Seasonal Weather Outlook, Friday, June 26, 2026
El Niño has arrived in force, and forecasters now put better-than-even odds on one of the strongest events in the modern record peaking in Northern Hemisphere winter, a signal that bears directly on heating demand from Tokyo to Rotterdam.
NOAA's Climate Prediction Center confirmed El Niño conditions developed over the past month, with the weekly Niño-3.4 index reaching +1.9°C as of June 17. The NMME multi-model mean projects that index exceeding +2.0°C by the October-November-December season, and NOAA assigns a 63% probability to a very strong event during November-January, one that would rank among the largest in the record back to 1950. The C3S June multi-model ensemble is similarly definitive: 75% of its grand ensemble members exceed 2.5°C amplitude by November. High oceanic heat content and expanding westerly wind anomalies across the equatorial Pacific underpin the high confidence. The uncertainty is no longer whether El Niño strengthens, it is how regional teleconnections translate the ENSO signal into demand patterns across different markets.
The teleconnection picture is mixed. The NAO stands at -0.31, technically neutral, and the GEFS 16-day ensemble shows it drifting mildly negative over the coming fortnight before recovering. An AO that is currently slightly positive at +0.30 trends upward through mid-July in the GEFS ensemble, reaching values above +1.5 by the final days of the outlook. A positive AO phase tends to keep the polar vortex contained, favouring warmer-than-normal conditions across higher latitudes. The MJO is active at Phase 7, amplitude 1.3, positioned over the western Pacific, where enhanced convection can drive downstream Rossby waves into the North Atlantic on a 2-3 week lag. Phase 7 has historically been associated with a modest negative NAO tendency at extended range, worth watching as the signal propagates. The QBO at 50hPa reads -1.5 m/s, weakly easterly, under the Holton-Tan relationship, an easterly QBO phase tends to favour a weaker polar vortex and raised odds of blocking in the mid-winter months, but this is a probabilistic tendency, not a deterministic one.
6-Week Temperature Trajectory
The EC46 ensemble for northwest Europe shows a two-stage signal. Week one reflects the current heatwave, Frankfurt at 25.0°C, Amsterdam at 22.4°C, London at 21.6°C, all above seasonal norms. Week two delivers the break: Frankfurt falls to 20.1°C with an ensemble spread of 15.6°C to 24.9°C, one of the widest in the six-week window. That width signals high model uncertainty about where the anticyclone breaks and how quickly Atlantic westerlies reassert. Weeks three through six show Frankfurt stabilising around 21°C, with the ensemble spread remaining 10°C or more, the models disagree on whether the pattern flips decisively or continues oscillating.
Spain holds firm. Madrid runs 28-29°C throughout the six-week period, with relatively narrow spread, suggesting the Iberian heat signal is more entrenched than the northwest European one. Notably, EC46 revised Frankfurt temperatures down by 2.6-3.0°C for the period around July 20-23 compared to yesterday's run, a meaningful downward revision for central Europe's late-July outlook.
For Japan, the signal moves in the opposite direction. Nagoya rises from 22.9°C in week one to 26.3-26.8°C by weeks three through five, Osaka tracking a near-identical path. The EC46 revised Tokyo July 27 cooler by 2.6°C to 26.0°C, but the broader warming trend into July and early August remains intact. Houston sits at 28-30°C through the six-week period with a narrowing spread, confident heat for the US south.
Regional Seasonal Outlooks
For Europe, the key question entering autumn is how the El Niño signal interacts with the Atlantic circulation. Strong El Niño events have historically shown a tendency toward positive NAO in mid-winter, which would mean milder-than-average temperatures across northwest Europe and below-normal gas demand. But the correlation is noisy at the regional level. The current anticyclonic setup, visible in the French heatwave, demonstrates how a blocked pattern can override the background ENSO tendency. ECMWF's seasonal ensemble does not yet show a consensus winter European signal in the current data.
In East Asia, El Niño's warming tendency is more reliable. JMA's standard climate products flag El Niño as a driver of above-normal temperatures across Japan during winter, historically, strong El Niño events are associated with warmer Januaries across Honshu, with implications for LNG spot demand. NOAA's NMME confirms this tendency. Both Korea and Japan would see reduced LNG import requirements relative to a neutral or La Niña winter if the strong event materialises as forecast.
In the Americas, NOAA CPC's JAS seasonal outlook shows above-normal temperatures across the western CONUS, particularly the Pacific Northwest, and extending to the Southeast and East Coast. Below-normal precipitation is projected for the Southern Plains and Lower Mississippi Valley. For winter, strong El Niño historically shifts the southern US jet into an active storm track, wet for California and the Gulf Coast, warmer for the northern tier.
Hydro and Storage
The Sao Paulo EC46 trajectory deserves attention. The latest run added warmth for early July (+3.7-4.1°C) but then cooled late July into August, consistent with the winter dry season pattern in southeast Brazil. El Niño typically suppresses rainfall over Brazil's key hydro catchments from July onward, and a strong event raises the odds of below-normal reservoir accumulation heading into the wet season. That matters for Brazilian power pricing and potential LNG spot demand from the country's thermal fleet if hydro reserves run short.
Strategic Positioning
- El Niño winter premium on JKM is the clearest directional signal: a very strong event reduces Japan and Korea LNG demand in Q1 2027. Front-month JKM currently at $15.38. The risk is that a strong El Niño moderates the peak demand months that typically underpin winter JKM rallies.
- European TTF winter curve exposure is less clear-cut. A positive NAO tendency associated with El Niño would be bearish for winter gas demand, but the current blocked pattern and QBO's easterly phase both argue against assuming a smooth transition. Watch NAO evolution through July for the first signal on winter positioning.
- US gas: NOAA CPC projects above-normal temperatures for the southern and eastern CONUS in JAS. Combined with elevated power-sector cooling demand, this is supportive of summer NYMEX Henry Hub, but the 8-14-day outlook already flags a heat wave spreading across the central and eastern CONUS.
- Brazilian hydro: monitor June-July rainfall deficits in the Paraná basin. If El Niño suppresses accumulation through the dry season, the October re-fill window becomes the key risk event for regional power prices.
- EC46 Frankfurt revision lower (-2.6-3.0°C for late July) suggests European power markets may be pricing too much heat risk for the July 20-25 window. Watch the pattern break signals closely next week.