Highest temperature in NYC on Apr 4, 2026?

Specific long-range ENSO forecasts are not publicly available. Direct projections from NOAA's CFSv2 and the ECMWF seasonal models for the Niño 3.4 sea surface temperature anomaly during the March-April-May 2026 period are not accessible via public sources. Operational seasonal climate forecast models from centers like NOAA's Climate Prediction Center (CPC) and the European Centre for Medium-Range Weather Forecasts (ECMWF) typically issue outlooks for lead times ranging from approximately 6 to 13 months ^[1]. The March-April-May 2026 period extends to approximately 15 to 18 months beyond current initialization windows.

Forecast skill diminishes significantly for distant ENSO predictions. At such extended lead times, the ability of even advanced seasonal models to accurately predict specific El Niño-Southern Oscillation (ENSO) states, including a precise Niño 3.4 sea surface temperature anomaly, substantially decreases ^[1]. As a result, public resources like the CPC ENSO Diagnostic Discussions, IRI Quick Look, and ECMWF seasonal charts do not offer definitive numerical projections for the Niño 3.4 region for this distant future period, and any such projections would be subject to extreme uncertainty ^[1].

The UK Met Office anticipates a mixed North Atlantic Oscillation signal for April 2026. Their Spring 2026 outlook indicates "no strong signal for a consistently positive NAO" phase for April 2026 ^[1]. Instead, the Met Office foresees a "mixed picture" for the NAO, with "periods of both positive and negative phases" leading to changeable conditions ^[1]. This suggests uncertainty regarding prolonged milder, southerly airflows for regions like New York City, which are typically associated with a persistent positive NAO phase ^[1].

Conversely, the Copernicus Climate Change Service (C3S) does not explicitly detail specific NAO index predictions. C3S comprehensive seasonal forecasts, based on a multi-model ensemble approach, do not explicitly detail specific predictions for the North Atlantic Oscillation (NAO) index for April 2026 within their general seasonal forecast pages ^[2]. C3S seasonal forecasts typically provide probabilistic outlooks for parameters such as temperature and precipitation anomalies, often discussing larger-scale drivers, but a direct prediction of the NAO index phase for a specific future month like April 2026 is not readily available in these summary resources ^[2].

Multiple climate outlooks project an ENSO-neutral state for April 2026. Forecasts for April 2026 consistently indicate ENSO-neutral conditions. The Climate Prediction Center of NOAA projected these conditions through May 2026 as of March 2026 ^[1]. This outlook was supported by the International Research Institute for Climate and Society’s (IRI) March-April-May 2026 forecast ^[4], the World Meteorological Organization’s (WMO) Global Seasonal Climate Updates for March-April-May 2026 ^[5] and April-May-June 2026 ^[6], and the WMO’s February 2026 El Niño/La Niña Update ^[7].

Identifying analogue years for April 4th is currently not possible. The research, however, lacks a specific projection for the Atlantic Multidecadal Oscillation (AMO) state for April 2026, as source ^[2] provides an archive rather than a forecast. This absence, combined with the lack of a comprehensive database of historical conditions or specific output from an "ENSO Analog Year Generator" ^[3] that aligns with both ENSO and AMO criteria for 2026, precludes the identification of the top five analogue years since 2000. Consequently, while historical daily maximum temperatures for April 4th at New York City's Central Park (KNYC) are available in almanac data ^[8], these specific temperatures cannot be extracted for the requested analogue years.

Long-range ensemble models for March 2026 presented a mixed outlook for early spring warming. Forecasts for mid-March 2026 specifically indicated a significant snowpack across the Great Lakes and southern Canada, with predictions for a major blizzard capable of bringing potentially record snowfall to parts of the Upper Midwest and Great Lakes region ^[1]. This suggests that an unusually low snowpack, a key precursor favorable for rapid early spring warming, was not anticipated for this area. Broader seasonal forecasts for Spring 2026 also noted a shift from a La Niña to an emerging El Niño pattern, which can influence climate conditions across the U.S. and Canada ^[3].

In contrast, warmer-than-average sea surface temperatures were consistently projected off New England for March 2026. Long-range ensemble models consistently projected elevated sea surface temperatures (SSTs) for this region. Specific outputs from models such as the Climate Forecast System (CFS) indicated positive SST anomalies across the North Atlantic region ^[4]. These projections for warmer coastal waters align with broader global seasonal climate updates for the March-April-May 2026 period, which generally anticipated warmer oceanic conditions across various areas ^[5].

Overall, conditions for rapid early spring warming were not fully met according to these projections. While warmer-than-average coastal waters off New England were anticipated, the forecasts for potentially record snowfall across parts of the Great Lakes and Upper Midwest in mid-March 2026 indicated that the condition of an unusually low snowpack, which would favor rapid early spring warming, was not expected ^[1]. This presented a mixed scenario where both precursor conditions were not simultaneously present.

April 4, 2026, enters 10-day forecasts on March 25. Both the high-resolution ECMWF (HRES) and Global Forecast System (GFS) weather models will first include April 4, 2026, within their operational 10-day forecast horizons on March 25, 2026. This is determined by calculating 10 days backward from April 4, 2026, which sets March 25, 2026, as the latest forecast run date to encompass the target date.

Both models provide global forecasts with distinct operational schedules. The ECMWF HRES model offers a global, high-resolution deterministic forecast that extends out to 10 days (240 hours) and is run twice daily ^[2]. Similarly, the GFS model, a global numerical weather prediction system, provides forecasts up to 16 days (384 hours) in advance, with four operational runs each day ^[3].

Despite range differences, both models align for a 10-day view. Although the GFS has a longer maximum forecast range of 16 days, for the specific purpose of a 10-day operational forecast horizon, its inclusion of April 4, 2026, aligns with the ECMWF HRES. Consequently, model runs from both ECMWF HRES and GFS on March 25, 2026, will begin to illustrate the meteorological conditions for April 4, 2026, within their 10-day forecast windows.