Added together, the eastern and central Pacific tables sum to 326.1 against 2018’s 318.1, in NHC’s tables since 1991. Neither basin alone is a record. El Niño is the leading explanation, but no one can say how much of the season it owns.
Two NOAA tables, read at 15 UTC on 13 October, give a combined accumulated cyclone energy of 326.1 for the eastern and central Pacific this season. The same sum for 2018, the previous highest season in NHC’s tables, is 318.1, and the tables start in 1991. The Atlantic stands at 18.0. That is a real record on one definition and not a record on another, and the difference is the first thing worth getting right before asking what El Niño contributed.
The Atlantic half of this story is already on the site: the quiet season before any hurricane and Isaias, the first hurricane. This is the other side of the same ledger. Our 16 August piece set out the mechanism and NOAA’s outlook. This one checks the outcome against it.
ACE is the sum of the squares of a named storm’s maximum sustained wind, in knots, taken every six hours while it is at least tropical storm strength, in units of 10,000 knots squared. Squaring the wind is the whole point. One six-hour reading at 155 knots adds 2.40 units. One at 40 knots adds 0.16. A single reading in a violent hurricane therefore counts as much as about 15 readings in a weak tropical storm.
So ACE measures how much wind energy a storm produced over how long. It does not measure damage, rainfall, landfall or storm count. NHC’s eastern Pacific summary line shows no direct deaths and no US damage for the season so far, on an ACE total of 218.0. The Atlantic is the reverse case: Isaias reached Destin at 105 mph, and the Atlantic season total is still 18.0.
NHC publishes the eastern Pacific table and the Central Pacific Hurricane Center publishes a separate central Pacific one, split at 140°W. NHC’s footnote says each ACE total covers only its own basin, so a storm that crosses 140°W has its energy divided between the two tables, and adding the two does not double count. Lowell is the clearest case: 2.0 units in the eastern table and 42.4 in the central one.
Our sum of the two season totals is 326.1. We ranked every season from 1991, the first year NHC’s tables cover, and 2026 is first on the sum, with 2018 second at 318.1, 1992 third at 294.6 and 2015 fourth at 290.6. The margin over 2018 is 8.0 units, about 2.5 percent.
| Season | Eastern Pacific (NHC) | Central Pacific (CPHC) | Sum, east of the dateline |
|---|---|---|---|
| 2026 (to 13 Oct) | 218.0 | 108.1 | 326.1 |
| 2018 | 202.1 | 116.0 | 318.1 |
| 1992 | 258.0 | 36.6 | 294.6 |
| 2015 | 163.3 | 127.3 | 290.6 |
| 1993 | 171.5 | 30.3 | 201.8 |
Neither table is a record alone. The eastern Pacific total of 218.0 is second to 1992’s 258.0, and the central Pacific total of 108.1 is third behind 2015 (127.3) and 2018 (116.0).
Our reading. “Record” is fair for the whole region east of the dateline, and wrong as a description of either NOAA table. It is also a narrow record. The margin is 2.5 percent, ACE is still accumulating, and operational intensities can be revised after the season. The tables begin in 1991, so we cannot say anything about earlier seasons.
Counts tell only part of it. NHC’s eastern Pacific summary line reads 18 named storms, 8 hurricanes and 6 major hurricanes. Against NOAA’s 21 May outlook, named storms and major hurricanes are inside the forecast ranges and hurricanes are one under the 9 to 14 range. NHC counts each storm in the basin where it peaked, and Lowell and Nolo peaked after crossing into the central Pacific. Tallying the peak-wind columns of the two tables ourselves, 11 distinct storms reached hurricane strength and 9 reached 96 knots or more, with three at 137 knots or more (Genevieve, Lowell and Polo). That tally is this site’s, not an NHC figure.
| Measure | NOAA outlook, 21 May | NHC/CPHC tables, 13 Oct | Read |
|---|---|---|---|
| Eastern Pacific named storms | 15 to 22 | 18 | Inside the range |
| Eastern Pacific hurricanes | 9 to 14 | 8 | One below the range, on NHC’s basin-of-peak counting |
| Eastern Pacific major hurricanes | 5 to 9 | 6 | Inside the range |
| Eastern Pacific ACE | 120 to 190% of the median | +118% against the 1991-2020 normal, which is 218% of normal | Higher than the top of the range, with the reference caveat below |
| Central Pacific storms | 5 to 13 named storms and depressions combined | 6 named storms (5 hurricanes, 3 major) | Inside the range; depressions are not listed in the table |
The energy came from persistence and intensity. Our per-storm arithmetic, adding each storm’s share from the two tables, puts Polo first at 50.2, then Lowell at 44.4, Nolo at 31.5, Karina at 31.2 and Rachel at 26.7. Those five storms account for 184.0 units, 56.4 percent of the total. Polo’s 155 knots and 892 millibars are NHC’s table values. The reference problem in the ACE row matters too. NOAA’s outlook gave ACE as a percentage of the 1991-2020 median, and NHC’s table gives the percentage difference from the 1991-2020 normal. We have not converted between them, so treat the ACE comparison as direction, not a score.
The Atlantic and the Pacific are on opposite sides of the same hypothesis. NOAA’s own explainer says El Niño raises vertical wind shear over the tropical Atlantic and Caribbean, which suppresses hurricanes, and it also notes that El Niño often increases activity in the eastern and central Pacific. The Pacific outlook issued on 21 May named El Niño first among its favourable factors, alongside above-average sea surface temperatures in the formation region and below-normal wind shear. The weekly relative Niño 3.4 index was +2.4°C for the week centred 7 October. The Pacific tables sum to 326.1 and the Atlantic to 18.0, a ratio of about 18 to 1.
That pattern is what the forecast said to expect. It is consistent with El Niño being the leading basin-scale explanation. It is not a measurement of how much of the season El Niño produced, and this site will not assign a percentage. One season has no counterfactual, and we do not claim El Niño caused Polo, Rachel, Simon or any other single storm. Individual storms are weather. The seasonal claim is about the distribution those storms were drawn from.
Other ingredients also shaped this particular season. NOAA’s outlook flagged warm eastern Pacific water as a separate factor and described the ENSO influence on Pacific activity as dependent on the background sea surface temperature pattern. NHC’s first advisory discussion for Simon describes a disturbance south of Mexico in low shear over very warm water.
Our reading. A season this lopsided between the Pacific and the Atlantic is the pattern an El Niño-tilted outlook described. NOAA’s own outlook lists other factors alongside El Niño, so the defensible reading is a leading explanation, not a sole one, and we cannot say how large a share it holds.
Read the current table, not this page. NHC and CPHC update the season tables as storms are rated, and a later reading can differ from 326.1 and 218.0. The record depends on the sum, on the 1991 start of the tables, and on intensities that are still operational estimates. The questions this piece leaves open are whether the final tables keep the margin and whether storm-by-storm review changes Polo, Lowell or Nolo.