2018 Pacific Hurricane Season

Opening to the 2018 East Pacific Hurricane Season

Updated May 15, 2018 @ 12:00 am EST

May 15! It’s that time of year again when water temperatures become prime and wind shear levels begin to decrease. It is the official opening of the East Pacific Hurricane season! Many of us probably do not pay too much attention to this region of the world and the hurricanes that are born. Most of the time the storms that do form stay out to sea and travel on a typical WNW track over the open ocean. However, those who live along Central America’s west coast and particularly in Baja California monitor these storms very closely throughout the Hurricane Season. This basin gave birth to notable storms, one being Hurricane Odile (2014), which became the most intense tropical cyclone to make landfall in Baja California in the satellite era. This dangerous Category 4 hurricane with winds of 140 mph (220 km/h) was a particularly hard storm to forecast for many meteorologists. Once the warnings were issued locals and tourists were only given a few short hours to prepare and evacuate. Also, who can forget Hurricane Patricia (2013)? Patricia went on to become the second-most intense tropical cyclone on record worldwide, right behind Typhoon Tip (1979), with a minimum barometric pressure of 872 mb. “Luckily” Patricia weakened before making landfall near Cuixmala, Mexico in a generally rural area, yet it was still the most intense Pacific hurricane on record to strike Mexico. The east Pacific basin has produced strong and catastrophic storms for years and will continue to do so, but the question now is how active will the 2018 season be for this basin?

We are already off to a potentially busy start with the first Tropical Depression forming late last week: Tropical Depression One-E.

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Track of Tropical Depression One-E taken on May 12, 2018 (Courtesy of Weather Underground).

This storm was short lived, posed no risk to land, and was not expected to strengthen; but it is an indication that areas in the East Pacific basin are prime for development. May is not a particularly active month for the East Pacific mostly because cool sea surface temperatures are lingering and atmospheric wind shear is generally remaining strong in the upper levels of the atmosphere; these two complication hinder tropical storm formation. However since 2000, 19 named storms have been recorded in this area and many have even made landfall across Mexico and Central America:

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Track and intensity of named tropical systems for the month of May. Data compiled from 2000 to 2016 (Courtesy of Weather Underground).

The frequency and intensity of East Pacific storms do not really start to ramp up until mid June, but it could be a quiet start to this ocean basin because of a lingering La Niña event. A La Niña helps to suppress tropical storm formation in the Pacific because of the effects it has on the sea surface temperatures.

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May 14, 2018 current global sea surface temperatures (Courtesy of Weather Underground).

While there is no solid scientific explanation as to why this phenomenon occurs (El Niño Southern Oscillation – ENSO) it does affect weather patterns worldwide depending on if there is an El Niño event (warm phase) or a La Niña event (cold phase). Relating to the image above, take a look off the west coast of South America by Ecuador and Peru and you will see a swirl of temperatures around 22 – 26° C (depicted as orange) that extends westward towards the central Pacific. This is the location of an ENSO event. During La Niña events this area is cooler than the surrounding Pacific waters (what we are currently experiencing). An El Niño event will show the reverse, where the waters will be warmer than the surrounding area. We are currently in a La Niña event and have been for about two years now. However, it is showing signs of weakening steadily with forecasters predicting a switch to an El Niño event by autumn. If these forecasts are correct the East Pacific could see a sudden spike in hurricane activity right during the peak of the hurricane season (September – October). Therefore, while it might be a quiet start to the season over the summer months it may pick up in the later months. This ocean basin may be less active during a La Niña event but this cold phase has the opposite effect in the North Atlantic Basin. The Atlantic during a La Niña event experiences higher than normal sea surface temperatures on average, and therefore it will see an increase in hurricane activity with the possibility of more major hurricanes (Category 3 and higher) being produced. This event is linked to the 2017 Atlantic Hurricane Season and why it was so active both in terms of cyclone frequency as well as intensity. The East Pacific, on the other hand, as well as the whole Pacific basin in general saw less hurricane activity for the 2017 year.

  • 2017 Atlantic Hurricane Season

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  • 2017 East Pacific Hurricane Season

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  • 2017 West Pacific Typhoon Season

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Tracks and intensities of named tropical systems for 2017 for the North Atlantic, East Pacific, and West Pacific  basins (Courtesy of National Hurricane Center)

First image shows the total number and track of hurricanes for the 2017 Atlantic Hurricane Season. This season was known as a hyperactive season with 17 named storms; 6 which were designated “major” (Category 3 or higher). This year also ended the decade long hurricane drought. Since 2005 the continental United States has avoided a direct hit by a major hurricane. In addition, the state of Florida had not been directly impacted by a hurricane since 2005.

The second figure depicts the hurricanes for 2017 in the East Pacific basin and was labeled to be a moderately active season with 18 named storms, and 4 major hurricanes – most of these being weak and short lived storms. However, it was a season that was significantly less active than the previous three seasons. The final image above shows the number of hurricanes (typhoons) formed in the 2017 West Pacific typhoon season. The image may seem like there were many storms that formed, but believe it or not this season was labeled as a below-average season with 27 names storms, 11 typhoons, and 2 super typhoons.

Looking ahead to the 2018 Hurricane Season for the East Pacific: forecasters are already warning for a potentially active season, particularly later on into autumn.

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AccuWeather’s 2018 East Pacific Forecast (Courtesy of AccuWeather)

AccuWeather forecast calls for 16 – 19 named storms with about 4 – 6 of these becoming major hurricanes of Category 3 strength or higher on the Saffir-Simpson Hurricane Wind Scale. Tropical Depression One-E may have been an indication of what is to come for this hurricane season. Storm frequency and intensity will likely be on the rise as we enter into the summer months but with the potential of a La Niña transforming into an El Niño event we could see a substantial increase later in the hurricane season with activity slowly dying in the North Atlantic basin during the autumn months but increasing in the Pacific. However, it is important to always be prepared. Last hurricane season forecasts were calling for an El Niño event to quickly form when in fact the La Niña event kept lingering throughout 2017 making it a particular deadly year for the Atlantic. The issue is that meteorologists, climatologists and forecasters do not know very much about the ENSO phenomenon and can make only educated guesses based off climatological almanac data on when a transition may occur. Regardless, the East Pacific Basin is prime for hurricane activity and it will only increase as we enter the summer months and sea surface temperatures begin to rise. Now is the time to prepare because there will always be another hurricane forming on the horizon.

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