Ladies and gentlemen, welcome to the Atlantic hurricane seasons of the mid-2000s, when the “exceptional” is unexceptional and the “unheard of” is commonplace!

As promised, Dr. Jeff Masters today explains why the remainder of June could be an unusually busy time in the tropics:

[T]he model forecasts over the past few days from the reliable GFS, NOGAPS, and Canadian models are showing a weather pattern more typical of mid-July developing over the tropical Atlantic. This may make for a exceptionally active June. The Intertropical Convergence Zone (ITCZ) is forecast to be far more active and further north than usual, and the GFS model has been predicting that one or two tropical cyclones may form in the mid-Atlantic from African waves interacting with the ITCZ. This is almost unheard of in June. Wind shear over the Caribbean and tropical Atlantic is expected to be much below normal, and with sea surface temperatures 0.5 - 1.5 degrees C above normal, it would not surprise me to see two more named storms this June. One saving grace is that the subtropical jet stream is expected to stay active and relatively far south, with should act to bring hostile wind shear to any storm that might move into the Gulf of Mexico. In addition, a series of strong troughs are forecast to move across the Atlantic Ocean the remainder of the month, which should act to recurve any storm that might form there away from land.

While there is nothing threatening looking out there today, we should keep an eye on the ITCZ just off the coast of Africa south of the Cape Verde Islands, and the region just north of Panama, in the coming days.

Lest anyone assume this is a sign of things to come, Masters is careful to point out that “past history has shown that an active June in the Atlantic has no correlation with hurricane activity later in the season.” That said… my unscientific guess is that it’s probably a sign of things to come. :)

Masters also has a very interesting analysis of Alberto. Among other things, he notes that “the official NHC forecast outperformed all the [computer] models” in predicting Alberto’s track. Way to go, NHC! Masters talks about the Loop Current’s impact, too. Read the whole thing.

The National Hurricane Center has issued its final advisory on Tropical Depression Alberto — but the season’s first tropical cyclone will live on, as an extratropical storm that may blow up into quite a gale off the Carolina coast.

Meanwhile, InstaPundit shows us the awful aftermath. Heh.

Remember when I blogged about the “absurd” GDFL model run that showed Tropical Storm Alberto strengthening over Georgia? Well, don’t look now, but it sure looks on radar like Alberto is trying to wrap some heavy rain around his center of circulation… which is looking a bit more like an eye!

Don’t get me wrong… Alberto isn’t going to become a hurricane over land. If anything, the storm’s healthy appearance on radar even as it moves well inland — it is, at this very moment, crossing the border from Georgia into South Carolina — probably means its transition to an extratropical storm (i.e., not dependant on warm ocean waters) is already underway. This thing is going to become a strong extratropical gale over the Atlantic once it moves back out to sea. Here’s what the NHC said at 11:00 PM EDT:

STRENGTHENING INTO A SIGNIFICANT EXTRATROPICAL GALE AREA OFF THE NORTH CAROLINA OUTER BANKS SEEMS QUITE PLAUSIBLE AT THIS TIME. IT IS ALSO POSSIBLE THAT ALBERTO MAY NOT DROP BELOW TROPICAL STORM STATUS BEFORE EXTRATROPICAL TRANSITION OCCURS… WHICH WOULD REQUIRE A NORTHWARD EXTENSION OF THE TROPICAL STORM WARNING AREA IN THE NEXT ADVISORY.

P.S. Here’s the satellite loop. Definitely some convection firing up near the center!

UPDATE, 5:55 AM MST: Alberto has been downgraded to a Tropical Depression. According to FLhurricane, “It’s held on so long because of the transformation into an extratropical system going on now.” The NHC says:

DOPPLER VELOCITIES AND OBSERVATIONS FROM BUOYS AND CMAN STATIONS OFF THE GEORGIA AND SOUTH CAROLINA COASTS INDICATE THAT WINDS HAVE DROPPED BELOW TROPICAL STORM FORCE. HENCE…THE TROPICAL CYCLONE HAS BEEN DOWNGRADED TO A DEPRESSION AND ALL TROPICAL STORM WARNINGS HAVE BEEN DISCONTINUED. HOWEVER…GALE WARNINGS ARE IN EFFECT ALONG PORTIONS OF THE CAROLINAS IN ANTICIPATION OF ALBERTO’S RE-STRENGTHENING AS AN EXTRATROPICAL CYCLONE. … ALBERTO IS QUICKLY LOSING TROPICAL CHARACTERISTICS AND EXTRATROPICAL TRANSITION SHOULD OCCUR IN THE NEXT 6-12 HOURS WITH ADDITIONAL INTENSIFICATION FORECAST ONCE THE SYSTEM RE-EMERGES OVER WATER.

