GaWx

That’s why I feel it’s better to continue to repost JB’s posts regarding Dr. Viterito’s undersea volcanoes warming from underneath hypothesis (like Don just did and I’ve been doing) so that it can be repeatedly be refuted here with facts.

The 0Z UKMET once again has just a rather weak low (not even a TC on the textual output; it has yet to show TCG in the Caribbean on this output though it awhile back had several runs with TCG east of the Lesser Antilles) and again into Nicaragua. The last 5 runs have shown a weak low either hitting Nicaragua (0Z 10/19, 12Z 10/18), barely E of Nic. but heading into it (0Z 10/18, 12Z 10/17), or still 200 miles E of Nic. but likely headed into it (0Z 10/17). Looking at the H5 vorticity, it appears that as the AOI on the TWO comes into the E Car that a portion of it turns sharply right like the GFS but unlike that model it never develops. Then what looks like a split from this, possibly incorporating additional vorticity coming off northern S America, causes the weak low to move into the SW Caribbean, which then goes into Nicaragua. So, the UKMET remains a SW outlier. I should add that yesterday’s 12Z JMA is similar and it has been similar all of the way back to the 12Z 10/15 run. So, the JMA has had 4 12Z runs in a row with just a weak low into Nicaragua or just offshore headed there. Thus the UKMET and JMA have a good chance to both either fail badly or end up doing the best of the major operationals with this. ——— 0Z 10/19 UKMET 156 12Z 10/18 JMA 168

Don, I want to make sure I’m following you correctly. You’re saying the errors increase at depth but that the at depth data is still reliable?

Thanks, Don. What you’re saying seems intuitive. Do you think these at depth SSTA maps can be trusted for accuracy?

12Z UKMET: still no actual TCG shown in textual output but 1007 mb low is E of Nicaragua headed slowly in the direction of Nicaragua. Don’t know yet if it will landfall there though. Run not finished. Edit: looks like it on 10/24.

In a big change from prior runs, the 12Z CMC hits Nicaragua on 10/24-5 with a strong TS!

It’s mainly about empathy to better feel for them.

Ensembles as well as this time of year climo/history suggest that E NC has almost as much of a chance at getting hit from this directly as S or C FL, including a scenario where both get hit. I’m not saying either is favored to get hit though. Right now neither is at high risk but a nontrivial risk is there.

Fwiw due to it being way out in fantasyland, the 12Z Euro has Mitch-like/Eta-like/Iota-like flooding in N Honduras as it stalls just to the N of Honduras for a few days and intensifies followed by E and then ENE/NE movement to W of Jamaica headed toward C Cuba at the end as a trough picks it up.

This just made the TWO for first time (0/20): Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Thu Oct 16 2025 For the North Atlantic...Caribbean Sea and the Gulf of America: 1. Caribbean Sea: A tropical wave located over the tropical central Atlantic is expected to move westward at 15 to 20 mph during the next several days. Some slow development of this system is possible when it reaches the central portion of the Caribbean Sea by the middle part of next week. * Formation chance through 48 hours...low...near 0 percent. * Formation chance through 7 days...low...20 percent.

12Z: Icon joining the consensus turning it sharply right as it goes into DR after forming in E Caribbean; also very weak entire run CMC once again is the only model with a TCG E of the Lesser Antilles; TS goes through Windwards; it like the Icon joins the consensus turning it sharply right as it, too, goes N over DR. Then the weakened main part moves NE toward Bermuda GFS forms in E Caribbean and then moves N over PR followed by turn to NE/OTS UKMET text again shows no TCG through day 7 but again a sfc low is there (1007 mb) that’s further S than 0Z with it 300 miles S of Jamaica moving slowly W at 168; so this not turning right by 168 is exception so far of 12Z operationals JMA only out to 72 so far (inconclusive) Euro is next

As I showed yesterday, seasons with no H hits on the Conus have shown no notable signal one way or the other for the subsequent winter temperatures. What about the other extreme, winters after seasons with 3+ Conus H hits since 1950? 17 winters: 2024-5, 2020-1, 2017-8, 2008-9, 2005-6, 2004-5, 1999-00, 1998-9, 1989-90, 1985-6, 1979-80, 1971-2, 1964-5, 1959-60, 1954-5, 1953-4, and 1950-1. Here’s their average using climo of 1951-2010: slightly mild but that’s likely a little too warm considering that 3 are post-2010 What about winters after seasons right at the 2 Conus H hit average since 1950? 13 winters: 2022-3, 2021-2, 2019-20, 2018-9, 2016-7, 2012-3, 2003-4, 1996-7, 1995-6, 1986-7, 1966-7, 1960-1, and 1955-6. Here’s their average using climo of 1981-2010: mainly slightly warm to near normal but I’d rather call it near normal overall considering that 1981-2010 climo is slightly too cool being that 6 of the 13 are post-2010 and only 3 are pre-1981 —————— Also, maps for winters following the 29 seasons with exactly one Conus H hit came out right at normal everywhere. ———————— So, to summarize the maps for winters following Conus H seasons with 3+, 2, 1, and 0, the differences are pretty small. Thus there’s little signal one way or the other for winter temperatures based on the # of US conus H hits of the prior season.

0Z Icon: big change from prior runs with virtually no sfc low and the main part of its H5 vorticity recurves sharply into Haiti It almost looks like a split with something else weak going into SW Caribbean headed for Nicaragua/Costa Rica. UKMET still has yet to have a run with a TCG in the Caribbean from this. CMC: has yet to have a TCG in the Caribbean as it once again has TCG E of the Car that heads through the Lesser Antilles; ends in W Caribbean as a weakening low GFS: TCG S of Dom. Republic; moves slowly N to E tip of Dom. Republic and then accelerates NNE OTS Euro: it again pretty similarly takes its time as prior runs with a TCG not til ~10/23-4 in SW Caribbean with a N move to W. Jamaica and C. Cuba followed by NNE recurve to C. Bahamas. Cat 2 H C Cuba to C Bahamas. At 2AM and 8AM, it still didn’t make the TWO.

The answer is no. Winters following no Conus H hit seasons haven’t been far colder on average and not even frequently colder. First of all, keep this in mind: since 1851 there have been 34 (20%) seasons with no Conus H impact on record. Of these 34, there were only 6 during La Niña (1872, 1890, 1892, 1973, 2000, and 2010) vs a much higher 15 during El Niño, which is intuitive. So, one needs to keep in mind that winters following no Conus H hit years are biased toward El Niño/away from La Niña. ————————— Winters since 1950 following no Conus H hit seasons: a mix 2015-6: mild 2013-4: cold 2010-1: cold 2009-10: cold 2006-7: normal 2001-2: mild 2000-1: cold 1994-5: mild 1990-1: mild E; cold W 1982-3: mild 1981-2: cold 1978-9: cold 1973-4: mild 1963-4: cold 1962-3: cold E, mild W 1951-2: mild E; cold W Of 16 winters in E half of US, 8 were cold, 7 were mild, and 1 was normal…so no signal W half of US: 9 cold, 6 mild, 1 normal…ever so slight cold signal in W Here’s the map for all 16 winters since 1950 combined: near normal nationwide/no cold signal at all: ————— *Edit: here’s the avg for 10 winters following no Conus H hit seasons 1895-1949: actually leaned slightly mild 1937-8: normal E; mild W 1931-2: mild E; cold W 1930-1: mixed 1927-8: mixed 1925-6: cold E; mild W 1922-3: mixed but mainly mild 1914-5: cold 1907-8: mainly mild 1905-6: mixed but mainly mild 1902-3: mixed but mainly cold

Reminder: there’s a dedicated thread for this potential storm: https://www.americanwx.com/bb/topic/62328-e-mdr-aew-models-support-car-tcg-next-wk/

Latest on record first Conus H impact of season is 10/20 (1853). Next is 10/18 of 1968.

New thread

All 12Z ops (except CMC’s near Leewards) have shifted actual (or imminent in case of UK) TCG from the prior favored E of Car to the C Car, which matches favored climo. TCG there would be ~10/20-10/23. Check out the 12Z EPS, which has a whopping 18 H (36%) with 11 in the dangerous W Car and 7 recurving in SW ATL: Climo: 10/11-20 TCG: 10/21-31 TCG:

I assume you realize 25-26 and 13-14 are opposites with regard to QBO. Are you including that as part of the reason you said 13-14 is an awful polar analog?

Consistent with the 0Z, the 12Z UKMET has the followup MDR system moving WNW through the central Lesser Antilles on 10/19 and then into the far E Caribbean: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS FORECAST POSITION AT T+138 : 13.9N 57.2W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 19.10.2025 144 14.2N 59.0W 1010 33 0000UTC 20.10.2025 156 14.6N 61.9W 1010 34 1200UTC 20.10.2025 168 15.1N 64.9W 1009 35

This won’t be a popular take here, but I think articles like this do more harm than good as regards believability regarding the affects of CC in general. It has a sensationalist, “Day After Tomorrow” tone to it imho. This isn’t the way to convince nonbelievers. Some of the words/phrases used in the article were these: catastrophic, catastrophic ripples, devastating consequences, alarming, catastrophic global consequences, catastrophic outcome for all humanity I think that articles like this do more harm than good. And I’m saying this as one who’s extra concerned about sea level rise and stronger hurricanes being that I’m not far from the coast.

BULLETIN Tropical Storm Lorenzo Advisory Number 1 NWS National Hurricane Center Miami FL AL122025 500 AM AST Mon Oct 13 2025 ...TROPICAL STORM LORENZO FORMS OUT IN THE CENTRAL TROPICAL ATLANTIC... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...14.2N 40.3W ABOUT 1095 MI...1760 KM W OF THE CABO VERDE ISLANDS MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 17 MPH...28 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES ——————- FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 14.2N 40.3W 40 KT 45 MPH 12H 13/1800Z 15.0N 41.7W 40 KT 45 MPH 24H 14/0600Z 16.2N 43.4W 40 KT 45 MPH 36H 14/1800Z 18.0N 44.4W 45 KT 50 MPH 48H 15/0600Z 20.1N 44.7W 50 KT 60 MPH 60H 15/1800Z 22.4N 44.2W 55 KT 65 MPH 72H 16/0600Z 25.1N 42.6W 60 KT 70 MPH 96H 17/0600Z 30.9N 36.9W 55 KT 65 MPH 120H 18/0600Z 33.2N 29.6W 45 KT 50 MPH $$ Forecaster Papin

Thanks, Don. It’s probably due to randomness, but keep in mind that the last 3 Euro Oct winter forecasts did poorly as they all missed in the NE US by 3-4F (two too cold and one too warm). Those are the 3 largest misses of the last 8 October NE winter forecasts. OTOH, the prior 5 October forecasts’ avg miss was only 1F.

The 0Z UKMET is the first run with the followup MDR AEW as a TD with it going just N of due W at a rather brisk pace through the middle of the Lesser Antilles on Sunday (10/19): keep in mind that this is a top tier model that is sometimes genesis shy NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 150 HOURS FORECAST POSITION AT T+150 : 13.5N 57.7W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 19.10.2025 156 13.8N 59.5W 1010 32 0000UTC 20.10.2025 168 14.1N 62.8W 1009 34 —————— Also, the Icon (0Z) has it yet again.

Hey Don, What do you feel are the chances that the Euro winter outlook will verify to be significantly too warm in the NE US similar to other Euro Oct winter forecasts like the +4F miss of last winter or the +2.5F miss of 2020-1? Or do you think it has a decent shot at verifying significantly too cool like 2023-4 and 2022-3, which each missed by -3F? OTOH, 2021-2, 2019-20, 2018-9, and 2017-8 all missed <2 in either direction. -Oct DJF prog misses for NE US for the 8 winters starting with 2024-5 and ending with 2017-8: +4, -3, -3, +1, +2.5, -1.5, 0, +0.5. So, avg Oct miss for DJF in the NE was ~0F meaning no apparent bias. @Daniel Boonebecause I told you I’d review the Euro to see if there were a detectable bias in either direction. I’d say the answer is no.