Eastern North Pacific Hurricane Season Outlook 2022 NWS Climate Prediction Center College Park MD 1100 AM EDT Tue 24 May 2022 TEST TEST TEST This is a test message TEST TEST TEST Note: figures mentioned in the discussion are available on the internet at http://www.cpc.ncep.noaa.gov NOAA 2022 Eastern Pacific Hurricane Season Outlook Issued 24 May 2022 This 2022 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 the NOAA National Hurricane Center /NHC/ and the Hurricane Research Division /HRD/. The eastern Pacific hurricane region covers the eastern North Pacific Ocean east of 140degW 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 even a 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/, 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 climate model forecasts, and on predictions of large-scale climate factors and conditions that are known to strongly influence seasonal eastern Pacific hurricane activity. The outlook also takes into account uncertainties inherent in such climate outlooks. Sources of uncertainty in this seasonal outlook 1. Predicting El Nino and La Nina events /also called El Nino-Southern Oscillation, ENSO/ and specific impacts on eastern Pacific hurricane activity is an ongoing scientific challenge facing climate scientists today. Such forecasts made during the spring generally have more uncertainty than those made closer to the peak of hurricane season. 2. Uncertainty as to whether the eastern Pacific has shifted to a persistent low-activity era, or 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 combined impacts associated with the Pacific Decadal Oscillation /PDO/ and the Atlantic Multidecadal Variability /AMV/ remains a challenge, especially when they have different temporal variability that sometimes results in competing influences. 4. Many combinations of named storms and hurricanes can occur for the same general set of climate conditions. For example, one cannot know with certainty whether a given climate signal will 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, possibly affecting seasonal hurricane activity. 2022 Eastern Pacific Hurricane Outlook Summary a. Predicted Activity NOAAs 2022 eastern Pacific Hurricane Season Outlook indicates a below-normal season is most likely /60 percent chance/. There is a 30 percent chance of a near-normal season and only a 10 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 140degW and north of the equator. The 2022 outlook calls for a 70 percent probability for each of the following ranges of activity: 10-17 Named Storms 4-8 Hurricanes 0-3 Major Hurricanes Accumulated Cyclone Energy /ACE/ range of 45 percent-100 percent of the median. The activity is expected to fall within these ranges in 70 percent of seasons with similar climate 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 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-September /JAS/. There will be no further updates to this outlook. b. Reasoning behind the outlook Two climate factors are expected to contribute to a below-normal 2022 hurricane season across the eastern /and central/ Pacific hurricane basins, as follows: 1/ The latest monthly sea surface temperature /SST/ anomalies reflect the ongoing La Nina and negative PDO structure, while also showing the North Atlantic SSTs as above-normal for the entire basin. Similar to 2021, negative SST anomalies are measured in the tropical eastern Pacific. The predicted SST anomaly patterns indicate below- or near-average SSTs across the eastern Pacific hurricane region, and near-average SSTs across the Atlantic Main Development Region /MDR/. Historically, this combination tends to be associated with near- or below-normal hurricane activity in the eastern Pacific. 2/ The most recent forecast from the NOAA Climate Prediction Center indicates La Nina 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. The combination of La Nina and above-normal temperatures in the Atlantic MDR tends to favor reduced eastern Pacific hurricane activity, often resulting in a near- or below-normal hurricane season. La Nina, combined with a warm Atlantic MDR and negative PDO, can result in a wide range of outcomes, centered just slightly below the 1991-2020 averages. DISCUSSION 1. Expected 2022 activity NOAAs 2022 eastern Pacific Hurricane Season Outlook indicates a below-normal season is most likely /60 percent chance/. There is a 30 percent chance of a near-normal season and a 10 percent chance of an above-normal season. The 2022 eastern Pacific hurricane season is predicted to produce /with a 70 percent probability for each range/ 10-17 named storms, of which 4-8 are expected to become hurricanes, and 0-3 of those are expected to become major hurricanes. These ranges are centered 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 2022 outlook indicates a 70 percent chance that the ACE range will be 45 percent-100 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 climate 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 2022 eastern Pacific Hurricane Season Outlook reflects two main factors, as follows: 1/ The predicted SST anomaly patterns indicate near to below-average SSTs across the eastern Pacific hurricane region, and above-average SSTs across the Atlantic MDR. For the Pacific, these conditions also project onto the negative phase of the Pacific Decadal Oscillation /PDO/ and also onto the warm /positive/ phase of the Atlantic Multidecadal Oscillation /AMO/ and the Atlantic Meridional Mode /AMM/. Historically, this combination of climate patterns tends to be associated with low-activity eras in the eastern Pacific hurricane region, and with near- or below-normal eastern Pacific hurricane seasons. The exact interplay and net result of the interbasin relationships is uncertain and still a focus of ongoing research. 