Super-Intense Bermuda High!

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The catalyst to all of the extreme weather in the U.S. during early summer including historic rains in the northwest Gulf States, a strong Southwest Monsoon and anomalous heat over the Northwest has been, in-part a super intense Bermuda high-pressure system (Fig. 1). So far in July, the Bermuda high-pressure system has averaged an astounding 4-6 MB stronger than normal. SLP has routinely been in the 1030 MB range which is unusually high for summertime.

Super Intense Bermuda High Creates a Fast/Well-established Tropical Trajectory into the Gulf of Mexico to the Southwest U.S. Next up? Hurricane trajectories for August/September.

Fig. 1: The North Atlantic Bain sea level pressure anomalies (SLPA) identify the super intense Bermuda high-pressure system (and the low pressure associated with an upper trough over the North Atlantic Warm Hole off Western Europe).

Discussion: The recent emergence of the Southwest U.S. Wet Monsoon is stronger than predicted by most climate models. Prior to the evolution of the wet Southwest U.S. Monsoon the northwest Gulf of Mexico States observed one of their wettest late spring/early summer seasons on record. The wet climate pattern in that zone continues. Of course, once the rainfall pattern is established, anomalous heat risk is suppressed. There are upstream effects…the persistent tropical rains release latent heat to the atmosphere traveling pole ward causing amplifying upper ridge patterns bringing scorching heat to the West/Northwest U.S., West Canada and now central portions of North America.

The catalyst to all of the extreme weather described has been, in-part a super intense Bermuda high-pressure system (Fig. 1). So far in July, the Bermuda high-pressure system has averaged an astounding 4-6 MB stronger than normal. SLP has routinely been in the 1030 MB range which is unusually high for summertime.

The new issue is likely trajectories for tropical cyclones. Once the most active part of the season arrives (August 1st), the location and strength of the Bermuda high-pressure system pretty-much guarantees a well-established low-latitude tropical cyclone track. In the deep tropics, waters are warmest and potential for hurricanes greatest. Long distance travelers, known as the “Cape Verde Storms” are the type of tropical cyclone track setting up for August and September. This track is dangerous! Historically, the strongest hurricanes develop in the tropical trajectory track.