Saturday, May 26, 2018

Subtropical Storm Alberto: May 25, Update A

Hello my friends! Did ya miss me? And more importantly, are you ready? Yeah... me neither! But no time for sleeping in... or hibernating at all apparently this year. I guess Mother Nature thought it would be a hoot to start a wee bit early. Can someone take her off the caffeine please? ;-)

As some of you noticed, for the first time in over 10 years, I didn't quite manage to wrap up the 2017 season with my traditional end-of-season post; a consequence of the hurricanes that hit Puerto Rico meant I got caught up in a crazy world tour (in 2.5 months, I flew over 72,000 miles and travelled about 1,500 by road/rail/ship) (more about why in this BBC article). But we'll have a proper catch-up over a nice cup of tea later. For now we have that pesky little Subtropical Storm Alberto hanging out off the Yucatan Peninsula causing a bit of a ruckus.

Officially he's at 19.4N, 85.7W, heading E at a relatively sedate 5mph. He is pretty weak at the moment - barely a storm actually - with winds of 40mph (TS range: 39-73mph) and a central pressure of 1006mb. He is disorganized as you can see in this colour satellite imagery (which goes from light and colourful in the daytime to black and white at nighttime):
This is from the National Hurricane Center (NHC) website. Deary me, it looks like they made a lot of changes on their site since last year and, at first glance, some are for the worse because some useful graphics and satellite imagery features have been removed. Grrr (shaking my head). I'll have to do some digging to see if I can find what we really need, but in the meantime, this satellite imagery will have to do. It does illustrate how poorly organized he is - you can clearly see the center of circulation which is just east of the Yucatan peninsula, but most of the convection (rain storms) are even further east and north east - closer to Cuba. This is because he is under some wind shear which is pushing that convection to the east.

The current track has him going generally north as a Tropical Storm, making landfall somewhere on the northern Gulf coast:
I would agree with this general track and the computer models at the moment because there isn't any good pressure data available and he is quite weak.

For his intensity, he is weak because there is wind shear and also some dry air being pulled into the system. The reason he has any real convection at all is because he is currently sitting over an area of the ocean where the sea surface temperatures are warm, and the warm water is deep (this is part of the Loop Current system - which I'm sure I'll talk about later in the season). But the good news is that as he moves into the Gulf, although the sea surface temperatures are warm, the warm water is not as deep - the Loop Current does not extend as far into the Gulf at the moment as it has in previous years. Also, it looks like the wind shear will continue for a while as he moves north, so although he may intensify a little as he moves north, at the moment I would agree with the NHC that he remains a Tropical Storm.

I'll be back tomorrow with more on STS Alberto and also maybe a wrap up to 2017 and a proper start to 2018... after all, I'm wide-awake now. :-)

Toodle pip,

These remarks are just what I think/see regarding tropical storms (my storm blog). If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast. This is not an official forecast.

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