Hurricane Paloma has continued its rapid intensification this evening, and is now a major hurricane with Category 3 sustained winds of 115 mph as it passes Grand Cayman Island, approaches Cayman Brac and Little Cayman, and menaces Cuba.

Paloma’s right-front quadrant, where the strongest winds are located, is expected to make a direct hit on Cayman Brac and Little Cayman tomorrow morning. It is possible the storm will be even a little stronger by then. Storm Carib has coverage from a local perspective. See also Cayman Net News and the Cay Compass.

Here’s a look at the impressive storm on satellite:

You can also now just begin to see the storm’s eye on Cuban radar; see also here.

Paloma’s eventual impact on Cuba remains uncertain. Certainly, the storm will weaken before it reaches that island, as wind shear is expected to markedly increase shortly after Paloma passes the Caymans. By this time tomorrow, Paloma will definitely be less organized than it is now.

That said, the extent of pre-landfall weakening — if in fact there is a Cuba landfall — is a question mark, as is the storm’s track. The National Hurricane Center’s 10pm EST discussion explains the divergent track scenarios in the computer models:

AS HAS BEEN THE CASE FOR THE PAST 36 HOURS…THERE REMAINS A BIFURCATION IN THE NHC MODEL SUITE WITH THE UKMET…ECMWF…AND NOGAPS MODELS RAPIDLY WEAKENING PALOMA AND TURNING IT WESTWARD SOUTH OF CUBA BY 36 TO 48 HOURS…WHEREAS THE GFS…GFDL…AND HWRF MODELS MOVE A SOMEWHAT STRONGER CYCLONE ACROSS CUBA AND INTO THE CENTRAL BAHAMAS. BASED ON THE CURRENT SATELLITE TRENDS AND REPORT FROM RECON AIRCRAFT…THE OFFICIAL FORECAST TRACK LEANS TOWARD THE GFS…GFDL…AND HWRF SOLUTIONS…ALBEIT SOMEWHAT SLOWER.

In other words, the NHC is guessing that Paloma will hit Cuba early Sunday morning as a weakening hurricane (probably Category 1), but it’s really just that — a guess, albeit an educated one. Forecasters just aren’t sure what Paloma is going to do beyond the Caymans.

Hurricane Paloma is continuing to strengthen as it approaches the Cayman Islands. Officially, the intensity is 90 mph as of 1:00 PM EST, and it’s possible we could see Paloma upgraded to Category 2 status at the next advisory, given what Dr. Jeff Masters writes:

Between 1 pm and 3 pm EST, an Air Force Hurricane Hunter aircraft dropped two sondes in the northwest eyewall of Paloma, and found winds of 90 and 97 mph at the surface form these sondes. The threshold of Category 2 strength is 96 mph.

Dr. Masters also notes that Paloma is showing some fascinating structural features, which could portend either imminent strengthening, an impending eyewall replacement cycle (which would tend to temporarily retard intensification), or perhaps both: a brief rapid-deepening phase, followed by an ERC. Masters writes:

The central pressure of Paloma is dropping at about 1-2 mb per hour. The Hurricane Hunters noted that Paloma appears to be forming a second eyewall concentric with the main eyewall, and there is also evidence of this on visible satellite loops. There was also a gap noted in the SSW side of the eyewall by the Hurricane Hunters, and the storm is undergoing some substantial structural changes. Formation of a secondary concentric eyewall will ordinarily slow down intensification of a hurricane, but is also spreads out the highest winds over a larger area. Recent infrared imagery shows that the eye has warmed, indicating strengthening. Some very impressive thunderstorms with high, cold tops are firing up at several points in the eyewall, also indicative of strengthening. These thunderstorms may be “hot towers”, which are often observed when a hurricane is embarking upon a major intensification phase. 

Although forecasters don’t have the ability to predict rapid intensification bursts or eyewall replacement cycles with any degree of precision, conditions are generally favorable for strengthening, and thus Paloma is expected to continue getting better organized for the next 24 hours or so. Officially, the storm is forecast to peak as a low-end Category 3 hurricane, with peak winds of 115 mph, tomorrow morning.

