Hurricane Ike is serious business now. Not that we had been taking the storm lightly before now, but it's really heating up. I'm prepping this diary early to save some time - work is really pressing this week, due to Ike, so it's tough to keep up with these diaries - so, the text of the body below the fold will have the latest info; and I don't want to state any specific data in this intro because of that. But let me just say that as I prep this, in spite of a modest satellite depiction, Ike's pressure has begun dropping into dangerous territories. And although winds have been slow to respond, there is some indication, based on dropsonde data, that Ike's winds may be stronger than implied from flight level reconnaissance aircraft data suggests. Well, let's just jump below the fold and get on with it...
Ike has only just started to get the press in the MSM. So, I don't think the nation is tuned in very well yet. I guess the MSM just doesn't care so much if we can't have a New Orleans redux. But this is really turning into a serious situation. Readers of this diary series now know that I try not to overhype these storms, like some media-types and big name "hot shot" forecasters do. And there is still some opportunity for Ike to be more bark than bite. I'm not sure there's much room for Ike to not hit the U.S. as a significant hurricane, but of course, anything's possible in the weather. Short of that, Ike could come in weaker than expected or, the best shot for the "more bark than bite" scenario is for the storm to strike a lower population region of the coast. Of course, those affected would see plenty of "bite", but in terms of the large-scale impact, that's the best chance of minimizing impact - Ike staying away from major metro areas.
Anyway, let's just get on with it here as time is tight and Ike poses a serious threat to the upper Texas coast - as the forecasts have shifted north somewhat - as has mine. Here's how Ike stands right now... A recent satellite image of him:
...this shows Ike to be more impressive than last night, though still only modest looking for a storm with a low pressure as deep as Ike's (one might expect a pretty distinct eye, for example). The pressure, as measured by aircraft reconnaissance was at 946mb this morning. It was actually a bit lower last night, but not appreciably. So, Ike has been pretty steady intensity-wise during the last several hours (as of early Thu AM), in spite of the improved satellite depiction. And, not surprisingly, the latest official National Hurricane Center advisory keeps Ike at an 85kt (100mph) minimal Category 2 hurricane. It should be noted, however, that there have been occasional indications that Ike may be stronger. A few dropsondes from recon have indicated that surface winds are equal to flight level winds (unusual, but not unheard of at the level the recons are flying at) - and flight level winds have hit a couple of spots of winds around 95kts... bot no dropsondes were released at those sites. And a dropsonde on Wednesday, at one spot, recorded 90+kts near the surface. NHC leaving Ike at 85kts is reasonable, given the infrequency of these reports, the usual reduction from flight level to surface, and Ike's modest appearance. Just know that Ike may be a bit stronger... and if there is any verification of this coupled with actual intensification, Ike could quickly ramp up to a Category 3.
Ike's track has, unfortunately, shifted up the coast. Well, this isn't unfortunate for everyone. For example, Corpus Christi, which will likely still see some pretty significant conditions, now looks like they'll be on the south side of the storm. That would reduce impacts pretty substantially. The south side of Ike is weaker and the winds would be further weakened in the Corpus area due to friction, as the wind is an over-land wind, and the surge would be considerably lessened with those offshore winds. But I say this is "unfortunate", because I'm trying to look at the macro picture. That is, landfalling closer to major population centers is worse. And, now, the track is encroaching on the Houston/Galveston area - considerably larger than Corpus. What bothers me is that what now looks like the likely track is still a little south of Galveston. So, if these trends continue, there is still room to get closer to Galveston/Houston without getting past them (if the track shifted "past" them - i.e., to the north - that would be a big deal, putting them on the same side as Corpus), yet the current track is already close enough for pretty severe impacts in Galveston/Houston - assuming Ike comes in as strong as is currently predicted.
