GaWx

The complete data is in here: https://tropical.colostate.edu/archive.html Regarding how they did each year, go here for what actually occurred: https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy And go here for even more: https://www.nhc.noaa.gov/data/ I’m looking forward to your report!

CSU doesn’t consistently overestimate. Rather, they tend to overestimate only when they predict extremely active seasons. That’s why I was referring only to the 5 highest April ACE predictions rather than all of them. If you look at how they have done overall, I believe it is fairly balanced with some close, some missing too high (especially their most active progs), and some missing too low. As I said back in April, betting CSU is going to be too high tends to be a good bet when they’re going very high. That’s why I said I’d short their 4/24 progs of ACE, HDs, etc. But if they weren’t going super active, I wouldn’t make the same bet. I feel that CSU does as good a job as just about any organization and thus am thankful they make these freely available predictions. I like to hear their thoughts. But clearly they, just like all, are far from perfect and have had some very bad predictions. One thing I like about them a lot is that I feel that they neither are weenies nor are downplayers.

I sincerely hope your optimism is on the right path about any EC LF, but unfortunately it’s way too early imho to feel comfy about this, especially with the cold neutral to weak La Niña ENSO. Patterns, even persistent ones, often change after a few weeks. For example, in the 2016 Niña, Savannah in early Oct. had its worst H (Matthew) since way back in 1979 (David). Furthermore, seasons have become more backloaded overall as I recently posted about, likely related to CC. Many storms still would recurve safely, but having more activity increases the risk. In addition, a place like the NC OB that sticks way out remains vulnerable late despite increased chances for troughing. Lastly regarding outside of the E coast, FL’s Gulf coast is most at risk in Oct due to increased tendency toward troughing. Related to that, fast moving Gulf landfalls of strong storms often have major impacts well inland.

The JJA ONI-RONI came in at -0.49. The last 6: -0.63, -0.62, -0.64, -0.61, -0.54, and -0.49.

It’s good that you took that Twitter source saying nearly +20 with a grain as it not surprisingly ended up way off. The record high back to 1948 is only +15.62. August came in modestly higher than July’s +6.91. It was +8.61. There’s almost no way it has peaked as it hasn’t peaked below +9 since way back in 1973, which covers ~23 cycles. It has peaked within 5-13 months after the prior low point every time on this chart with an avg of ~8-9 months. So, my educated guess is that the peak will come during fall or winter (likely no earlier than Oct). https://psl.noaa.gov/data/correlation/qbo.data

