Saturday, September 14, 2013

Post-Tropical Low Humberto and Hurricane Ingrid: September 14, Update A

For the second time this season, I have news! At some point last night my blog website crossed the 60,000 hits mark!! This means it has had 10,000 views with only 25 new entries and in just under 3 months (50,000 was June 20)! Thank you all for reading (…or at least clicking on the page ;-)). I am fortunate to have such intelligent, witty, and wonderful readers like you! J I shall drink wine and be merry later today to celebrate. J

Post-Tropical Low Humberto

The NHC downgraded Mr. Humberto Humperdink (no relation to Englebert ;-)) to a post-tropical low pressure system in their 11am advisory this morning because, although he has a bit of circulation, there hasn’t been any convection in the system (as you saw yesterday). I think this was a good call. He is moving WNW at 13mph, has winds close to 40mph and a central pressure of 1004mb and is currently at around 25.7N, 36.6W. The track forecast is a general WNW-NW movement in the next couple of days, and then he’ll turn to the north again. Seems reasonable to me at the moment.

You can see the circulation in this visible satellite image, in which there are still light clouds lurking (with a patch of heavier ones in the northeast):

The NHC still think he will be a Tropical Storm again by tomorrow evening and a Hurricane by Weds evening. I am not yet as convinced about this, although there are a couple of things that may flip the Tropical Storm switch (not the hurricane switch). The circulation in the middle troposphere continues to decrease and he is in a region of strong wind shear which doesn’t look like it will go away by tomorrow. However, it looks like he will be moving over slightly warmer water temperatures  (just over 26 deg C) and there is a little more water vapor in the air. It will be a battle between these forces of good and darkness! ;-)

Hurricane Ingrid

Really?!? A hurricane? I guess she was upgraded in a rush to check off another hurricane on the numbers list!! Although there is some circulation in the lower half of the troposphere, there isn’t enough in the upper troposphere to make this a hurricane! She has been lingering over warm water (she was stationary yesterday), so she has had time to get her ducks in order and become a tropical storm by separating from the Tropical Storm on the Pacific side of Mexico (TS Manuel – which is another story!), but she is not yet a hurricane! Not only that, but this upgrade was been done before the hurricane hunter plane reached the system because they saw an eye in the visible satellite image:

Do YOU see an eye??? I’ve looked at the movie loop of satellite images for the last ~7 hours, and there is a small shadow that one could squint at and pretend was an eye. It appeared for one snapshot, but it quickly lost that shadow and it hasn’t returned. One data point is not enough to upgrade a storm!!!

I do agree that the convection is very strong, and you can see that in this I satellite image:

but the water is warm and she’s a tropical storm now, so of course this is no surprise.   

She is currently at around 21.3N, 94.4W, officially heading N at 7mph. Winds are officially 75mph (grr), central pressure is estimated to be 987mb (cat 1 range: 74-95mph). The forecast track takes her a little more north, and she’ll turn west and into Mexico, making landfall on Monday afternoon. I agree with the track direction, although they also say they are not 100% sure of the timing of landfall – she may be a little slower.

I do think their current estimate of intensity is high but it does look like there is room for her to intensify further. Sea surface temperatures are 28-30 deg C, with water warmer than 26.5 deg C in the upper 75m. So she has warm water aplenty. There is also plenty of water vapor around:

Interestingly, this water vapor is partly from a storm that’s just off the left edge of the map, in the eastern Pacific – Tropical Storm Manuel – which is aiming for a west Mexico landfall tomorrow. There is some wind shear at the moment, which looks like it will weaken a little in the next day or so. The one factor she has against intensification is that she is interacting with land, but with rain from Manuel and rain from Ingrid, I don’t think that will amount to much of a factor before landfall.

I’ll be back tomorrow with an update on what’s what and who’s who and why’s why.  

Have a good evening… it’s wine-o-clock where I am, so I will have a good evening too! J


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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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