thus not threatening, the W Car/Gulf activity level is even higher for 9/29-10/12 vs that of 9/22-28, which is consistent with peak climo for that region -I sincerely hope this relative “dud” of a season continues, especially after the overall high impact to the SE US (including 5 storms with significant impact to my area!) and Gulf during 2016-24. We are so overdue for a break. But with relatively dangerous ENSO on avg (weak La Niña), with late seasons recently being bad, and with what the most recent EWs have shown, the Conus will need good luck to get out of 2025 unscathed. *Edit: Actually, the US won’t get out unscathed as both TS Chantal and H Erin significantly affected parts of the Carolinas.

0Z runs -are fairly similar to the 12Z for the Icon, GFS, and CMC -This time the UKMET is even further W and threatens Bermuda: 0Z UK: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS FORECAST POSITION AT T+ 72 : 18.0N 48.8W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 18.09.2025 72 18.0N 48.8W 1008 38 1200UTC 18.09.2025 84 20.0N 51.3W 1007 42 0000UTC 19.09.2025 96 21.2N 53.2W 1007 38 1200UTC 19.09.2025 108 22.7N 55.1W 1008 30 0000UTC 20.09.2025 120 22.5N 57.2W 1008 32 1200UTC 20.09.2025 132 23.1N 58.3W 1009 31 0000UTC 21.09.2025 144 23.3N 59.8W 1008 33 1200UTC 21.09.2025 156 23.9N 61.0W 1008 35 0000UTC 22.09.2025 168 24.3N 63.1W 1007 31

I walked outside again at the park just like I did late afternoon Fri. I had low 70s temps and dewpoints of 60. Despite no breeze, I didn’t sweat at all and actually could feel a very slight chill!

After waiting 2 1/2 weeks for the daily WCS PDO to update, it FINALLY updated today! A lot has been happening since. As of the previous update, it had bounced back down some to ~-2.75 after having risen a lot to ~-2.0 ~ten days earlier. Since then, it rose back up steeply to ~-1.5 on Sept 6th. Then it fell back some to ~-1.95 on Sept 11th. It rose back some since to the -1.77 shown below for Sept 13th. As a reminder the comparable NOAA daily would likely be ~~-2.75, which itself represents a steep climb from the daily lows near -4.5 in July:

12Z runs regarding this 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

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