Then, wind shear is forecast to increase markedly, and thus Paloma will probably weaken back to a Cat. 1 before landfall in Cuba overnight Saturday night. After crossing Cuba, Paloma may “lose vertical coherence,” according to the 10am NHC discussion; in any event, it will continue to degrade rapidly, and will eventually become extratropical.

Meanwhile, weatherblogger Alan Sullivan is now aboard the cruise ship Noordam, preparing to sail in Paloma’s general direction. He writes:

There seems something apt about sailing into a hurricane on a luxurious cruise ship in such times. Paloma continues to strengthen steadily. In the stronger scenario we will experience tropical storm conditions at sea tomorrow, while the center of Paloma runs onto Cuba’s south coast. In the weaker scenario, we hit squally thunderstorms as upper energy shears northeast while Paloma fades in the Caribbean.

Well, that was fast: barely 24 hours after being designated a tropical depression, Tropical Storm Paloma has officially become Hurricane Paloma as of 7:00 PM EST. Further rapid intensification is expected.

Details to come shortly.

UPDATE: From the 7pm NHC advisory:

…PALOMA RAPIDLY STRENGTHENS INTO A CATEGORY 1 HURRICANE…

. . . MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 75 MPH…120 KM/HR…WITH HIGHER GUSTS. PALOMA IS NOW A CATEGORY 1 HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE. PALOMA CONTINUES TO RAPIDLY ORGANIZE AND ADDITIONAL STRENGTHENING IS LIKELY. PALOMA IS EXPECTED TO BECOME A CATEGORY 2 HURRICANE ON FRIDAY.

Weatherblogger Alan Sullivan, who is scheduled to embark Friday for a cruise on Holland America’s Noordam, with scheduled stops in the Caribbean and the Bahamas, writes of Paloma:

The model projections fall into two distinct camps, as they often do. One group is weaker and slower. The storm is sheared apart before Cuban landfall, or it lingers dying in the Caribbean. They other group is faster and stronger. The storm accelerates with the upper flow, maintaining its integrity longer. This would mean real trouble for Noordam. It would also echo what happened with Omar last month. I deem it the more probable scenario.

We shall see. Dr. Jeff Masters has more.

Tropical Storm Paloma has formed, and is strengthening:

SATELLITE IMAGES SHOW AN ORGANIZING TROPICAL CYCLONE WITH A CENTRAL DENSE OVERCAST FEATURE DEVELOPING NEAR THE APPARENT CENTER. BANDING FEATURES ARE ALSO BECOMING MORE PROMINENT ESPECIALLY NORTH OF THE CENTER. THE INITIAL INTENSITY IS INCREASED TO [45 MPH] . . . AN AIR FORCE AIRCRAFT IS SCHEDULED TO BE IN THE AREA AROUND [1:00 PM EST] TO PROVIDE A BETTER ESTIMATE.

Further strengthening is forecast; Paloma is expected to be a hurricane by Friday evening, and a Category 2 hurricane by Saturday. It’s also possible the storm could get stronger than that, and/or could strengthen more quickly. Indeed, the National Hurricane Center estimates that the chances of rapid deepening (which is always very difficult to predict) are 3 to 4 times higher than the climatological average.

Dr. Jeff Masters says Paloma is “already starting to build an eyewall.” As for the forecast, Dr. Masters notes that wind shear is now expected to increase significantly on Saturday night, likely weakening Paloma before the expected landfall in Cuba on Sunday. The Caymans may still get hit by a Cat. 3 major hurricane, however.

Just when you (and I) thought hurricane season was effectively over, Tropical Depression Seventeen has formed off the coast of Nicaragua — and it could be a major threat to the Cayman Islands and Cuba this weekend.

