I found some good advice worth sharing...
Tropical Storm Laura
She's officially at 18N, 68.7W, currently heading W at 18mph...
She stayed a little south of Puerto Rico, but should be making landfall in the Dominican Republic very soon. She has got slightly stronger, but is officially still a pretty weak Tropical Storm with winds of 50mph, central pressure of 1004mb (TS range: 39-73mph). I think she's a bit stronger than that - there is some circulation in the upper levels of the troposphere, which means she has a pretty decent structure now.
The NHC don't expect any strengthening between now and when she emerges from Cuba. I more-or-less agree with this, but expect some weakening (assuming that the center goes over the islands) as she goes over land, and then a little strengthening as she hops from Haiti to Cuba, where warm waters run deep. As for her intensity in the Gulf, well, she has a lot of factors that will impact her before getting to that point and I'm not sure she will be a hurricane in the Gulf either (see Marco, below).
She's looking a lot better than yesterday and the convection is still very strong:
That's because sea surface temperatures are 29 deg C, with the upper 100-125m of the water column being warmer than 26 deg C, so there is a lot of warm water to feed her habits (you can see this in the image below). Wind shear has also decreased now, although there is still some so her convection is actually a little to the west of the center. You can see this in the satellite imagery because the convection/clouds extend ahead of her. As her center moves over land, I do expect the convection to decrease and for her to weaken. The only hiccup to my cunning plan here is that the water to the south of the islands is really warm, so the farther inland she is, the better.
Tropical Storm Marco
He is currently at 22.3N, 86.0W, heading NNW at 13mph. The track has, indeed, shifted to the east and now landfall is projected to be over the Mississippi Delta neighbourhood on Monday afternoon (around the time that Laura is projected to be over Cuba) as a cat 1 hurricane. Please note that it's the entire cone you have to keep an eye on and therefore landfall currently can be anywhere from Alabama to Texas. This is the same area that Laura is forecast to make landfall in a couple of days later - bu we'll see how strong she is once she gets to northern Cuba. I do have some thoughts I'd like to share about the intensity of Marco as he crosses the Gulf, some of which may apply to Laura too.
He has strengthened quite a lot today, which is what I was expecting. He is a strong Tropical Storm now with winds of 65mph, central pressure 994mb. There is a lot of convection...
...but s strengthened quite a lot today,
... but you may notice that even though there is a lot of convection, the clouds aren't in a very circular pattern. That's because there is A LOT of wind shear in the southern half of the gulf which is why they are streaming off to the northeast.
<Forecasting Alert!> Wind Shear - how do I find out about wind shear? I go to the University of Wisconsin CMISS page, which is the excellent website that I've mentioned a few times this year - it has the Saharan Air Layer map and the vorticity map. Here is the 'slightly' complicated map/data I look at (works well with wine ;-))...
You can see both Laura and Marco here as those are the white cloudy clumps. The land is outlined in white. Got your bearings? Now, find Marco. See the pink lines to the north (over the Gulf) - the closer they are the stronger the wind shear. If you follow those lines to the north and east, across the eastern US and out to the Atlantic, you can see a faint grey stream of clouds that are being carried away because of the wind shear. The pink lines are the most important bits in this. The other colourful lines are contours showing wind shear and how favourable those areas are for storms.
Go to
http://tropic.ssec.wisc.edu/tropic.php if you want to look for yourself (and I'm sure you all do!! :-)). Click on the colour block in the lower map (Regional Real-Time Products) for the part of the world you are interested in (North Atlantic in this case), and in the drop-down menu you will see 'Winds & Analysis'. Click on that, and then click on 'Wind Shear' in the block of buttons at the top, and you will see the map above. Now you can check out wind shear for yourselves any time you like. :-) <End Forecasting Alert!>
This wind shear looks like it will be in place as he moves north, so it will inhibit his growth once he gets into the Gulf and, should he even get to hurricane strength (which may not happen), I'm not convinced he'll remain one as he moves across the Gulf.
Looking at the ocean next. The reason I'm not a surprised that he has strengthened is because he has been moving over some very warm waters of 30 deg C, with deep warm waters underneath. As I showed yesterday, this map shows how deep the water is that's warmer than 26 deg C...
He's been moving over that red area which is where the upper ~150 meters of the ocean are warmer than 26 deg C. But if we look at his path as he crosses the Gulf, there seems to be an area of cold water that he'll go over tomorrow afternoon (ish). That will also inhibit his growth in the mid-Gulf.
As for Laura - if she makes it into the Gulf, as she is only a couple of days behind Marco, he will have cooled the waters down a fraction in the northern Gulf - close to landfall - which will help us out (at least a little) in inhibiting her growth. She is coming in from a different angle, so there's a chance that she would cross more warm water in the Gulf than Marco will. Given how close they are, there is a very strong possibility that they will both be aiming for about the same neck of the woods... but I would not be surprised if Laura's track in the northern Gulf shifts eastward towards Florida.
If I were you guys, I'd be ready for a very soggy week, but hopefully the winds will be a little weaker than currently forecast. If you want, we'll gladly take the rain here in California!
Ok, it's definitely wine-o-clock here, so I'm signing off for today. But I'll be back tomorrow to watch this scientifically interesting, but tricky weather play out.
A bientot! (French wine tonight! :-)),
J.Twitter: jyovianstorm
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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 local 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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