The Atlantic is quiet, but a southwestern Gulf low could still spin up late this week

Nothing in the Atlantic basin carries a name or a number right now, and the National Hurricane Center’s own outlook says so in one line: “There are no tropical cyclones at this time.” What it does carry is a single patch of Gulf water. The center expects an area of low pressure to form around the middle of the week over the southwestern Gulf of America, and gives that low a 40 percent chance of becoming a tropical cyclone within seven days.

The odds come with a sharp split in time. Over the next 48 hours the chance is near zero, which means any development is a late-week story, not a tonight story.

The 8 p.m. Sunday outlook from NHC Miami

The product is the Atlantic Tropical Weather Outlook, written by forecasters at the NWS National Hurricane Center in Miami and reissued every few hours. The 2:00 p.m. EDT edition on Sunday, October 4, signed by forecaster Cangialosi, called for “some slow development” and said “a tropical depression could form late this week while the system drifts northward.” The 8:00 p.m. EDT edition that evening, written by forecaster Pasch, kept the same 48-hour and seven-day numbers: near 0 percent and 40 percent, the latter in the “medium” category.

Both versions hedge on the setting. Conditions are “only expected to be marginally conducive,” the outlook says, which is forecaster language for an environment that allows a low to organize but does not help it. The chance has also climbed during the weekend. A Saturday evening outlook put the seven-day figure at 20 percent for a broad low that “could develop” within a few days, and Sunday morning’s edition showed 30 percent, so the Sunday afternoon and evening 40 percent reflects a system that has become somewhat more likely to form, not less. The wording moved with the numbers: Saturday’s text said a low “could form in a few days,” while Sunday’s said one is “likely to form around the middle of the week,” a shift from a possibility to an expectation, even though the chance of a tropical cyclone out of it still sits below even odds.

The outlook is issued four times a day, at 2 a.m., 8 a.m., 2 p.m. and 8 p.m. Eastern, so the text read for this article is a snapshot that a newer issuance can replace. The last one retrieved, the 8 p.m. edition on October 4, is the one every figure here is tied to, and a morning edition on October 5 could already have moved the percentage up or down.

A below-normal season with El Niño in place

The hurricane center’s front page lists no active Atlantic cyclone, and the season has fit the forecast made for it. In its August update, NOAA maintained a below-normal prediction: 7 to 13 named storms, 2 to 6 hurricanes and 0 to 2 major hurricanes, with a 75 percent chance of below-normal activity. At that point two named storms, Arthur and Bertha, had formed.

The agency’s reasoning was El Niño. Matt Rosencrans, NOAA’s lead hurricane forecaster, said in that release that “when El Nino emerges, it usually becomes the dominant factor in total hurricane season activity,” because the pattern raises wind shear across the Atlantic, which tears apart the tall, upright structure a young storm needs. That explanation fits the outlook’s cautious tone about the Gulf low, though NHC’s text does not itself name El Niño as the reason.

Reading the 40 percent seven-day number

The percentage is a probability that a tropical cyclone forms somewhere in the outlined area during the window, not a forecast of strength, track or rainfall. At 40 percent the outlook sits at the bottom of the “medium” band, so on the center’s own scale a failure to develop remains the more likely result, and the low could simply drift north as a messy area of showers.

October is also a month when the Gulf and western Caribbean remain open for business. NHC’s climatology pages note that an average season has produced its third major hurricane by October 28, and the agency’s historical maps show where storms have formed month by month. A weak Gulf depression in early October would be a normal event in a below-normal year.

The outlook names no coast, rainfall total or wind speed, because no low exists yet to measure.

The next checkpoints are the center’s scheduled outlooks, and the figure to compare is the 7-day percentage written into the first one that arrives after the low actually forms on Wednesday or Thursday. If it climbs past 60 percent, NHC’s scale would label the chance “high”; if the low fails to appear, the number should drop instead.

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

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