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Eastern North Pacific Hurricane Season Outlook 2025
NWS Climate Prediction Center College Park MD
1100 AM EDT Thu 22 May 2025


Note: figures mentioned in the discussion are available
on the internet at http://www.cpc.ncep.noaa.gov

  NOAA 2025 Eastern Pacific Hurricane Season Outlook
Issued 22 May 2025

This 2025 eastern Pacific hurricane season outlook is an
official product of the National Oceanic and Atmospheric
Administration /NOAA/ Climate Prediction Center /CPC/, and is
produced in collaboration with hurricane experts from NOAAs
National Hurricane Center /NHC/ and the Atlantic Oceanographic
and Meteorological Laboratorys /AOML/. The eastern Pacific
hurricane region covers the eastern North Pacific Ocean east
of 140deg W and north of the equator.

Interpretation of NOAAs eastern Pacific hurricane season
outlook This outlook is a general guide to the expected overall
activity during the upcoming hurricane season. It is not a
seasonal hurricane landfall forecast, and it does not imply
levels of activity for any particular location.

Preparedness Hurricane-related disasters can occur during any
season, even for years with low overall activity.  It only takes
one hurricane /or tropical storm/ to cause a disaster. It is
crucial that residents, businesses, and government agencies of
coastal and near-coastal regions prepare for every hurricane
season regardless of this, or any other, seasonal outlook. The
Federal Emergency Management Agency /FEMA/ through www.ready.gov
/English/ and www.listo.gov /Spanish/, the NHC, the Small
Business Administration, and the American Red Cross all provide
important hurricane preparedness information on their web sites.
NOAA does not make seasonal hurricane landfall predictions NOAA
does not make seasonal hurricane landfall predictions. Hurricane
landfalls are largely determined by the weather patterns in
place as the hurricane approaches, which are predictable when
the storm is within several days of making landfall.

Nature of this outlook and the "likely" ranges of activity
This outlook is probabilistic, meaning the stated "likely"
ranges of activity have a certain likelihood of occurring. The
seasonal activity is expected to fall within these ranges in
7 out of 10`seasons with similar conditions and uncertainties
to those expected this year. They do not represent the total
possible ranges of activity seen in past similar years.

This outlook is based on model forecasts, and on predictions of
large-scale factors and conditions that are known to strongly
influence seasonal eastern Pacific hurricane activity. The
outlook also takes into account uncertainties inherent in
such outlooks.

Sources of uncertainty in this seasonal outlook 1.  Predicting
the El Nino-Southern Oscillation /ENSO/ phases, which include
El Nino and La Nina events and ENSO-neutral and their specific
impacts on eastern Pacific hurricane activity is an ongoing
scientific challenge facing scientists today. Such forecasts
made during the spring generally have more uncertainty than
those made closer to the peak of the East Pacific hurricane
season /July-September: JAS/.

2. Uncertainty as to whether the eastern Pacific has shifted
to a long-term low-activity era, or that the recent quiescent
period will be short lived and there will be a return to the
high activity era that lasted from 2014-2019.

3. Predicting the combined impacts associated with the ENSO,
Pacific Decadal Oscillation /PDO/, and the Atlantic Multidecadal
Oscillation /AMO/ remains a challenge, especially when they
have different temporal variability that sometimes results in
competing influences.

4. Many combinations of named storms, hurricanes, and major
hurricanes can occur for the same general set of conditions. For
example, one cannot know with certainty whether a given signal
may be associated with several short-lived storms or fewer
longer-lived storms with greater intensity.

5. Shorter-term weather patterns that are unpredictable
on seasonal time scales can sometimes develop and last for
weeks or months within a season, possibly affecting seasonal
hurricane activity.