Although T.D. 17 currently has maximum sustained winds of just 35 mph, conditions are ripe for strengthening, with warm waters and extremely low wind shear. Tropical Depression 17 is expected to become Tropical Storm Paloma sometime Wednesday, and Hurricane Paloma within 48 hours. After that? Watch out:

[B]oth the GFDL and HWRF models … predict TD 17 will pass though the Cayman Islands on Saturday morning as a Category 2 hurricane, and strengthen to a Category 3 or 4 hurricane by landfall Sunday morning in central Cuba.

Other computer models, it should be noted, are less aggressive than the GFDL and HWRF, which is unsurprising; those models are not infrequently high-end outliers when it comes to intensity forecasts. Nevertheless, there is a real chance of a major November hurricane for the Caymans and Cuba (with some possible impacts on Jamaica). Dr. Jeff Masters writes, “I give TD 17 a 70% chance of becoming a hurricane, and a 40% chance of becoming a major hurricane.” 

Of course, even if that 40% comes to fruition, it is possible proto-Paloma could become a major hurricane, but then weaken before landfall. That seems to be what Alan Sullivan is tentatively anticipating.

Alternatively, it is also possible the storm might not be picked up at all by the trough of low pressure that’s expected to take it toward Cuba, in which case it could meander near land or over upwelled waters, potentially inhibiting its development. But that scenario gets less likely as TD 17 gets stronger, because the storm is more likely to “feel” the trough if it is better organized.

In any case, while it’s too early to make any definite predictions, this one definitely bears watching.

Dr. Jeff Masters wrote on Saturday:

The tropical Atlantic remains quiet today. There are no threat areas to discuss, and none of our reliable models are calling for tropical storm formation over the next seven days. The next area to watch is the Western and Southern Caribbean beginning on Wednesday, when a cold front will stall out over the area and potentially act as a nucleus around which a tropical storm could form. This should give time for flooding to subside in Honduras, where 29 are dead and 14 missing due to recent rains.

Although that post was written two days ago, there’s nothing new to report. The tropics remain very quiet, even moreso than you’d expect for this time of year (though the season is winding down, climatologically). That’s partly due to the premature winter pattern, which I’ve mentioned several times before, and which Alan Sullivan refers to today as Christmas at Halloween.

Even as an early winter pattern largely shuts down the Atlantic hurricane season, with little threat of further hurricane activity in the U.S., areas closer to the equator remain at risk of death and destruction, including from weak, nameless systems. Take Tropical Depression 16 and “Invest 91L,” which have combined to reak havoc on Central America with their heavy rains:

A week of heavy rains over northern Honduras, northern Guatemala, and Belize due to Tropical Depression Sixteen and a Western Caribbean tropical disturbance (91L) have resulted in record flooding and deadly mudslides across the region. In Honduras, a nationwide state of emergency has been declared, and at least eleven people are dead and two missing from the flooding. Two large landslides blocked the Coyol River in western Honduras yesterday, forming a lake 500 feet deep. Engineers are attempting to drain the lake today, but they won’t be helped by the weather–91L promises to move little the next two days, and will continue to dump heavy rains on the region. In Belize, damage is already estimated in the ten of millions, and some areas are seeing flooding worse than was experienced during Hurricanes Mitch and Keith. In northern Guatemala, at least 70 towns have been cut off by flood waters and a state of emergency has been declared. Satellite estimates suggest up to a foot of rain has fallen over the region in the past week.

That write-up is from Dr. Jeff Masters, who adds (and the NHC concurs) that “91L” is very unlikely to develop — it’s too close to land, and wind shear is too high. But that hardly matters to the people in the affected regions. Even a nameless, undesignated tropical disturbance can cause massive destruction in vulnerable areas, and this one is doing just that.

