Take a look at this graphic from back on June 4 – just when the Atlantic hurricane season began. There was an awful lot of blue coloring across the deep tropics; the so-called MDR or Main Development Region. As such, seasonal forecasts began to be revised downward. It looked like a below average season was at hand and there as constant talk about how cool, compared to average, the MDR was. This would lead to higher pressures over the tropical Atlantic, less energy for tropical waves to tap in to, etc. etc. It seemed as though we might have a very slow hurricane season – unless things changed.
Now, let’s take a look at that same graphic from August 27, just a few days ago. Quite a difference isn’t it? The MDR has warmed significantly since June and is now running just slightly above the long term average. Why is this important? For one, we are no longer looking at cool to cold anomalies or departures from normal in the area where hurricanes like to form. That is no longer an inhibiting factor as we head in to September. The other reason this is important is that tropical waves or other seedlings don’t know that the SSTs were cooler earlier this summer. These strong impulses of energy that emerge from the west coast of Africa need warm, moist air to work with and that is derived from warm ocean temps – which we now have. It does not matter what the SST pattern was like in June or July. All of that talk about how cold the water was compared to last year or other years is moot now; just when we are entering the peak period of the Atlantic season.
And look what is happening, right on cue. A tropical depression is likely to form just off the coast of west Africa and will go on to become the season’s next hurricane – right in the middle of the MDR where SST values were quite a bit cooler just a couple of months ago. Just goes to show how things can and do change. It also signals that we are likely to be in an active period for development over the coming weeks, lasting in to early October most likely. That’s 5-6 weeks of favorable conditions. A lot can happen during that time period so don’t let your guard down – the 2018 Atlantic hurricane season is making a comeback and may be full of more surprises just yet.
8:45 AM ET August 30