GaWx

Thanks, Chuck. Winters (DJF) with avg of sub -0.25 NAO: -16 of 25 (64%) of 1954-5 through 1978-9 -6 of 45 (13%) of 1979-80 through 2024-5 (1984-5, 1986-7, 1995-6, 2009-10, 2010-11, 2020-1)

The east tropical Atlantic (20-60W) has warmed rapidly over the last week:

This afternoon was the rainiest and most thunderstormy in quite a long time in this area! Lots of street flooding. The rush hour traffic was a big mess!

Thanks. Andy H said: “If this forecast is accurate, we could see the 3 big NH basins (West Pacific, East Pacific, Atlantic) all struggle to produce TCs this year.” You never know as he may be into something. But based on the Euro and other things and the fact that no El Niño is forecasted, this sounds quite a bit overdone for the Atlantic basin. The ATL could imho easily have a NN season as the Euro predicts. But having a quiet season there seems unlikely to me. And I’m saying this being someone near the coast who would love nothing better than the lowered stress of a quiet season with last year being particularly bad. The SE US is overdue for a low stress season. But I don’t forecast based on my desires/wishcast.

Charlie, You’re making virtually the same point I was suspecting about Dr. V’s confusing (to me) thoughts about the wind speed. He was thinking the paper was saying sfc winds increased at 40 degrees latitude instead of upper winds shifting N. I thought I might have been lost. But with you matching my thoughts, I feel more confident Dr. V misunderstood. Yeah, Dr. V was focused on only the Atlantic portion instead of also including the Pacific portion at 40N. I didn’t understand why. I agree that Dr. V’s point about the narrow baseline period as well as where the paper’s starting period (2005) was are valid concerns.

Thanks, Ray. I also wonder about CC’s effect. -Don’t forget 2009-10 -Including March actually brings 2012-13 into the list due to the -1.61 in March making DM average -0.39 -Including March would take 2020-1 out for me because DM averaged only -0.14, which I call neutral -Based on DJF, I have 2009-10, 2010-11, and 2020-21. Based on DJFM, I have 2000-01, 2009-10, 2010-11, and 2012-13.

Charlie and others, Dr. Arthur Viterito responded to this paper by Trenberth et al. He doesn’t buy it. However, I feel like Dr. Viterito may be going a bit off on tangents and thus may be addressing items that are irrelevant or deceiving. He may also be misunderstanding what the paper is saying. I’d like to see what others think about this response: —————— So, one is led to believe that stronger winds are driving warmer and stronger currents in these narrow bands. Furthermore, that strengthening commenced in 2005 and has proceeded through 2023. If we examine the global zonal wind anomaly (surface) since 1940, we see the following: The global trend in zonal windspeed is slightly negative, not positive (Y=-0.0003X - .0067). The time series of zonal winds for the 40 degree North latitude band is depicted in the following graph: An important detail that must be noted is that Trenberth et al. used the 2000 through 2004 timeframe as their baseline. A baseline which is that short is very unusual as baselines of 30 years or more are the accepted norm in climate analysis. This questionable "baselining" of the data is, in my opinion, a serious flaw that can skew the results. I will adjust to a 30 baseline (1971-2000) and analyze off of that.

The last two runs of the Euro Weeklies for the week 5/26-6/1 have backed way down on the chance for W Caribbean/gyre originating activity later threatening FL/SE US:

Hot off the press: 1. The May 2025 Euro Atlantic basin forecast numbers for 2025 are pretty similar to the April 2025 Euro forecasts for 2025. They’re actually slightly less active with ACE of 110% vs 120%. That’s still an ACE of 130-140, not at all quiet. 2. The May 2025 Euro forecasts for 2025 are way less active than those of the May 2024 forecasts for 2024, but they’re not calling for a quiet season as they’re calling for near the normal for the current active era: -ACE: 110% vs 200% -# of H: 7.1 vs 12.8 -# of NS: 14.5 vs 22.8 -Activity from Gulf through NW Caribbean, Florida, and Bahamas is similar to last month’s forecast, which is notably lower than 2024 with it enhanced in May of 2024 (almost all red on the map those areas) vs mainly near normal (vs current active era) in May of 2025 (actually has slightly reduced vs active era’s normal (blue) in small areas)(see images below) In summary, the latest Euro (May) is similar to the April forecast for the 2025 season with near normal vs current active era (not quiet) vs well above normal in their 2024 forecasts. May 2025 forecast for 2025: near normal of current active era May 2024 forecast for 2024: very active

We now have a +OHC!

