9/10, 11:45 PM EDT: Hurricane Ike’s barometric pressure dropped from 958 mb to 947 mb between 3:00 and 7:00 PM EDT, and fell again to 944 mb as of 11:00 PM. The winds have not yet increased to reflect this change — they still stand at 100 mph, low-end Category 2, as they have since 2:00 PM — but wind increases often lag some hours behind pressure drops, so it would not be surprising if the winds finally “ramp up” overnight. At 9:19 PM, Dr. Jeff Masters wrote, “I expect Ike will be at least a Category 3 hurricane by morning, and probably a Category 4.”
On the other hand, the National Hurricane Center seems to be getting less bullish in predicting strengthening. The 2pm, 5pm and 8pm public advisories all stated that Ike “IS EXPECTED TO BECOME A MAJOR HURRICANE WITHIN THE NEXT 24 HOURS.” But the 11pm public advisory says only that “IKE COULD BECOME A MAJOR HURRICANE ON THURSDAY OR FRIDAY.” And the discussion suggests that Ike might actually weaken in the next 24 hours, due to the possible combination of an eyewall replacement cycle and Ike’s passage over a cooler patch of water:
IKE IS A LARGE CYCLONE . . . [BUT] PARADOXICALLY…IKE HAS A VERY SMALL INNER CORE…AND THE EYE HAS A DIAMETER OF ONLY ABOUT 8 TO 10 N MI. . . . THE SHORT-TERM INTENSITY FORECAST IS CONTINGENT UPON HOW LONG THE EXTREMELY SMALL INNER CORE SURVIVES. SINCE IT COULD DISINTEGRATE AT ANY TIME…AND SINCE IKE WILL BE PASSING NEAR OR OVER A COLD EDDY IN THE CENTRAL GULF DURING THE NEXT 24 HOURS…THE HURRICANE COULD WEAKEN. IF…HOWEVER…THE TENACIOUS INNER CORE REMAINS INTACT…AND GIVEN THE RECENT PRESSURE FALLS…IKE COULD STRENGTHEN SOME AS REFLECTED IN THE OFFICIAL FORECAST [WHICH SHOWS IKE AT 110 MPH IN 24 HOURS].
It should be noted that, normally, a pressure of 944 mb would translate into a borderline Category 3/4 hurricane, with winds roughly in the 125-135 mph range. However, ever since its passage of Cuba, Ike’s winds have consistently been lower than you’d expect, compared to its pressure. This is due mostly to the storm’s expansive wind field. The notion of a 944-millibar hurricane with “only” 100 mph winds seems bizarre to long-time hurricane watchers, but that’s what Ike is right now, and for whatever reason, the NHC does not seem convinced it’s going to change right away.
Over at the Eastern U.S. WX Forums, there is fevered speculation about what exactly the forecasters are thinking. “Just reading between the lines… these forecasters aren’t looking for explosive development even with the pressure drop,” one commenter writes. “These guys are seeing something that we aren’t,” says another. “Still could intensify, but I sense that for reasons unknown to me, something less bullish than 3 and 6 hours ago is being witnessed now at NHC.”
However, it is worth remembering that even the best forecasters have very limited skill at predicting intensity changes in big hurricanes, particularly when rapid intensification is involved, so even the statements of NHC forecasters — although they’re undeniably the best in the world at what they do — should not be taken as gospel. The truth is, nobody knows for sure what’s going to happen.
Besides, what happens overnight, or even in the next 24 hours, is not the most important thing. What happens on Thursday and Friday is even more crucial, and the news on that front is not good. Again quoting from the discussion:
BEYOND 24 HOURS…THE UNDERLYING OCEAN HEAT CONTENT WILL INCREASE ALONG THE FORECAST TRACK…AND IKE WILL REMAIN WITHIN A WEAK WIND SHEAR ENVIRONMENT…SO MORE ROBUST STRENGTHENING IS FORECAST AT 36-48 HOURS [UP TO A PEAK OF AT LEAST 125 MPH]. . . . NO WEAKENING TREND IS ACTUALLY ANTICIPATED LEADING UP TO FINAL LANDFALL.
That is a scary thought. So often in recent years, residents of various Gulf states have lucked out due to last-minute weakening of major hurricanes. Ike may buck that trend, and if so, it could be a major disaster.
