GaWx

Today as expected was the 2nd day in a row setting a new record high Oct. AO. It was 4.873. The old Oct record high was set yesterday at 4.578. Before 2024, the Oct. record was only 3.754. The 4.873 also sets a new record high for met. autumn. The old record was 4.578 set yesterday.

Thanks for posting this. I need to clarify my earlier post about the lack of a TS+ hitting or near the lower 48 on Election Day. I meant to say during Presidential election years as I was only checking those. My bad for leaving that off. Weather Tiger is showing the Yankee H hitting S FL overnight 11/4-5 and then just offshore in the Gulf at 7AM on Election Day in 1935. I didn’t include that because it wasn’t a Pres election year. But it definitely counts for Election Day in general. I see they have a 2nd one (a TS) in S FL on Nov 5th, but I’ve yet to figure out the year. So, I don’t know when Election Day was that year. **Edit on 10/24: I just figured out that the 2nd one in S FL on Nov 5th is TS Mitch in 1998. However, Election Day that year was Nov 3rd, when Mitch was in the Bay of Capeche:

All four seasonal models: Euro, CFS, CANSIPS, and NMME (which overlaps since includes CFS and CDN model(s)) are drier than normal for Nov-Dec. For Jan-Mar, CANSIPS and NMME continue dry but it’s overall more of a mixed bag on Euro/CFS. Dry during La Niña Nov-Mar is common, especially SE half of SE. I’m loving the dry for outdoor activities, especially after the very wet mid to late summer, which included for me garage flooding 11” from Debbie.

Maybe but fwiw good news is that new Euro Weeklies is much less active, especially in vicinity of W Cuba/S FL/Bahamas/Bermuda, than prior runs for 11/4-10: New run: 2 x climo (ACE of ~4.5)(Peak run was 5 days ago’s 4 x climo (ACE of ~9) Prior run: 2.9 x climo (ACE of ~6.5) it

Per records, there hasn’t been a TS+ anywhere near the lower 48 on or even near Election Day. Hopefully that won’t change in 2024. Ensembles are actually suggesting a slight chance for that to occur. Can you imagine the media coverage that day for the two things converging should this occur? Also, the conspiracy theorists would probably be going crazy.

Followup: Today’s AO is as has been well forecasted by GEFS easily a new record high for Oct back to 1950 at +4.578. The old record was 3.754 set 10/24/2008. The GEFS is still suggesting it could peak a little higher tomorrow before starting a plunge. There’s little correlation to the subsequent mean DJF AO. Winters following Octobers with very high AO spikes have varied from strong + to neutral to solid - with avg AO of only +0.1 for all of the subsequent winters combined. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.gefs.z1000.120days.csv

What about 2020-1? It was an +EPO dominant La Niña: it had 47 +EPO, 32 neutral EPO, and only 11 -EPO days. DJF had an avg daily EPO way up at +60, a solid +EPO avg for a 90 day period: https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt Edit: Also, what about 2007-8? It was also +EPO dominant. It had this breakdown for # of days: 50 +EPO, 21 neutral, and 20 -EPO. It also averaged ~+60 over the 91 days. Edit: I consider a -50 to +50 individual day to be neutral EPO.

However, Sep-Nov of 2021 had a solid +EPO similar to Sep-Oct of 2024 and the winter of 21-2 ended up with a neutral EPO fwiw.

Unfortunately for S FL, the latest Euro Weeklies has shading over it, which is a change from prior runs. Also, the Bahamas and Bermuda are shaded. This doesn’t mean likely for all of these areas but it does mean whatever forms in the W Car might bear watching for them as the mean ensemble track has shifted NW:

1. Brooklyn was also warning me and others about comparing single runs vs multi runs. The only WB CFS maps that go out through Feb (all of DJF) are control runs. Also, when JB shows winter CFS, they are always control runs. 2. The only multi run CFS maps WB has are control runs. 3. The WB CFS mean of 10 days of runs I showed earlier was a mean of control runs. That’s all they have for DJF. 4. Check this out: mean of 30 days of control runs for DJF: look how cold it is! 30 days! This is absurd! Their CFS mean is about always too cold in the E US along with having the Lake Michigan nonsense.

