Hurricane forecast: More big storms

The Atlantic and Caribbean tropical storm and hurricane season is off to a fast start for the 2020 season. As of late last week, there were eight named storms. The normal, based on a 30-year average, is 12 named storms for each season.

During an average year, six hurricanes form. Three of the six hurricanes are usually classified as “major,” which is a Category 3 or higher. For the rest of the 2020 season, Cliff and I expect to see an above-normal 20 named storms, a total of eight to 10 hurricanes and four major hurricanes. Colorado State University, known for its tropical storm and hurricane forecasts, is also predicting 20 named storms, nine hurricanes and four major hurricanes before the season ends on Nov. 30.

This year is particularly favorable for storm development as sea-surface temperatures near the Equator are a little cooler than normal. During El Nino years, when ocean waters in this region are warmer, the development of these tropical systems is limited due to wind shear.

Also, sea-surface temperatures off the coast of Africa, where many of the storms originate, westward toward the U.S. East Coast are warmer than normal. Therefore, the ingredients are there for another big year for tropical storms and hurricanes in the Atlantic and Caribbean waters.

The peak of the tropical storm and hurricane season is usually from late August through September. According to the National Hurricane Center, the season’s climatological peak of storms occurs around Sept. 10.

The Atlantic and Caribbean tropical storms receive more publicity as they often impact populated regions. However, in the eastern north Pacific Ocean, this is the second-most active area for tropical storm and hurricane development. During a normal season, which runs from May 15 through Nov. 30, there are 16 named storms, with nine of them becoming hurricanes and four strengthening into major hurricanes.

Most tropical systems that form in this part of the world will travel westward. However, there have been cases when one of these storms will move northward toward California. As the system moves over colder waters to the north, it will usually fall apart, but still may bring some moderate to heavy rainfall to Southern California.

In recorded history, there has only been one instance when a hurricane that formed in the eastern north Pacific reached California. It happened way back in 1858 and was called the San Diego Hurricane. Very heavy rainfall that led to extensive property damage was reported. In today’s dollars, it’s estimated that the cost of that storm would have been around $500 million.

In the central Pacific Ocean, the tropical storm and hurricane season began on June 1. Although the number of tropical storms and hurricanes is higher in the Pacific Ocean versus the Atlantic Ocean, hurricanes rarely make landfall on the Hawaiian Islands. Recently, Hurricane Douglas, a Category 1 storm, was on track to make a direct hit on Hawaii. But the storm veered to the north and skirted by the islands. However, heavy rains and strong winds did occur on Maui.

Due to the vastness of the Pacific Ocean, it’s rare for a hurricane to strike the Hawaiian Islands. Some scientists believe that the mountains on the Hawaiian Islands help keep away these major storms.

In recorded history, only two hurricanes have made landfall in Hawaii. In 1959, Hurricane Dot moved over Kauai as a Category 1 storm. The biggest hurricane to strike Hawaii occurred in 1992 when a very strong Category 4 system, Hurricane Iniki, caused over $3.1 billion in damage and destroyed 41 percent of the island’s homes. Although there have been only two hurricanes to have made direct hits on Hawaii, other storms have passed closed enough to the islands to cause significant damage.

In Idaho, despite the fact that we are far to the north of the eastern north Pacific Ocean, there were two instances in history when the remnants of a named storm brought moisture to the state.

In 1976, Hurricane Kathleen weakened to a tropical storm and brought record rainfall to California. Parts of Idaho received over 2 inches of rain from that system. In 1982, Hurricane Olivia dropped nearly 2 inches of rain over Idaho when it weakened to a tropical depression.

In terms of our local weather, we had a 99-degree high on Friday at Cliff’s station in northwestern Coeur d’Alene. Other outlying stations did report temperatures at or above 100 degrees. Spokane and Post Falls soared to 102 degrees with Hayden, Rathdrum, North Idaho College and Worley topping out at 101 degrees. The last time we hit 100 degrees in Coeur d’Alene was on Aug. 10, 2018, with a record high of 104 degrees.

More hot and dry weather is expected through the middle of the month. Cliff and I wouldn’t be surprised to see another day or two with highs challenging the 100-degree mark. By late August and September, we should start to see an increase in moisture.

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Contact Randy Mann at randy@longrangeweather.com