For his part, Dr. Masters clearly is very, very concerned about Ike. I quote again from his newest post:
The satellite presentation of the hurricane has improved markedly, as Ike has walled off the dry air that was bothering it, and has built a solid eyewall of 9 miles diameter of very intense thunderstorms. … Ike is almost as large as Katrina was, and this large wind field is already beginning to pile up a formidable storm surge. … NOAA’s experimental storm surge forecast is calling for a 10% chance that the storm tide from Ike will reach 10-12 feet at Galveston, and 18-21 feet on the south and east sides of Houston.
Ike is likely to be a extremely dangerous major hurricane at landfall, and will likely do $10-$30 billion in damage. The chances of hundreds of people being killed in this storm is high if people do not heed evacuation orders. It is possible that Ike will make a direct hit on Galveston as a Category 4 hurricane with 145 mph winds. The potential storm surge from such a hit could be in the 15-25 foot range, which is capable of overwhelming the 17 foot sea wall in Galveston. I put the odds of such an event at about 5%. …
The intensity forecast remains the same. Water temperatures are a warm 29.5°C in the Gulf of Mexico, and wind shear is expected to be modest, 10-15 knots, for the remainder of Ike’s life. Ike will be skirting the edge of a warm Loop Current eddy, but the heat content of the waters near the Texas coast are high. Ike has the capability of intensifying right up to landfall. This is the forecast of the HWRF model, which has Ike hitting Port O’Connor as a Category 4 hurricane with 145 mph winds. The weakest I think Ike will be at landfall is a Category 2 hurricane with 100 mph winds. Even at this weak strength, Ike will still carry a 10-15 foot storm surge to a 100+ mile long stretch of Texas coast.
Relatedly, Dr. Masters’s site, Weather Underground, has posted an excellent page with worst-case storm surge graphics for various Texas landfall scenarios. Definitely worth checking out.
As for Ike’s track: it appears the “left turn” referenced in an update to my previous post may finally be happening:
THE CENTER OF IKE HAS CONTINUED TO MOVE NORTHWESTWARD OR 315/6…A LITTLE TO THE RIGHT OF THE PREVIOUS FORECAST TRACK…BUT VERY RECENT SATELLITE IMAGERY AND THE LAST FIX FROM THE NOAA HURRICANE HUNTER AIRCRAFT SUGGESTS THE TURN TOWARD THE WEST-NORTHWEST COULD BE STARTING.
Now, attention shifts to that all-important “right turn” I discussed in “Question #4″ of my previous post:
ALL MODEL GUIDANCE FORECASTS A WEST-NORTHWESTWARD MOTION DURING THE NEXT 48 HOURS TO THE SOUTH OF A STRONG RIDGE OVER THE SOUTHEASTERN UNITED STATES THAT IS FORECAST TO BUILD WESTWARD. IN A COUPLE OF DAYS…ALL OF THE MODELS FORECAST A WEAKNESS IN THE RIDGE TO DEVELOP OVER TEXAS AND EVENTUALLY INDUCE A TURN TO THE NORTHWEST AND NORTH…BUT THEY DO NOT AGREE ON WHEN THAT TURN WILL OCCUR. THE HWRF IS ON THE LEFT SIDE OF THE GUIDANCE ENVELOPE AND FORECASTS A STRONGER AND LONGER-LASTING RIDGE THAT TAKES IKE INTO DEEP SOUTH TEXAS BEFORE TURNING NORTH. CONVERSELY…THE GFDL IS THE RIGHTMOST MODEL WITH A WEAKER RIDGE THAT ALLOWS IKE TO TURN INTO THE GALVESTON AREA. THE OTHER MODELS ARE IN BETWEEN…AS IS THE OFFICIAL FORECAST[.]
The official forecast track can be seen here. Please note, the straight line between the Friday and Saturday points is misleading; that would actually be a curved line, resulting in a landfall point considerably further from Galveston than the track line would seem to imply. Freeport is not actually the official landfall “bullseye,” at least not yet! (I’d say roughly 20-30 miles down the coast from Freeport is the true “bullseye” at the moment.)
Regardless of that, the larger reality is that we still simply don’t know where Ike will come ashore. It’s an incredibly important question, obviously — despite the storm’s sprawling size, the most devastating effects by far will be very close to, and just to the “right” of, the eye’s landfall point — but it’s a question that’s totally impossible to answer at this point, due to the models’ stark disagreement over the timing of that right-hand turn.
