Oy vey, I've been absent a long time. I've been on something of a political hiatus. Doing my best to stay active - calling/emailing legislators on relevant issues (like the recent marriage equality fight here in New York, where I moved to just a couple of months ago). But it's been a crazy time for me, moving, personal issues aplenty, employment questions (which have worked out well, thankfully), etc. So, I've been too busy tending to my own issues. In fact, this is my first diary posting here on the not-so-new-anymore DKos site! Wow, it's been a long time! In fact, jumping in with one of my politically off-topic weather diaries seems a bit presumptuous, especially since my good dKos online compatriot weatherdude has done such a superlative job covering critical weather events! But I'll continue these hurricane posts so long as folks in this community find them informative and helpful. They may not be germaine to our political discussion, but it's my way of applying my expertise in a way that's helpful to the masses. :P So, jump below for the first real threat of the 2011 season.
*UPDATE (6:40PM EDT): The below discussion is left untouched. I'm just posting a quick update to inform you that, based on the issuance of new model data from the National Hurricane Center, their header data identifies this as "Tropical Cyclone Irene" with an initial intensity of 45kts. In short, the National Hurricane Center will shortly be upgrading this to Tropical Storm Irene, probably with winds of 45kts... but that could vary by 5kts by the time they issue their initial advisory on it.
I'd emphasize that when I say first real threat, I mean for the U.S. Some get offended by my U.S.-centric focus on these forecasts, and may be particularly sensitive as Tropical Storm Harvey is currently flooding parts of Central America. Honestly, it's simply a matter of necessity. I have personal interests in Asia and would like to provide informative commentary on those storms as well. Unfortunately, time is limited... so, I do what I can... and since this site is primarily made up of U.S. folks, that's where my focus is.
Anyway, enough of the babble. Enough of you have read my stuff in the past to be familiar with me... a meteorologist in the field for about 20 years with a bit of a focus on hurricanes and some limited experience helping out emergency management with preparedness, so I've grown passionate about sharing this information such that if it raises just one person's awareness of an upcoming threat, it's worth it.
Well, we're looking at a real potential threat coming up for the U.S. late in the upcoming week. That's enough days away so that it's still not clear who is under the gun yet. The biggest focal point of the computer models is Florida, but the storm in question should be making a sweeping curve around the time it reaches Florida. So, it could dodge the state and go west of them (towards the Gulf Coast - though extreme southern Florida will likely have some impacts as it goes by), or even to the east of them (aiming towards the Southeast U.S. or, less likely and hopefully, curling out to sea).
Why do I keep saying "the storm" without any reference to name? Well, the storm is just now in its formative stages and is not yet classified by the National Hurricane Center. Air Force reconnaisance (more wasteful government spending our precious Republicans can cut? no?) is currently, as I write this Saturday afternoon, investigating the system and has found no closed circulation yet. So, I don't think the National Hurricane Center will classify this thing at 5PM today (when they do their next update).
But make no mistake, this thing should develop. The NHC (at the link above) says it has a 90% chance, and recon has found winds surface and aloft exceeding 30kts, including one instrument estimated surface wind over 35kts. 35kts is the borderline for a tropical storm. So, once this thing gets classified as a tropical depression - assuming it does - it will likely almost immediately jump up to tropical storm status. If it does so, its name will be Irene. Why are the winds so high already? Because the pressures are so low. The low pressure area is broad, allowing it to have no real circulation yet. That broadness should lower the wind speeds, but there is enough high pressure to the north to increase that pressure gradient. That's what causes winds... so the winds are especially high.
Here's how this system looks right now:
It's the mass of clouds east of the Caribbean. All of you are pretty much familiar with what one of these storms looks like, so you can tell that this is a pretty disorganized system right now. But you can also tell that it's pretty large and contains a decent amount of convection (thunderstorms ...identified by the deep red colors on that image). The other thing I want you to notice on that image is the decent "fanning out" of the clouds around the edge of the system. This is evidence of good upper level "outflow". That simply means upper level conditions that are pushing the air away from the top of the storm. This is favorable for development (a hurricane sucks in air at the bottom - low pressure - and evacuates it at the top; sitting underneath this outflow has the system in a position where its convection should be maintained, though it'll likely pulsate a bit, and, therefore, development is likely).
As for where this storm is headed, the various computer models have all been handling troughs (just think "cold fronts") horribly over the U.S. next week, and these are critical to turning the storm, as these fronts try to bash through the ridge that's driving the storm west or westnorthwest. But today these computer models have come into better agreement. An assortment of them, courtesy of Clark Evans' page look like this:
I should note that this isn't all of the solutions from the various computer models. A couple of them (the UK's model and the Canadian's model are considerably further west than most of these solutions). The Euro model's solution is also not on this plot... it sends the storm up the SE coast of Florida before nudging inland near Cape Canaveral. Thereafter it slowly drives north, briefly offshore for another landfall in Georgia, then wraps NNW, staying inland over Georgia before dying and being absorbed by a cold front. Anyway, point is, there isn't quite as much model agreement as this image indicates.
As for intensity, well, here's a nice image of the various model intensity forecasts:
This comes from Brian Tang's great site. Unfortunately, the most notable hurricane-specific models on this chart are the three on the top of the curve. All three indicate that this system should be hurricane once it approaches the U.S., with a couple of them up over 90kts, meaning that it could be approaching intense hurricane status (which means a Category 3, which begins at 100kts). The best hope the U.S. has for this storm staying weak is if it treks over Hispaniola, whose mountains could do a number on this storm. But that's hardly consolation as it would wreak havoc on the constantly beaten-up nations of Haiti and the Dominican Republic.
Of course, we can hope that these models are just wrong and this thing never develops. At this point, though, it looks like it probably will develop and intensify. So, we could be looking at Tropical Storm Irene at any point over the next 24-48 hours. Then, after that, it looks like it'll become a threat to the U.S. Where and at what intensity are questions that are too early to be answered. Best estimate by the various computer guidance is that it'll threaten/strike Florida as a hurricane. But again, that's just too early to know. And as I mentioned above, the models have been awful in handling the troughs over the U.S. next week - which will help guide this storm. And the specific of that track will also greatly influence its intensity, as it will determine how much land it traverses on its way to the U.S.
So... stay tuned. I'll try to update on a daily basis (and perhaps multiple times per day if/when the storm becomes a major threat). But my job responsibilities may preclude this sometimes, or force me to keep my updates uncharacteristically brief - unlike my usual tome. I'll do my best, but apologies in advance if I fall down on the job.