Eventually, 91L will move away from Central America and head toward Florida, though by then its tropical potential should be gone entirely:

A trough of low pressure swinging across the Midwest U.S. should be able to start pulling 91L northward or northwestward by Thursday. Once 91L enters the Gulf of Mexico on Thursday, the trough should swing the storm to the northeast, bringing it across the west coast of Florida between Tampa and the Big Bend region on Friday night. Wind shear will be very high over the Gulf of Mexico this week, in the 30-40 knot range, and 91L is expected to make a transition to a very wet extratropical storm by Friday. The storm should bring sustained winds of 30-35 mph and heavy rains of 2-3 inches to Florida.

In other news, a Houston Chronicle report out today reveals that Hurricane Ike damaged more than half of Houston’s 2,000 apartment complexes. The Chronicle also has a section on its website devoted to Ike’s missing.

Finally, on an almost entirely unrelated note, check out these amazing photos and videos of the Sun, courtesy of the Boston Globe’s excellent “The Big Picture” blog. (Hat tip: Eric Berger.)

[UPDATE: This report by Dr. Jeff Masters suggests there was somewhat more damage that I thought when I first published this post. The damage was caused in part by Omar's "unusual west-to-east motion [which] resulted in storm surge and waves affecting the western side of the islands, which are not as well-defended against these effects.” Read the whole thing.]

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First off, no, the title of this post isn’t a typo. I just couldn’t resist calling Hurricane Omar “Omarrr,” in light of the fact that “Ol’ Chumbucket” — one of the “Pirate Guys” who created International Talk Like a Pirate Day — filed several video reports on Omar from St. Croix. Arrr!

(It should be noted that Chumbucket & family were in Frederiksted, on the west end of the island, so they would have experienced far less severe conditions than those on the east end, where the eyewall hit.)

On a more serious note, Dr. Jeff Masters writes this morning that Omar caused mostly minor damage across the affected islands:

Thankfully, no deaths or injuries have been reported from the storm, which avoided making a direct hit on any islands. Hardest hit appears to be the island of Antigua, where 5.71″ of rain was recorded at the airport. Severe flooding washed out roads and prompted many boat rescues, putting up to 100 people in shelters. St. Croix, whose eastern tip caught the eyewall winds of Omar, received minor damage, according to media reports. The storm did knock out power to the entire island for nearly a day, and caused considerable damage to piers and boats in the main harbor, though. Flooding was also reported in the British Virgin Islands, St. Martin, and St. Kitts and Nevis. On St. Martin, high waves dumped rocks and sand of the runway of the airport, forcing its closure. The airport was scheduled to be reopened today.

As Masters notes, stormcarib.com has more details on Omar’s impact.

Masters also writes this:

Several computer models are predicting the development of a tropical depression in the Atlantic’s southwestern Caribbean, off the coast of Nicaragua or Honduras, about 5-8 days from now. Wind shear is expected to be low, 5-10 knots, across most of the Caribbean for the next ten days, and I would not be surprised to see a tropical storm develop in the Caribbean next week.

A hypothetical proto-Paloma? (Hypo-Paloma?) We shall see.

Hurricane Omar peaked overnight at 959 millibars and 130 mph sustained winds, making it a borderline Cat. 3/4 hurricane, but it took a “best-case scenario” track through the narrow Anegada Passage between the Virgin Islands to the west and St. Maarten and Anguilla to the east.

A few miles further west, and Omar would have made a direct hit on St. Croix, instead of delivering a glancing blow there. A few miles further east, and the impact on St. Maarten and Anguilla would have been quite severe. Instead, the storm “threaded the needle,” as Alan Sullivan put it yesterday, and spared everyone the worst. Sullivan, who has a friend living on a boat in St. Maarten, is understandably relieved.

Dr. Jeff Masters notes that St. Croix did experience hurricane-force winds, but Omar certainly will not have been the disaster that was possible if it had taken a slightly different track. Such are the unpredicable vagaries of these intense but fickle beasts we call hurricanes.