While my TWC buddy Mark Newman explains why he sat Alberto out, Mark Sudduth at HurricaneTrack writes, “With the exception of the immediate coast, the effects from Alberto have been more beneficial than anything else.” Dr. Jeff Masters agrees, saying the season’s first storm produced “modest damage” and “beneficial rains.” But the big story from Masters’s wrap-up of Alberto is his tantalizing preview of his next blog post:

Tomorrow, I’ll analyze Alberto’s sudden burst of intensification Monday morning, and report on what the rest of June may hold for us. It could be an exceptionally active June.

I’m definitely curious now!

Meanwhile, on the Weather Channel Blog, Stu Ostro says that “just because there’s a tropical storm or hurricane this early doesn’t necessarily mean anything for the remainder of the season.” That absolutely true — but so is this:

But yikes, look at the deep tropical Atlantic in this colorized infrared satellite image below from this morning! One has to remind oneself that this is mid-June, not July or August …

Here’s the satellite image he’s talking about:

Yikes is right! And so is “exceptionally active”! But according to the NHC, development is not expected:

A VIGOROUS TROPICAL WAVE IS PRODUCING NUMEROUS SHOWERS AND A FEW THUNDERSTORMS OVER THE EASTERN CARIBBEAN SEA… MUCH OF THE LESSER ANTILLES… AND ADJACENT ATLANTIC WATERS. ALTHOUGH ENVIRONMENTAL CONDITIONS ARE UNFAVORABLE FOR DEVELOPMENT OF A TROPICAL CYCLONE… AN INCREASE IN THUNDERSTORM ACTIVITY IS EXPECTED TONIGHT AND WEDNESDAY THAT COULD BRING BRIEF PERIODS OF HEAVY RAINFALL AND STRONG GUSTY WINDS TO THE LEEWARD ISLANDS… PUERTO RICO… AND HISPANIOLA AS THE WAVE MOVES WEST-NORTHWESTWARD AT 20 TO 25 MPH.

ANOTHER TROPICAL WAVE LOCATED ABOUT 1350 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS IS MOVING WESTWARD AT 15 TO 20 MPH. THIS SYSTEM REMAINS BROAD AND DISORGANIZED… AND FURTHER DEVELOPMENT IS NOT EXPECTED AT THIS TIME.

The NHC doesn’t address the most noticable feature on the above satellite map, the massive blob of red and orange just off the African coast. The wave “1350 miles east of the Southern Windward Islands” is the middle wave of the three pictured above (I think). So I’m not sure what’s up with the wave on the right. Maybe it just developed, and they’ll talk about it in the next Tropical Weather Outlook.

Animation here.

UPDATE: Here’s the official word.

Am I crazy, or does it appear on the radar loop that Tropical Storm Alberto has slowed down and taken a last-minute eastward — or even east-southeastward — jog?

Not that it really matters much at this point. Although Alberto’s center remains just offshore, most of the heavy weather — such as it was — has already occurred, in squalls well ahead of the center. And, as noted earlier, the winds have not lived up even to the modest expectations of a strong tropical storm; for whatever reason, the flight-level winds detected by hurricane-hunter aircraft haven’t translated down to the surface at the normal 90% ratio. Dr. Jeff Masters reported at 9:10 AM EDT (6:10 MST) that surface stations were generally reporting sustained winds in the 30-40 mph range (just under tropical storm strength) with gusts to 45 mph or so. Not exactly a fierce wind-maker. (Apropos of which, Glenn Reynolds offers a photo of Alberto’s devastation: “one of several chairs blown over on our deck.” Heh.)

Alberto roars ashore. Well, okay, maybe “roars” is a bit strong. Would you believe “Alberto tiptoes ashore”?

