Every time I post one of these, I apologize for cluttering up dKos with weather stuff. I appreciate the support y'all have shown in this regard. Personally, I view the immediate concern of these potential disasters as overriding some of the political issues. Ultimately, politics will trump this, as we are all impacted by the policies of our elected officials. But, at temporary times, like this, I feel like this storm information is important. I also question that, though, as my perception may be skewed given my career. So, again, the support I've received for these posts here on dKos this past week has been remarkable. And I will try to continue these updates so long as these storms are a major threat (which, unfortunately, both Hanna and Ike are). As explained in the Gustav "series", sometimes it's tricky for me to post or update, since I often do it from work; but I'll do what I can.
O.k., before we get to Hanna & Ike, just a bit of background on me, since it's been asked a couple of times in the comment threads. In the interest of maintaining the wonderful world of anonymity on the internet :-) ...let me just be general... I'm a meteorologist who graduated from a university in the northeastern U.S. I've been involved in both research meteorology and forecasting for my entire career. That forecasting has focused on Atlantic hurricanes, Northeast weather, and Eastern U.S. temperature predictions. As my career has shifted around a bit over the years, so has my focus. But, in some way, shape or form, I've been focusing on all three of those areas - both in research and forecasting - for over 15 years. Oh, and as has been guessed in the comments... no, I'm not a research meteorologist in the military - though I'm pleased one could make that error (I tried to join the AF to be a meteorologist, but was unqualified to join due to a childhood injury). Enough info?
Okay, Gustav is not a done deal, with flooding rains for some regions (ArkLaTex) and lots of cleanup ahead for the Gulf Coast. But, as a forecaster, and with Hanna becoming somewhat imminent, it's time for me to shift my focus to Hanna. And Ike will likely be hot on her heels, unfortunately. So, by the time we're done with Hanna, Ike may be imminent. There remains some question as to whether or not Ike will pull north enough to hit the U.S., but it does appear likely... moreover, while Kos Nation is focused in the U.S., there are others who will be in Ike's path if he fails to curl north to the U.S. Then there's TD#10 ...soon to be Josephine... behind Ike... but her potential threat is questionable and far off. So, today, the primary focus is Hanna, with Ike secondary.
Here's how Hanna's faring right now:
You don't even need to
loop this image to see that Hanna is being squashed to the south and southeast.
It's hard to imagine Hanna not weakening under this shear, but she's held up remarkably against it so far. Actually, just as I'm preparing this, the National Hurricane Center has downgraded Hanna to a tropical storm. Not surprising. But given Hanna's tenacity, I'd expect her to rebound if wind shear decreases.
...indeed, that wind shear is expected to start decreasing later tonight or tomorrow. I'd like to include a shear map here, but there aren't any good ones available, quite frankly. Most incorporate two levels to calculate shear, one of which includes too much of the storm. So, the storm's own circulation coupled with the upper level "outflow" (which goes in the opposite direction of the storm circulation) creates an apparent (false) high shear impression. More confusing that it's worth. But here's a look at the model intensity forecasts:
The most reliable ones in that image are the hurricane-specific HWRF and GFDL. Outside of an early up-spike in the GFDL, you'll note that both models either oscillate Hanna around her current intensity or weaken her some during the next 24 hours. They're both a bit too strong right now (since hse's just been downgraded and both still show her as a hurricane), but on balance, they seem to be handling Hanna correctly. And notice that, in keeping with the aforementioned reduced shear, both show Hanna rebounding... though they hold off her "recovery" until late tomorrow or early Thursday morning (rather than early tomorrow, as the shear reduction may imply). The GFDL landfalls her as an 80kt storm, the HWRF as a 100kt storm.
...I should point out that those two model solutions are slightly outdated, as some brand new data (as of the time I'm writing this) is available. The new GFDL model does not really show much short-term weakening, and and now shows landfall as about a 100kt storm - much like the previous HWRF. But this isn't convergence as the new HWRF has actually backed off. It now, properly, shows the short-term weakening quite superbly, then shows the re-intensification, with landfall as an 85-90kt hurricane.
Model track guidance is in excellent agreement:
...showing landfall on the Georgia coast on Friday. That track map, however, does not show a number of "global" models, most of which have landfall further up the coast in South Carolina. That's why the official NHC track:
...is up the coast a bit, into South Carolina. The best performing global model, the European (called the ECMWF), has landfall along the GA/SC border Friday afternoon.
Given that the Euro model, the HWRF and GFDL have been the best performers, I'll stick with them... landfall near Savannah, perhaps up a bit north towards the GA/SC coast, midday Friday (leaning early as most storms seem to hit earlier than predicted ...see: Gustav), as a Category 2 hurricane. Of course, you should follow the NHC's "official" guidance (which is further north). But that's my take.
Some words of warning... On the plus side, there is a small chance that Hanna could actually dissipate. The shear is strong and any further southward drift could shove Hanna over Haiti. The combined impacts could demolish her. That's not likely, but there is some hope for that. On the negative side, Hanna will cross a large section of the Gulf Stream:
...on her way to landfall. In that image you'll see that the Gulf Stream heat potential is paltry compared to where Gustav was. Nonetheless, it is still quite warm compared to surrounding waters - warm enough for Hanna to rev up once/if/assuming upper level conditions become less hostile for her.
