Another storm has a 60% chance of forming off southern Mexico within seven days

The National Hurricane Center puts a 60% chance on a new tropical depression forming off southern Mexico within seven days, according to its Friday, October 16 outlook for the eastern Pacific. Forecasters rate that probability as medium, and they attach a long fuse to it: the chance of formation through the first 48 hours sits near zero. The area of interest is the next one in line behind Hurricane Trudy, which was already pushing toward Mexico’s Pacific coast on Friday afternoon.

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The percentage comes with a timing caveat built into the same forecast. The low has not formed yet, and forecasters do not expect it to until early to the middle of next week, so the earliest plausible depression is still several days out. A 60% figure over a week means the disturbance is more likely than not to organize, but nothing on the map today is a storm, and the odds will move with each new run of the outlook.

A low expected to form offshore of southern Mexico

In the text of the Eastern Pacific Tropical Weather Outlook, NHC forecaster Adams describes a low-pressure area expected to form offshore of southern Mexico in the early to middle part of next week. Conditions look favorable for gradual development after that, the outlook says, and “a tropical depression could form during the latter half of next week” while the system moves generally west to west-northwest across the eastern and central East Pacific. The formation chance through 48 hours is listed as low, near 0 percent, and the seven-day chance as medium, 60 percent.

The wording matters because it ties the 60% to a specific stretch of time. Nothing in the outlook calls for a depression this weekend.

The figure has also held steady through several editions. The 11 a.m. Pacific outlook on Friday, issued at 1800 UTC, repeats the same 60 percent seven-day chance and the same near-zero 48-hour chance that appeared in the 5 a.m. Pacific edition and in the 11 p.m. Thursday edition. Three consecutive issuances with identical numbers suggest that forecasters have not yet seen the disturbance gain or lose organization enough to change the odds, though the later edition is the one readers should treat as current.

Hurricane Trudy and the storm that is already there

The new area of interest is being watched against a busy backdrop. NHC Public Advisory 14, issued at 3 p.m. CST on Friday, October 16, found Hurricane Trudy to be a Category 1 hurricane with maximum sustained winds of 85 mph and a minimum central pressure of 982 millibars, based on Hurricane Hunter aircraft reports. The center was about 225 miles southwest of Acapulco and 315 miles south-southeast of Manzanillo, moving north-northwest near 5 mph. Hurricane-force winds extended up to 30 miles from the center.

Forecaster Beven wrote that a faster northwestward motion was expected through Sunday, with the center approaching the southwest and west-central Mexican coast on Saturday and passing near the coast Saturday night into Sunday. A hurricane warning covered the coast from Manzanillo north to Cabo Corrientes, with a hurricane watch from Manzanillo south to Punta San Telmo and a tropical storm warning from Manzanillo south to Zihuatanejo. Rainfall of 4 to 8 inches, with isolated totals near 15 inches, was forecast for Michoacan, Colima and Jalisco, raising the risk of flooding and mudslides.

Tropical Storm Simon, which the morning outlook placed a few hundred miles south-southeast of the southern tip of the Baja California Peninsula, did not last through the day. The final advisory on Simon, number 38 at 2 p.m. MST, listed maximum winds of 35 mph and a central pressure of 1006 millibars, with the system moving northwest near 13 mph, and the hurricane center stopped issuing advisories because the storm had dissipated.

How to read a seven-day outlook

An outlook is a different product from an advisory. Advisories exist only for systems that have already become tropical depressions, tropical storms or hurricanes, such as Trudy, and they carry watches, warnings and forecast tracks. The outlook covers areas that have not reached that stage, and it expresses the odds in two time windows instead of drawing a track. For the low off southern Mexico, that means the outlook is the only official product that exists today.

The English text of the outlook is the official version; the page also carries a Spanish translation, and it states that the English wording governs. Readers on the Mexican coast who want the full set of current products, including any advisory that begins if the low develops, can find them on the hurricane center’s current cyclones page.

For now the practical reading is narrow. Trudy is the storm with warnings in force and a landfall window on Saturday night into Sunday, and the new area is a forecast about the middle and end of next week. A 60% chance that a depression forms in that period is a reason to keep checking the outlook, not a reason to expect a storm on any particular date or at any particular place along the coast.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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