Saturday, September 09, 2017

Hurricane Irma and Hurricane Jose: September 9, Update C

Wine-o-clock here and you know that means it’s time for an update.

I know this is tricky timing, but I did want to take a moment to thank all of you super intelligent, gorgeously good-looking, fabulous readers as this blog reached a milestone today! Sometime in the last few hours we passed the 200, 000 hits mark (honest, it wasn't just me hitting refresh ;-)). I am truly amazed and humbled and will probably gush some more once my head gets back to its normal size and this season is over. But for now we have other more important things to talk about... such as the wind shear that is in front of Irma...  

Hurricane Irma
She is still a cat 3 storm with winds of 125mph, central pressure 932mb (cat 3 range: 111-129mph):
She is at 23.4N, 80.9 W, heading WNW at 9mph still. The track is still pretty much a west Florida thing – but please pay attention to the entire cone as she could go anywhere in there:
The rain bands are bigger than the track of course, and with the wind shear kicking in to her north and whisking away some of that energy, I see that most of the Florida peninsula is experiencing some sort of convection – ranging from just clouds all the way to thundery weather with tornadoes:
Although she is over the Florida Straits now, she hasn’t really intensified much yet. In addition to the land impacts as she leaves Cuba, it does look like that wind shear that I mentioned earlier has actually moved south over the last few hours and is now kicking in between the Keys and Naples – a little closer to her center, which is a good thing. This should inhibit her development as it is quite strong. 

<Technical Alert!> Want to see the wind shear? Here’s a map of the wind shear from the amazing University of Wisconsin-CMISS group (who produce the vorticity maps and other fun stuff):
Marvelous image of squiggly lines (that's technical jargon for 'squiggly lines'), isn’t it? Meteorology-geeks Unite! J

To figure out what this shows, first, find the white outline of land (no, it's not a chalk outline!)… let’s pick Florida just for the heck of it - nothing much going on there. ;-) The wind shear is indicated by the lovely pale peach (possibly orange but look peach on my screen) lines that are flowing from the southwest to the northeast - from the Gulf and into the Atlantic. These contour lines show the direction of wind shear, and the closer those lines are, the stronger the wind shear. You should be able to see the satellite image of clouds that this is overlaid on, so you should be able to trace this high shear to the northeast and see that the clouds that are streaming off in that direction more-or-less correspond to the shear.

To put a value on the wind shear, the green, yellow, and dark red lines essentially show the amount of shear in knots, where 1 knot = 1.15 mph. Currently Irma is in an area of low wind shear – somewhere around 15-20 knots = 17.25-23 mph, but when you get to the red lines, the shear is around 30-50 mph. This is about 25-40% of her wind speed (at the moment), so I would expect this to have some impact on her as she gets closer to south Florida. <End Technical Alert!>

Here’s the latest from the Key West Radar:
From the wind sensor at Key West airport, the wind speed is now around 40mph at the airport – so just about Tropical Storm force. The highest wind speed recorded at the moment is at Vaca Key, from the Tides Online sensor:
You can see that the water level is almost 1.5 ft above normal and the winds are a steady 40 knots = 46 mph… the data across the Keys indicates that they are now experiencing Tropical Storm winds (TS range: 39-73mph).

Hurricane Jose
Not too much change here… he is currently at 19.7N, 63W, heading NW at 14mph. Winds are 145mph, central pressure is 945mb. This makes him a mid-sized cat 4 storm – cat 4 range: 130-156mph:
He is moving away from the Leeward Islands (thank goodness!!) and is going to go and hang out in the Atlantic for a bit and contemplate the meaning of Life, the Universe, and Everything:
They think he will be stuck there for a bit because of he is forecast to be under a high pressure – I am not yet sure about this. With Irma breaking through, the high has eroded a bit (although it can certainly build back up), which will give him some room to move… but it is a few days out so this track is quite uncertain.  

Stay calm and safe Florida! 

I'll be back. Toodle pip!

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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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