Even the much-ballyhooed storm surge doesn’t appear to be too bad, if the tidal gauges at Cedar Key (tide 4 feet above normal) and Apalachicola (tide 5 inches above normal…heh) are any indication. Masters says areas north of Cedar Key can expect storm surges of up to 7 feet, but… well… if your house can’t withstand a 7-foot storm surge along the Florida coast, I’m sorry but it’s time to move somewhere else. Anyway, “since this is a relatively unpopulated stretch of coast, damage should be relatively low.”

So, Mother Nature’s opening pitch was a slow curve down the middle. Good. Now let’s not get all uppity and start thinking that’s all she’s got in the tank for this year, because I’m pretty sure she’s got some knuckleballs, split-fingered fastballs, and Rob Dibble*-type heaters in her arsenal.

(more…)

From the 5 am NHC discussion:

WITH A SLUG OF DRY AIR OVERTAKING THE CENTER OF CIRCULATION… ALBERTO’S CHANCES OF BECOMING A HURRICANE ARE EVAPORATING. THERE IS NO DEEP CONVECTION NEAR THE CENTER AND THE CYCLONE IS TAKING ON A LESS-THAN-TROPICAL APPEARANCE ON SATELLITE IMAGERY.

Maximum sustained winds are reported to be 65 mph based, with a pressure of 995 mb. The observed flight-level winds still don’t translate into 65 mph at the surface, and the NHC’s reported value is based on quikscat data. The NHC wind speed probability table reports only a 5% chance of intensification to hurricane strength during the next 36 hours, but hurricane warnings remain in effect between Longboat Key and the Ochlockonee River. The tropical storm warning area in the Gulf extends south to Englewood, west to Indian Pass. On the Atlantic coast, the tropical storm warning starts at Flagler Beach and has now been extended northward to South Santee River, SC. Alberto’s forecast track spends a substantial time overland near the coastline in Georgia into the Carolinas. For the Florida Gulf coast, the public advisory describes today’s storm surge threat:

COASTAL STORM SURGE FLOODING OF 7 TO 9 FEET ABOVE NORMAL TIDE LEVELS CAN BE EXPECTED MAINLY TO THE EAST AND SOUTH OF WHERE THE CENTER MAKES LANDFALL.

The NHC’s 2:00 AM EDT intermediate advisory is out, and the headline is:

…ALBERTO NOT STRENGTHENING AS IT APPROACHES THE GULF COAST OF FLORIDA…

In fact, Alberto isn’t just “not strengthening,” he’s actually weakening — down to 65 mph now, according to the official advisory. And Charles Fenwick argues convincingly that Alberto’s not even that strong. The flight-level winds simply aren’t translating to surface winds at the normal ratio; the highest recorded surface winds as of midnight EDT were around 35 mph, which isn’t even tropical-storm force! “It is evident that the rules of thumb for the relationship between flight level and surface winds are not holding at this time, so I don’t understand why the NHC advisory is using them,” Fenwick writes.

Despite that, and despite Alberto’s acknowledged weakening, the NHC is leaving the Hurricane Warnings up, justifying it by playing the “it could still strengthen” card:

MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH…105 KM/HR…WITH HIGHER GUSTS. ALTHOUGH ALBERTO HAS WEAKENED SLIGHTLY…SOME POTENTIAL STILL EXISTS FOR RESTRENGTHENING PRIOR TO LANDFALL.

Well, some potential still exists for pigs to fly, or for O.J. Simpson to find the real killers, but sorry, with all of the strongest convection and heaviest rainfall now over land, and with strong surface winds basically not showing up, I’m thinking Alberto’s pretty much a bust, wind-wise. The rain is heavy and the surge will be decent, but in terms of any potential for reaching hurricane status, methinks this puppy’s ship has sailed. Alberto is never going to be a hurricane — and he may never have been as strong as we thought he was, if Fenwick is right.

As an aside: far be it for me to question the NHC forecasters’ expertise, which is about 1,000 times greater than mine. But in terms of applying that expertise, I believe they have a tendency at times to be overcautious when it comes to dropping already-issued watches and warnings, once those watches and warnings become clearly no longer justified under the NHC’s own criteria. A Hurricane Warning means that hurricane conditions are expected within the next 24 hours. Can anyone honestly say that is true at this point? If not, shouldn’t the warning be dropped? But in my observation, the NHC tends to leave warnings up once they’re issued, presumably because they want to avoid lulling people into letting their guard down, and also to avoid the ping-pong effect of warnings being switched on and off and on again, in the event of a change in the forecast. That’s all well and good, and reasonable so far as it goes… but, look, if Alberto doesn’t produce surface winds of better than 40 or 50 mph in the Hurricane Warning zone, there is going to be a serious “boy who cried wolf” danger the next time around. I’m just saying that’s something they need to consider when they’re deciding whether to let a Hurricane Warning outlive its objective meteorological justification.

Now watch, after saying all that, I’ll wake up in the morning to find that Cat. 2 Hurricane Alberto is making landfall on the front step of Glenn Reynolds’s motel in Apalachicola. :) No, but seriously, I’m going back to my prior descriptor “anticlimactic.” Which is, I suppose, a good thing… though honestly, I wish Alberto had reached minimal hurricane strength, if only just for one advisory, so we could say we had a June hurricane. Oh well.

Here are some Florida tidal gauges. Specifically, Cedar Key and Apalachicola. Nothing too extreme-looking, yet.

Tropical Storm Alberto’s pressure has dropped from 997 mb to 995 mb in the last six hours, and the NHC says “SOME SHALLOW CONVECTION HAS BEEN DEVELOPING AROUND THE LOW-LEVEL CENTER DURING THE PAST FEW HOURS.” So, will it be Tropical Storm Alberto or Hurricane Alberto that makes landfall in Florida tomorrow morning? It could be a close call. The storm looks decidedly unimpressive on satellite, but the 11pm EDT discussion is still predicting intensification from a 70 mph tropical storm to a minimal, 75 mph hurricane:

WHILE GULF WATER TEMPERATURES ARE ONLY AROUND 79-80F AHEAD OF ALBERTO… THE 00Z UPPER-AIR SOUNDING FROM TAMPA INDICATES THAT THE ATMOSPHERE AHEAD OF THE CYCLONE HAS BECOME MORE UNSTABLE SINCE 12Z THIS MORNING. SINCE THERE IS AVAILABLE INSTABILITY TO SUPPORT THE REGENERATION OF SIGNIFICANT CONVECTION LATER TONIGHT AND TUESDAY MORNING… A FORECAST OF ALBERTO POSSIBLY REACHING HURRICANE STRENGTH BEFORE LANDFALL APPEARS TO STILL BE IN ORDER.

Bryan Woods at The Storm Track is skeptical. So is AccuWeather: “There is a slight chance that thunderstorms could form around the storm’s well defined circulation overnight. We have been keeping an eye on this and as of late Monday evening have not seen this happening just yet. Also a more recent reconnaissance pass through the storm’s circulation showed a pressure rise of 3 millibars.” (The pressure rise, though, “could be just a poor dropsonde placement.”)

Really, it’s a largely academic debate: 70 mph estimated maximum sustained winds vs. 75 mph estimated maximum sustained winds doesn’t make that much of a difference. Alberto will mostly be a flooding threat — due to heavy rain and storm surge, thanks to the especially vulnerable geography of this part of the coast. But as for the wind? Woods is right: “This doesn’t seem like a particularly dangerous storm and damage should not be high on the mainland. However, this is a great dry run for Florida residents for the coming season. Ok, maybe a great wet run.” Heh. I just hope the heavy hype for Alberto, which will probably (mercifully) be followed by minimal damage, doesn’t lead people to become complacent the next time a genuinely dangerous storm comes knocking. Something tells me, though, complacency is not going to be a huge problem this year.

Mike C. at FLhurricane certainly isn’t complacent. Although all signs point to a not-too-damaging storm, he’s remembering what happened 24 hours ago, when “all signs” were pointing to Alberto falling apart:

Tropical Storm Alberto is holding, and not looking as good as it was earlier in the day. However, I remember being in this position last night when it wasn’t looking very well for alberto, and unfortunately waking up to Hurricane Warnings. Also the latest recon reports have the pressure down to 996 and it holding itself well despite the appearance on satellite. It may be more of a hybrid system now than a pure tropical one as well.

Mark Sudduth of HurricaneTrack is in Florida now. According to AccuWeather, “We still expect the storm to make landfall over the northwest Florida coast near Dekle Beach which is just north of Cedar Key and southeast of St. Marks. This is in an area that is not real populated. Landfall time will be between 6AM and 10AM Tuesday morning.”

Here, again, is the latest radar loop.

I’m working late at the office tonight, but the legal memo-writing will have to wait for a moment, so I can take a brief break to update y’all (and myself!) on Tropical Storm Alberto.

Before I get to the latest NHC updates, some required reading for anyone who really wants to understand what the heck is going on with this storm: Bryan Woods’s fascinating post about the Loop Current and Ekman pumping. Read it.

Now then… as of the 8:00 PM EDT (5:00 PM MST) intermediate advisory, Alberto still has 70 mph winds (which means he’s blowing signficantly less hard than the USA soccer team did earlier today) and a minimum central pressure of 997 mb — the same as three hours ago, when the meteorological discussion said:

AFTER THE SUDDEN STRENGTHENING EPISODE OBSERVED EARLIER TODAY…THE STORM HAS LEVELED OFF IN INTENSITY. THE LAST FIX FROM THE HURRICANE HUNTERS SHOWED THAT THE CENTRAL PRESSURE WAS HOLDING NEAR 997 MB AND THE HIGHEST FLIGHT-LEVEL WINDS WERE 67 KT…SO THE INTENSITY IS UNCHANGED AT 60 KT. SATELLITE IMAGES INDICATE THAT THE AMOUNT AND INTENSITY OF DEEP CONVECTION HAS DIMINISHED AND THE CLOUD PATTERN HAS BECOME RATHER ELONGATED. THE STORM HAS LEFT THE AREA OF HIGHEST OCEANIC HEAT CONTENT…I.E. THE GULF OF MEXICO LOOP CURRENT…BEHIND. NONETHELESS SLIGHT STRENGTHENING IS STILL POSSIBLE BEFORE LANDFALL…ESPECIALLY DURING THE DIURNAL CONVECTIVE MAXIMUM EARLY ON TUESDAY.

There’s nothing more recent than that from the NHC (only the full advisories have discussions; the intermediate ones don’t), but Woods wrote at 4:08 PM EDT: “There has not been a whole lot new over the last few hours. Alberto’s convection has weakened and the storm is not as symmetric. At times Alberto has looked subtropical in nature, but the models are not indicating this. There is now a very clear center of circulation, but most of the heavy storms are displaced to the north. Hurricane warnings remain up for much of the western Florida coast, but could be overkill.”

Overkill or not, hurricane or not, the computer models are indicating a storm surge of up to 10 feet along parts of the Florida coast, even from a strong tropical storm landfall. Here are some projected maps of what the surge might look like in the Cedar Key area, the Tampa Bay area and the Appalachicola area. (Hat tip: FLhurricane.com.)

Palm Beach Post weatherblogger Bob King has more on storm surge, and wisely advises coastal residents: “Don’t fool around with surge. If you’re in a vulnerable area and your local authorities tell you to evacuate, get out.” Amen. In a battle between you and the ocean, the ocean will win.

That said, with the NHC declaring that “TROPICAL STORM FORCE WINDS [ARE] NEARING THE WARNING AREAS” and urging that “PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION,” I assume we are approaching the point of no return, where if people haven’t left yet, or very soon, they’ll need to hunker down and stay put. But I’m just talking through my hat. Don’t listen to me — listen to your local authorities!

And that goes for you, too, Professor Reynolds! :) Glenn, you see, is visiting the Florida Gulf Coast at the moment, and he is apparently getting some of his Alberto updates from me, given that he linked to me unbidden (InstaBoost LX!) earlier today. I’m tempted to take advantage of this unique opportunity to tell the Professor to “get the hell out” :) — but in all seriousness, especially considering that I don’t know exactly where he is, I’d just advise Glenn (and everyone else down there) to do whatever the local authorities say. Hopefully they’re more competent than some other local authorities I could mention. (Plus, Alberto is no Katrina, thank God.)

Landfall is expected to occur late tomorrow morning, though most of the worst weather will precede the arrival of the center — so we’re talking overnight tonight, basically starting now and getting worse through the wee hours. Here’s the latest radar loop. Keep staying tuned to the NHC, and the other sites linked at top right, for the latest.