I imagine large-scale evacuations will have to begin tomorrow, though. Folks in vulnerable areas cannot “wait and see” forever.
P.S. The Houston Chronicle‘s Eric Berger agrees:
If the forecast remains centered upon Brazoria County and especially Freeport — and of course that’s a big if — I would expect widespread evacuations in southeast Harris County and Galveston County to be called Thursday morning. I am not one to make editorial comments, but I am surprised that Galveston County has not yet called for a mandatory evacuation.
There will, of course, be fluctuations in the forecast location during the next two days, prior to landfall late Friday or early Saturday. Areas from Corpus Christi to southwestern Louisiana remain potential landfall sites. But as of now Houston couldn’t be much more at risk than it is.
P.P.S. Alan Sullivan is decidedly less alarmed than Masters or Berger:
Ike is a large storm, with extensive wind field and well developed outer bands; but it is not showing any visible sign of becoming a major hurricane again at this time. Intensity models diverge, and NHC is still going with stronger ones. . . . Bottom line: it is time to prepare for a category one or two landfall everywhere from Corpus Christi to Port Arthur. . . . But there is no need for Houston to be panicking. This is not The Big One — except in size. If Ike can develop no more than it has over the Loop Current, it will not be spinning suddenly to category four, fifty miles off Galveston.
I understand Sullivan’s logic about the Loop Current thing, but I think he is being way too confident in his prediction. Hurricanes are inherently unpredictable beasts, and I get the sense from the NHC forecasters that even they don’t fully understand what is driving Ike’s failure to strengthen more than it has. Such present mystery implies future uncertainty. Certainly, Ike may very well prove not to be The Big One, but to tell people they need only prepare for a Cat. 1 or 2, strikes me as sheer folly. I call it underhype.
Thanks for the update. My parents live in Houston and I am actively watching this storm since I’m so far away from them in california.
Fully agree with you Brendan. This one bears careful watching.
Ike has been such a difficult storm to figure out, and he does seem like a pretty dangerous threat to a densely populated area right now. So if by pure luck he weakens and fizzles a little, I certainly won’t crying “hype” afterwards.
“Folks in vulnerable areas cannot ‘wait and see’ forever.”
I commented something similar to that on SciGuy’s blog, and now I’m not allowed to comment there anymore. I didn’t think I was overly rude (maybe the Chron blocked me for saying Eric should get a big raise in another blog post):
“I was cooking and not paying attention to Galveston’s Mayor’s speech. She doesn’t have evacuation plans yet?
“I’m a firm believer in allowing coastal residents a decent chance to evacuate before storms, but I’m rethinking that just a bit:
“Just like inlanders are supposed to give coastal people a decent head start because coastal people are in more danger, coastal people also supposed to give inlanders ample time to evacuate too.
“I live in Zone C, and I’ve been reading lots of people further inland than me planning and making reservations already.
“So maybe the coastal cities might want to consider that others might want to evacuate also, and not wait until the last minute, causing another Rita fiasco.”
http://is.gd/2tgD
Brendan: thanks. In Houston, we sit, debating whether to live our lives, hunker down, or head for higher ground.
Leaving is a pain. It is exhaustion beyond belief. This was Rita; it may repeat itself.
Hurricane did make turn left. Now heading 295 vs 315. Discussion suggests that may be the extent of that turn. If so, the official track has storm landing at Freeport, TX. Then the right turn (more likely with land interaction) will cause the storm to travel up the 288 cooridoor into downtown Houston.
Good news, not much talk of Cat 4 anymore. Still Cat 2. With that information, I’d agree with Alan Sullivan. No need to panic (i.e. Rita).
There is never a need to “panic,” but I think it’s totally foolish to not prepare for something worse than a Cat 2. It’s entirely possible Sullivan will be right in the end, but no one can know with sufficient certainty right now. We don’t understand intensity forecasting well enough, particularly with such a bizarrely structured storm as Ike, to just assume it won’t get significantly stronger in the next 48 hours. There may be “not much talk of Cat 4 anymore,” but Cat 4 is still possible, and Cat 3 certainly is — we just don’t know!
NHC places the chances of Cat 4 or 5 as 1 in six. For now.
It’s a simple equation: would you roll a six-sided die*, if, on a six, you would be in danger of losing your life? (How much danger? Ah, that’s the rub.)