I’m currently leaning against it being intentional as my nature is to give the benefit of the doubt initially. It is hard for me to believe they’d do this on purpose when it is so easy for anyone to compare to other sources of CFS output. So, I’m still thinking unintentionally badly flawed company algorithms. But the longer this goes on without fixing it, the more I start to wonder somewhat since colder E US sells in winter. And shouldn’t they have at least noticed that cold spot in S Lake Michigan and warm spot in N Lake Michigan that almost always show up by now? Is it possible they (including JB) still have no idea that their CFS maps differ so much? I say it’s possible because they may never look at other CFS output. But what about those everpresent cold/warm spots? If they really still don’t know now and they later figure it out, would they then be honest and fix the algos or ditch their versions?

For the 2nd run in a row, the UKMET has Oscar get down to its lowest SLP yet (low enough to support a H) later this week after threatening Bermuda: TROPICAL STORM OSCAR ANALYSED POSITION : 20.3N 75.2W ATCF IDENTIFIER : AL162024 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 21.10.2024 0 20.3N 75.2W 1004 33 0000UTC 22.10.2024 12 21.5N 75.0W 1003 31 1200UTC 22.10.2024 24 23.1N 73.9W 1004 33 0000UTC 23.10.2024 36 25.2N 71.3W 1000 38 1200UTC 23.10.2024 48 28.2N 68.0W 997 45 0000UTC 24.10.2024 60 33.4N 65.2W 990 46 1200UTC 24.10.2024 72 35.6N 64.0W 980 55 0000UTC 25.10.2024 84 38.8N 59.3W 983 48 1200UTC 25.10.2024 96 45.3N 53.2W 984 53 0000UTC 26.10.2024 108 51.9N 44.8W 995 41 1200UTC 26.10.2024 120 POST-TROPICAL

Hoping the CONUS, especially S FL, won’t have any more to worry about. Regardless, Oscar is far from done. Bermuda could be impacted. Also, the chances of an upcoming TCG in the W Caribbean are high.

Don/others, Compare this to WxBell’s 10 day avg for DJF (see image below)(apples to apples): WxBell is significantly too cold in the E 2/3 of the US! In the NE for example, WxBell averages ~-1C/-1.8F vs CPC’s ~+0.75C/+1.35F. So, WB is ~3F too cold! Another ex: Atlanta is ~2F too cold on WB. This is further proof that WB CFS maps tend to be significantly too cold in the E US. In addition note once again on the WB CFS map that everpresent cold spot in S Lake Michigan and warm spot just 250 miles N in N Lake Michigan/N Michigan: **Edit: Also, WB’s climo base is 1981-2010, which would make their maps even warmer than going against 1991-2020. In other words, if WB were to change the climo to 1991-2020, their maps would be even colder. So, WxBell may actually even be further off vs CPC than what I stated above!

Today’s AO: +3.4 A new record obliterating high AO peak for Oct is still on track over the next two days with high +4s to near +5 still progged by GEFS. Current record +3.754 set 10/24/2008 (Oct records have been late in the month more often than early, which is intuitive to me). This new record will also be higher than the Nov record of +4.544 (11/2/1978).

@bluewave Added mins for RONI, which I feel is a superior metric to ONI, and MEI: October 2022…Phase 6 peak +2.177....ONI….-1.0..RONI….-1.1….MEI….-1.7 October 2021….Phase 5 peak +2.087….ONI….-1.0….RONI….-1.2….MEI….-1.5 October 2020…Phase 5 peak +2.818….ONI…..-1.3….RONI….-1.5….MEI….-1.2 October 2017….Phase 6 peak +3.353….ONI….-1.0….RONI….-1.3….MEI….-0.8 October 2016….Phase 5 peak +1.800….ONI….-0.7….RONI….-1.1….MEI….-0.5 October 2011….Phase 6 peak +1.674….ONI….-1.1….RONI….-1.1….MEI….-1.3 October 2010….Phase 5 peak +2.880…ONI…..-1.6….RONI….-1.7….MEI….-2.4 MEI: https://psl.noaa.gov/enso/mei/#datacomp RONI: https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt

Chris and others, What do you think about comparing RONI instead of ONI?

The rest of October through Nov 2nd is forecasted by the latest Euro ensemble mean to have near record low US pop weighted HDDs for the period (on left) <1/2 the normal. That means for CDDs (on right) near record high levels for the same period (3 times the normal). To put it into a different perspective, normally HDDs are 8 times as high as CDDs for this period, but they’re forecasted to be only 1.25 times as high! The purple line is based on the 12Z Euro ensemble mean (yellow was the 0Z). The dashed green lines are normals:

-The year was referring to Oct but same idea as your assumption. -I’d love a 1989-90 repeat as Dec gave us down here the first major winter storm in 17 winters! The next one wasn’t for another 28 winters! Since 1900, this area has had a major winter storm about once every 20 winters on average. But there are a good number more lighter measurable events along with an even higher number of trace events. But not even a trace of wintry precip here since 1/2018….7 winters is a new record long period w/o even a T! This one was from an offshore SE coastal storm which was windy and one of the coldest ever (snowing with low 20s….can you believe that way down here and close to the coast?!?)

Do I see a correlation between Octobers with a 3+ AO peak and the following winter’s mean AO during La Niña? No although the sample size is small: Niña Octobers with a 3+ AO peak: -1954: moderate -AO winter -0.7 -1983: weak +AO winter +0.3 -1989: strong +AO winter +1.2 -2008: weak +AO winter +0.3 -2022: moderate -AO winter -0.6 AVG winter AO: +0.1 (neutral)

Thanks for mentioning this. Because of what you said I was curious enough to go through the dailies. The upcoming ~10/23 peak won’t be just one of the strongest +AOs on record in Oct. It will be THE strongest Oct +AO peak on record and by a large margin: The current strongest Oct on record (back to 1950) is the 3.754 of 10/24/2008, which is about to be exceeded by ~1+! Strongest Oct +AO peaks back to 1950: 3.754 10/24/2008 3.560 10/6/1994 3.425 10/27/2003 3.379 10/10/2022 3.371 10/30/1983 3.294 10/31/1978 3.184 10/24/1989 3.078 10/20/1954 3.037 10/10/2001 3.009 10/17/1986 Since 1950, the only AO peaks exceeding +4.75 have been during Dec-March: 5.078 1/20/1957 4.917 3/16/1968 5.040 12/2/1979 4.800 12/5/1979 5.582 1/14/1989 5.147 2/9/1990 5.991 2/26/1990 5.245 1/14/1993 4.909 1/21/1993 5.588 3/8/2015 5.910 2/10/2020 6.073 2/21/2020 5.536 3/11/2021 (Note that the very highest peaks (6 of them at 5.5+) were almost all within Feb 10th-Mar 11th.) So with all of the +4.75+ peaks back to 1950 in Dec-Mar up til now, this is even more evidence of how anomalous the upcoming +AO peak will be! Even Nov has yet to have one at +4.75+ with its highest being the +4.544 of 11/2/1978. (Only Novs with a peak of +4+ were 1978, 1994, and 2013.)

That’s it! Thank you! I’m saving this as a bookmark this time. I have many bookmarks but for whatever reason I hadn’t saved that one and had instead always gotten that link easily via Googling “MJO historical data”. Recently when I’ve been Googling that, that exact link no longer was appearing.

Do you know where to find these? I’ve searched and searched and can no longer find a link to these great charts. I’ve been using them for at least a decade. Fortunately I have some saved here like this one, but those are all I can see now. They were copyrighted by Australia’s Bureau of Meteorology. If nobody knows here, I may try to email the BoM when I get a chance if I can find a good email.

What are the implications of a strengthening MJO wave in Oct?

The Oct 1-18 WCS version of the PDO is averaging ~0.2 lower than its Sept PDO, which was ~-2.55 vs NOAA’s -3.54. Depending on how Oct 19-31 ends up, Oct of 2024 will have a chance to break the -3.65 NOAA record low (set in both April 1859 and July 1950). More significantly, Jan-Oct of 2024 is headed for ~-2.57 which would be a new record low that barely beat’s 1894’s -2.55. Even more impressive is that April-Oct of 2024 is headed toward ~-3.03, easily the lowest April-Oct on record currently held by 1894’s -2.67 followed by 1950’s -2.66 and 2024’s -2.60. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat