Atlantic hurricane season activity could increase through September



Despite near-unanimous predictions that there would be above-average activity, the start of hurricane season has been eerily quiet — though that could still change in the weeks to come.

There hasn’t been a named storm anywhere in the Atlantic Basin since Colin, a whirlwind of gusty downpours that scraped along the Carolina coast on July 3 with minimal impact. Since then, it has been quiet despite timing close to September, when hurricane season historically peaks in activity.

There are signs that after a quiet week ahead, a reversal could be in the cards for the final days of August. The National Hurricane Center has described a system to watch and said a sudden increase in activity is possible. It’s far from a guarantee, but it stands to reason that tropical sleep can’t last forever.

Warming oceans are fueling early Atlantic hurricane seasons, study finds

The historic peak of hurricane season is around September 15, but most of late August through mid-October is considered the busiest period of weeks when it comes to tracking the tropics. A given season averages 14 named storms, seven of which could be hurricanes, but NOAA forecasters continued to echo earlier calls for 14 to 20 named storms, six to 10 hurricanes and three to five major hurricanes.

Even the calmer seasons have stirred up weather monstrosities.

For example, there were only seven named storms in 1992, but the first was Category 5 Hurricane Andrew, which besieged South Florida and raked the headquarters of the National Hurricane Center with a gust of wind. at 163 mph. Conversely, what might have been busier seasons on paper had relatively less human impacts when the storms spent their lives over the open ocean.

But when it comes to tropical storms and hurricanes, it only takes one.

Tropical Disturbance in the Caribbean

As of Wednesday morning, the National Hurricane Center was monitoring a disturbance centered near the northern coast of Honduras. Most of any inclement weather, including robust thunderstorm activity, was located north of the land and over the western Caribbean.

The system is currently out of balance, but it had evidence of healthy flow or exhaust at its upper levels. Tropical storms and hurricanes breathe one way, and the higher they exhale, the more warm, moist air they can ingest near the surface to fuel their continued growth and maturation.

The minimum organization of this disturbance is likely until Thursday, but it will slip into the Bay of Campeche until Friday. There it will encounter very warm sea surface temperatures – favorable for strengthening – but wind shear is moderate. Wind shear, or a change in wind speed and/or direction with height, has been known to play a tug-of-war with tropical cyclones. High wind shear can inhibit the vertical development of a storm, often disrupting it.

It’s impossible to be certain what may happen with the system longer than three or four days, but broadly it is likely to drift northwest, into northern Mexico near Tamaulipas or the extreme south texas. Localized heavy rainfall is possible if left undisturbed, but any forecast beyond that is pure speculation.

The National Hurricane Center estimates a 20% chance of a well-formed tropical cyclone possibly developing, but it’s worth watching regardless.

On the other side of the Atlantic, there are signs that activity could start to recover more significantly in the next 10 days.

Weather patterns focus on more aggressive tropical waves rolling off the African coast and propagating westward through the MDR, or Main Development Region. The MDR, sometimes referred to as “Hurricane Alley”, is the belt of the tropical Atlantic that can occasionally produce powerful, long-lasting storms one after another.

It is far too early to diagnose the simulated waves as a potential storm, but several other current factors could contribute to storm formation. Wind shear appears likely to pause, which may allow for better vertical development of a storm. Sahara dust could also thwart the formation of storms, but the layer of warm, dry air at mid-levels of the atmosphere in which it is embedded is expected to thin over time. This could allow some tropical systems to expand, especially as the oceans continue to warm.

The Gulf of Mexico could also become increasingly favorable to possible storms towards the end of the month; the gulf extends from about half a degree to one degree above average in terms of sea surface temperature.

Put simply, August has come in like a lamb – but its exit may not be so sweet.


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