GaWx

It looks like this will likely be Invest 93L shortly. Based on how the models did with Ian last year, I'll be paying somewhat extra attention to the UKMET. The reason is that it did the best by a good margin for Ian last year in having runs a good number of days out with a SW FL instead of Tampa or further north landfall. The bulk of other models had Tampa north until much closer to landfall. ICON was second best although back a ways.

0Z Euro ~995 mb TS landfall FL Big Bend at hour 138. Then to Jacksonville at 992 mb at 144. Heaviest rainfall 4-6" in narrow band part of N FL/SE GA.

Yes, +1.5C is usually considered the start of strong. So, OISST dailies have just made it to there although ERSST is likely slightly cooler. I think what he's saying is that one day, alone, isn't enough to upgrade to strong since dailies fluctuate a lot. Regardless, it is just a matter of time imo. I'm pretty confident that Sept on ERSST will be the first strong month.

0Z UKMET a bit stronger (60 mph when goes offshore E US at end) (UKMET often conservative with winds as 990 mb usually corresponds to stronger TS than 50 mph) with similar to 12Z run but slight NW shift. It again landfalls in the FL Big Bend and then goes NE through SE GA and then offshore from SC: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 66 HOURS FORECAST POSITION AT T+ 66 : 21.4N 88.3W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 28.08.2023 72 21.3N 87.9W 1004 22 1200UTC 28.08.2023 84 23.4N 86.2W 1000 43 0000UTC 29.08.2023 96 25.1N 84.9W 996 39 1200UTC 29.08.2023 108 27.6N 84.8W 992 40 0000UTC 30.08.2023 120 29.2N 83.9W 990 43 1200UTC 30.08.2023 132 31.3N 82.0W 993 44 0000UTC 31.08.2023 144 33.1N 78.5W 991 45 1200UTC 31.08.2023 156 34.4N 74.6W 991 48 0000UTC 01.09.2023 168 35.2N 70.6W 993 52

Yes, Aug on OISST through today is averaging ~+1.275. It will likely end up near the +1.3 to +1.35 range for August as a whole. That implies that ERSST will probably end up near +1.25 to perhaps +1.30 for Aug.

Yep, obvious huge difference between controlled fire and a wild fire! Meanwhile, per model consensus, parts of the SE US are quite possibly going to be threatened (W FL)/affected by a new TC forecasted to start forming in the NW Caribbean or SE GOM this weekend and then moving NE across FL and/or further up into the SE Tue-Wed. Folks should keep an eye on this just in case although I have to go all of the way back to storm #6 of 1880 to find an analog of this in late Aug or early Sep during El Niño:

The 12Z UKMET (typically overly conservative model) is significantly stronger than the 0Z with the W Car/GOM TC (partially due to being over water longer) with a TS instead of just a TD and 10 mb lower SLP. Also, instead of it moving NE across S FL, it moves NE from the FL Big Bend across N FL into the Atlantic: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS FORECAST POSITION AT T+ 72 : 20.9N 86.3W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 27.08.2023 72 20.9N 86.3W 1005 22 0000UTC 28.08.2023 84 21.2N 85.7W 1003 24 1200UTC 28.08.2023 96 22.8N 84.8W 1002 36 0000UTC 29.08.2023 108 24.8N 83.7W 1000 36 1200UTC 29.08.2023 120 27.2N 83.6W 997 38 0000UTC 30.08.2023 132 28.6N 83.4W 994 37 1200UTC 30.08.2023 144 30.3N 82.1W 994 40 0000UTC 31.08.2023 156 32.3N 79.5W 993 41 1200UTC 31.08.2023 168 34.4N 77.1W 996 39

This GOM threat is a tough one to predict. Whereas there's good model agreement for something, I have to go all of the way back to storm #6 of 1880 to find an El Niño with a similar track in either late Aug or early Sep: Meanwhile, the 0Z UKMET had a TD form in the W Caribbean and then move NE over S FL. The 12Z will be out shortly.

Good point. Indeed, if I include March, that adds as you said 2022-3 (+NAO winter), 2017-8 (+NAO winter), 2012-3 (neutral NAO winter), 2004-5 (+NAO winter), and 1980-1 (+NAO winter). So, there'd still be a lot of hope for one solid -NAO month of DJFM even without an overall -NAO winter.

I'd love to end up wrong in not going with the first -NAO winter while average+ sunspots since 1978-9 and only 2nd -NAO of last 13 winters. But for now at least, I'm predicting either neutral NAO (i.e., between -0.25 and +0.25) or +NAO. Of course, even with a neutral NAO, there can easily be one solid -NAO month of the winter as occurred in 2005-6 (Feb), 2002-3 (Dec), 2001-2 (Dec), 2000-1 (Dec), 1997-8 (Dec), 1996-7 (Dec), 1985-6 (Feb), 1981-2 (Jan), and 1979-80 (Jan). So, that makes 9 out of the 12 neutral NAO winters having one solid -NAO month of the three. Also, 1989-90 (Dec) and 1982-3 (Feb) actually each had a solid -NAO month despite being an overall +NAO winter.

