GaWx

Regarding the SST the Johnson Key buoy's low this morning was 1.1 warmer than yesterday meaning 90.0 (8AM). Today's 3PM SST of 96.1 is 1.3 warmer than the 94.8 of 24 hours ago. There's potentially still another 3 hours of SST warming with full sunshine and no showers anywhere nearby. Thus, there's a good chance that yesterday's 97.2 SST high will be exceeded today. Edit: An hour later (4PM) the SST rose from 96.1 to 97.5 with potentially another two hours of warming. https://www.ndbc.noaa.gov/station_page.php?station=jkyf1

Please comment on the possibility that AGW as well as increased CO2, itself, lead to increased crop sizes due to the possibility of : -longer growing seasons in existing crop areas due to warming -areas further north becoming more conducive to growing crops due to warming -increased CO2 being conducive to larger crops since CO2 leads to increased photosynthesis IF these things are true and we're already getting larger crops such as corn due to AGW and increased CO2, how much of that increased corn crop mentioned in the article is actually due to AGW and more CO2, themselves? If true, would that mean a negative feedback from AGW to actually slow the rate of GW? If so, is that negative feedback properly built into the climate model assumptions?

I think strong is most likely as I've thought for awhile. Also, I still have a small chance for super. However, I've still not eliminated the small chance for upper end moderate. For one thing, Sea of Peru is favoring a moderate peak SOND as was recently posted and discussed ITT: https://cdn.www.gob.pe/uploads/document/file/4887781/Comunicado_Of_ENFEN N° 11-2023.pdf?v=1689986929 Secondly, the latest OHC having dropped from +1.35 in mid June to only near +0.9 in mid July gives me pause:

There's been a somewhat notable 11 straight day -SOI streak and this will very likely dip to the lowest tomorrow (7/25). I expect tomorrow will be well down into the -30s with as low as ~-40 possible. This will be the lowest daily SOI since 5/25/2023. After that, it appears there will be a pretty steep rise that may get it up to ~+10 on 7/30-31. July SOI as a whole looks to come in ~-3. Compared to the July SOI for the seven incoming super strong El Niño events since 1877, the -3 is weak: 1877: -10 1888: -16 1965: -21 1972: -17 1982: -18 1997: -9 2015: -14 *AVG: -15* OTOH, six of the 11 incoming strong El Niño July SOIs had either similarly weakly negative or even slightly positive: 1899: -5 1902: +1 1930: -4 1957: +1 1991: -2 2009: +2 So whereas a -3 SOI for July of 2023 doesn't at all support an incoming super Nino when considering the -15 average July SOI for the seven super events, the fact that 6 of the 11 incoming strong events were in the general vicinity of -3 (+2 to -5) for July tells me that the -3 for this month is not at all out of July climo range for an incoming strong. https://www.longpaddock.qld.gov.au/soi/

0Z GEFS for the AEW about to move offshore looks like the most active run yet with 10 Hs out of 31 members by my count!

The very shallow (5 ft) waters at the Johnson Key buoy in N FL Bay hit 97.2F today at 6PM, the first time the SST got back into the upper 90s since the week before last. It was very dry today. The AM SST low was 88.9F meaning at least an 8.3F spread today, which has been fairly typical there since I started checking it a few weeks ago. https://www.ndbc.noaa.gov/station_page.php?station=jkyf1

Miami's high today of 98 was a record high. Since records started there in 1895 only one day has been hotter, 7/21/1942's 100! Meanwhile, Marathon's 96+ streak continues into today for day 17! There have been 18 total this month. The previous record going back to 1950 of the largest # of 96+ days in a year was the 11 days of 1987. Edit: Miami's mean so far today is 90. If the AM low of 82 holds up for today's low, the 90 mean would tie with 7/24/1983 for the hottest mean on record!

Miami's high today of 98 was a record high. Since records started there in 1895 only one day has been hotter, 7/21/1942's 100! Edit: Miami's mean so far today is 90. If the AM low of 82 holds up for today's low, the 90 mean would tie with 7/24/1983 for the hottest mean on record!

