2020 Pacific hurricane season

Season overview

By number of storms, 2020 was an ordinary eastern Pacific year; by strength, it was a quiet one. The tally of tropical storms came in slightly above the 1981 to 2010 average of about 15, but only four storms became hurricanes, roughly half the usual number, even though three of those four went on to become major hurricanes. The archive behind this map gives the season an accumulated cyclone energy of 77.3, the same figure Colorado State University calculated from the National Hurricane Center's best track.

Forecasters had leaned toward a subdued year. In May, NOAA called for a below-normal to near-normal season, pointing to near- or below-average sea surface temperatures across the eastern Pacific and an El Niño–Southern Oscillation that was expected to stay neutral, with a chance of La Niña developing. Mexico's national weather service issued a somewhat higher forecast. Through the year, many systems struggled against wind shear, dry air and cool water, and most of the season's tropical storms peaked well short of hurricane strength.

The site's counts of 17 tropical storms, 4 hurricanes and 3 major hurricanes match the official season summary. Only 16 storms received names, though: the seventeenth is an unnamed tropical storm in July that was advised on as a tropical depression and upgraded only in the Hurricane Center's post-season review, after scatterometer data showed it had briefly carried tropical-storm-force winds. Four other systems never got beyond tropical depression strength, for 21 tracked systems in all.

How the season unfolded

The season started unusually early. Tropical Depression One-E formed on 25 April, three weeks before the official 15 May start, and was the earliest tropical cyclone to form in the eastern Pacific since the satellite era began in 1966. It lasted about a day over open water before dry air and shear took it apart. Activity then paused until late May, when Tropical Storm Amanda formed close to the coast of Central America, and June brought only Tropical Storm Boris, which stayed weak far out at sea, and a short-lived depression off southern Mexico.

July was busier but still restrained. Tropical Storm Cristina peaked at 60 kt in the second week of the month, just short of hurricane strength, before running into cooler water. Another depression and the brief unnamed tropical storm came and went, and it was not until 22 July that Hurricane Douglas became the season's first hurricane, one of the latest dates on record for the basin to wait that long. Douglas then became a Category 4 hurricane and carried on into the central Pacific toward Hawaii.

August brought the season's main burst. Hurricane Elida formed off southwestern Mexico on 8 August and reached Category 2 before swiftly weakening. Within the next three weeks came Tropical Depression Ten-E, Tropical Storm Fausto, Hurricane Genevieve, and then Tropical Storm Hernan and Tropical Storm Iselle, which formed on the same day in late August from an active monsoon trough.

September produced four more storms. Tropical Storm Julio formed on 5 September from the mid-level remnants of Atlantic Hurricane Nana, which had crossed Central America after striking Belize. Tropical Storm Karina and Tropical Storm Lowell followed over open water, and at the end of the month Hurricane Marie formed and quickly became the season's strongest storm.

The final phase was sparse. Tropical Storm Norbert, the only storm to form in October, spent about ten days wandering south of Mexico, opening into a trough and then briefly regaining tropical storm strength on 14 October. After nearly a month without a new storm, Tropical Storm Odalys formed on 3 November and Tropical Storm Polo on 17 November; both were short-lived and stayed away from land, and Polo's dissipation on 19 November closed the season. No tropical cyclone formed in the central Pacific all year, although Boris and Douglas crossed into it from the east.

Strongest storms

Hurricane Marie was the most powerful storm of the year. It formed on 29 September about 360 n mi southwest of Manzanillo and, over sea surface temperatures of 28 to 29°C with abundant moisture and easing shear, it intensified rapidly after becoming a hurricane on 1 October. By 06:00 UTC on 2 October it peaked at 120 kt, Category 4, with a minimum pressure of 945 hPa and a clear eye ringed by very cold cloud tops. Marie held Category 4 strength for about another day before crossing into cooler, drier air on 4 October and weakening quickly. It stayed well away from land and was also the longest-lived system in the archive's record for the season.