*Sorry, I’m a gamer; I have to specify die size. It’s in the rules.
Brendan, I urged preparation for a larger than usual area, but we cannot know where in that area the small core will go ashore, and I remain skeptical that the core will produce strong winds at the surface. It did not do so on the south coast of Cuba, or in its Gulf crossing so far. There is still time to raise higher level of alert if further tightening and increase in winds occurs when the storm gets closer. IMO it is premature to panic people with the notion that, say, Houston, could experience an extreme hurricane in this situation. There is one more day to watch. If all cat two preparations are complete today, cat four preparations can occur in a refined landfall location, should that be necessary tomorrow.
There is one more day to watch. If all cat two preparations are complete today, cat four preparations can occur in a refined landfall location, should that be necessary tomorrow.
Alan, do you really think it is possible to evacuate everyone who would need to get out of the way of a Cat. 4 (but not necessarily a Cat. 2) — not to mention all the people who would unnecessarily evacuate, at the last minute, if it blows up into a Cat. 4 tomorrow — in a mere 24 hours?? (Less than that, really, since tropical storm force winds will arrive during the day tomorrow.) Without a substantial risk of people being stuck on the highway in the storm??
Your phrase “refined landfall location” seems an attempt to address this issue — i.e., by narrowing the evacuation zone — but considering the right-hand turn is expected to happen at the very last minute (final 6-12 hours), how can you be so confident the landfall location will be all that “refined” 24 hours before landfall? What if tomorrow morning arrives, the storm “suddenly” looks prone to become a Cat. 4, and forecasters still can’t narrow the landfall down to anything smaller than a 125-mile stretch of coastline, centered the heart of the metro area? What then? Now you’ve got to conduct a massive evacuation in less than 24 hours! That’s crazy!
I know you like to come right out and say what you think will happen, rather than pussyfooting around with a range of possibilities, best- and worst-acse scenarios, etc. That’s one of the things I like about you (even if I don’t generally emulate it). You call it like you see it. I respect that. And I don’t necessarily disagree with your logic here, re: the growing unlikeliness of a catastrophic hit. But there’s a huge difference between telling people what to EXPECT and telling them what to be PREPARED for. The cliche “prepare for the worst” is cliched for a reason! I’m sorry, but the notion that people need only prepare, today, for a Cat. 1-2, strikes me as wolf-face crazy. Even if it’s 90% likely to be correct. (And I’m not at all sure the odds are that favorable. But even if they are!)
Disaster planners have to make prudent decisions based on possibilities and probabilities, not just follow their gut. It is totally imprudent to just assume things won’t be too bad, when there’s still a significant (though well under 50%) possibility they will be quite bad, and inadequate time to react if that significant possibility becomes a reality in 24 or 36 hours.
Brendan, with cat 2 preparations, all the really vulnerable coastal locations will be cleared anyway — in the huge swatch of coastline where that is needful. The real concern now is Houston. But that city is somewhat inland. If the core is drawing a bead on that area tomorrow, and if Ike has strengthened a lot, conditions in Houston won’t preclude additional evacuations at that time. Staged evacuation is always best anyway, to avoid everyone on the road at once.
Additional point: I would like to see more emphasis on the flooding risk, which is think is the major issue here. Size, duration, and available moisture for rainfall in Ike — all indicate a really serious flood for east Texas — and not just on the immediate coastline. Also I think it is time to start talking about tornadoes. That odd core structure could be a killer, at a considerable distance inland.
I think Alan makes my point again about the Panic. For me, “panic” is code for people north and west of the beltway evacuating. Houston has bad drainage issues, so some neighborhoods should leave, but people in Spring or the Woodlands, for example, or myself in Atascocita (survived 30″ of T.S. Allison y2k without water in yard) don’t need to hit the road. The people south and east of the beltway need to seek higher ground. By the looks of transtar, evacuations are going without major congestion. That is the way it should be.
Preparation is another thing, and it should be done. I’ve filled the propane tanks for grilling, filled the gas cans for the generator, tanks in the car, purchased food that won’t spoil this morning, and have a week supply of potable water. Yard is cleared of debris. Luckily, it is trash day, so getting rid of any clutter in the house. I’m already prepared to volunteer at the local hospital tomorrow morning. I hope Glenn would be proud.
All I need to do now is laundry, since the nice machines may not be online for several days.