If you’re talking about the monthly NAO table that goes back to 1950 and had July at +1.46 (see link below), that won’t be anywhere close to a record high. Based on the dailies, I expect it will most likely be near the +0.4 to +0.6 range with a small chance to be as high as +0.7 to +0.75 or so. It still isn’t out at this very late hour but it could be released later today. Even if it hits the upper end +0.75, that would be only the 17th highest of 74 August NAOs since 1950. The record high is the +1.97 of 2018. https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table I looked at August NAOs >+1 when JAS RONI wasn’t at a moderate or stronger Nino level: 1) 1955 (Niña) +1.07: Aug very active with 3H incl MH Connie; Sep also very active with 5H incl 3MH 2) 1967 +1.44: Aug very quiet but Sept active with 3H including MH Beulah 3) 1971 +1.55: Aug moderate activity; Sep very active including 4H, with one MH 4) 1976 +1.92: Aug very active with 4H including MH Belle; Sep active with 3H including 1 MH 5) 1983 +1.76: Aug active with 2H including MH Alicia; Sep pretty quiet 6) 1984 +1.15: Aug quiet; Sep active with 2H including MH Diana 7) 1991 +1.23: Aug only 1 NS but it was MH Bob; Sep 3 NS including MH Claudette 8) 1996 +1.02: Aug active with 3H including MH Edouard; Sep very active with 4 MH 9) 2018 +1.97: Aug quiet; Sep active with 3H including MH Florence 10) 2022 (Niña) +1.47: Aug very quiet (no NS); Sep very active with 4H including 2 MH —————— So for these 10 seasons with strong Aug +NAO: -Aug: 4 were quiet, 2 had moderate activity, and 4 were active. So, Aug was balanced as compared to climo. -Sep: only one was quiet (1983), one had moderate activity (1991), and 8 were active. -In summary regarding the 10 seasons with a strong Aug +NAO: none were shut down in both Aug and Sep, Aug was balanced between quiet and active, and Sep was mainly active. Thus, I see no discernible correlation between a +NAO in August and reduced hurricane activity. Are -NAOs more common in Aug during La Niña? Here’s the Aug NAO when JAS RONI was -0.50 or colder: 1954: -1.90 1955: +1.07 1964: -1.77 1970: +0.10 1973: -0.06 1975: -0.26 1988: +0.04 1995: -0.69 1998: -0.02 1999: +0.39 2007: -0.14 2010: -1.22 2016: -1.65 2020: +0.12 2021: -0.28 2022: +1.47 So, tally for RONI based Niña JAS since 1950: 7 -NAO, 6 neutral, 3 +NAO; AVG NAO -0.3 For RONI based El Niño JAS: 1951: -0.22 1953: -0.71 1957: -0.55 1963: -0.64 1965: +0.45 1968: -0.66 1972: +1.32 1976: +1.92 1977: -0.28 1982: +0.26 1986: -1.09 1987: -0.83 1991: +1.23 1994: +0.38 1997: +0.83 2002: +0.38 2004: -0.48 2015: -0.76 2023: -1.16 So, tally for RONI based Niño JAS since 1950: 10 -NAO, 1 neutral NAO, 8 +NAO AVG NAO 0.0

The Euro Weeklies’ ACE climo base is 2004-2023 (running 20 year). What I discovered is interesting for 2004-23 vs 1991-2020 climo for ACE: - 8/26-9/1: decreased ~1/8 - 9/2-9/8: little change (tiny increase) - 9/9-15: little change/still peak week - 9/16-9/22: increased ~1/7; now as active as 9/2-8; old climo was 1/10 less active than 9/2-8 - 9/23-29: increased 28%; slightly more active than 8/26-9/1; used to be just over 1/4 less active than 8/26-9/1 - 9/30-10/6: increased 1/4 So, peak day for ACE appears to be ~2 days later. With a drop in late Aug and a rise last 1/2 of Sep through early Oct, the season is significantly more backloaded ACEwise 2004-23 vs 1991-2020. Total seasonal ACE is 131 vs 122.

If it doesn’t get more active that would be fine with me. And of course it may not. But the Euro weeklies have done well so far this season. They had very high activity in late June and early July. Also, they did very well with the recent quiet period. They’ve been calling for a substantial increase in late Sep for a full week. Of course even if it gets more active they could still mostly avoid land.

Today’s Euro Weeklies added a new week, Sep 30-Oct 6, and that week is quite active vs climo. In addition the week before is also progged to be active as has been the case on many runs. So this run suggests that activity will pick up markedly next week though would still be below avg. After a similar subsequent week, activity is suggested to pick up substantially in late Sep and continue into early Oct vs climo: 9/3/24 Euro Weeklies (EW) mean ACE projections as % of climo: 9/2-8: 20% per yest.’s run (meaning ACE of 3) 9/9-15: 60% (meaning ACE of 10)(climo peak week) 9/16-22: 70% (meaning ACE of 11) 9/23-29: 130% (meaning ACE of 17)(vs peak wk climo of 16) 9/30-10/6: 140% (new week)(meaning ACE of 13) So, today’s EW progs by week are 3-10-11-17-13 meaning two most active weeks are at the end despite climo having dropped off substantially from peak by then. That would get 2024 to ~110 ACE as of Oct 6.

The Euro Weeklies sort of agree. More later.

