Hurricane season is off to a fast start — at least in the Pacific Ocean

Washington Post

a day ago

A flurry of tropical cyclone activity over the past two weeks in the eastern Pacific Ocean just off the west coast of Mexico has produced three named storms so far — with more storms expected.
Early Wednesday, a system named Cosme was a weak tropical storm about 500 miles from the southern tip of the Baja California peninsula. Earlier in the workweek, Barbara became the first hurricane of the season in the northern hemisphere when it maxed out at a 75 mph Category 1. The storms follow Alvin, which formed in late May. All have been swirling out at sea, none threatening land thus far.
This spurt of activity shows no signs of ending for now. Additional disturbances are already on the map, and the same general pattern is expected to persist through the month.
It's a whole other story in the Atlantic Ocean, where it has been calm and no storms have yet developed.
The National Hurricane Center is monitoring two additional areas in the eastern Pacific Ocean.
The first, currently south of the Gulf of Tehuantepec, has a 90 percent chance of storms in the next week. It is slated to take a similar path to recent systems, tracing the coast of Mexico several hundred miles offshore.
Weather model forecasts suggest a coherent low pressure system will slowly develop and could become a named system in a region similar to the earlier three.
On its heels, there are signs that yet another disturbance will form near the coast of Central America late weekend or into early next week. It is also expected to end up in an environment favorable for a tropical cyclone, but since it's more distant, the forecast is less certain.
Any concerns of storms hitting landfall are minimal for now. Instead, the storms are expected to bring moisture to Mexico and the southern U.S.
Storms in the Pacific have mostly formed where expected this time of year; they have just been more frequent than typical. The three named storms to date are more common at the end of June or early July.
Similarly, the first hurricane in the Pacific doesn't typically arrive until the last week of June.
A somewhat favorable phase of the tropical Madden Julian Oscillation may have helped recent storms along. The MJO is characterized by eastward propagating weather patterns that either promote rising air and storminess or sinking air and stability. This pass of the MJO was expected to trickle into portions of the Atlantic ahead but may stall out before getting much past the Central American continent.
While the burst of storms has been notable, it's far from unheard of. As recently as 2021, there were three named storms by June and six by the end of the month.
Closing in on two weeks into the Atlantic hurricane season that began June 1, there has yet to be anything serious brewing in the basin. That may continue for a while as there are minimal signs of development in the near future.
While it's not unusual for the Pacific Ocean to kick off first — its season begins May 15 — many recent years have featured early named storms in the Atlantic Ocean. This year is unusual.
Over the past decade all seasons but one had a named storm in the Atlantic by this date. The exception was 2024, when the first named storm in what would become a very active and destructive season waited until June 19 to capture a name.
Water temperatures remain warmer than average in most of the Atlantic despite comparative cooling versus this time last year.
Frequent episodes of dust associated with the Saharan Air Layer and unfavorably strong winds across development regions may be helping stifle activity, although most storms this early in the season form closer to home in the Gulf of Mexico or near the Southeast coast. The fact that cold fronts have tended to get hung up over the Southern U.S. rather than further offshore may play a role as those zones tend to offer development in May and June.
The global hotspot for tropical development is expected to remain in the eastern Pacific through the rest of June, according to the Climate Prediction Center.
Released Tuesday, their outlooks for the weeks of June 18 to June 24 and June 25 to July 1 indicate a high likelihood of additional tropical development in the region.
As far as the Atlantic goes, the center also includes the Bay of Campeche in the potential development region mid-month but tends to favor quieter conditions. Even so, disturbed areas of weather can become tropical cyclones on short notice — and it's important to remain vigilant as the summer progresses.