Here's the latest NHC track:
...I'm not sure what to say about this, in terms of any critique or hedging in either direction. This forecast looks almost exactly what I would go with at this point. If I was forced to pick, north or south of that track, I'd go just north, due to the model trending. Here's what these models look like right now:
...those following these diaries know by now that these model images come from Allan Huffman's weather page. You also know that these images are missing two routine models... one very important one... the Euro model, which has been among the best models this season. The latest Euro model is in excellent agreement with the NHC track, up near or just north of Freeport, TX. The other model, which is much worse quality, the Canadian, has landfall at or just south of Galveston. So, you can see, as I just mentioned, the model mean is about halfway between Matagorda Bay and Galveston Bay. However, the true mean would get weighted north by the Euro and Canadian, the models up towards Galveston have been the superior performers and the trend has been up in that direction. So, NHC landfall south of Galveston looks about right - and it hedges north enough such that minor continued model trends should not require further track adjustments. Of course we're just far enough out so that larger model shifts remain possible - though we shouldn't see anything too severe (for example, a Port Arthur landfall seems highly unlikely... impossible? no... unlikely? yes).
Bottom line on track: The precise landfall location remains tough to pin down, as the models continue shifting around. And the model cluster hasn't gotten too much tighter. Although, as I've been writing this the early morning models have come in... the HWRF remains south (Matagorda), but the GFS has shifted north a bit (between Matagorda and Galveston), and the GFDL - importantly - shifted back south to north of Matagorda. So, with the exception of the way-south HWRF, there actually is more convergence of the model solutions when you take these new runs into account. The GFS, one of the southernmost in the overnight runs, has pulled north; and the GFDL, one of the furthest north overnight has pulled south. So... most models are now clustered between Matagorda and Galveston. And the focus and confidence is increasing on that. Again, if I were to hedge one way or the other, I'd lean closer to Galveston... but certainly a landfall anywhere between those two locales or, frankly, within about 25 miles or so either side of them, is very high risk.
Let me also remind you of something I put in the previous diary... remember, Ike has a very large wind field. In areas near the landfall point, the precise location is important, as the difference between onshore and offshore winds will significantly impact storm surge (and, to a lesser extent, wind speeds). (Locations south of landfall will see offshore winds; north of landfall - onshore.) But for the surrounding areas (Houston to Port Arthur - assuming landfall does not occur north of Houston, and Matagorda Bay down to Corpus Christi) landfall is somewhat inconsequential... again, not totally because, obviously, a landfall at Galveston will bring much worse conditions to Houston than a landfall at Matagorda. But, the point is, regardless of the precise landfall point, all locales from Corpus to Port Arthur will see very significant winds, and all points north of the landfall point to Port Arthur will see notable surge/increased tide heights. In fact, those north of the projected landfall need to also keep in mind that the concave shape of the coastline is particularly bad, as it helps funnel the water in.
Speaking of that surge, an excellent resource for surge expectations maps and evacuation routes for coastal Texas can be found here. For quick reference, here's the storm surge for a Category 4 hurricane in Galveston (note, these are maximum innundations and Ike is officially not expected to be a Cat 4 at landfall ...the storm is expected to be a Cat 3, but the GFDL shows a Cat 4 - so, I'm showing the Cat 4 images here):
...and if the landfall is further south towards Matagorda:
...or even further south, towards Corpus Christi:
So, that gets us to intensity. Not too much to address there. Since I've begun this, new recon data indicates little change in intensity - perhaps a resumption of very, very slow intensification, as pressures have nudged down slowly; and the satellite image shown above indicates some improved organization - but not a spectacular looking storm - supporting the notion of very slow intensification. Also as noted above, I believe Ike may be a shade stronger than NHC currently advertises... though I'm not disagreeing with them, per se... it's a tough call, and their 85kt setting is fine. My point is that it may be easier for him to jump to a strong Cat 2 or weak Cat 3 quicker than some might anticipate if the "core" of the storm gets better structured. The model forecast intensities are seen here:
...the HWRF has backed off somewhat - surprisingly, given its history. Nonetheless, it remains more intense at landfall than NHC's official forecast. NHC takes Ike up to 110kts by landfall. The newer, early morning HWRF is actually even weaker than that plot, and now weaker than NHC, but appears to have a problem early in the forecast period... raising Ike's pressure (weakening the storm) by 10mb in the first six hours. It takes the model some time to run, so we can already verify that six hour forecast... Ike has held steady or deepened a couple of milibars in that time. So, that run of the HWRF is way off (off by 12mb right now). Plus, its outlier southern track may bring Ike through a different atmospheric regime than other models show. So, the early morning HWRF is being disregarded. So, use the overnight run from that chart... which shows landfall at about 115kts (130mph). The GFDL on that chart shows landfall near 130kts (150mph). However, it is somewhat weaker in its early morning run, down to around 105-110kts (120-125mph) at landfall. Since not too much new data gets into the models for the early morning runs, we have to consider the overnight GFDL run plausible as well. That means we're basically looking at a range, in the hurricane-specific models, of 105-130kts at landfall. NHC sits near the low end of that. As such, I would not be surprised if Ike comes in a bit stronger than their forecast (esp. since I believe the storm is slightly stronger right now than they indicate). But what I would predict (around 115kts) is within the noise... intensity forecasting accuracy is not within 5kts two days out... so, landfall anywhere between about 95kts and 120kts would be a reasonable range.