Thanks for the detailed well thought out reply! Here are my thoughts in response: 1. As you can see, I analyzed in detail just the current era of rare -NAO winters (last 44 winters) that has had 59% +NAO, 27% neutral NAO, and only 14% -NAO. This is in stark contrast to the prior 25 years of -NAO dominance with only 24% +NAO and 12% neutral NAO but 64% -NAO. With that stark a change and with a nice sample size of 44 for this current +NAO era, I figured that sticking to just these 44 winters at least for now would be best in looking ahead to the upcoming winter prospects. We're in a different NAO era and I don't know why. 2. Based on quite low sunspot activity for ALL 6 of the -NAO winters occurring during the last 44 years, it's very hard for me to accept the idea in the current era that the chance for a -NAO winter is higher near a solar max than near a min. After all, the average monthly sunspots were all low to very low: 20, 6, 12, 22, 33, and 14 for an average of only 18. This 18 compares to the longtime average monthly sunspots of 85 (based on 1900-2022 data). I mean NONE of these six low #s are anywhere near the 150+ that we're likely headed toward this winter and they're not even close to the 85 average. 3. I'm more open to the idea even in the current +NAO era that ascending may give a better chance than descending for a -NAO. After all, four of the six -NAO winters of the current +NAO era occurred during ascending: 1986-7, 2009-10, 2010-1, and 2020-1. But the thing is that these four ascending were only 4, 13, 25, and 13 months, respectively, past min. So, pretty much within only two years of the min, which in all four of these cases is significantly closer to the min than max since the subsequent max was 34, 51, 39, and a projected ~~50 months, respectively, later. So 4 vs 34, 13 vs 51, 25 vs 39, and 13 vs ~50 months, respectively. So, whereas I'm very open to the possibility that chances are currently truly higher for ascending than descending, I can't at all get behind the idea of ascending nearing a max being the best shot in this era. I'm much more open to the possibility of ascending soon after min being the best shot.

Please explain

I appreciate your work and optimism about a -NAO this winter since I'm also a winter lover and thus hope you're right. Over the last 44 winters, -NAOs (I define as sub -0.25) for DJF have been few and far between: 1984-5: (NAO -0.70) (moderate La Niña) headed down in cycle 21 with limited sunspots averaging only 20/month; this was 20 months before the minimum of Sept 1986 1986-7: (NAO -0.30) (moderate El Niño) very early in cycle 22 four months after the Sept 86 minimum with very limited sunspots of only 6/month 1995-6: (NAO -0.62) (moderate La Niña) headed down in cycle 22 with limited sunspots of only 12/month nine months before Sept 1996 minimum 2009-10: (NAO -1.67) (strong El Niño) one year into cycle 24 at 13 months after the Dec 2008 minimum just starting to head upward but with still limited sunspots of only 22/month 2010-11: (NAO -0.68) (strong La Niña) two years into cycle 24 at 25 months after the Dec 2008 minimum headed further up but still low at 33/month 2020-1: (NAO -0.42) (moderate La Niña) early into cycle 25 at 13 months after the Dec of 2019 minimum just starting to head up but still with limited sunspots of only 14/month --------------------- Note that there has been either one or two -NAO winters during each of the last four quiet portions of the cycles! So, based on the last 44 years of -NAO winters, the data clearly shows that being within two years of a minimum (ascending or descending) along with limited sunspots (so, nowhere near a cycle max) has given the best chance for a -NAO winter. The average distance from minimum was only 14 months. So, for these last six -NAO winters, the average monthly sunspots were all low to very low: 20, 6, 12, 22, 33, and 14 for an average of only 18. This 18 compares to the longtime average monthly sunspots of 85 (based on 1900-2022 data). --------- Where are we going to be in the current solar cycle this winter? 49 months past the prior minimum (Dec of 2019), which is much closer to the upcoming maximum than the prior minimum. We're at 134/month so far in 2023 with it rising. So, per extrapolation, there's a very good chance that this winter will be 150+ or not far from twice the longterm average of 85. So, very high sunspot activity nearing a maximum is quite likely. So, if this winter were to have a -NAO, it would be practically totally opposite of the others over the last 44 years regarding the solar cycle. This along with there being a -NAO (sub -0.25) during only 1/7 of the last 44 winters and only one of the last 12 winters tells me that anyone who doesn't predict a winter -NAO often but is doing so this winter would deserve major kudos if a -NAO were to verify since the odds seem to me to be so stacked against it. Thus, it will quite interesting to see what happens this winter, -NAO or not. As a winter lover, I'd love to see the recently rare -NAO. I'll probably later also post this in the winter prediction thread. Monthly NAO since 1950: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table Monthly sunspots: https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt

Per the graph below and consistent with your animation, it does appear to me like it may finally be starting to reaccelerate upward. Your animation ends about four days (your last image centered on 8/20) after the graph below, which ends near 8/16. I continue to expect a significant OHC rebound over the next few months (likely to new highs for this El Niño), which would be needed to support the Nino 3.4 ONI peak of +2.0+ that I now think is likely (70% chance):

I just checked the Key West Buoy's SST and it is all of the way down to 87F, down 5F from just over two weeks ago! After being warmer than the coral bleaching SST of ~87.3F since mid June at Key West and peaking in the high 92s on the hottest days, it has finally cooled to just below that crucial temperature and is now just under 87F! Some good news that probably won't be reported by many news outlets. Let's see how long it will stay down in that vicinity. https://www.ndbc.noaa.gov/station_page.php?station=kywf1

Don was impressive and an overachiever vs expectations.

@donsutherland1 Do you happen to have any feel yet for where you expect the very crucial NAO to be this DJF? I'm asking you because I recently had looked at several 2019-20 winter forecast threads and you were the only one I saw who explicitly called for a +NAO, which we know verified quite well: Strongest +NAO DJF since 1950: 2014-5: +1.66 2011-2: +1.37 1994-5: +1.36 2015-6: +1.31 1999-0: +1.30 2017-18: +1.30 2019-0: +1.27 1988-9: +1.26 1993-4: +1.02 2021-2: +1.02 -all 10 since 1988-9 -6 of the 10 since 2011-2 -NAO (sub -0.25) DJF since 1950-1: - 22 of them (30% of winters since 1950-1) - 16 of these 22 were between 1954-5 and 1978-9 (~50% of winters during that period) - Only 4 of the 22 sub -0.25 winters were after 1986-7 (11% of winters since 1987-8): 1995-6, 2009-10, 2010-1, and 2020-1 - So, only 1 of the last 12 winters (8%) sub -0.25 - Why has there been such a strong tendency away from -NAO winters since 1987-8? Could it be the +AMO? GW? - Is anyone yet predicting a sub -0.25 NAO for the upcoming DJF? If so, based on what?

Indeed, the models suggest it will eventually move away from strongly east based like it is now. But in the meantime it will take a good bit of time since it is so strongly east based now and thus they suggest Nino 3 anomalies will likely still be warmer than 3.4 through Dec with them perhaps getting close together in Jan and maybe matching each other in Feb. Nino 4 anomalies remain cooler than Nino 3.4 through Jan. on all of the models.

The wild OISST Nino 1+2 anomaly, which plunged ~0.5C yesterday and nearly 0.9C over just a three day interval, rebounded by nearly half of yesterday's drop today from 2.756C yesterday to 2.980C today (see below). But it still has a long way to get back to the top. Thus, I do lean toward the top being in based on using model consensus as a guide. Nino 1+2 was reported today to be at +3.3 again. Nino 3.4 rose from +1.2 to +1.3, Nino 3 rose from 1.8 to 2.0, and Nino 4 remained at 0.9. Based on model projections, I expect the current east based Nino (1+2 and 3) to eventually yield to a cross between east and center based for DJF. By F, itself, it would probably be getting close to center based.

So this thread went from discussion just yesterday of the NHC being too slow to upgrade to the exact opposite today. From yesterday: "The NHC’s lack of propensity to name obvious tropical cyclones is starting to get annoying. It took them far too long to name Emily and the day before TD 6. Just because it’s in the open ocean doesn’t mean you don’t initiate advisories when it’s an obvious TC." But I do agree that Gert is no longer a TC.

For Fri-Sun (8/18-20), LV has received 0.85" with ~0.55" of it from Hilary. They're very fortunate considering the ~2" progged by model consensus Fri through today and with it currently looking like little for today. Definitely an underachiever there, which is great news for them.

I'd think this should help cool the water some. But as of yesterday per OISST, the MDR SST anomaly was still very warm and actually it had warmed the last three days:

A couple of us just yesterday were talking about how the NHC has been too slow this season to date in upgrading systems vs years like 2020 and possibly overreacting to criticism then. Example:

Oops, yes, 3-0-0. I think I was looking ahead at Franklin model projections to become a H down the road.

-With the upgrade of TD6 to Gert, August is already up to 3/1/0. -Gert now joins Arlene, Bret, Cindy, and Emily as names that go back at least to 1981 and which will return in the 2029 list. - Arlene at 12 times had already been the most frequently used Atlantic name through 2023. Now it will be back for at least #13.