One final warning, if Hanna comes in as far south as I expect, this is an area where landfalling hurricanes are rare, due to the shape of the coastline. As such, impacts could be disproportionate for a storm of its magnitude. As a veteran of Hurricane Gloria, I can attest to this. I went through Gloria in a location not prone to frequent hurricanes. We hadn't had one in 25 years. At my location, sustained winds never exceeded tropical storm force. Because of the rarity of storms, old, weak, dead trees abound. So, Gloria cleaned house, causing massive tree damage. After the storm, roads were impassible for days and at my house we were without power for over a week. Hurricane Bob swept through several years later with much stronger winds, yet less impact from tree damage, because Gloria had previously wiped out all the weak trees. North Florida and Georgia are in a similar position. So, if landfall holds more southward, towards Georgia, residents should prepare for extensive power outages.
Switching to Ike very briefly, I'm not going to say much on him just yet. Just know this, he is a significant potential threat. Here are the track and intensity forecast maps for Ike:
...so, there is excellent agreement in bringing Ike to between Hispaniola and the southeast Bahamas by Saturday. And the two "best" models (HWRF and GFDL) have him getting impressively intense by then - only backing him down at the end because both of those models take him over Hispaniola - meaning that the reduction may be temporary. Beyond day 5, the "best" model (Euro) has Ike in the eastern Gulf... but even though it's been the best model this season,it hasn't been that good this far in advance (recall, it also had Hanna in the eastern Gulf ...which is wrong). So, let's not get alarmist about the Gulf. But, suffice it to say, Ike is a threat
Gotta end it here, work calls... and no time to check for typos - sorry if there are some. But I'll try to update as conditions warrant.
Oh, and credit where credit is due: I'm yanking those track and intensity charts from Allan Huffman's great site!
UPDATE 11:25AM EDT ...okay, not much of an update this time, just wanted to make sure everyone had the latest - but there's not much new news out. I'll post a better update - time permitting - this afternoon, once some new model data becomes available. But here's a bit of new info...
The 11AM update from the National Hurricane Center has nudged Hanna westward. Given the discussion above, this isn't surprising. However, they are still a bit north of where I'm thinking. But, as it's a day 3 forecast, that's splitting hairs. The newest NHC forecast is basically the same as mine. Other news on Hanna is that she continues to get battered by shear, which is good news. But don't get too overjoyed. While NHC's discussion talks of the disintegration of Hanna's core, their timing is particularly bad. Shortly after their discussion, Hanna's convection began to re-flare near her center. I encourage you to check out that satellite loop link. If you do, the reds are deep convection. Hanna's center is near the Turks and Caicos (north of Hispaniola)... notice the small explosion of reds in the final few frames. In short, Hanna continues to battle. As long as she does so for the next day - until the shear abates - she'll likely survive and then intensify.
In other news, Tropical Depression #10 is now Tropical Storm Josephine. No surprise there. She's no immediate threat, so we'll leave that alone. But on a side note, the storm train continues:
...barring some interference from shear, cool water immediately off of Africa, or some other unforseen inhibitor that system in western Africa is also destined to develop. So, within the next 48-72 hours (2-3 days) we may well be looking at Tropical Depression #11, or even Tropical Storm Kyle. But that's getting ahead of ourselves.
UPDATE 2PM EDT Since we've rolled off the rec list, I'm not sure how many people can/will see this update. So, I'm going to keep it short, sweet and graphics free...
New model data has come in and shifted Hanna further west. Some (UK and a Canadian) model are still up around a South Carolina landfall. But that's even a westward shift for the Canadian (it was up into NC). The HWRF is now down to landfall between Cape Canaveral and Jacksonville, while the GFDL is up near Savannah or just south. So, my southward thinking (compared to NHC) looks okay, but it's possible that even I'm a little too far north too. So, all interests from FL to NC should remain on alert. But JAX to SAV looks like the most likely landfall location. Intensity forecasting is a lost cause right now. The two best models have jumped the shark in their latest runs... HWRF has 28mb of deepening accompanied by 2kts of weakening (whether or not you understand that, let's just say that's almost physically impossible); GFDL deepens Hanna dramatically during the next 18 hours, under a hostile environment, then has no further intensification thereafter, while Hanna goes through the Gulf Stream and a better environment. Useless. The best estimate is just to say that she'll hold steady in the near term, then intensify slowly through landfall - meaning about an 85kt hurricane at landfall (weak Category 2). And given Hanna's continued successful battle against shear, I think holding her steady the next 24 hours (or maybe some slight weakening) is reasonable.
As for Ike... not much new there... models have actually diverged a bit. So, really no change in thinking... comes towards the Bahamas or Hispaniola by Sunday, with reasonably significant intensification. And he does, presently, appear to be intensifying.
That's all for now, and no more updates until tomorrow AM, since I'm not sure how accessible this diary is now.