Hurricane Katrina has turned southwestward and sped up a bit, so she will emerge over the Gulf of Mexico in just a few hours. (Radar loop here.) That’s good for south Florida, which will get less rain than expected, but bad for wherever this hurricane heads next. Katrina hasn’t weakened much at all during her brief sojourn over the Florida peninsula; even now, as the center nears the state’s west coast, she’s still at 75 mph. The NHC’s forecast that Katrina would only attain minimal Category 2 strength over the Gulf was based on the premise that she would weaken to 50 mph first. So her failure to significantly weaken is distinctly bad news, and should substantially change the intensity forecast. With steady intensification expected once the center re-emerges over water, I suspect Katrina will be at least Category 3 at second landfall.

UPDATE: Charles Fenwick at Eye of the Storm writes: “More than four hours over land and STILL a hurricane. Remarkable.” (Now it’s more than five hours.) But Fenwick offers a good explanation for why: “Katrina’s southerly course is taking her over the Everglades. The difference between the Everglades and open water is slight.”

Regarding the track, Steve Gregory says “there is is still way too much uncertainty with the exact timing of the turn northward, and the entire Gulf coast, from Louisiana eastward to Tampa could ultimately be at risk for the next and final, landfall of Katrina.” Dr. Jeff Masters says “an area from New Orleans to Cedar Key, Florida at risk. In the center of this risk area lies the U.S.’s very own hurricane magnet, the Pensacola region, where Ivan and Dennis struck.”

I can certainly understand Pensacolans being nervous. What makes me nervous is that Katrina’s southwestward turn and refusal to weaken makes a New Orleans doomsday scenario considerably more plausible than it seemed just a few hours ago. Still unlikely, but more likely than it was.

UPDATE, 12:17 AM: Katrina has finally weakened to a tropical storm as of midnight EST, approximately six hours after making landfall. But that won’t last long. She’s already got her “feet wet” over the Gulf, seven hours ahead of schedule.

From the NHC’s 8:00 PM EST advisory:

…KATRINA RELENTLESSLY POUNDING SOUTH FLORIDA…CALM OF THE LARGE EYE EXPERIENCED AT THE NATIONAL HURRICANE CENTER…

Heh.

Christian Wilson, a 1L, writes that his family lives next-door to NHC Director Max Mayfield, and “we only shutter [our windows] when he does.” Talk about a personalized forecast! :) As Katrina approached, “He shuttered only the west side of his house because he says the winds are coming from that direction. I found that pretty amusing….a partial shutter situation.”

In every school year, there are various “firsts.” First class… first football game… first night out at The Backer… and of course, first nap on the law-lounge couch:

(Photo by Lisa.)

Tropical Storm Katrina (seen here on radar) is strenghtening as she nears south Florida, with 70 mph winds as of 2:00 PM. She’s expected to be a hurricane (i.e., 74+ mph winds) when the center makes landfall later tonight or early tomorrow. The likely landfall point is near Fort Lauderdale, according to Dr. Jeff Masters.

Here’s a news article from the South Florida Sun-Sentinel.

After hitting Florida peninsula and slowly inching westward, what then? The official track calls for a second landfall, again as a Category 1 hurricane, on the Florida panhandle Sunday night or Monday morning. But there are lots of different computer model scenarios, ranging from the Mississippi Delta to Savannah.

The 11:00 PM discussion on Tropical Storm Katrina notes:

This forecast is rather difficult since one of the more reliable models…the GFS…shows that the cyclone barely touches the East Coast of Florida before moving northward….while the outstanding GFDL moves Katrina south of due west across extreme South Florida and the Keys as a very intense hurricane. The GFDL scenario would be very dangerous for South Florida. This appears to be unrealistic at this time but because of the good past performance of this model…we must pay close attention to future model runs.

The GFDL track is the green line on this map. Here’s the official track.

Russell may have been on to something when he wrote yesterday that Tropical Storm Katrina, then just a nascent tropical depression, could become a monster hurricane before landfall. The official forecast calls for Katrina to hit south Florida as a Category 1 hurricane with 80 mph winds on Friday, but the latest NHC discussion raises the possibility that she may reach major hurricane status:

With the improved banding features…symmetrical upper-level outflow…and relatively weak shear…at least steady intensification of a normal rate of 10 kt per 12 hours until landfall occurs seems justified. This is similar to the SHIPS intensity model…but much less than the now very bullish GFDL model which brings Katrina to 111 kt [130 mph, borderline Category 3-4] just before landfall. It should be pointed out that with SSTs near 31c and a low shear environment…conditions are favorable for possible rapid intensification to occur between now and landfall. This is suggested by the SHIPS model experimental rapid intensification output…which indicates a 57 percent probability of that occurring. The only inhibiting factor is the dry air that surrounds Katrina and has been working its way into the inner-core region and eroding the deep convection. If the dry air mixes out within the next 12 hours…then intensities would likely be higher than the official forecast is indicating.

There’s also the matter of re-emergence over the Gulf of Mexico. Charles Fenwick at Eye of the Storm writes, “It is a bit soon to rate the probabilities of the scenarios, however, it is worthwhile for residents of the Gulf coast from Mobile, Alabama to St Mark’s, Florida to be aware of the possibility of a significant hurricane affecting their area in six days.”

Fenwick also notes that, thanks to Katrina, the 2005 Atlantic hurricane season has now given rise to the earliest recorded formation dates for the fourth, fifth, sixth, seventh, eighth, ninth, tenth, and eleventh named tropical storms of the season. That’s eight consecutive “earliest ever” records! (Details here.) However, the twelfth-storm record is August 28, and nothing else looks too likely to develop at the moment, so that streak may be nearing an end.

