Thursday, October 01, 2015

Hurricane Joaquin: October 1, Update A

The poor Bahamas are really getting a beating! Hurricane Joaquin continued to move southwards and he grew, and now the islands are under the truly worst part of the convection. The red/grey areas in the infrared satellite image show the areas of highest cloud tops and therefore the strongest thunderstorms, tornadoes etc.:

If you want a quick reminder of how to read these IR satellite images, look at the technical alert here!

He is officially currently at 23.4N, 73.7W, heading WSW at 5mph. This means he's barely moving, which of course makes it even worse for the Bahamas! Speaking of track, here's the latest from the NHC:
He'll start to move away from the Bahamas on Saturday. It is interesting that the cone of uncertainty is so broad, but that is because this storm has pretty much stalled, which adds another level of uncertainty (plus we are looking at 4-6 days out, which is always poorly forecast - I trust the 1-2 day forecast at the most!). If he had continued to move, we would have more certainty because he would have been swept into the Atlantic by the low pressure front that is moving through the US east coast (that's why you all had so much rain this week). But because he stalled, that front is moving through and not really interacting with him. The uncertain track is in trying to figure out how much the front will impact Joaquin. You can see that in the low tropospheric level vorticity map - the low is that streak of yellow/green along the US east coast:

I think he will stay off shore for most of the way up and by the time he gets up to the general New York area, he should be a bit weaker so hopefully the impact won't be that much (and he may even be quite far offshore by that time). HOWEVER, it's best to get ready (if you don't already have your supplies of water, ice cream, candles, and wine ;-)) and pay attention to your emergency managers as they have the most up-to-date local information. 

His winds are officially estimated to be 120mph (central pressure 942mb), which makes him a strong cat 3 storm (cat 3 range: 111-129mph). The upper levels of the troposphere also have a good signal, which means he is very strong. Here's the map from 200mb (the highest level of the troposphere):
I don't see a solid eye in Joaquin in the visible satellite imagery though, which indicates that he may not be quite that strong at the moment...
But, he has just emerged from the night and there is a hazy eye, so I would definitely place him as a cat 2 storm at least. 

Another travel day today. More tomorrow!

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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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