First hurricane of the season forms near Azores

The 2022 Atlantic hurricane season finally has its first hurricane in the books, Danielle.  But it didn't form in the tropics, or even the subtropics -- it's way up at 38°N, 700 miles west of the Azores!

Zooming way out, this track forecast and "cone of uncertainty" overlaid on a map of sea surface temperature puts this remote location in perspective.  Hurricane Danielle is centered about 1800 miles due east of Delaware and 1800 miles due west of Portugal.  Although it's forecast to strengthen more, perhaps a Category 2 hurricane this weekend, it will not affect any land.

Over the past fifty years, the median date of the first hurricane formation is August 6 so this is definitely on the late side.  The last time it took longer to get the first hurricane: Hurricane Humberto on September 11, 2013.  On this chart below, also notice that in the past fifty years there is virtually no trend in the date (dashed gray line) and no hurricanes formed prior to June 1 (solid cyan line).  I don't count Hurricane Alex in January 2016 as the first hurricane of the 2016 season, but rather as the last of the 2015 season, meteorologically.

In terms of ACE (Accumulated Cyclone Energy), the season is now at 12% of average for the date, using that same 1972-2021 baseline.  The last few seasons with such low levels of activity through September 2 are 1988, 1941, and 1929.  But it's worth pointing out that in 1988, the 13th tropical cyclone of the season was Gilbert (yes, the first 12 were easily forgotten), and that formed on September 8 and went on to become one of the most intense hurricanes in Atlantic history on September 13.

There's still interest in Invest 91L too, which is just 300 miles east of the Leeward Islands.  NHC has decreased its probability of formation to 70% in the next five days, but models are still strongly suggesting that it will become Tropical Storm Earl very soon and the season's second hurricane early next week.

This GFS ensemble forecast shows two very different paths the storm could take: remain weak and disorganized and keep tracking toward the west-northwest, OR intensify and turn to the north.  It's about a 50/50 split!  If it does intensify, the only land that might potentially be at risk is Bermuda next weekend.

Invest 94L, the one that was near Cabo Verde yesterday, is rapidly losing any hope of development and I won't go into detail on it unless it miraculously escapes the shroud of dry air it's in.

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Danielle ends the 61-day named storm "drought"

The last named storm, Colin, formed and dissipated on July 2.  The Atlantic has been incredibly quiet since then, but Tropical Storm Danielle has just formed on the first say of September.  However, you may be surprised to see that Danielle is not anywhere near the tropics, but is actually just west of the Azores, way up at the top-center of the satellite image shown above.  I'll discuss the other two areas of interest later.

It is just a minimal tropical storm now, but is forecast to become the season's first hurricane this weekend.  It is also not expected to travel much in the near future.  The last time it took this long to get a first hurricane was 2013, and that was on September 11.

The next feature is Invest 91L, the same wave I discussed in my previous post last Friday.  It's now centered about 600 miles east of the Lesser Antilles, and has been very slow to get organized.  But, NHC is giving it an 80% chance of formation within the next five days.  If it becomes a tropical storm, the next name on the list is Earl.

In this satellite animation, I am showing Invest 91L on the west side, and Invest 94L on the east side (over Cabo Verde).

91L has been surrounded by very dry air, but that is expected to change in the coming days as it passes north of Puerto Rico.  The American GFS ensemble generally keeps it weak for the next four days or so, then intensifies it as begins to turn north.  Very few members of this ensemble, and of the European ensemble, keep it tracking toward the west-northwest -- and of the ones that do, they do not intensify it.

Finally, Invest 94L is near Cabo Verde and will be a victim of dry air... there's minimal model guidance that indicates it will be a feature of interest for much longer.  NHC is giving it a 30% probability of becoming a tropical depression in the next couple of days, then that's likely the end of it.

We happen to be halfway through the hurricane season today in terms of time, but in terms of ACE (Accumulated Cyclone Energy), we are climatologically only one-third through the season.  Compared to the average over the past 50 years, this year's activity is down to 9% for the date!  Even with an active named storm now, it would take a steady 70-kt Category 1 hurricane just to keep pace with climatology this time of year.

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Tropics slowly waking up from a long slumber

It has been 55 days since the last named storm, Colin, formed in the Atlantic.  Since then, there has barely been a whisper of activity anywhere across the basin.  Even now, there is nothing imminent, but there are a couple areas of interest that could develop in the coming week.

This map shows a recent infrared satellite image with areas of potential development highlighted (x is the current approximate position, the "blob" is the potential area of formation over the next five days).  NHC is giving the one to the west a 20% probability of formation and 30% for the one in the east.  Note that even at the current positions, the cloudiness is extremely scattered and disorganized.

I will start the with the western one.  It is anemic and strangled by dry air right now, but some model guidance indicates a chance for development in the western Caribbean and into the Gulf of Mexico next week.  Although the vertical wind shear is low and the water temperature is plenty warm, there is a LOT of dry air that will inhibit any development in the next 2-3 days.  From this satellite animation, it's evident that dry air is dominating the area and choking off cloud/thunderstorm development.

In terms of model guidance, the European global model and its ensemble do virtually nothing with it.  But the American model does, so it's worth paying attention to as a possibility.  This image shows tracks of low pressure centers in the American GFS ensemble -- note that the tracks don't start until it's in the western Caribbean, and at that point, they generally go toward the northwest.  I ended the tracks at 7 days from now, and even then, you can see the spread in intensity and forward speed.  So it's not anything to worry about AT ALL now, just something to watch in the coming days.

The eastern wave (waves?) looks more robust, but is also more complicated.  There are a couple areas with signs of rotation clustered together, and it's not clear which one will become dominant or if they will merge.  NHC places that yellow X in the top image somewhere between the two areas of thunderstorm activity west of Cabo Verde.  Messy.

As has been the case for the past couple of months, dry air is widespread in the area, especially to the north.  This map shows areas of dry dusty air from the Sahara in shades of yellow, orange, and red. This air can easily work its way into the tropical waves and hinder development.  But farther west (in a few days), there's a chance.

The European and American global models are more uniform in developing this.  They both bring it to hurricane intensity in 7-8 days (Sep 2-3) just north of the Lesser Antilles, so clearly, this is one to watch closely.  These are the most recent comparisons of model-predicted low-level wind and pressure fields next Saturday, Sep 3.  Of course lots can and will change, but it's unusual to see this level of agreement in an 8-day forecast.

So just how quiet has it been lately?  Using the common metric called ACE (Accumulated Cyclone Energy), the season is at just 13% of the average value for the date, using the past fifty years as the baseline.  ACE is a measure of the duration and intensity of storms, so the number of storms is not a factor.  This chart below puts that value into historical perspective.  The last seasons to have such low ACE by August 26 were 1988, 1984, 1977, 1967, 1962, etc.  So it's certainly not unprecedented, but it's rare. Of those five seasons that I mentioned, 1967 and 1988 ended up near or slightly above average by the end of the season.

Whenever the next storms do come along, Danielle and Earl on the names on deck. Again using the past fifty years as the baseline, the average dates of the fourth and fifth named storm formation are August 19 and August 28.

 

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