Friday, October 07, 2016

Hurricane Matthew and Hurricane Nicole: October 6, Update B

I have been hearing from people all across Florida today. It sounds like everyone is ready - evacuated or hunkering down with supplies... 
(thanks to Keith L. for sharing this photo from yesterday - posted by JoAnn T.).

Hurricane Matthew
Matthew is definitely looking weaker. He is officially at around 27.6N, 79.7W, heading NW at 14mph. The NHC dropped his winds to 130mph (central pressure of 938mb) this afternoon, making him a border-line cat 4 storm (cat 4 range: 130-156mph). They just dropped them again to 120mph, which puts him firmly in the cat 3 range (111-129mph). I think he may be slightly weaker - possibly a strong cat 2 (cat 2 range: 96-110mph) now though because his eye is not clear, and his convection has decreased slightly:

He still has good circulation in the upper troposphere, so he can re-intensify, and regardless, he will still be a tough storm - the red areas are strong winds with heavy thunderstorms and tornadoes. Regarding his intensification, although he is over the warm waters of the Gulf Stream, he is now skirting the edge of Florida so he is feeling some land effects. Also, he is moving into an area of slightly higher wind shear, which will also inhibit his development. 

The main things are power loss (Jan P. said he lost power in Vero Beach about 2-3 hours ago) and storm surge. Because storms swirl in an anti-clockwise direction, as he moves up the coast, he will be pushing water into the coast in front of him. For those who missed where to look for storm surge data, this is from an earlier post: 

<Technical Alert!>  You can look at the storm surge from this Tides Online link. At the moment they have kindly pulled the links out for a bunch of the east US coast to make it easy for you to see those, but in general click on the 'State Maps' tab on the left, and then click on the State you are interested in, and then the location within that State. For example, here is the data from Trident Pier, Florida at the moment:

The top graph shows the water level. In this graph, the red line is the actual observed sea level, the blue line is what the predicted water level would be because of the tides, and the green line is the difference between the two. The height of the green line gives you the storm surge level, so Trident Pier currently has a storm surge of over 2ft and rising.  The graph below that is wind speed and direction - you can see the winds are still increasing, and they are from the northeast, meaning he is still to the south of this location. Below that is air pressure which is steadily dropping, and below that is air and sea surface temperature (but who cares about that in a storm, hey? ;-)). <End Technical Alert!>

A few people have asked about any storm surge prediction models. I don't normally do models, but the NHC have started to put out an experimental storm surge model. I am very curious to see how this compares to real data! The link to that is from the NHC main page - under the storm, it is called 'Storm Surge Inundation'. It looks like the Storm Surge in the Trident Pier area is forecast to be above 1 ft... hmm. 

The other place to look for real data (ok, and some models :-)) is the SECOORA website (Southeast Coastal Ocean Observing System Regional Association). They have put up a special Hurricane Matthew page. There are all sorts of flavours (with a 'u') of cupcakes on this page - from buoy data to radar data that show the water current velocity, to wind sensors along the coast. 

There is also of course the National Weather Service Radar, and the National Data Buoy Center, where you can get winds for sites that are offshore (some of which are part of SECOORA). Here is Matthew from the NWS Radar in Melbourne:

So his track is a bit loopy (haha... all puns are intended! :-)). At the moment it looks like he is heading back on Tuesday to finish visiting the islands in the Bahamas that he missed this time around! 
I don't have enough high quality data at the moment on this, but as I said yesterday, this is a very complicated pressure field we have out there, so it is difficult to say what exactly will happen at days 3-5... which is why the cone is so huge - a lot of uncertainty. Stay focussed on the the 1 and 2 day track, which actually also has way more uncertainty in it than usual. 

Hurricane Nicole
She is currently at 27.4N, 65.2W, heading nowhere in particular. She is stationary and stuck in that high pressure that is also messing with Matthew. 

The NHC have said she's a cat 2 storm with winds of 105mph, central pressure 968mb. I'm not sure I buy this (ok, I think they are quite off!) - at the most, I would say she's a cat 1 storm with winds just around 85-90mph, but not a cat 2! The upper level vorticity (circulation) is barely there, and she doesn't have much of an eye to talk about: 

Huh. Cat 2. 

That's it for today. Tomorrow I'll make up some more stuff. 

I hope everyone is safe tonight and tomorrow - a long day for Florida... and then we move onto Georgia and South Carolina! 

Ciao for now,

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DISCLAIMER: These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

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