2025 Eastern Pacific Hurricane Outlook Summary

a. Predicted Activity NOAAs 2025 eastern Pacific
hurricane season outlook indicates a below-normal season
is most likely /50 percent chance/. There is a 30 percent
chance of a near-normal season and only a 20 percent
chance of an above-normal season. See NOAA definitions
/https://www.cpc.ncep.noaa.gov/products/Epac_hurr/Background.html/
of above-, near-, and below-normal seasons. The eastern Pacific
hurricane region covers the eastern North Pacific Ocean east
of 140deg W and north of the equator.

The 2025 outlook calls for a 70 percent probability for each of
the following ranges of activity: ?  12-18 Named Storms ?
5-10 Hurricanes ?2-5 Major Hurricanes ?     Accumulated
Cyclone Energy /ACE/ range of 60-130 percent of the median.

The activity is expected to fall within these ranges in 70
percent of seasons with similar conditions and uncertainties
to those expected this year. These ranges do not represent
the total possible activity seen in past similar years. The
predicted ranges are centered near or below the 1991-2020
averages of 15 named storms, 8 hurricanes, and 4 major
hurricanes.

The eastern Pacific hurricane season officially runs from May
15th through November 30th. The peak months of the season are
July-August-September /JAS/.

There will be no further updates to this outlook.

b. Reasoning behind the outlook Two primary factors are expected
to contribute to a below-normal 2025 hurricane season across
the eastern Pacific hurricane basin, as follows:

1/ The latest monthly sea-surface temperature /SST/ anomalies
reflect ENSO-neutral conditions, a negative PDO structure, and
North Atlantic SSTs above-normal for much of the basin. There
is some evidence of influence from the negative PDO related
circulation pushing cooler waters southward. The cooler waters
are expected to occur mainly west of 120deg W, so that may limit
intensity and duration of storms that do develop. SSTs across
the Atlantic Main Development Region /MDR/ are above normal,
especially the western portions. Historically, this combination
of cooler Pacific SSTs near the equator /Negative PDO/ and
warmer Atlantic /positive AMO/ tends to be associated with
below-normal hurricane activity in the eastern Pacific.

2/ The most recent forecast from the NOAA Climate Prediction
Center indicates ENSO-Neutral conditions are likely through
the hurricane season. The ENSO influence on eastern Pacific
hurricane activity is highly dependent upon the background
SST patterns across the eastern Pacific hurricane region and
the Atlantic MDR. In 2024, the combination of cooler SSTs
near the equatorial Pacific and above-normal temperatures in
the Atlantic MDR resulted in a below- normal eastern Pacific
hurricane season. For 2025, the Atlantic MDR SSTs are predicted
to be above normal, but the tropical Pacific is most likely
to experience ENSO-neutral. However, many of the models do
indicate negative Nino 3.4 index values /though not full La
Nina conditions/, so that contributes to a slight tilt toward
below-normal activity.

DISCUSSION 1. Forecast 2025 activity

NOAAs 2025 eastern Pacific Hurricane Season Outlook indicates a
below-normal season is most likely /50 percent chance/. There
is a 30 percent chance of a near-normal season and only a 20
percent chance of an above-normal season.

The 2025 eastern Pacific hurricane season is predicted
to produce /with a 70 percent probability for each range/
12-18 named storms, of which 5-10 are expected to become
hurricanes, and 2-5 of those are expected to become major
hurricanes. These ranges are centered near or below the
1991-2020`seasonal averages of 15 named storms, 8 hurricanes,
and 4 major hurricanes.

An important measure of the total seasonal activity is NOAAs
Accumulated Cyclone Energy /ACE/ index, which accounts for
the combined intensity and duration of named storms and
hurricanes during the season. This 2025 outlook indicates a
70 percent chance that the ACE range will be 60-130 percent
of the median. An ACE value of 80 percent-120 percent of the
median indicates a near-normal season. Values above this range
reflect an above-normal season, and values below this range
reflect a below-normal season.

