World Climate Service

March, April, and perhaps even May monthly records will fall next week in the historic western U.S. heat wave. Here's a tool to query ERA5 monthly/annual records for a few variables s2s.worldclimateservice.com/wcs/era5_recor…

@TomMcMurtryNZ ECCC skill is comparable to the other good models, no reason to exclude it on that basis

@WorldClimateSvc The lowest is least credible? ECC clusters a bit lower also than the others. Is this one wuite credible?

While the amplitude of the latest El Niño forecasts is a worthy headline, the latest C3S models show more variance than last month - both for traditional and relative Niño3.4 SSTs. All models have warmed, but some much more than others. (DWD is less credible - poor skill)

Eagerly waiting for new 50r1 ECMWF model upgrade today - unfortunately running late

Good news as the U.S. Midwest growing season gets under way: drought/dryness have all but disappeared in the heart of the Corn Belt in the last two months, even as the Plains and Southeast have been very dry.

@GavinPartridge Interesting that 2007 is my top analog year for both the AMO (past 12 months) and the NAO (past 3 months). But yes, near-opposite Pacific this year

Posted without comment (but if you know, you know) - Atlantic SSTs from 4th May 2007 Vs 4th May 2026 Disclaimer: Pacific state (ENSO/PDO) VERY different this year to 2007)

@Snowlover111232 Traditional, 1993-2016 baseline in this case

@WorldClimateSvc Is that the relative or traditional index?

The progression of ECMWF seasonal VP200 forecasts shows the strengthening of this summer's atmospheric El Niño signal in recent months

@Ronnie721131565 Not useless at all

@WorldClimateSvc Models are useless in the spring . But you Mf keep on going with the hype.

Yet another leg up in today's CanSIPS Niño3.4 forecast update. The ensemble mean shows 9 months above +1.5°C anomaly. The ERSSTv5 record (1991-2020 baseline) is 8 consecutive months in 1997-98 and 2015-2016.

@MarkVogan Poor in terms of cloud and rain yes, but often warm. Propensity for heat waves depends very much on the pattern over northern Europe, which has historically been highly variable during El Niño.

@WorldClimateSvc From what I can see, NW Europe (esp UK/Ire) tends to have poor summers with developing strong EN's but with heat spikes. Curious what your thought's are and any charts you may have?

The major El Niño episodes of recent decades have tended to develop in tandem with significant Arctic sea ice loss (2023, 2015, 2002, 1997). However, there's only a slight overall correlation with summer ENSO. Mid-high latitude SSTs and flow anomalies are more closely related.

2025-26: cold northeast, record warm west

With another La Niña winter on tap, U.S. seasonal forecasters could be forgiven for scratching their heads 🤔 4 of the past 5 winters have seen La Niña, and 4 very different outcomes have occurred: 2020-21 cold south 2021-22 cold north 2022-23 cold west 2024-25 cold east

@ryanweather @seckhardt Have a look at May and especially September 1992 in Alaska 🥶

Late May 1992 was record chilly in the Great Lakes. Chicago recorded latest freeze on record (May 25th) This was due to late spring "polar vortex" disruption likely related to eruption of Mount Pinatubo on June 15, 1991. 🌋

@MassachusettsWx That's interesting. The regime plot said 20260426 on their website, but the image export gave me 20260427 - I didn't notice. Similar forecast, +NAO strongly favored around May 4-5

@WorldClimateSvc I'm a little confused! The ECMWF map says initialized the 26th, while the right is the subseasonal fcst from last night.

A question for weather #regime fans: would you consider this ECMWF day-10 forecast more +NAO or -NAO? ECMWF regimes show +NAO, but their +NAO summer pattern has a trough from Ireland to Scandinavia (very unconventional in summer) Our 4-regime scheme suggests more -NAO alignment

@NbergWX The model agrees

Lot of fall and winter rain and severe storm chances on the Florida Peninsula at the end of 2026 if this does in fact occur. Rain and tornadoes happen most frequently in Florida in the 'off' season during only Strong El Nino's.

The CFSv2 El Niño forecasts have been a bit cooler than the Copernicus multi-model mean in recent months, but the CFS is making up for lost time now. The latest 10 days of initializations show SSTs locally more than 4°C above the 1991-2020 normal in the Niño3 region by Oct-Dec.

@webberweather @mattlanza The SPB is significantly overcome by April. We don't have to wait until June to have a very good idea what's going to happen.

@mattlanza I think a lot of climate scientists have the wrong impression that the SPB *has to* mean the difference b/t no enso event at all & a moderate-strong one In some years like this, its actually the difference between a moderate & a very powerful one when low freq signals are clear

I understand trying to be a “voice of reason” in the sea of hype that is social media, but this is just obnoxiously wrong and dishonest.

The contiguous U.S. states were more than 50°F warmer than Alaska on a monthly basis in March - a first in @NOAANCEI data (1925-present). The most similar past years (extreme March temperature difference) were 2007 and 2012, notable years for extreme summer Arctic sea ice loss.