In April CSU predicted ACE of 210. Their prior highest April progs were 160-183 (five years). Of these five, all progs ended up too high with even the closest being 34 too high! (That day I predicted 176 ACE based on it being 34 under 210.) The five averaged a whopping 85 too high for ACE! So, if their April of 2024 forecasted ACE ends up 85 too high, it will end up at 125.

Looking more closely, this new CANSIPS is forecasting Aug of 2025’s Nino 3.4 to be ~+1.0C unadjusted or ~.+0.5C adjusted downward for surrounding warmth. It has Nino 3.4 warmest and Nino 4 2nd warmest (only modestly cooler). So, it literally has a Modoki Nino forming by late summer. Of course fwiw due to very low probability of being accurate that far out. I can see it now. @George001titles next year’s main ENSO forecast thread “2025-6 Modoki El Nino”.

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024 We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely. (as of 3 September 2024) https://tropical.colostate.edu/Forecast/2024-0903.pdf

12Z UKMET has a strong TS form well off the US E coast Wed night that then moves NE and hits Nova Scotia this weekend: @WxWatcher007 NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 66 HOURS FORECAST POSITION AT T+ 66 : 34.8N 70.6W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 06.09.2024 72 36.8N 68.9W 1010 34 0000UTC 07.09.2024 84 39.2N 66.8W 1005 45 1200UTC 07.09.2024 96 41.4N 64.9W 997 43 0000UTC 08.09.2024 108 44.0N 63.3W 998 39 1200UTC 08.09.2024 120 47.1N 62.3W 1003 32 0000UTC 09.09.2024 132 49.4N 60.9W 1007 25 1200UTC 09.09.2024 144 CEASED TRACKING

The ICON (12Z) still has not backed down and thus is once again slowly developing a LLC in the NW Gulf off TX late this week.

Fwiw, this CANSIPS map for Aug of 2025 implies a developing Modoki El Niño in time for ‘25-26. Opinions? @PhiEaglesfan712 @snowman19

Is there any peer reviewed study done that actually confirms that high solar warms the upper troposphere significantly and more than lower levels like Joe D’Aleo is implying? If so, please provide a link.

1. The last week has been during peak and has had these three AOIs all at or S of 15N. 2. La Niña not being near as robust as forecasted isn’t normally hostile to development like El Niño typically is. Even if we call it neutral ENSO, that in itself isn’t typically hostile.

1. There are three AOIs on the TWO that are between 12N and 15N, which are not north at all. Furthermore, they’ve been at 15N or further S since leaving Africa: 2. Nino 3.4 has been warmer than expected. But cold neutral isn’t typically hostile for activity. In addition, on a RONI basis we’re already near -0.7 (weak Niña). 3. Joe D’Aleo *fwiw* has recently been suspecting the current very active sun causing reduced instability in the atmosphere via a warming of the upper atmosphere. The August sunspot mean of 215 was the highest for August since 1991. There MAY be a partial correlation that puts a ceiling on ACE (i.e., perhaps making it very difficult to have a hyperactive season when sunspots are very high). The highest season’s ACE that has occurred with ASO sunspots of 175+ is the 149 of 1980 fwiw. With Aug at 215, there’s a high chance that ASO of 2024’s sunspots will be 175+: https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy

0Z 9/2/24 WB CFS control DJF in S Lake Michigan is as cold as 19 F BN (which obliterates the coldest winter back into the late 1800s) while far N Lake Michigan is right at normal : different run but same distribution of anomalies in that area yet again

My sources don’t show an August update yet. Are you talking raw number or anomaly? The anomalies were headed in that direction. But if that’s the raw, that would be a huge jump.

