Currently in the Atlantic - October 7, 2022

by Glenn "Hurricane" Schwartz

It has been 1 1/2 weeks since rain from Ian started moving into part of the U.S. Finally, we can say that the rain triggered by Ian has left the country. Look at the total rainfall across Florida and then in the mid-Atlantic states:

Ian track & rain totals - Florida
Ian becomes an ocean LOW - mid-Atlantic 

So, Ian ended up producing enough rain for flooding in TEN states. Plus, the contribution to coastal flooding over nearly the entire East Coast.

It's time for a tropical "break" in the Atlantic. That may be true for the U.S. but not for the entire Atlantic Basin. This time, the main threats are to Central America and the northern tip of South America. Tropical Depression #13 is far east in the Atlantic and poses no threat to land. But the one near the north coast of South America is the one to watch.

Next tropical storm in Caribbean

Being close to the South American coast is leading to a lot of rain there, but it prevents it from intensifying, too. But simple geography indicates a continued west movement will bring the storm into the extra warm waters of the Caribbean. And if the westward track continues after that, the main threat is to Central America. Computer models agree on this:

Computer models keep westward track

Normally a tropical storm in the Southern Caribbean could pose a threat to the Gulf of Mexico and even Florida.

If you live in the Eastern or Midwest U.S., you probably have a local forecast that makes it much cooler over the weekend. Well, the upper-air system causing that is what will likely keep TC13 on a straight westward track, even as it intensifies, even to hurricane strength (as predicted below).

West track to hurricane strength

The continued west track will likely take the hurricane directly into Nicaragua and Honduras. One concern is how intense it will become:

Hurricane strength likely by Sunday

The computer models show a rapid intensification to hurricane strength. But the National Hurricane Center is even more concerned about intensification due to the output of their in-house model:

"SHIPS Rapid Intensification (RI) indices indicates a 65-75 percent chance of a 65-kt increase over the next 3 days"

TC13 was classified as max winds of 30 knots at the time of this writing. A 65-kt increase would take it to 95-kt, or about 110-mph. That's almost a Category 3.

Nicaragua and Honduras have horrible hurricane histories, due to their location and mountains. The worst was Category 5 Hurricane Mitch in 1998, which was considered the deadliest Atlantic hurricane in over 200 years. Deaths totaled about 11,000, with another 11,000 missing. The slow movement led to deadly flooding after as much as 75 inches fell.

Category 5 Mitch-1998

Mitch eventually emerged into the Southwest Gulf of Mexico and hit Florida as a tropical storm. In the current case, this particular weather pattern may cause this next storm to avoid the U.S., but our concern now shifts to Central America.

Glenn "Hurricane" Schwartz    thehurricaneschwartz@gmail.com

What you need to know, currently.

Forecasters are expecting La Niña to last through February of 2023, the only time the phenomenon has spanned three winters in the last century, according to the World Meteorological Organization.

“It is exceptional to have three consecutive years with a La Niña event. Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend,” WMO Secretary-General Professor Petteri Taalas said in a press release.

La Niña is the complement to El Niño, opposing weather patterns in the Pacific Ocean — formed through a slight shifting of trade winds and a confluence of air pressure and ocean temperature — with the power to affect climate patterns around the world.

In a La Niña year, the jet stream tends to shift to the north, bringing warm, dry winters to the southern United States and cool, wet (or wetter) weather to the Pacific Northwest. In an El Niño year, the jet stream shifts south, reversing the pattern.

A new study published in Geophysical Research Letters suggests that this protracted La Niña pattern has been caused by climate change. Researchers found that even as global temperatures have risen, the sea surface in the southern Pacific has cooled. Scientists aren’t entirely sure why that’s happening —  but when those cooler waters off the coast of South America meet shifting trade winds, they result in the La Niña conditions that have helped extend the prolonged drought in the Western United States.

"At some point, we expect anthropogenic, or human-caused, influences to reverse these trends and give El Niño the upper hand.” lead author, Robert Jnglin Wills, a research scientist in atmospheric sciences at the University of Washington said in a statement. “The climate models are still getting reasonable answers for the average warming, but there’s something about the regional variation, the spatial pattern of warming in the tropical oceans, that is off."