We're about to be pummeled here with strong thunderstorms moving toward the NE!

I don't think they don't want it. Rather, I think many of them are primarily hoping it isn't east based and/or super strong.

The CFS has given up on its many days earlier this month (the last time as recently as just four days ago) having a moderate MJO phase 5-6-7:

Per this, Nino 3.4 wasn't focused on until 1997: "Niño 3 (5N-5S, 150W-90W): This region was once the primary focus for monitoring and predicting El Niño, but researchers later learned that the key region for coupled ocean-atmosphere interactions for ENSO lies further west (Trenberth, 1997). Hence, the Niño 3.4 and ONI became favored for defining El Niño and La Niña events." https://climatedataguide.ucar.edu/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni

This is close to the most impressive looking cat 1 I can recall ever seeing. All 12Z trop models, which had it at cat 1 as of 18z, strengthen it to well into cat 2 (90-95 knts) as we head into tonight with a peak near DMAX/6Z. The NHC otoh has it weakening back to 60 knots at 6Z: "Today's strengthening was the result of the storm passing over the warmer waters of the Gulf Stream, however it will move north of those warmer waters later this evening, and Don has likely peaked in intensity. Weakening should begin overnight, with a faster rate of weakening expected Sunday through Monday as Don moves over even colder waters and the vertical wind shear increases. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 40.1N 50.0W 65 KT 75 MPH 12H 23/0600Z 42.0N 49.6W 60 KT 70 MPH 24H 23/1800Z 44.5N 47.6W 50 KT 60 MPH 36H 24/0600Z 46.4N 44.5W 40 KT 45 MPH...POST-TROPICAL 48H 24/1800Z 47.7N 40.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 25/0600Z...DISSIPATED $$ Forecaster Brown"

Don's a cane officially!

Not only that, but the 12Z models don't have Don reach peak strength for still another 12 hours (DMAX): -HWRF has it drop from 995 mb at 18Z to 988 mb at 6Z along with an increase from 70 knots at 18Z to 95 knot winds tonight -HMON rises from 80 to 90 knots -HAFS A rises from 65 to 95 knts -HAFS B rises from 70 to 95 knots So, the 4 Hurr models already have him cat 1 and strengthen him to strong cat 2!

1. Ooops, I misinterpreted that since they're in S Hem although them saying summer of 2024 instead of summer of 2023-4 threw me off, too. Thanks for pointing that out. 2. I looked at the report to better decipher what they're saying: https://cdn.www.gob.pe/uploads/document/file/4887650/Informe Tecnico ENFEN 20 JULIO 2023.pdf?v=1689981215 I looked at tables 8 and 10 along with figure 41. They have in table 8 moderate as being most likely by a good margin Sept-Dec with 65-61% chances with weak at only 10-21%. So, they're saying the best chance by a good margin is for Sept-Dec to have a moderate peak. But then table 10 shows weak favored over moderate for DJFM averaged out 43% to 38%. So, I'd say we're both right. They are calling for a moderate peak most likely for fall/early winter peak. But after that period when looking at the average for DJFM, alone, they're saying there's a slightly higher chance (43% vs 38%) for it to weaken to weak rather than maintain moderate. So, they are going against the model consensus in saying a moderate rather than strong+ peak. That's significant. And they're calling for a rapid enough weakening starting by Jan to allow DJFM to have a slightly better chance to average only weak.

They're saying that weak (43%) is more likely than moderate (38%) "by summer of 2024". That's after weakening from its fall/winter max, which would be moderate+.

I just checked all 4 6Z hurricane models. All strengthen to a peak near 6Z tomorrow/DMAX. All 4 have minimal H force winds somewhere between 0Z and 6Z.