Holy cow! So much for anticlimactic! When I went to bed last night, Alberto was a weak tropical storm on death’s door, with maybe a 50/50 chance of making it to the Florida coast before disintegrating into oblivion. I confidently dismissed as “pretty unlikely” the GFDL computer model forecast that it would become a hurricane before landfall. So imagine my surprise when I woke up this morning to the news that Alberto is now expected to become a hurricane! As Sean explains, the storm’s center has re-formed near the deep convection, and the winds are up to 70 mph. The NHC’s 11:00 AM EDT discussion explains that a familiar culprit played a role in all this:

THE STORM HAS BEEN INTERACTING WITH THE WARM GULF OF MEXICO LOOP CURRENT…WHICH HAS LIKELY BEEN A CONTRIBUTOR TO THE INTENSIFICATION.

Ah yes, the loop current… that patch of deep, warm water that helped several of last year’s Gulf hurricanes achieve their monster status. Just as no one ever expects the Spanish inquisition, no one ever seems to anticipate that the loop current will have quite the effect that it does. Wow.

Mark Sudduth at Hurricane Track takes an academic approach: “Alberto will be one of those storms that we can learn a lot from. There was little chance, or so it seemed, of it becoming a hurricane. Now it is well on its way.”

So, what next? The NHC declares: “ENVIRONMENTAL FACTORS WOULD APPEAR TO MITIGATE AGAINST SIGNIFICANT ADDITIONAL STRENGTHENING.” Dr. Jeff Masters concurs: “The shear has not changed much in the past 12 hours, nor is it expected to do so over the next few days. This should limit Alberto’s intensification. Hurricane Ophelia last year strengthened in the face of similar amounts of shear, and I anticipate that Alberto will grow no stronger than Ophelia. Maximum sustatined winds of 80 mph are probably the highest we will see from Alberto.”

Seems reasonable enough… but you gotta wonder. Is 2006 already becoming an extension of 2005, the hurricane season when the seemingly impossible happened again and again? As Masters puts it: “All this strengthening occurred in the face of strong wind shear of 20-30 knots, which is unusual. I was calling for a 10% chance of Alberto becoming a hurricane, but Alberto certainly has other ideas! The storm’s central pressure was a very unimpressive 1006 mb last night when I thought the storm might get ripped apart, but the 9 mb drop in pressure since then is an impressive achievement for a storm under 20-30 knots of wind shear.”

Oh, well… all the meteorologists can do is make sensible predictions and hope Mother Nature doesn’t throw us too many more curveballs!

As Sean noted, storm surge is now a major concern with Alberto, thanks to the geography of the coastal area it is targeting. Says Sudduth: “This is now a very serious situation as the area forecast to take the right-front quadrant of Alberto is extremely vulnerable to storm surge. It would not surprise me to see 8 to 10 feet of surge in some areas near Cedar Key - and points south.”

Sudduth continues:

After making landfall in Florida tomorrow, Alberto is now projected to be inland along the Southeast coast. Georgia and the Carolinas will have a wet and windy week ahead- at least the first half. Even people farther north along the East Coast could have adverse weather from Alberto by later in the week. This will be a major newsmaker and indeed I will be covering it for this site and our HurricaneLiveNet site. I will be in Florida tonight and will post video updates and reports as often as possible. Jesse Bass will remain in Virginia to get ready for any potential impacts along the Va. Capes or the Outer Banks. I will have another update here later this afternoon as I head south towards Florida. Here we go….

From the 11 am EDT discussion from the National Hurricane Center:

THE AIR FORCE HURRICANE HUNTER PLANE FOUND THAT THE CENTER OF THE CYCLONE HAS ABRUPTLY REFORMED NEAR THE DEEP CONVECTION

So it seems that we no longer have the huge displacement between the circulation center and deep convection, the primary factor that made this storm appear unhealthy. The maximum sustained winds have risen to 70 mph, just below hurricane strength, and the pressure has fallen to 997 mb. The system will be moving over cooler waters and continue to experience significant shear, and regarding the intensity forecast

THESE ENVIRONMENTAL FACTORS WOULD APPEAR TO MITIGATE AGAINST SIGNIFICANT ADDITIONAL STRENGTHENING. NONETHELESS….GIVEN THE UNCERTAINTIES IN PREDICTING INTENSITY CHANGE WE MUST NOW ALLOW FOR THE DISTINCT POSSIBILITY THAT ALBERTO COULD BECOME A HURRICANE.

For these reasons, a hurricane warning has been issued for the Florida Gulf coast between Longboat Key and the Ochlockonee River. A tropical storm warning extends west to Indian Pass, and south to Englewood. A tropical storm watch continues further south to Bonita Beach. The NHC forecast tracking map shows landfall expected somewhere in the vicinity of Perry, FL on Tuesday evening.