In other news, I’ve found some more computer-model maps: here and here.

Tropical Storm Katrina is now forecasted to become a hurricane by landfall, and Hurricane Watches are up from Vero Beach southward to Florida City. Here are the latest computer models.

Tropical Depression 12 is now Tropical Storm Katrina, the eleventh named storm of the Atlantic hurricane season.

Tropical Depression 12 is slowly strengthening. It’s not Katrina yet, but it’s getting there.

Most of the computer models are continuing to call for a track that takes the storm over Florida and then back out over the Gulf of Mexico (though they diverge on the details). Here’s the official track. Looks eerily familiar.

Meteorology student Charles Fenwick says: “Residents of south Florida will certainly want to keep a close eye on this, because if it were to become become organized, it could intensify fairly quickly (but not so much that it would be a dire threat).” Fellow weatherblogger Steve Gregory agrees: “Despite some extremely warm water ahead of the system right up to the coast, all the ingredients for rapid intensification are not quite there. When reaching the Gulf of Mexico by Sunday — the chances of significant intensification seem a lot more possible.” Here’s a look at wildly divergent computer-model intensity forecasts.

Just a few hours after Tropical Depression Jose was declared dead over Mexico, Tropical Depression 12 formed over the southwestern Bahamas. It could become Tropical Storm Katrina.

UPDATE: Hurricane Katrina? I could happen; Hurricane Watches may be required later tonight, as T.D. 12 may threaten Florida late in the week.

P.S. This is interesting:

The NWS rules governing the naming of tropical cyclones specify that…within a basin…when a cyclone forms from the remnant of a previously existing cyclone…the old name/number is retained. Tropical Depression Twelve has a complex genesis that likely includes a mid-level remnant of former Tropical Depression Ten. A review of satellite and rawinsonde data over the past week or so suggests that a second disturbance approached and combined with the mid-level remnant of Tropical Depression Ten on 20 August. Because it is impossible to determine which of these two systems is associated with today’s genesis…we have elected to use the designation twelve rather than ten for the new depression. This situation differs from last year’s regeneration of Ivan…in which the low-level remnant of that system remained a distinct feature that could be followed continuously until it regenerated.

Well, it’s interesting if you’re a nerd like me, anyway. :)

Tropical Depression Ten has fizzled. According to the 10am NHC discussion: “Because the system does not have sufficient organized deep convection…it no longer meets the criteria for a tropical cyclone. Therefore advisories are being discontinued at this time.” Barring regeneration, T.D. 10 will go down as the first tropical depression of 2005 that did not develop into a tropical storm. The name “Jose” will have to wait.

Meanwhile, Tropical Storm Irene is almost a hurricane.

If Tropical Storm Irene were to continue moving in the linear direction of its current forward motion, it would make landfall in New York Harbor.

That’s not going to happen, though. :)

Irene is strengthening again, and could become a hurricane tomorrow, out over the open waters. As for T.D. Ten (or “proto-Jose”), he’s still at 35 mph, and the computer models are all over the place.

The National Hurricane Center is now formally declaring that Tropical Storm Irene “poses no threat to land.” The same may or may not be true of Tropical Depression Ten, which, as expected, was officially declared at 4:00 PM EST. It “has the potential” to become Tropical Storm Jose tomorrow.

Meanwhile, it’s raining in South Bend, thanks to what looks for all the world like a mini-hurricane:

It’s not, of course; it’s just a regular old low pressure system, riding eastward along a stationary front. But look at the animated radar! I name it Hurricane Toby, in an attempt to make up for my failure to Friday-catblog yesterday. :)

Barring a totally unexpected reversal, Irene is no longer a threat to the United States mainland — or any land, for that matter. Alan Sullivan at Fresh Bilge notes: “All models now agree that Irene will stay well offshore, and the storm has already turned more to the north.” Dr. Jeff Masters writes: “Last night’s mission by NOAA’s G-IV aircraft gathered a large high-resolution set of data surrounding Irene, and this data was used to initialize this morning’s models. These models continue to show that Irene will turn to the north and northeast, missing the U.S. coast by a wide margin. This is a high-confidence forecast, due to the excellent data used to initialize the models and the continuity of the model forecasts from yesterday to today. “

Irene has also apparently weakened significantly. As of the last advisory, at 10:00 AM, she was still officially at 70 mph (though the NHC expressed some doubt about whether that was perhaps too high), but shortly after that advisory was issued, “The Hurricane Hunters just paid a visit to Irene, and found a substantially weaker tropical storm. The central pressure was just 1000 mb, and maximum flight-level winds were 40 mph on the west side of the storm.” (That’s according to Dr. Masters again.) So the 4:00 PM advisory will probably announce that Irene is substantially weaker.

The 4:00 PM advisory may also announce the formation of Tropical Depression 10, a thousand miles east of the Lesser Antilles. Dr. Masters has an initial take on the proto-depression: “The storm will continue to move to the northwest or west-northwest over the next few days, not posing a threat to any islands until perhaps Wednesday. The GFS model moves the storm northwest, bypassing the Caribbean islands, then tracks it on a more westerly course towards the U.S. late next week. The storm is headed into an area of very dry air to its northwest, which may inhibit its growth and intensification. However, water temperatures are warm (28 - 30C) ahead of it and vertical wind shear is light, so it is likely that it will attain at least tropical storm status. If so, it will be named Jose.”

In other news, today is the one-year anniversary of the Florida landfall of Hurricane Charley, the first (and arguably worst) of the four hurricanes to strike the “Sunshine” State last year.