Bottom line on intensity: Though the "reasonable range" I just mentioned includes a high-end Category 2, it it more likely the Ike comes ashore as a Category 3. There is also some risk that he hits as a Category 4. If we were to break down the odds... and this is mere educated guesswork, based on the fact the NHC's official landfall intensity is two-thirds of the way up through Cat 3, and I'm leaning towards what they have or slightly stronger... I'd say: 5% Cat 1, 15% Cat 2, 40% Cat 3, 35% Cat 4, 5% Cat 5.
Whew, long write-up this morning. Sorry if it got a bit disjointed... writing my thoughts as I'm viewing new data, so occasionally my ideas may shift slightly in mid-paragraph. But the basic points are as follows:
- Ike should intensify and make landfall in the mid or upper Texas coast Saturday morning.
- Ike is a large storm with a huge wind field. That means that locales up through southern Louisiana and down beyond Corpus Christi will see significant impacts. But that also means that effects of Ike will begin reaching the coast well in advance of "landfall". So, preparations should come to completion today or, at the latest, very early Friday morning.
- Ike's breadth and the coastline shape will also yield larger storm surges - to the right (north) of the landfall location - than would be normal for a storm of its intensity. Although, keep in mind that coastline shape is considered in the flood maps shown and linked above. So, only Ike's size and "fetch" could make the surge worse than innundation maps indicate (which is another reason why I showed the Cat 4 maps... the innundation should not exceed those maps... unless Ike comes in as a strong Cat 4, with a direct strike, at high tide - I'd surely hope no locale could have such terrible luck).
- Please remember to heed the official National Hurricane Center warnings. I appreciate all the support from the dKos community with these diaries, but NHC is the official word on this. If you're in harm's way or have loved ones who are - make sure you follow NHC's warnings and advice.
- Be prepared. The lone saving grace in hurricanes is that we can see them coming, unlike tornados. Certainly, the forecasts do change - and have, a lot in the long range - with Ike. And 48hrs out, there can still be some modest shifts. But, certainly, the general idea of where landfall will occur is in pretty good focus. So, with proper preparations, much threat to life and property can be minimized. Obviously, if you own a place precariously perched in Galveston, well, perhaps there's not too much that can be done if a large storm surge comes in. But, in general, good preparation can mitigate many effects from the storm. That's not to say it can mitigate all effect. Heaven knows... just ask the folks in Baton Rouge, still powerless after Gustav. So, I'm not trying to minimize the impact folks experience. My point is simply that preparation is critical to mitigating some of the potential consequences of the storm's impact.
That's all for now. I'll post updates as warranted and as time allows. Hopefully, at this point, the forecast will be more about fine tuning... not any more significant shifts. But, Ike has been troublesome to forecast. So, keep tuned to NHC for updates and/or changes.
