Tropical Slumber Looks Likely to Last At Least into July

The eastern tropical Pacific is warming fast, the Atlantic and the Caribbean are cool, upper-level winds are hostile, and Saharan dust season is really kicking in. The net net is that no tropical development is expected for the rest of this month and likely into July.

We use words like "expected" and "likely" because weird things can happen. And if something is going to develop, it's probably going to be close to the U.S. coast. The focus of the atmospheric hostility is across the Caribbean and the tropical Atlantic. But in the northern Gulf and off the Southeast coast, annoying systems can always develop.

Tropical Storm Arthur was one of those. It was one of the shortest-lived tropical storms on record, and it was also one of the least tropical-storm-looking named systems you’ll see. But the threat of dangerous and damaging rainfall was real – and was realized. If attaching Arthur to the sloppy system with confirmed winds around 50 mph helped alert people to the flooding danger that was coming, then naming the system was a good thing.

Looking Ahead

Long-range computer forecast models don't show any messy Arthur-like storms or anything else in their projections. In fact, the long-range outlook from the NOAA Climate Prediction Center shows suppressed activity through July 7. Brown indicates below-normal rainfall. Red indicates some chance of tropical development in the Pacific.

Toward the end of this week, the National Hurricane Center is showing a couple of areas between Mexico and Hawaii that have chance of developing. Both disturbances will head away from Central America. There is no indication of a threat to Hawaii.

The much-heralded El Niño is happening. Ocean temperatures along the equator south of Hawaii are much warmer than normal and on a trajectory to reach record or near-record levels. There is a lag between the time the ocean warms and the effect on the atmosphere begins, but computer projections indicate that that process is underway. The long-range forecasts call for continued hostile winds over the Caribbean and tropical Atlantic. This pattern is indicative of the El Niño – the extra warm pool of water in the Pacific – affecting the atmospheric flow.

A large plume of Saharan dust covers much of the tropical Atlantic and Caribbean. The dust is so thick in Puerto Rico that air quality is degraded. No tropical development is expected in the tropical belt anyway due to the hostile upper-level winds, so the dust is just providing an extra layer of whammy.

Enjoy for now. But of course, we're just getting started.