Two other storms reached 115 kt, Category 4. Hurricane Douglas peaked on 24 July after gaining strength rapidly, becoming a major hurricane only 12 hours after reaching hurricane strength, and crossed into the central Pacific at that intensity as the strongest hurricane to do so since Lane in 2018. Hurricane Genevieve followed in mid-August, strengthening by 50 kt in 24 hours to peak on 18 August about 195 n mi west-southwest of Manzanillo with a minimum pressure of 950 hPa. Its peak was brief: within hours it began weakening over water that Elida had likely cooled about eight days earlier.

The season's fourth hurricane, Hurricane Elida, peaked at 90 kt, Category 2, on 11 August, while Tropical Storm Cristina, at 60 kt, came closest of the remaining storms to hurricane strength. No storm reached Category 5.

Landfalls and impacts

The deadliest storm was also one of the weakest. Tropical Storm Amanda formed on 30 May about 100 n mi south of Puerto San José, Guatemala, and made landfall in southeastern Guatemala on 31 May with 35 kt winds, only the second known tropical storm to strike Guatemala's Pacific coast, after Tropical Storm Agatha of 2010. Its remnants helped spawn Tropical Storm Cristobal in the Bay of Campeche. Together with Cristobal and heavy rains around a broader Central American weather system, Amanda was linked in the National Hurricane Center's report to 40 deaths in El Salvador, Guatemala and Honduras, 30 of them in El Salvador.

El Salvador bore the worst of it. Nearly 700 landslides and widespread flooding damaged or destroyed about 3,000 houses, some 119,000 people were affected and more than 12,100 sought shelter while the country was dealing with the COVID-19 pandemic. The Hurricane Center describes Amanda as the most devastating weather event in El Salvador since Hurricane Mitch in 1998, and the country's president put the damage there at US$200 million in 2020 dollars. In Guatemala, more than 520,000 people were affected.

Hurricane Genevieve brought the season's closest hurricane approach to Mexico. After weakening from its peak, it jogged north and its center passed about 45 n mi southwest of Cabo San Lucas early on 20 August as a 70 kt hurricane. A station at Cabo San Lucas Marina recorded sustained winds of 61 kt and a gust of 78 kt, and 11.2 inches of rain fell at Cabo San Lucas. The Hurricane Center counted six direct deaths in Mexico: four from landslides and swollen rivers in Oaxaca and two surf drownings at Los Cabos. The insurer Aon estimated damage at no less than US$50 million in 2020 dollars.

Tropical Storm Hernan never made landfall at tropical storm strength but hugged the coast of western Mexico in late August. Together with the monsoon trough, it brought torrential rain to Jalisco, Colima, Michoacán and Sinaloa, with 23.24 inches reported at Cihuatlán, Jalisco. Flash floods and mudslides damaged at least 630 homes, washed out roads and cut power to up to 97,000 people. The Hurricane Center recorded one indirect death, a man in Jalisco who fell from a roof while checking for damage, and gave no monetary estimate; a later estimate put the damage in Mexico at about 1.1 billion pesos, or US$51.4 million in 2020 dollars.

Hawaii had a close call with Hurricane Douglas. Weakening over marginal waters, Douglas passed just north of the main islands on 27 July and came within 60 n mi of Oahu as an 80 kt hurricane, prompting hurricane warnings. Because the islands stayed on its weaker southern side, no tropical-storm-force winds were measured on land, and no damage or casualties were reported. Elsewhere, moisture drawn north from the remnants of Tropical Storm Fausto fed the dry-lightning thunderstorms of 16 and 17 August that sparked hundreds of wildfires across Northern California, though Fausto itself stayed far from land.

Names and records

The season used the same list of names as 2014, except that Odalys replaced Odile; Odalys was used for the first time in 2020. No names were retired after the season, and Polo was the last name used. Beyond One-E's record-early formation, the season is notable for its late first hurricane and for its contrast between a near-normal count of storms and a sharply below-normal number of hurricanes.