2/ The most recent forecast from the CPC favors La Nina /58 percent chance/ conditions with low odds for the development of El Nino /4 percent/. Historically, during low-activity eras when the negative PDO and warm AMO/AMM are present, La Nina conditions would also tend to favor a below-normal season. However, if the positive PDO pattern emerges, or the warm AMO/positive AMM do not emerge, conditions could favor activity near the upper ends of our predicted ranges, closer to near-normal. a. La Nina favored La Nina conditions are present at this time. As of May 16, 2022, the weekly SSTs are currently below average across the central and eastern equatorial Pacific, and the SST index for the Nino 3.4 region is -1.1degC. The weekly Nino 3.4 index had been below -0.5degC since October 2021. The Nino 3.4 index has varied from as low -1.2degC to -0.7degC in the past few months, but has not shown any significant trends away from the La Nina range. The wind and outgoing longwave radiation /OLR/ patterns over the central Pacific are also reflecting a continuation of atmospheric response to La Nina. Looking forward, model-predicted SST anomalies in the Nino 3.4 region generally indicate La Nina /Nino 3.4 index less than -0.5degC/ conditions throughout the hurricane season. The dynamical model average /dashed black line/ indicates La Nina through the summer and autumn of 2022, with only one modeling system indicating ENSO-neutral, but still on the cold side. NOAAs Climate Forecast System /CFS/ and the North American Multi-model Ensemble /NMME/ are predicting La Nina. The CFS and NMME both predict above-normal shear over the East Pacific. The shear predicted this year is stronger than what was predicted last year /further from climatology/ for much of the hurricane development region of the eastern Pacific. Closer to Baja California, the models predict weaker than normal shear. These patterns are consistent with a robust La Nina. If La Nina is not maintained, or is disrupted by intraseasonal oscillations during the seasonal peak /July-August-September/, then the seasonal activity could be within the upper portion of the forecast ranges. 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, though it is not clear if the recent lull is indeed an end to a high-activity era, or simply a pause. These are different from the high- and low-activity eras in the Atlantic hurricane region. 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 more ACE points, 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 strongly 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 Pacific Decadal Oscillation /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 Atlantic Multi-decadal Oscillation /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 1982-1994 high-activity era was associated with a cold AMO and a positive PDO, while the period from 2014-2019 exhibited higher activity and primarily featured a strong positive PDO, there is uncertainty about the classification of the activity regime in the Pacific. Such a short period of years would not define an activity era. This lull in activity could just be more consistent with repeat La Nina events overriding the multi-year signals. The intervening 1995-2013 low-activity era featured a warm AMO and negative PDO. Of the years when the August PDO was negative, approximately 70 percent of those years were near normal or below normal for activity /16 of 22 since 1971/. The current value of the PDO is -1.52, and the SST patterns from this spring are similar to many low-activity years. There is medium confidence that the current negative PDO pattern will persist through the hurricane season. One reason is that SST forecasts made several months ahead tend to have limited skill. Another reason is that the current negative PDO signal partly reflects the synoptic-scale wind and pressure patterns associated with persistent higher-than-normal pressures over the North Pacific. In addition, August Nino 3.4 values and August PDO values are highly correlated, and the predictions for Nino 3.4 are well below zero /i.e., La Nina/ in many models. The official probabilities largely reflect the relatively high likelihood of La Nina during a low-activity era, which are typically associated with a negative PDO. NOAA FORECASTERS Climate Prediction Center Matt Rosencrans, Physical Scientist; Matthew.Rosencrans@noaa.gov Dr. Hui Wang, Physical Scientist; Hui.Wang@noaa.gov Dr. Daniel Harnos, Meteorologist, Daniel.Harnos@noaa.gov National Hurricane Center Eric Blake, Senior Hurricane Specialist; Eric.S.Blake@noaa.gov Dr. Chris Landsea, Meteorologist; Chris.Landsea@noaa.gov Hurricane Research Division Stanley Goldenberg, Meteorologist; Stanley.Goldenberg@noaa.gov $$