Predictions of the location, number, timing, and intensity of
hurricane landfalls are ultimately related to the daily weather
patterns which determine storm genesis locations and steering
patterns. These patterns are not predictable weeks or months in
advance. As a result, it is currently not possible to reliably
predict the number or intensity of landfalling hurricanes at
these extended ranges, or whether a given locality will be
impacted by a tropical storm or hurricane this season.


2. Science behind the Outlook

NOAAs eastern Pacific Hurricane Season Outlook is based
on predictions of the main factors and their associated
relationships to the hurricane season, as well as direct
output from numerical models. The outlook is based on
extensive monitoring, analysis, research activities, a suite
of statistical prediction tools, and dynamical models. The
dynamical model predictions come from the NOAA Climate Forecast
System /CFS/, NOAA Geophysical Fluid Dynamics Lab /GFDL/ HiFLOR
and SPEAR-MED modes, the North American Multi-Model Ensemble
/NMME/, the United Kingdom Met Office /UKMET/ GloSea6 model,
and the European Centre for Medium- Range Weather Forecasting
/ECMWF/ Seas5 model. ENSO forecasts are also provided from
the NMME dynamical models contained in the suite of Nino 3.4
SST forecasts, which is compiled by NOAAs CPC.

NOAAs 2025 eastern Pacific Hurricane Season Outlook reflects
the following atmospheric and oceanic factors:

1/ The predicted SST anomaly patterns across the eastern Pacific
hurricane region indicate near- average SSTs with above-average
SSTs across the Atlantic MDR. SST anomalies in the regions
where many of the tropical storms and hurricanes form /110deg W -
140deg W/ are warmer than average /cooler/ in the east /west/. For
the Pacific, these conditions also project onto the negative
phase of the PDO, while the Atlantic SSTs project onto the
warm /positive/ phase of the Atlantic Multidecadal Oscillation
/AMO/. Historically, this combination of atmospheric and oceanic
patterns tends to be associated with below-normal activity in
the eastern Pacific hurricane region.  The exact interplay
and net result of the interbasin relationships is uncertain
and still a focus of ongoing research, and that uncertainty
is reflected in the relatively moderate probabilities in
this outlook.

2/ The most recent forecast from the NOAA Climate Prediction
Center indicates ENSO-Neutral conditions are most likely through
the hurricane season. The ENSO influence on eastern Pacific
hurricane activity is highly dependent upon the background
SST patterns across the eastern Pacific hurricane region
and the Atlantic MDR. In 2024, the combination of La Nina
and above- normal temperatures in the Atlantic MDR resulted
in a below-normal hurricane season. For 2025, the Atlantic
MDR SSTs are predicted to be above normal, but the tropical
Pacific is most likely to experience ENSO-neutral. Many of the
models do indicate Nino 3.4 index values below normal, so that
contributes to a slight tilt toward below-normal activity.

a. ENSO-neutral favored ENSO-neutral is the most likely outcome
during the JAS period, though odds are at 63 percent, so there
is still a possibility /~25 percent/ that a weak La Nina could
emerge, or that the atmosphere reflects La Nina forcing in some
ways. The weekly SSTs are currently slightly below average
across much of the central and eastern equatorial Pacific
and the SST index for the Nino 3.4 region is -0.1deg C. The
Nino 3.4 index has shown no significant trend since March of
2025. The wind and outgoing longwave radiation patterns over
the central Pacific are also reflecting a breakdown of the
atmospheric response to last winters forcings, which resembled
La Nina, though the Oceanic Nino Index /ONI/ values did not
meet the threshold for enough consecutive 3- month seasons.
Looking forward, model-predicted SST anomalies in the Nino 3.4
region generally indicate ENSO-neutral conditions throughout
the hurricane season. The dynamical model average /dashed
black line/ indicates ENSO-neutral through the late summer and
autumn of 2025, with one modeling system indicating La Nina
conditions early in the summer.  NOAAs Climate Forecast System
/CFS/ and the North American Multi-Model Ensemble /NMME/ are
predicting ENSO-neutral. The CFS and NMME predict above-normal
vertical wind shear over the eastern Pacific. The highest wind
shear anomalies are expected to be located over the area from
110deg W to 130deg W, the region where most of the eastern Pacific
hurricanes develop and track. Wind shear closer to Hawaii is
expected to be near to, or lower than, normal. Vertical wind
shear is one of the most important factors determining the level
of seasonal activity with lower- /higher-/ than-normal vertical
wind shear associated with higher- /lower-/ amounts of activity.