Thank you! Thus is great info. So, the nearby pavement is why highs are hotter than Key West. That along with SSTs in the low 90s is allowing upper 90s highs. But what I'm trying to decipher is whether or not we have an apples to apples comparison to past Marathon records. How far back has there been similar pavement closeby? I don't think the article is real clear on that.

The heat and humidity has been awful all week here with mid to upper 90s highs and DPs averaging in the low 70s. All of my walking for the last month+ has been on the treadmill in AC. That's not unusual for most of the summer. I miss my summer trips to the beautiful and so comfortable CO Rockies! Maybe I'll go back there again at some point.

Thanks. I forgot to mention that it has been VERY dry in the FL Keys and surrounding areas. That lack of rainfall/above average sunshine has played a part in the hot waters there, especially the shallow ones, as it typically does in other areas in the summer. In my daily looks at the Johnson Key buoy, I see this with SSTs cooler on the few showery days.

Don a bit stronger and now forecasted to reach 55 knots: SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...36.6N 47.5W ABOUT 755 MI...1215 KM SSE OF CAPE RACE NEWFOUNDLAND MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES ------------ FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 36.6N 47.5W 50 KT 60 MPH 12H 22/0600Z 37.9N 48.9W 55 KT 65 MPH 24H 22/1800Z 40.0N 50.2W 55 KT 65 MPH 36H 23/0600Z 42.4N 50.0W 50 KT 60 MPH 48H 23/1800Z 44.6N 48.6W 40 KT 45 MPH...POST-TROPICAL 60H 24/0600Z 47.1N 45.1W 35 KT 40 MPH...POST-TROPICAL 72H 24/1800Z 48.7N 41.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 25/1800Z...DISSIPATED $$ Forecaster Brown Edit: The 12Z models including hurricane models and Euro ens don't have Don peaking til near DMAX early Sun AM. But this NHC forecast has him peaking before that and then weakening early Sun AM.

05L DON 230721 1800 36.2N 47.0W ATL 50 998 This drop of 4 mb from 1002 to 998 is the first change in the pressure by the NHC since way back at 11PM EDT Wednesday night. It had been stuck at 1002 mb for 36 hours. Edit: He is approaching his own wake and will be crossing it tonight. I wonder if reduced SSTs from that will lead to weakening through tonight. Also, DMIN is approaching. Opinions?

All four of the new hurricane model runs (12Z) now strengthen Don through DMAX of early Sunday morning. That's a full 36 hours from now. They're all stronger than recent runs and the HMON is the strongest run yet for it as of that time.

To show how unprecedented in the records is the heat this month at Marathon in the FL Keys (records back to 1950), the largest # of days with highs of 96+ for the entire YEAR before 2023 was 11 in 1987, followed by 9 in 2019 and 8 in 2022. There have been 15 straight days counting today with highs of 96+ and 16 total days this month! That's truly amazing for a location surrounded by ocean. Prior to this month, the warmest month on record was 88.0 set in June of 2019. July of 2023 is at 90.0 MTD! Should that hold up, a two degree margin over the prior record for a station surrounded by water would be quite notable. Assuming there haven't been any recent changes in or location of the sensors at Marathon Airport, July of 2023 there will be considered astounding. I'm not aware of any. The 90.0 MTD air temp there is very believable when considering SSTs in and near the Keys averaging in the low 90s MTD. If they were, say, instead in the upper 80s, I might have questioned the Marathon sensors as the average air temp is often 1-2 F cooler than the average nearby SST. Besides the background support from AGW, what else is causing this extreme marine heatwave? Any ideas? What is causing SST averages in the area to be stuck in the lower 90s for the entire month? Some of the very shallow waters such as at Johnson Key buoy to the north in FL Bay even had 5+ days of upper 90s SST highs last week! (That location has water that is only ~5 feet deep though. So, it routinely has daily ranges of 8+ degrees. So, even when it had SST highs of 97+, it had SST lows of upper 80s/near 90 and daily averages near 93.) Is the Tonga volcano that put a lot of water vapor in the air an additional factor there and worldwide?