UPDATED 11:25AM EDT ...typical of my late morning updates, not much to say. Just want to do the update to relay the latest NHC advisory. But it doesn't contain much new news in it. Ike status quo. In their discussion they explain their reasoning for leaving Ike at 85kts, and suggest he may be even weaker, because high level winds aren't mixing down. I understand their reasoning, but disagree. While some dropsondes show poor mixing, others (as noted above) have shown excellent mixing. And I've not seen a single dropsonde released in a spot where the max flight level winds were reached. Moreover, flight level winds have increased to up over 100kts at the maximum reading... which typically would support 90kts sustained... which is what I think Ike should be set at. No matter, as I mention in the comments... 85kts, 90kts, it's splitting hairs at this point. Otherwise, in the specifics, virtually no change in NHC's forecast. Very similar track to previous. And a 5kt reduction in peak intensity, but it's still Cat 3 at landfall, and that reduction may be more a function of the specific datapoints than a forecast change.
Some good news for Texans, though, can be found in the recon data... Pressures have held steady (945-947 range) over the last few hours, and Ike's satellite depiction hasn't improved. So, there appears to be no ongoing intensification. And the best opportunity for Texas to escape serious damage from Ike is for the intensity forecast to bust - and for Ike to not intensify. That still seems rather unlikely under the circumstances, but it's definitely plausible given Ike's current "status quo" situation. Hopefully, he'll continue to struggle a bit. We'll see.
New model data about to come in... will update on that between 3:00 and 4:00PM EDT.
UPDATE 3:45PM EDT ...once again, no grfx for this update... sorry about that... boring old text. But a couple of links I'd encourage you to click on. First off, here are the latest model guidance tracks. The Euro and Canadian are missing from that plot, but are right in that cluster of lines. The Euro is at or just south of Galveston. The Canadian is at or just north. So, obviously, we're homing in on Galveston for landfall. Given Ike's recent (and current) tendency to lean right, a track on the north side of Galveston Bay or just north of there also seems plausible. This is critical to whether Galveston/Houston see a big surge or not. Presently, NHC expects Ike to come in on the south side of Galveston. I agree, but wouldn't be surprised if that had to shift north slightly.
The big, big, big question is intensity. Ike is not intensifying. Recon recently indicated a significant pressure rise since this morning. But a dropsonde picked up an 89kt wind at the surface. However, I don't think that 89kt surface wind indicates intensification. I believe it's just further evidence that Ike is around 90kts, as I surmised earlier. Now whether NHC ups Ike to 90kts at 5PM is doubtful, given the pressure rise. But just be aware that 89kt sustained surface winds were picked up by a dropsonde from recon. Again, though, this is not intensification. Ike has not intensified and, based on pressure readings, the storm has, if anything, weakened slightly.
So, why hasn't Ike intensified as predicted, and will this change? Well, the second question would be easy to answer if the first question were. And, unfortunately, it's not. Conjectures have been flying around like bad cliches at a Republican National Convection... from land interaction because if Ike's large circulation, to dry air intrusion, to MJO (Madden-Julien Oscillation) subsidence, and any other number of things. I'll be blunt, no one really knows, as far as I can tell, including me. My best guess is that it is related to dry air and weak shear associated with the ridge to Ike's northwest. This is supported by upper level GFS plots from the latest model runs, which shows dry air impinging pretty severely on Ike from the west side this afternoon, as well as mild northwest shear beating down on Ike.
This is merely an educated guess here. So, if this is the cause, the question then is... will this abate to allow Ike to intensify. Hopefully not. Unfortunately, the answer looks like... "yes"... so, hopefully, my analysis is wrong. If you examine the model loop linked above, you'll see that the dry air intrusion on the west side begins abating as we speak and is totally eliminated tomorrow morning. The mild shear, likewise, is gone tomorrow morning (though it is slower to abate tonight). This will leave Ike about 24 hours to intensify prior to landfall Friday morning through early Saturday morning... possibly a bit longer than that, if Ike responds to the improving conditions while those conditions improve (rather than waiting until they become ideal Friday morning). But this is also tricky to gauge... sometimes storms will respond the moment conditions even begin to improve (the would be this evening for Ike), but sometimes storms take a good 6-12 hours to respond even once conditions are ideal (this would be late tomorrow for Ike). So, it's very difficult to judge how much, if any, intensification would take place. I would estimate about 10-15kts worth of intensification. That would put Ike, at landfall, between 95 and 105kts (depending on whether you accept that he is at 85kts or 90kts right now). The good news is, that's lower than previous expectations, with a real chance that he comes in as "only" a Cat 2. The bad news is, that's still a better than 50-50 shot that he comes in as a "major" Category 3... and, since intensity forecasting is tricky, there remains a small but real chance for him to come in as a Cat 4 (I don't think, unfortunately, a Cat 1 is plausible, since conditions improve tonight, which should prevent weakening... but if I'm wrong about what's inhibitting Ike, and whatever it is continues, there may even be some chance for that - weakening to a Cat 1... but at this point I think that very unlikely). So, I guess, all in all, that's good news - an increased chance of a weaker storm. But it's fairly tepid good news, as I do still anticipate some intensification on Friday. But, you never know with these fickle storms, so, hopefully, I'm wrong!
