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Ocean waters are warming

| May 8, 2023 1:05 AM

Until recently, our planet’s weather patterns have been influenced by a three-year-long La Niña event in the waters of the south-central Pacific Ocean. As mentioned in numerous articles, La Niña is the abnormal cooling of sea-surface temperatures. During La Niña events, much of the northern U.S. will often experience higher-than-average snowfall seasons.

Here in North Idaho, the 2022-23 snowfall season was above average in many locations. Coeur d’Alene’s final snowfall seasonal total topped out at 83.8 inches, compared to the normal of 69.8 inches. Even Spokane and some mountain locations also reported above-average snowfalls for this last season.

Despite the cooler La Niña event, the world’s ocean temperatures have been at record levels for warmth, especially over the last few years. According to a study that was featured in Advances in Atmospherics Sciences, an international worldwide team of scientists determined that our oceans have been warming at a dramatic rate since the 1950s.

The study also reports that the world’s oceans were the warmest on record in 2022. The research article also points out that the ocean heat content (OHC) was the highest in the North Pacific, North Atlantic, Mediterranean Sea and southern oceans. During the La Niña event, the cooler waters were concentrated along the equatorial regions. As of late April 2023, ocean temperatures have already exceeded the record levels in 2022.

Scientists say that approximately 90% of the Earth’s excess heat went into the oceans, especially since the 1970s. They also believe that the increased warming of the oceans is largely due to the warming of the planet caused by increased greenhouse gases. However, it’s possible that underwater geothermal activity could also be another factor. At least several hundred hydrothermal vents that are driven by the Earth’s magma have been discovered, mainly along the plate boundaries. According to NOAA, more than 80% of our oceans are “unmapped, unobserved and unexplained.” Due to the excessive costs of ocean exploration, researchers have relied on sonar to generate maps of the seafloor.

With ocean waters warming up, especially over the last month, global weather patterns may start to reflect this change later this summer and fall season. In fact, the Australian Bureau of Meteorology and the National Oceanic and Atmospheric Administration are increasing the chances of a new, warmer El Niño event being declared before the end of 2023. In fact, it’s quite possible that this new El Niño may be official as early as our fall season.

With ocean waters above average in the Atlantic Ocean and the Gulf of Mexico, forecasters are saying that the upcoming tropical storm and hurricane season will be close to average. The season begins June 1, but storms could start forming later this month. Forecasters from the Colorado State University are predicting 13 named storms with six of them becoming hurricanes. At least two of these predicted hurricanes could develop into major events. Over the last 20 years, the average number of named storms for each season is close to 14.

Cliff and I would go along with this prediction, especially with the potential of a new El Niño. With the warming of ocean temperatures along the Equatorial regions, wind shear conditions often form that decrease the chances of the development of tropical systems in the Atlantic and Caribbean waters. However, in the central and eastern Pacific basins, an El Niño event favors stronger hurricane activity. Although the chances of fewer named storms are lower during an El Niño, the warmer waters can still enhance the storms that do form and pose a sizable risk to land areas.

In terms of our local weather, we were barely into the first week of May and we’ve already received more than half of our normal month’s precipitation. Over the first six days of the month, Cliff has measured 1.64 inches of rain as of Saturday, most of which fell Friday with a record-breaking 1.11 inches. The normal for the entire month is 2.37 inches.

The rainy conditions are expected to subside later this week. Then, a strong high pressure system is likely to build in across the western U.S. giving us warmer and dry weather before more showers arrive near the middle of the month. Thanks to the big rains Saturday, it now appears that we’ll have another month with above-normal rainfall. More on-and-off showers are possible through early June before we expect a long stretch of dry and very warm weather across much of the Inland Northwest.

With the increased chances of a new El Niño, our fall season may turn out to be drier than normal. The chances for a White Christmas are also much lower during an El Niño. But as we’ve said many times, with these extreme weather patterns, anything is possible.

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Contact Randy Mann at randy@longrangeweather.com.