Elevated TC threat SE US May 26th-June 1st per Euto Weeklies fwiw: signal has persisted for a few days for then and it looks like a W Caribbean/gyre origin:

Avg ~-0.20 for 03-07 (yep, pretty neutral overall). @bluewavesource appears to be using Mantua (though I can no longer find Mantua) and definitely just May-Sep

Red hot off the press: The 30 mb QBO for April came out at +6.94, a solid drop from March’s +11.82. Based on past patterns, the QBO will likely fall to below 0 by June: https://psl.noaa.gov/data/correlation/qbo.data

Hey @WxWatcher007, wasn’t there a theory that that mid season quiet period of 2024 was related to the ITCZ being so far north? I didn’t necessarily buy it and actually thought it was counterintuitive due to increased coriolis force further N of the equator, which itself should be positive for TCG. Do you buy that theory? Wasn’t it said by those agreeing with that theory that the so far N ITCZ had increased Saharan/dry air incorporated into the AEWs?

Hey Tony, -You have a unique and excellent way with words, always entertaining! For example, I love the way you described the airport as essentially being oblivious to reality. Hilarious and that’s pretty much spot on at times for the airport! Your posts often have a poetic quality to them. I and I’m sure Shack and others look forward to your posts as much as anyone’s. -There is no love lost between the airport and you and that’s quite understandable. Regardless and realizing their clear deficiencies, I still do like to look back at airport stats because they’re pretty much the most readily available for detailed Atlanta area official stats going back many decades. Thus they’re great input for my abacus. My abacus would do better if the airport were more reliably reflecting reality, but oh well. -In all fairness to the airport, it did report a trace of snowfall on 4/3/1987. Per @Shackwhat Griffin got, flurries in April, was truly amazing. But doesn’t that sound similar to the airport’s trace? -I was then living just outside the Perimeter not far from I-85 in Dekalb. I was absolutely mesmerized by this event. In my area, I followed the snow as it approached (via TV/radio), and I was so excited when it arrived. It was rain that changed to snow from W to E. I recall it snowing in Cobb a good bit before finally reaching Dekalb. As I recall, it did start sticking to roofs, cars, and grass soon after starting in the morning (not to pavement). Unfortunately, I think it went back to rain at some point after the short period of snow while it remained snow in Cobb and other areas further west. -That was a fantastic winter with 3 snows: ~5” of beautiful heavy wet snow in late Jan (biggest there since 1983), a rare 1-2” snow in mid March, and then this early April miracle. -Tony, where were you on 4/3/1987?

Thanks Chris, Keep in mind that that analysis is likely based on the Mantua et al PDO, which is more positive than NOAA’s, and is definitely based on only May-Sept for whatever reason (see image below). But if they had done it based on NOAA, it would have been more negative. In addition, why not look at the entire year?

The image below of daily WCS PDO shows it has recently fallen and is at -0.86 as of yesterday. The corresponding NOAA PDO is likely ~~-1.75.

Despite Chris’ good thoughts and sources, I’m with you and @40/70 Benchmarkand still say 2014-6 was nearly a carbon copy of the late 1950s, a couple of year long +PDO period during a couple year long El Niño with a strong to very strong El Niño peak in the middle of a -PDO regime. This graph you posted says it all. The late 1980s was fairly similar but the opposite situation.

