bluewave

Last winter was a weak La Niña and the SSW occurred in late November. This early PV disruption is occurring nearly a month earlier before the vortex fully sets in. Plus it’s forecast to rebound pretty quickly. So the amount of potential cold air is going to be fairly limited this early in the season especially against the record Northern Hemisphere temperatures in association with the historic super El Niño. We didn’t have much success with the two SSWs during a much weaker super El Niño in January 2024 and March 2024. Also the weak PV during January 1998 actually enhanced the warmth when the -AO linked up with the Southeast ridge.

You need the Pacific to back off in order for that to happen which is difficult with such an historic east based El Niño.

If you are going warm for December than why are you giving the week 3+ weeklies any credence?

The exact locations of the +10 and greater departures are difficult to forecast until we are into the first week of the month. We have had 17 such months since December 2015 with departures exceeding +10 or greater for some portion of the CONUS. So December 2015 became a trendsetter and not an outlier. DEC…2015….NYC….+13.3 MAR…2016…MOT….+10.5 JAN…2017….BTV…..+11.0 FEB….2017….ORD….+10.3 FEB…..2018…ATL….+10.6 FEB….2019…MGM….+10.5 JAN….2020…YAM….+9.8 DEC….2021….DFW….+13.2 JAN….2023….DXR….+12.3 FEB….2023…..SSI…..+9.8 DEC….2023….INL…..+15.8 FEB…..2024….FAR…..+17.5 DEC….2024…..LND…..+11.3 DEC….2025….CPR…..+12.1 JAN….2026….RIW……+10.2 FEB…..2026….LND…..+11.3 MAR….2026….PHX…..+12.5

That’s the classic week 3 to 4 Euro default 500 mb pattern it was running with during November 2015. It didn’t start to see the actual December 2015 pattern until the month already started. For much of the 2023-2024 super El Niño season it was doing the same thing even following the two rare SSW events for a super El Nino in January 2024 and March 2024. https://repository.library.noaa.gov/view/noaa/67133 Description: Major sudden stratospheric warmings (SSWs) occur in the Arctic around six times per decade. During winter 2023/2024, two major SSWs occurred – a relatively rare event, having occurred on average only once per decade. Here, we summarise the evolution of the two SSWs, their dynamics and impacts on stratospheric chemical processing and tropospheric weather patterns. While both SSWs were displacement events, they evolved remarkably differently. The 16 January SSW was short‐lived and did not exert a canonical influence on surface weather. In contrast, the 4 March SSW followed a more typical evolution, albeit with only weak coupling to the troposphere. Forecast Verification

We can say that the pattern the last few weeks has been reversed from the same time period back in 1997. The strongest 500 mb trough and STJ is near the Southwest rather than the Southeast leading to the flooding and severe weather more focused in the Southwest. This is why the CONUS and in particular the Southeast has been so much warmer this October than it was back in 1997. The long range seasonal models from a month ago missed the more Southwest focused heavy rainfall. Same for the EPS weeklies beyond week 1 issued in early October. So we’ll just have to monitor going forward to see if some elements of this early season pattern continue. October 12th to 23rd 2026 500 mb pattern compared to 1997 October seasonal rainfall forecast issued in early September Verification

That’s a near record STJ off the Baja being forecast which will help to amplify the ridge over the Great Lakes and Northeast moving into early November.

Yeah, the warmest departures which have been out in the Rockies this month will shift further east as we head into November. Climatologist49 @climatologist49.bsky.social Follow After finishing with the record warmest July, the record warmest August, and the record warmest September, the Contiguous U.S. is on pace to have the 4th warmest October on record. The warmest, 1963, was 4.8F above normal. It's still possible that this October could move higher up the list. 11:30 AM · Oct 23, 2026

Yeah, the shift of the trough to the SW CONUS has allowed our area to dry out a bit this month.

The historic El Nino will he driving a deep trough into the West to close out October. So we get an impressive ridge amplification in the East. Models currently have upper 70s for the usual NJ warm spots on the 30th. Normal highs for the date are in the low 60s. Almanac for NEWARK LIBERTY INTL AP, NJ October 30, 2026 Daily Data Observed Normal Record Highest Record Lowest Max Temperature M 61 82 in 1946 41 in 1869

The models have been forecasting that low become more consolidated this month beyond 240 hrs. But once we get to under 240 hrs, the low is showing up more split. With one piece back toward the Bering Sea and another into the SW CONUS. My guess is that the splitting is a function of the stronger mid-latitude ridges leading to the warm pool from Japan to east of Hawaii. The effect of this ridge is to keep the PDO negative instead of strongly positive. The stronger eastward extension into the SW CONUS is probably a result of how east based the forcing is. So the significance of the warmth making it down to Atlanta is the ridge split leading to a stronger Southeast ridge than usual with the more -PDO pattern. The combination so far has been to enhance the El Nino warming through a stronger ridge across the CONUS. This is why October and the pattern since May has been so much warmer than usual for a super El Nino. New run for November 1st Old run

It’s actually looking possible that we could pull off a rare two consecutive 2026 weekends with no measurable rainfall in late October.

This has been the warmest October 1st to 22nd at Atlanta by a wide margin during a super El Niño. October 1st to 22nd Average Temperatures at Atlanta 2026….68.6° 2023….65.5° 2015….64.9° 1997….64.5° 1982….65.2° 1972…..62.1°

New Brunswick is the warm spot this month so far. They are at +3.2° through the 22nd. This is their 6th warmest October to date. Areas away from the onshore flow influence this month are warmest. Time Series Summary for NEW BRUNSWICK 3 SE, NJ Click column heading to sort ascending, click again to sort descending. 1 2007-10-22 65.1 0 2 2021-10-22 63.3 0 3 2017-10-22 62.4 0 - 1990-10-22 62.4 0 4 2013-10-22 61.7 0 5 2005-10-22 60.6 0 6 2026-10-22 60.4 1 7 2018-10-22 60.3 0 - 2011-10-22 60.3 0 8 1995-10-22 60.1 1 9 2016-10-22 59.7 0 - 1968-10-22 59.7 0 10 2025-10-22 59.4 0 MPO….+2.8 FWN….+2.5 SMQ…..+1.2 NBW….+3.2 EWR….+2.3 LGA……+1.7 NYC……+1.2 JFK……+2.4 HPN……+1.7 BDR……+0.8 ISP……..+2.0

Pretty impressive reversal from the norm with the historic east based El Niño focusing the heaviest rains relative to the means around San Diego this month. So San Diego is getting the least San Diego-like weather during October from what is normal for them outside El Niños. The CONUS has been getting an unusually warm October pattern for such a strong El Niño.