GaWx

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

-I’m not concluding/predicting where the OHC will be come hurricane season. I’m just showing how it looks as of April 16th vs other years. -I’m showing the area east of the Caribbean because it was so incredibly warm last year and has cooled so much since then as JB has been emphasizing recently almost every day. -Indeed, the Caribbean and Gulf are also very important regarding OHC. They’ve also cooled though not as dramatically. The subtropics are also important though this section doesn’t have OHC for it as it is a tropical waters section. Cheers

Thanks. The same website has OHC for the same region although it updates more slowly. I’ll be following this very closely also. This is the corresponding OHC for the same area as of April 16 as opposed to April 27. It shows that the OHC has also fallen a lot since one year ago, when it was way up at the 2013-24 average for late June! It was on 4/16/25 down to near the 2013-24 average for 4/16 although it actually was a bit warmer than 2023, which was within just days of rising rapidly and reaching then new daily record highs that would go all of the way into June of 2024: https://bmcnoldy.earth.miami.edu/tropics/ohc/ohc_east.png

Your link doesn’t show anything. But check the image below out: The image below is the SST for each year 1982-2025 for the tropical Atlantic 10-20N, 20-60W. The black line is the 1991-2020 average, the red is 2023, orange is 2024, and blue is 2025 to date. Note how much cooler it is as of 4/27/2025 (near the 1991-2020 average) vs both 4/27/2023 and 4/27/2024! https://kouya.has.arizona.edu/tropics/tropATLsst.png

Chris, I see what you’re saying regarding the rapid changes but: 1) Why are you calling it a record +PDO in 2015? It was solidly positive and much higher than surrounding years, but it was nowhere near a record: -2015 PDO: +0.9 But: -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 **Edit: almost all of these were during and/or immediately adjacent to El Niño 2) The period 3/2014-7/2016 was no doubt a solid +PDO period with it averaging +1.0 surrounded by solid negative years. However, that was during a predominant El Niño period including a record strong Nino. To me this looks similar to 6/1957-1/1959, which also averaged +1.0 PDO, was surrounded by solid negative years, and was during a predominant El Niño period. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat @40/70 Benchmark

Tony, -After a cold winter, March was mild and all but one day Mar 24th through April 4th had 80s! The consistent BN chill didn’t restart til 4/17. From then through August, most dailies were BN! Mid May had a 3 day period with lows in the 40s. -1909-10 was the middle of a 3 year long La Niña. After that 3 year period came 1911-12, a moderate El Niño with several significant wintry precip events and a cold JF. -Sunspots: 1909-10 was coming off the 1906-7 peak of the prior cycle, which was one of the two weakest cycles since after the early 1800s Dalton Minimum. The next cycle that was about as weak wasn’t until the one with the very weak min in 2008-9! -Other Atlanta April measurable snows were 0.6” (4/4-5/1891), 0.2” (4/11/1918), and 1987 (4/3)(measurable northside but only T at KATL).

When was the last year that JB didn’t call for early season activity?

T, - DJF was cold at 3 BN. But M was way warmer than normal! A was near normal. - Only 0.3” of other SN fell that winter. - The 1.5” of 4/1910 was the snowiest month since 1/1908 and wasn’t exceeded til 1/1912!

Believe it or not, the latest measurable (and non-measurable for that matter) snowfall way down at Atlanta is also on April 25th! It was on 4/25/1910 and is what I consider to be the freakest wx event of any kind in recorded Atlanta history, which goes back to 1878-9. They got 1.5”! It wouldn’t surprise me if this was a 1 in 1,000 year event. It almost had to have been a very strong bowling ball-ish upper level low.

Wow, they’re very bullish! I wonder why. Whereas that’s notable per the Barcelona Supercomputing Center, we’re talking only the results of 3 seasons. That’s not a long track record. It remains to be seen how they do in 2025. Going that much above 2024 seems counterintuitive but we’ll see. I wasn’t familiar with Gary Lezak (former KC met.) til now. Do you or does anyone else know what he predicted in 2022 and 2023?

And even moreso -NAO on average has been a summer thing 2007-2023: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table