I look at the tropical Atlantic SST/OHC as just one of several important factors. It is, after all, a measure of the level of potential energy that can be tapped depending on other important factors. After all, this was the main reason 2023 was forecasted to be so active despite a strong El Niño. But even so, it won’t have much impact til at least July, which is still over 2 months away. And the peak of Sept is still 4 months away. SST/OHC may change a lot before then. Be that as it may, the fact that it is currently much cooler than last year is notable and thus it will be interesting to follow going forward. It may warm up a lot as Barry suggests per the model prog. But even if so, will it reach the last 2 years’ levels? Regardless, two other regions (Gulf and Caribbean) are almost always quite warm throughout the season and thus their SST/OHC isn’t as crucial.

The Caribbean OHC was still AN as of April 16th, but not as warm as a year ago: The Gulf was NN as of 4/16/25 but that was actually near 4/16/24:

Barry, Please don’t twist my words. I didn’t say the MDR is cold. You can look back ITT and see that. What I said is that the tropical Atlantic isn’t nearly as warm as last year at this time (OHC and SST) and is close to normal. I didn’t forecast how that will be come H season, but I did imply that the Euro forecasting a near 30 year average season instead of well above like it did in 2024 was heavily influenced by that. I also said the Euro might be a bit underdone with NN. I personally feel the best chance is still for above average in 2025 and near to above average activity for the CONUS, but likely not as active for the CONUS, itself, as the terrible 2024 since the odds would favor not as bad.

Chris, Nice maps. But these maps for 2015-6 also reflect on the globe being warmer in general vs 1997-8 and 1982-3. So, that alone favors for 2015-6 both a larger above normal area off the W coast and a smaller, less intense area of below normal further offshore. It is as I assume you’d agree the contrast between those two main areas that determines the intensity of the +PDO rather than just the intensity of warmth just offshore the W coast.

Yaakov, Fwiw, the data driven April 2025 Euro forecast for 2025 has just a near normal CONUS risk vs an enhanced risk in the April of 2024 forecast for 2024: This was April of 2024: look at all of that red concentrated along the US coasts/in Gulf: Here’s April of 2025: no red…just mainly near normal (yellow): The Euro might be a bit underdone with just a near normal US risk, but the point is that the model clearly shows a significantly lower risk than it showed last year. And last year was a very bad year for the US in the Gulf/SE. I was personally heavily impacted by both Debby (flooding rains getting into my garage) and Helene (high winds leading to a multi-day power outage (longest since David of 45 years earlier) leading to loss of refrigerated/frozen food and miserable inside conditions), but this was nothing compared to what happened further west in GA, NW SC, and especially W NC from Helene as well as the severe impacts on FL from Helene and Milton. So, it not being nearly as bad this year wouldn’t be difficult. It will be interesting to see whether the May Euro outlook for 2025 is similar to April’s. The SE US/Gulf is especially due a quieter year as 2019 was the only fairly tranquil year since 2016! But Mother Nature doesn’t care about what’s due, which isn’t a forecast.

1. But the SSTs along the W coast are just a portion of the entire PDO calculation. Just looking at the W coast like you did seems more narrow to me. 2. The SSTs in 2014-5 being at the warmest on record (per what you said) aren’t surprising due to global warming. And again, the full PDO calculation also involves other areas.

1. Regarding the top bolded, there was a record strong El Niño ~2015 (per ONI) and a strong accompanying +PDO. However, the +PDO portion of the couplet wasn’t near a record: -2015 PDO: +0.9 This was similar to the strong El Niño/+PDO couplet of the late 1950s. But all of these years had a stronger +PDO: -1997 +1.3 -1993 +1.0 -1986 +1.0 -1987 +1.1 -1983 +1.2 -1941 +2.3 -1940 +1.8 -1936 +1.9 -1931 +1.0 -1926 +1.8 -1905 +1.4 -1904 +1.2 -1902 +1.2 2. Regarding the 2nd bolded section, that +PDO ended July of 2016. Then it went back and forth through June of 2017. So, I’m calling that 12 month period neutral. After that, I’m calling it overall modestly negative July of 2017 through 2019 before the strong -PDO took over. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat