jconsor

This is quite an active look for Nov of a strong El Nino.

Very nice find, Larry! While the seasonal model support for a strong -AO is mostly lacking, the sub-seasonal support is growing. There is increasing support for a -AO in the last two-thirds of Nov. EPS and GEFS long range weather regime charts show an increasing proportion with Greenland High (GH) or Alaskan ridge (AR) vs. prior forecasts. This is also reflected in individual member AO forecast charts from the long range EPS and GEFS. Taking El Ninos of any strength, the four with a Nov AO below -1.0 saw that -AO persist overall through the winter and most of these were memorable winters with at least one KU event: 1957-58: -0.9 1965-66: -1.5 1968-69: -2.3 2002-03: -0.6

I don't think Dr. Judah Cohen is a kook. Some of his ideas are unconvential, sure. He always explains his reasoning in his blogs... he's not just pulling 2009-10 out of a hat. FYI His company's subseasonal model beat all other entrants in the ECMWF AI WeatherQuest competition in fall 2025 and winter 2025-26: https://news.mit.edu/2026/decoding-arctic-to-predict-winter-weather-0108 https://news.mit.edu/2026/researchers-improve-weather-forecasts-looking-two-six-weeks-out-1014 https://www.nature.com/articles/d41586-026-03077-0

Dr. Judah Cohen did mention that he feels 2009-10 may be the best analog in the past 30 or so years: https://published.aer.com/aoblog/aoblog.html

Having a weak stratospheric PV in Nov is quite uncharacteristic of a strong El Nino: https://x.com/rjameswx/status/2115111708884869209

I disagree. Think we'll see 1-2 more named storms in early November. About a 30% chance of another hurricane. Best chances in the central Atlantic southeast of Bermuda. Also a chance off the SE US coast, though likely brief. Smaller chances near/sw of the Azores and in the western/central Caribbean. The "high over low" pattern encourages low level convergence and anomalously low shear in the subtropics.

The same guy (who uses statistical techniques to do long-range forecasts) has been flagging a high risk for a Nov SSW since the beginning of the summer: https://x.com/Statisticizer/status/2106770331985748036. He also suggests a high risk for a SSW in Feb: https://x.com/Statisticizer/status/2114022327008612489

Some interesting analog years with weak strat PV/SSW in here: https://x.com/Statisticizer/status/2114434656158224475

Here's the paper on the 1846 hurricane, from the SCI-HUB site: https://sci-hub.reatk.com/10.1080/24694452.2020.1838257. I'm a big fan of Prof. Cary Mock (one of the authors) and his historical tropical cyclone reconstructions. Chenoweth also has some excellent papers along the same lines. For instance, "A New Compilation of North Atlantic Tropical Cyclones, 1851–98": https://journals.ametsoc.org/view/journals/clim/27/23/jcli-d-13-00771.1.xml Another late season hurricane which - while not as intense as Hazel and the 1846 hurricane - interacted favorably with an upstream upper level trough and maintained unusually strong intensity well inland was the "Gale of 1878": http://www.wpc.ncep.noaa.gov/research/roth/galeof78.htm This is an interesting paper along the same lines which deals with several East Coast hurricanes from the late 1700s to early-mid 1900s: https://scispace.com/pdf/paleotempestology-reconstructing-atlantic-tropical-cyclone-103stxo9p4.pdf

Thanks Larry. While the UKMET and ICON are further offshore, even those scenarios would likely lead to significant beach erosion/coastal flooding issues from the Carolinas to the mid-Atlantic and even possibly southern New England, due to 5+ days of strong onshore flow driven by the gradient between the 1030-1035 mb high and the low to the south. Despite "only" having a ~1000 mb low, ICON shows an ~850 mile fetch of near gale force (30 kt+) E/NE winds from all the way out around 63W to the Carolinas! Also of note, the UKMET (like a few other models including AIFS) shows ridging rebuilding over the NE US/far NW Atlantic between day 6 and 7), which would likely trap the system and possibly force it back westward beyond day 7. In terms of coastal flooding, it could be argued that a solution like the UKMET and ICON (or 6Z AIFS) with a low moving offshore but very slowly could be as bad or even slightly worse than a solution like the ECMWF or 12Z AIFS - which have a low much closer to the East Coast, but it doesn't strengthen notably and never really has much time to sit over the Gulf Stream.

One of the SC tornadoes (Barnwell) has been upgraded to an EF-2: https://x.com/Gio_wx/status/2109995279244026310

The tornado outbreak across the Carolinas was unusual not just for a TC-associated outbreak, but for the time of year: https://x.com/GMengel/status/2109798674465198505

Historical context - Isaias is easily the strongest Oct-Nov GOM hurricane since the beginning of the 20th Century when considering the 15 strongest El Ninos. Note that 2002 (Lili) was excluded from this list as it was a Modoki Nino. https://x.com/yconsor/status/2108558918406328651

Impressive microwave pass confirming the last recon message which showed a closed eyewall. https://x.com/yconsor/status/2108197204842446876

Side comment - I think we will see 1-3 named storms after this one with about a 50% chance of of another hurricane (likely in the subtropics). But yeah, it's pretty comical that this one seems to be defying many of our expectations.