b. Eastern North Pacific high- and low-activity eras

In addition to year-to-year fluctuations, eastern Pacific
hurricane activity exhibits strong variability on decadal and
multi-decadal time scales. Periods of decreased activity /such
as 1971- 1981 and 1995-2013/ are called low-activity eras, and
periods of increased activity /such as 1982-1994 and 2014-2019/
are called high-activity eras, The differences in seasonal
activity between these two eras for the eastern Pacific are
considerable. High-activity eras average about 4.5 more named
storms, 2.8 more hurricanes, 2.3 more major hurricanes,
and 56 percent more ACE, than low-activity eras. During
high-activity eras, above-normal seasons occur about three
times more frequently /63 percent of seasons compared to 20
percent/, and below-normal seasons are about four times less
frequent /11 percent compared to 43 percent/.

High- and low-activity eras in the eastern Pacific hurricane
region are related to global patterns of SST anomalies that
change slowly and last for many years. It is upon these patterns
that the inter-annual ENSO signal overlays. One such pattern
is called the PDO. The PDO spans most of the North Pacific
Ocean, and is associated with decadal fluctuations in hurricane
activity. The positive /negative/ phase of the PDO tends to be
associated with high- /low-/ activity eras.  Another SST pattern
is the AMO, and when linked to wind patterns can be more broadly
described as Atlantic Multidecadal Variability /AMV/, measured
through the Atlantic Meridional Mode /AMM/. The cold /warm/
phase of the AMO increases the likelihood of a high- /low-/
activity era. The AMO helps to explain the inverse relationship
in activity between the eastern Pacific and Atlantic basins,
with a warm AMO/positive AMM favoring increased Atlantic
activity and decreased eastern Pacific activity. The AMO is
positive this year with warm SSTs in the North Atlantic.

The 1982-1994 high-activity era was associated with a cold AMO
and a positive PDO, which was then followed by a low-activity
era from 1995-2013 that  featured a warm AMO and negative
PDO. The period from 2014-2020 exhibited higher activity and
primarily featured a strong positive PDO. Such a short period
of years would not define an activity era. The variability in
recent years points more to intraseasonal signals overriding
the long-term signals.Of the years when the August PDO was
negative, approximately 70 percent of those years were near
normal or below normal for activity /18 of 24 since 1971/. The
current value of the PDO is - 0.41, and the SST patterns from
this spring are similar to many low-activity years. The SST
patterns in 2022 and 2023 were also similar, but the eastern
Pacific experienced near-normal activity and above-normal
activity, respectively, during those years. That variation
shows that interannual variability can override the decadal
signals. There is high confidence that the current negative
PDO pattern will persist through the hurricane season.


NOAA FORECASTERS Climate Prediction Center Matt Rosencrans,
Physical Scientist; Matthew.Rosencrans@noaa.gov Dr. Hui
Wang, Meteorologist; Hui.Wang@noaa.gov Dr. Daniel Harnos,
Meteorologist, Daniel.Harnos@noaa.gov Lindsey Long,
Meteorologist, Lindsey.Long@noaa.gov

National Hurricane Center Eric Blake, Senior Hurricane
Specialist; Eric.S.Blake@noaa.gov Dr. Chris Landsea,
Meteorologist; Chris.Landsea@noaa.gov

Atlantic Oceanographic and Meteorological Laboratory Stanley
Goldenberg, Meteorologist; Stanley.Goldenberg@noaa.gov


$$