UPDATE 5:30PM EDT ...another very brief, graphics-free update. Just wanted to relay NHC's latest thinking to you. I don't do this to blow my own horn, as this may well prove wrong, but given all the dispute over why Ike hasn't intensified yet, I wanted you to see that NHC was on the same page as me. From their 5PM EDT discussion:
THE INTENSITY GUIDANCE HAS COME DOWN SINCE THIS MORNING...ALTHOUGH
THE GFDL STILL MAKES IKE A MAJOR HURRICANE. FACTORS INHIBITING
DEVELOPMENT INCLUDE THE LARGE BROAD WIND FIELD...STRONG WINDS OVER
AREAS OF LIMITED OCEAN HEAT CONTENT ALONG AND NORTH OF THE PATH OF
IKE...AND AN UPPER-LEVEL RIDGE OVER TEXAS THAT IS FORCING DESCENT
AND CREATING DRY AIR AHEAD OF THE PATH OF THE HURRICANE. INDEED...
CONVECTION ON THE WEST SIDE OF IKE HAS BEEN RATHER THIN FOR MUCH OF
THE DAY. HOWEVER...THIS LATTER UPPER FEATURE IS FORECAST TO SLIDE
NORTHEASTWARD AS IKE ENTERS THE NORTHWESTERN GULF...AND IN THIS
CONFIGURATION WOULD PROVIDE AN UPPER PATTERN MORE CONDUCIVE TO
STRENGTHENING RIGHT BEFORE LANDFALL. CURRENTLY THE OUTFLOW IS VERY
WELL ESTABLISHED TO THE NORTHEAST AND SOUTHWEST OF THE CENTER. THE
OFFICIAL FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY AND IS IN
BEST AGREEMENT WITH THE GFDL GUIDANCE.
...while that statement doesn't agree identically with what I surmise, the basic idea is the same. I disagree with them on oceanic heat content... yes, it may be lower than it could've been, but it's plenty warm enough (84-86F out in front of Ike). And they do not mention any shearing from the ridge (though they do imply it in their discussion of the outflow - with no mention of the outflow in the NW quadrant, which is restricted). The big thing is that they mention the dry air being due to the ridge and that this will cease over the next 12 hours or so, as the ridge rolls over to the north of Ike. So, they are on the same page as I am, and we both anticipate that this should yield intensification tomorrow (and maybe some tonight).
They also finally allow that the dropsondes fully support their 85kt winds. Of course, I'd still claim that they support 90kts. But at least we're in the range of splitting hairs. At 11AM they actually impplied that their 85kt setting may be too high, due to lack of support from recon and dropsonde data. Now, they solidly back their 85kt setting. So my assertion that Ike is 90kts is a trivial disagreement.
I should also note that NHC has nudged their track further north. But the change is quite small... to very near Galveston. But it is one bit of encouraging news. If this trend can continue, we may see Ike's landfall shifted to north of Galveston/Houston. That would put Galv/Hous into the offshore winds, significantly reducing the potential for a major storm surge. Of course, that is not the forecast right now... right now is very nearly a worst case scenario for Galveston and Houston. And the forecast is not likely to shift much more, since we're beginning to close in towards landfall. But, the actual landfall is still over 24 hours away; typical 24-hour errors are just large enough so there does remain some hope that Ike will shift north of Galv/Hous. Don't count on it, but there is some reason for hope.