2023 AMI North Pacific Hurricane and Typhoon Early Outlook
Aerospace & Marine International (AMI)
Improving the safety, efficiency, & accuracy of offshore operations.
East Pacific
Based on current trends, we believe the East Pacific hurricane season will be slightly above average (see outlook numbers below).
One factor increasing the likelihood of hurricane formation is the expected change in the El Ni?o/Southern Oscillation (ENSO) through the fall.? Presently, La Ni?a (cold sea surface temperature anomalies) has weakened so that the eastern tropical Pacific is now in neutral to slightly above normal sea surface temperatures (SSTs).? The Climate Prediction Center (CPC) forecasts a 62% chance that El Ni?o (warm SST anomalies) will develop by May - July, and 80-90% by the fall.
El Ni?o typically creates more favorable conditions in the East Pacific for hurricane development by weakening upper level winds and reducing wind shear (wind speed variation with height) across the region.?
Working counter to the El Ni?o is the Pacific Decadal Oscillation (PDO - see graph above).? Since January 2020, the PDO has been consistently negative, meaning colder than average SSTs are present off the west coast of North America southward to central Mexico.? At this time, much of the waters north of 10°N between 125°W to near 170°W are too cold to support tropical development (SST must be at least 26°C/79°F). ? The cold PDO should keep SSTs below this threshold into the summer, which will weaken any tropical storms or hurricanes that move northward toward Baja, reducing their chances to become strong hurricanes.
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West Pacific
Based on the developing El Ni?o, we expect this year will be somewhat above average for typhoon activity.? Below is a table comparing AMI’s and Tropical Storm Risk’s (TSR) outlook numbers.??
Due to reduced windshear across the western North Pacific associated with El Ni?o, conditions will be more favorable for tropical development.? However, the cold phase of the PDO could be a mitigating factor, as there is a large, persistent pool of below-average SSTs between 20°N to 30°N and 140°E to 165°W.? It will be difficult for any tropical storms to develop over these waters.
When it comes to typhoons, El Ni?o’s influence depends largely on which part of the eastern tropical Pacific is warmest.? Looking into the late summer and early fall, the ECMWF shows the warmest waters will be located mainly between 90°W and 150°W, during the height of typhoon season.? Statistically, this shifts the most common area of West Pacific tropical storm development farther east and south, which promotes storms with longer tracks over warm water.? With this in mind, a larger proportion of tropical storms could strengthen to intense typhoons this season.
We will offer an update to our Outlook in early June.