The main concerns are rain and storm surge:

ALONG WITH THE HEAVY RAINFALL…THE GREATEST CONCERN WITH ALBERTO IS LIKELY TO BE STORM SURGE FLOODING ALONG AN EXTENSIVE PORTION OF THE FLORIDA GULF COAST. OWING TO THE CONFIGURATION OF THE COASTLINE AND THE SHALLOW CONTINENTAL SHELF…A STRONG TROPICAL STORM OR A CATEGORY ONE HURRICANE CAN PRODUCE A SIGNIFICANT SURGE IN THIS AREA.

Jeff Masters notes that “All this strengthening occurred in the face of strong wind shear of 20-30 knots, which is unusual.”

As of 2am EDT (11pm MST), Tropical Storm Alberto is still with us, and still at tropical-storm strength — though the latter conclusion is based on a generous assumption, as the NHC admits in its discussion: “THE 40-KT INTENSITY IS BASED ON THE ASSUMPTION THAT THE RECON AIRCRAFT MAY NOT HAVE SAMPLED STRONGER WINDS TO THE EAST OF THE FLIGHT TRACK WITHIN SOME OF THE STRONGER CONVECTION.” Translation: “the objective data doesn’t support the conclusion that this storm has the winds we’re saying it does, but we’re going to ignore that for the moment.”

According to the official forecast track, landfall is expected to occur around midday Tuesday near Cedar Key, Florida. But as Hurricane Track points out, “Because the center of circulation is currently not covered in deep thunderstorms, the passage of it will be anti-climactic. Most of the weather associated with Alberto will impact Florida tomorrow and tomorrow night.”

Hurricane Track’s 10:50 PM EDT update also states, “Once past Florida, there is some question as to what happens with Alberto. You don’t even want to know what the afternoon run of the famous GFDL model showed. It was absurd.” Naturally, I was curious, so I checked it out, and saw that the GFDL’s 18Z run had Alberto strengthening over land into a borderline Category 1-2 hurricane in south-central Georgia. Heh! (The 00Z run makes a little more sense, showing Alberto nearly falling apart, then getting his act together and making landfall as a Cat. 1 hurricane, then weakening over Georgia and then — presumably after transitioning to an extratropical storm — exploding into an intense storm as it exists the North Carolina/Virginia area, and becoming a major nor’easter off the New England coast. All very interesting, and less “absurd” than what the 18Z run showed… but still probably pretty unlikely.)

I’m going to bed now, and will be working (and thus not blogging) all day tomorrow, but hopefully my hurricane guestbloggers will be able to post a few updates… and in the mean time, I encourage everyone to check out the sites on my “hurricane blogroll” at right. Most of them are posting Alberto updates at least a few times a day.

The Storm Track predicts: “It is going to be very hard for more convection to fire up near the center of circulation. A quick look at the water vapor imagery shows the large mass of dry air over the Western Gulf of Mexico. At this rate Alberto may not survive the trip to Florida.”

HurricaneTrack speculates: “Recon flights in to the storm tonight might very well show that the season’s first storm has weakened back in to a depression. We will see.”

Given all the pre-storm hype, this is turning out to be quite possibly the most anticlimactic tropical event in recent memory. :) Not like that’s a bad thing, nor like we had any legitimate reason to expect otherwise.

As of the 5:00 PM EDT advisory (2:00 PM MST), Tropical Storm Watches are up for the Florida west coast, from just north of Bonita Beach to Steinhatchee. But Alberto remains an unhealthy tropical storm:

SATELLITE IMAGES SHOW THAT THE BANDS OF HEAVIER SHOWERS HAVE BECOME DISPLACED FARTHER EAST AND NORTHEAST OF THE CENTER THAN THEY WERE THIS MORNING. INDEED…THE SYSTEM HAS SOMEWHAT OF A SUBTROPICAL APPEARANCE AT THE MOMENT. BECAUSE THE SATELLITE PRESENTATION HAS BECOME LESS ORGANIZED SINCE EARLIER TODAY…IT IS POSSIBLE THAT THE CYCLONE IS WEAKENING.

The official forecast calls for slight strengthening, from 45 mph to 50 mph sustained winds, but the NHC doesn’t sound too confident in that.