Tuesday, September 26, 2017

Hurricane Maria and Hurricane Lee: September 25, Update A

I didn’t run away! I was away from a computer, experiencing the ups and downs of real life but now I’m back home; wine in hand, ice cream in the freezer for later, hubby in the kitchen making me dinner, and two cat 1 hurricanes to stalk. Things are back to normal(ish). J

Hurricane Maria
She is winding down (and about time too!). Currently she is at 32.3N, 73.1W, heading N at 7mph:
But as you can see, there isn’t much convection left in her. Hurray! It is mostly clouds with a splodge of rain (technical jargon ;-)) and a bit of a breeze. Officially she has winds of 80mph, central pressure of 969mb (which is quite low for such a weak storm), which makes her a weak cat 1 storm (cat 1 range: 74-95mph). Me likey. She is also generally steering clear of land:
North Carolina may get a spot of rain, but after that it looks like she may pop over to Scotland in a couple of weeks for a finger or two of Scotch and some deep-fried pizza and deep-fried mars bars. (For reference, I have about seven fingers of wine J). The reason she is moving at a relatively slow pace is because there is high pressure in front of her. There’s a small chance she may move a little closer to land than because of this high pressure, but generally I’d go with this track. The reason she is expected to speed up and move to the northeast is because there is a front moving across the US and that will scoop her up and carry her north. You can see this front in the satellite imagery:
There is still very good circulation (vorticity) throughout the troposphere, including the upper levels, which indicates that she is definitely still a hurricane. She is still also over warm water, with sea surface temperatures of 26-27 deg C.

Hurricane Lee
This little guy just doesn’t want to go away, does he? He is now at 30.2N, 51.5W, heading WSW at 8mph:
 He is officially a little stronger than Maria with estimated speeds of 90mph, central pressure of 979mb, which makes him a strong cat 1 storm. However, there is a very good eye which has not really gone away in hours and he has some decent convection, although not the red we see with strong tornado producing thunderstorms – given these clues, I would place him at a strong cat 2 storm at the very least (in my humble but not quiet opinion), with winds in the 105-110mph range! They haven’t sent a plane into investigate (from what I can tell) so the wind speed is truly their estimate.  

His track takes him a little closer to Bermuda, but then he will start to curve to the north and northeast:
The track is based on the high pressure that Maria is going to be curving around as well, and that front across the US, which and will scoop both Maria and Lee off to the NE.

For those of you who are still awake this far into today’s post (well done you!) and are paying attention to the tracks…
(Image created from the NHC track by Ben A.)
we get the (drumroll) ‘Venn Diagram of the Cone of Uncertainty’! Friday and Saturday are looking particularly dicey if you are sailing anywhere in the intersection.... I highly recommend that you stay off that part of the high-seas this weekend.

We have seen storms get close to each other before – Maria and Jose got a little close (but not close enough, fortunately, to join forces!).

In this case, Maria and Lee may be within 800 miles of each other and there is a possibility that we may see the Fujiwara Effect... ooh... time for a Science Alert! (although unlikely as they look like they are chasing each other, but it's a chance for a Science Alert so I'm going to grab it ;-)).

<Science Alert!> The Fujiwara Effect (or Fujiwara Interaction) happens if we have two rotating cyclones (within 800-850 miles) that get close to each other (with the western one moving slower than the eastern one). If that happens, they start to rotate around each other and around a point between the two systems. Eventually they will spiral in towards that central point and may even merge - if they don’t dissipate before they get too close. This is more frequently seen in the Pacific, but once every few years it happens in the Atlantic as well. For example, in 1995 between Hurricane Iris eventually absorbed the remains of Tropical Storm Karen, or in 2005, Hurricane Wilma gobbled up the remains of Tropical Storm Alpha (we had so many that year that we started the greek alphabet!). < End Science Alert!>

Hopefully more tomorrow!

Toodle pip,

p.s. RIP Uncle A. and thank you for everything. xxx

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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