Since 1851 here are the 18 years with 10 or lower sunspot avg during ASO (10% of the years): (* means El Niño (including incoming) season) *1855: 18 1856: 49 1878: 181 *1888: 85 1901: 99 *1911: 34 1912: 57 *1913: 36 1933: 259 1954: 111 1964: 153 1996: 166 2007: 74 2008: 146 *2009: 53 *2018: 133 2019: 132 2020: 180 AVG ACE for 18 years of 10- ASO sunspots: 104 (significantly > longterm avg) AVG ACE for 12 non-Nino years of 10- ASO sunspots: 124 (much > longterm avg) So, analysis of this post and post just above this for non-El Niño seasons only: - avg ACE was 124 for the twelve 10- ASO sunspot seasons - avg ACE was 82 for the nineteen 175+ ASO sunspot seasons - Whereas none of the 15 non-El Nino seasons with 175+ ASO sunspots had 150+ ACE, five of the 13 non-El Nino (38%) 10- sunspot seasons had 150+ ACE. Conclusions from the analysis in my 3 sunspot/ACE -correlation related posts: -I think @40/70 Benchmark’s idea about the tendency for high ACE seasons to be near solar min has a lot of merit and is backed up pretty well with the above data. That may also mean it is going to be difficult for 2024 or a typical future year with ASO sunspots >175 to get to 175+ ACE (or maybe even just 150+ ACE) despite other very favorable factors like La Niña and near record warm Atlantic MDR SSTs. -I think the research that Joe D’Aleo mentioned about the tendency for a strong solar spike to hamper hurricane activity via a lowering of instability due to warming of the upper atmosphere should be investigated further as quite possibly being one of the main reasons for the recent quiet. I read elsewhere about it being quite warm. @snowman19 Sources of data: Sunspots: https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt ACE: https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy ENSO pre 1950: https://www.webberweather.com/ensemble-oceanic-nino-index.html ENSO 1950+: https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

Since 1851 here are the 19 years with 175+ sunspot avg during ASO (11% of the years), where 2024 is very likely headed, along with their respective ACE (* means El Niño (including incoming) season): 1859: 56 1860: 62 1870: 88 1917: 61 1937: 66 1947: 88 1948: 95 1949: 96 1956: 57 *1957: 79 *1958: 110 1959: 77 *1979: 93 1980: 149 1981: 100 1989: 135 1990: 97 *1991: 36 2001: 110 AVG ACE for ASO sunspots >175: 82 (near longterm avg)(same if throw out El Niño seasons) Highest ACE for ASO sunspots >175: 149

Thanks, Ray. Great point. I’m going to look more closely now to see if I can confirm your suspicions about hyper seasons tending to be near solar min. Here are the 13 ATL seasons with 180+ ACE along with ASO averaged monthly sunspots: 1878: 5 (min) 1887: 20 (quiet) 1893: 160 (max) 1926: 110 (1.5 yrs before max) 1933: 5 (min) 1950: 95 (halfway from max to min) 1961: 75 (halfway from max to min) 1995: 20 (nearing min) 1998: 110 (2 years after min) 2004: 65 (3 years after max) 2005: 35 (quiet/3 years before min) 2017: 30 (quiet/2 years before min) 2020: 10 (just after min) So, of the 13 180+ ACE seasons, 7 had low sunspots, 3 had near avg, and 3 had above avg. though only one of those 3 had well above avg (1893) like 2024. And 2024 has an excellent shot at exceeding the 160 of 1893 since Aug was 215. It could end up near 200 for all we know now. I’d say 175+ is pretty safe. The avg monthly of these 13 seasons’ ASO sunspots was only ~55, which is well under the 1900-2022 avg of ~85 for all months. When looking at ASO averaged monthly sunspots of 135+, the only other high ACE were the 166 of 1969 (ASO sunspots avg 135), the 149 of 1980 (ASO sunspots avg of 215), and the 177 of 1999 (ASO sunspot avg of 140). So, the highest ACE during a 200+ ASO (edit: actually 175+) sunspot avg was only 149 (1980). https://en.m.wikipedia.org/wiki/Accumulated_cyclone_energy https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt