Alexandra Cranford / WWL Eyewitness News Forecast Team
A weekly discussion of the tropics from the Eyewitness News Forecast Team
This week in the tropics, the main focus is whether we’ll break a record for the latest first hurricane of an Atlantic hurricane season. And it could come down to the wire.
Right now, Tropical Storm Humberto is slowly spinning off the coast of Africa, just south of the Cape Verde Islands.
If Humberto doesn’t reach hurricane strength by 8:00am Wednesday, we’ll set a new record for the latest we’ve ever gone in a hurricane season with no hurricane. The current record was set on September 11, 2002.
But here’s why we may pull up short of that record:
Humberto could gain enough strength to cross over to Category 1 hurricane status just before the cutoff of Wednesday morning. The storm is getting better organized. There's decent circulation, and thunderstorms have been strengthening at its center. The current National Hurricane Center intensity forecast shows the storm becoming a hurricane on Tuesday.
But remember intensity forecasts are notoriously difficult to pin down. It’s certainly possible that Humberto could still be struggling to reach hurricane strength by Wednesday.
Bottom line: we may break the record… and even if we don’t, we’ll get very close. The next-to-latest first hurricane of a season formed on September 10 (that was Hurricane Diana back in 1984).
Now that we’ve discussed Humberto’s record-setting potential, let’s focus on where this thing is headed.
Humberto will likely veer north/northwest just after it scrapes by the Cape Verde Islands on Tuesday. It should stay on that general northwestward path for the remainder of its lifetime.
Why is this storm shooting north instead of trekking across the ocean toward North America?
It’s because of the Azores high, which is an area of semi-permanent high pressure over the eastern Atlantic. The Azores high will steer the storm north/northwest and keep it in the eastern half of the ocean. (By the way, the Azores high can also be called the Bermuda-Azores high. If the big high pressure ridge is farther west, it’s often just called the Bermuda high, which might sound more familiar.)
Once Humberto moves north over cooler waters, it will likely weaken back to tropical storm status and then fizzle out in the northeast Atlantic, away from land.
Humberto’s harmless path is a relief, because waves that form so close to Africa often grow into some of the worst hurricanes. About 85 percent of major hurricanes start out near the African coast. About 60 percent of all other named storms come from this area too.
So are you wondering WHY we’ve lucked out with such a quiet season so far? Here are the reasons:
1. As mentioned in many Talkin’ Tropics discussions earlier this season, there’s a ton of dry, dusty air over the Atlantic Ocean. That arid air comes straight from the Sahara Desert. So far, it’s robbed many storms of the humid, unstable air they need to thrive. And the dusty air is very widespread - dust particles from the Sahara Desert have shown up as far west as Texas. So the dry air has really helped to keep things quiet.
2. Some strong wind shear has knocked storms down before they could build.
3. Sinking air over much of the ocean has squashed a lot of development.
4. A weather pattern called the Madden-Julian Oscillation has stayed in a quiet phase for the Atlantic. Typically the MJO ramps up this time of year and starts spawning storms. It hasn’t taken off yet, but it could shift into a more active phase in the next few weeks.
The peak of hurricane season comes this week on Tuesday, September 10. That means we still have half the season to go, and conditions have gradually become a bit more favorable for storm formation.
It’s certainly not time to let our guard down, since many notorious storms have formed in the second half of the season. A recent example is Hurricane Sandy, which formed on October 29 last year.
Finally, let’s wrap up this week’s discussion with some good news for the Gulf Coast: long-range models are still keeping things quiet in our area for the next couple of weeks.
Keep checking our tropical video updates for the latest information through the week. Carl, Laura, Derek and I post new videos for you a few times a day.
See you back here next week for your Talkin' Tropics discussion. Every week, we'll post a fresh tropics forecast for the week ahead.