Now, Omar is quickly weakening as it moves out to sea, with maximum sustained winds down to 85 mph and dropping, inspiring the National Hurricane Center forecasters to opine in the 11am EDT discussion:

IT IS SIMPLY AMAZING TO ME AT HOW QUICKLY A HURRICANE CAN SPIN UP AND JUST AS QUICKLY FALL APART. OMAR REACHED NEAR THE THRESHOLD OF CATEGORY 4 EARLY THIS MORNING AROUND [2:00 AM] AND NOW WE HAVE AN EXPOSED LOW-LEVEL CENTER SHOWING UP IN THE VISIBLE SATELLITE IMAGERY JUST A FEW HOURS LATER.

Omar is expected to continue weakening over open water, eventually becoming extratropical as it heads toward the far distant Azores.

Meanwhile, Tropical Depression 16 has dissipated over Hondruas (there’s your unnamed T.D. for the season, Chris). Its remnants could potentially regenerate over the Eastern Pacific, which means that “proto-Paloma” is now “proto-Polo.” (Too bad “Marco” and “Polo” weren’t active at the same time. They could have shouted at each other, over Central America: “Marco!” “Polo!” Heh.)

With the demise of T.D. 16 and the decline of Omar, Sullivan thinks we’re done: “That should do it for the 2008 hurricane season,” he writes. Perhaps so, but if it sounds like you’ve heard that one before, well, you have: three weeks ago, Sullivan wrote, “with polar influences expanding so swiftly, there may never be a Kyle at this rate”; then, six days later, after the birth and death of Kyle and Laura, I wrote, “With an early winter pattern developing, there may never be a Marco.” Heh.

Since my brilliant prognostication, we’ve seen Marco, Nana and Omar — though Sullivan regards some of these late-season “designations” as “marginal,” specifically Laura and Nana, if I’m not mistaken. Along these same lines, commenter Steve Sadlov wrote this morning on Sullivan’s site, “Omar was not Omar, it was Marco.” I’m going to vote “present” on this particular “count-padding” question, but I’ll just add that, if we’re going to discount Laura and Nana, maybe we should add in the subtropical-ish system that hit the Carolinas in late September. In hindsight, maybe that was the true “Laura,” in which case Marco was still Marco, and Omar should have been Nana, no?

In any event, the hurricane season officially continues for another month-and-a-half, so I’ll hold off on declaring it “over” just yet. But at least in the short-term, according to Dr. Masters, things are likely to remain quiet: “No computer models are forecasting tropical cyclone development in the Atlantic over the next seven days.”

Hurricane Omar strengthened to a Category 3 storm tonight as it swiped St. Croix, the southernmost of the Virgin Islands, and moved toward the Anegada Passage in between the Virgin Islands and the northern Antilles islands of Anguilla and Saint Maarten.

Here’s the 11:46 PM EDT radar view from San Juan:

Here’s a wider radar loop.

Omar’s winds are currently estimated at 115 mph, and that “COULD BE CONSERVATIVE,” according to the National Hurricane Center’s 11:00 PM EDT discussion. Further strengthening is possible overnight.

The big question mark is Omar’s exact track. The current official forecast predicts that the storm will “thread the needle,” as Alan Sullivan put it hopefully earlier today, between the Virgin Islands and the northern Antilles. This is helpfully shown by the guiWeather Google Map layer:

However, as the NHC discussion notes, “THE MODEL GUIDANCE KEEPS FORECASTING A 15-20 DEGREE LEFT TURN THAT SO FAR HAS NOT OCCURRED.” If that turn doesn’t occur, or is delayed further, Anguilla and/or St. Maarten could take a direct hit from Omar’s eyewall. Sullivan is worried, writing at 11:53 PM EDT: “St. Maarten needs a northward, leftward wobble soon, or the worst part of the storm, the southern eyewall, may hit the island when the storm is peaking in strength.”

Here’s a look at Omar’s path so far, along with its wind field (tropical storm force winds in orange, hurricane force in maroon) and its accompanying watches and warnings (red for hurricane warnings, pink for hurricane watches, blue for tropical storm warnings, yellow for tropical storm watches):

StormCarib has coverage.