Tropical Storm Otis has since formed to its south and is expected to be a heavy rainmaker for parts of Mexico’s west coast.
The Atlantic is equally active. There’s Hurricane Tammy, which was located northeast of the Caribbean, and is expected to trace an odd looping shape before potentially affecting Bermuda later in the week. But there’s also a new disturbance that is consolidating in the Bay of Campeche.
The season overall has been about 10 percent more active than a normal year in the Atlantic, and we still have nearly six weeks to go before the “official” end to Atlantic hurricane season on November 30. The Northeast Pacific has been running about 18 percent ahead of average. And with abnormally warm and, in some cases, record-breaking ocean waters, there’s little reason to believe the oceans are about to wrap things up quite yet.
As of Monday morning, Hurricane Tammy had 80 mph winds, and was located 260 miles north of Anguilla, moving north at 7 mph. It was withdrawing from the northern Lesser Antilles, the island chain that bounds the Atlantic and Caribbean. Over the weekend, Tammy unleashed hurricane-force winds on Barbuda, a small island on the northeast flank of the Lesser Antilles, where it made landfall around 9:15 p.m. Saturday.
As the center of Tammy started to pull away from the Lesser Antilles Sunday, Tammy began to expand. It now has a broader core with more raggedy outer rain bands, possibly an indicator of a little dry air becoming drawn into the circulation. Conversely, though, once-disruptive high-altitude winds are easing a little bit, allowing for more healthy high altitude “exhaust” to exit Tammy. The more “spent” air that fans away from the storm at the upper levels, the more warm, humid air from below the storm can ingest to maintain strength or intensify.
Tammy will be steered northeast ahead of a trough, or dip in the jet stream filled with cool air and low pressure. A piece of that trough will break off from the jet stream, however, becoming a so-called cutoff low and yanking Tammy back westward. It could affect Bermuda with strong winds and rain squalls late this week.
Disturbance in Bay of Campeche
Forecasters are also monitoring an area of disturbed weather in the Bay of Campeche. Satellite imagery reveals a growing complex of thunderstorms. If a low-level center can become established and vertically stretched by a thunderstorm updraft, there’s a good shot it could become a last-minute tropical depression — the precursor to a named storm — before moving ashore over Nicaragua on Tuesday.
Gusty winds and a few heavy downpours were affecting the west coast of Sinaloa, Mexico on Monday morning, the remnants of much-weakened Hurricane Norma. But there’s a new system to watch.
It has the name Otis, and formed over the weekend because of an unusual process. Winds from the Atlantic blew north to south through a valley on the Isthmus of Tehuantepec. That’s the small strip of land that connects North and South America southwest of the Yucatán Peninsula. There are multiple mountain ranges on the southern edge of the Ithsmus, but a gap that allows winds through. That funnels the winds, forcing them to accelerate as air is expelled into the Pacific.
Some of that narrow channel of air curled in a counterclockwise shape, producing a lobe of vorticity, or spin, that acted as the seed for tropical development. That’s how Otis formed.
It’s not expected to be an overly strong system, but it is primed to trod along Mexico’s west coast and deliver heavy rains Wednesday and Thursday; landfall is probable Wednesday night.
“This rainfall will produce flash and urban flooding, along with mudslides in areas of higher terrain,” warned the National Hurricane Center.
A tropical storm watch remains in effect from Lagunas de Chacahua to Tecpan de Galeana, along the south coast of Mexico.
Otis would become the fourth named tropical system to make landfall along Mexico’s west coast just this month, following Lidia, Max and Norma.