Weather: Tropical cyclone Dorian

August 3, 2013 at 3:32 p.m. Eastern

Wow! The little storm that could has re-formed, per the NHC, back into a tropical depression. That’s not actually a cyclone, but rather an area of low pressure with surrounding thunderstorms that all tropical cyclones develop from.

It's still a gasper and expected to weaken later today, probably for good this time.

It’s still a gasper and expected to weaken later today, probably for good this time.

Dorian isn’t going to develop. Per Jeff Masters at Weather Underground, strong wind shear has stripped away the heavy thunderstorms near TD Dorian’s center of circulation, and the shear is going to only get stronger. He believes Dorian will be gone by Sunday.

TD Dorian on August 3rd, showing uncovered center of circulation.  (Source:  NASA Blue Marble imagery by way of Wunderground.com.)

TD Dorian on August 3rd, showing uncovered center of circulation. (Source: NASA Blue Marble imagery by way of Wunderground.com.)

Well, Dorian, the fourth named storm of the Atlantic hurricane season, formed this week. It’s currently a tropical storm and far from land.

There are no coastal watches or warnings in effect, though some of TD Dorian’s rains are probably reaching the Florida/Georgia/South Carolina coasts (maybe it will also lend some lightning to those NSSL researchers in Florida).

Things have been busy over in the Pacific, but hang in there, – the Atlantic hurricane season is just really getting started.

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I didn’t jump right on this right away because it really shouldn’t have been there.

Red dots on the model graphic

Of course, I know little to nothing about meteorology, but spending the 2005 Atlantic hurricane season in the Southeast US got my attention, and I have learned where to look for a little glimmer of information about future storms.

See Dorian in this current run of the GFS?

See Dorian in this current run of the GFS?

In this case, it is the tropical models here. There is a ton of information there for the trained mind, but I just look for little red dots that indicate where a tropical cyclone might form.

On this example to the left, by comparing to the NHC graphic above, you can see such a dot where Dorian now sits.

A couple weeks ago, there was a dot in that general area, too, and I thought – yep, a named storm. Then a week ago, it disappeared, and I figured the National Hurricane Center was getting ahead of itself in indicating interest in a tropical wave that had just come off the African coast.

That wave became Dorian, and the red dot reappeared on the model page.

Dorian’s future

Jeff Masters, at Wunderground, noted that given its small size and the challenges it faces – cooler waters, increased wind shear and now some dry air – Dorian might dissipate or “the little storm that could” might even surprise everybody and become a Category 1 hurricane.

Well, it hasn’t dissipated yet, but it is having rocky going.

For a while, the models page showed it holding together, cruising just north of the Caribbean and then intensifying before possibly having a go at either the East Coast or the Gulf.

Now, the GFS model on that page (there are different versions of this model, and I just follow that one for consistency) seems to show Dorian holding together until it reaches Hispaniola and then falling apart.

Current NHC five-day forecast cone.

Current NHC five-day forecast cone.

Who knows what the models will show tomorrow, but through it all, the meteorologists at the NHC study these and much more, and continue to issue their five-day forecasts multiples times a day. Hats off to them!

My job is stressful sometimes, but I’m glad it doesn’t involve issuing forecasts on which many citizens, emergency planners, governments and businesses must make decisions.

Nature follows her own rules, and we can only get a general idea of what she’s going to do next.

Luke McKinney once described math as the universe’s operating system, and physics as part of its hardware. With the little bit we know of Earth’s “desktop,” it’s pretty bold of humanity to try to predict something like a tropical cyclone – and yet, overall, we have done a pretty good job in recent years.

Well, I have no idea what’s going to happen next with Dorian, but at the moment it doesn’t appear to have the potential for becoming a Cape Verde monster, fortunately, though it quite likely is going to bring wind and rain and grief to Haiti and the Dominican Republic soon. Will update this if there is a drastic change in things.



Categories: Weather

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