TS Fay to develop next week?

Things look fairly quiet in the Atlantic basin at the moment. However, global model data issued by the UK Met Office earlier today suggests that a tropical storm will develop off the coast of West Africa next week. This would be the sixth named storm of the 2008 Atlantic season.

Here's an illustration (using Google Earth) of the UKMET forecast for proto-Fay, up to the end of the forecast period on Thursday:

(all times UTC)

The model calls for proto-Fay to remain a weak tropical storm for the duration of the forecast period.

I'll post a further update tomorrow.

Public service announcement

Possible Worlds now has a new URL: www.alectaylor.net.

The old address should still work (at least for the time being).

The new address might appear rather egocentric - but hopefully it will be a bit easier to remember.

Landfall: TS Edouard arrives in Texas

Edouard made landfall in Texas earlier today as a 65mph tropical storm. The NHC's declaration of landfall came at 1pm BST.

Landfall occurred in the McFaddin National Wildlife Refuge, east of Galveston Bay. This is to the the north of the guidance envelope as it stood when I posted last night. The more northerly turn seems to have resulted from the centre of Edouard reforming during the night (a phenomenon that often plays havoc with forecast tracks).

Here is my sketchy representation (using Google Earth) of the final hours of Edouard's journey to the Texas coast:

Bryan Woods has got a much snazzier 'streaming radar' graphic on his blog, which is well worth a look.

As is clear from the radar image above, Edouard is becoming rather ragged as it moves inland. It is expected to be downgraded to a TD by noon tomorrow. The following prognosis was delivered in the 4pm BST discussion:

"MODEL GUIDANCE IS IN GOOD AGREEMENT ON A CONTINUED WEST-NORTHWESTWARD MOTION WITH PERHAPS A SLIGHT REDUCTION IN FORWARD SPEED UNTIL THE CYCLONE DISSIPATES IN 36-48 HOURS."

By the time it dissipates, Edouard is likely to have dumped 3-5 inches of much needed rain on parts of southeastern Texas and southwestern Louisiana.

1950s council housing

Note the yellow ceramic tiles - talk about pushing the boat out!

Cool roof

Update on TS Edouard

Nothing particularly spectacular is happening with Edouard this evening.

A short period of rapid intensification last night was offset by the effects of northerly vertical shear during today. However, the storm is gradually becoming better organised this evening, with clearer outer bands now visible on the satellite imagery.

The computer models are currently in good agreement that Edouard will make landfall tomorrow in the Galveston area of Texas. However, as usual, there is considerably less agreement about intensity. According to the 10pm discussion this evening:

"THERE IS A LARGE SPREAD IN THE INTENSITY GUIDANCE...WITH THE GFDL TAKING EDOUARD TO 69 KT PRIOR TO LANDFALL...WITH THE SHIPS...LGEM...AND SUPERENSEMBLE STATISTICAL MODELS SHOWING LITTLE OR NO ADDITIONAL DEVELOPMENT."

Although Edouard is no longer suffering under the torment of strong northerly shear, it will quickly run out of the deep warm water that it needs in order to intensify. I have illustrated this by plotting a rough representation of the official forecast track over the current Depth 26.C Isotherm map:


The official forecast, which calls for Edouard to make landfall at around the TS / Category 1 threshold, effectively splits the difference between the computer model extremes.

The edge of the storm is currently scraping up against the Louisiana Gulf coast. Here's the latest image from the New Orleans weather radar:


NB: I'm having terrible trouble uploading images to Blogger this evening. Apparently I'm not the only one. All very annoying. I will upload the missing images from this post as soon as the bug is fixed.

UPDATE: Fixed.

Let us not waste our time in idle discourse

I have finally, finally got round to doing a links sidebar!

Hurrah.

EDOUARD

[Lunch break update]

I didn't quite manage to stay up late enough last night to say hello to Tropical Storm Edouard.

The 2008 season's fifth named storm was announced by the NHC at 11pm BST, just a few minutes after my last post.

More to follow later....

Introducing Tropical Depression 5: Texas to get hit again?

In the unlikely event that anyone reads this, I apologies for the appalling lack of updates. My day job is mostly to blame....

Breaking news: The NHC has announced the formation of Tropical Depression 5 in the northern Gulf of Mexico.

TD5 is located about 85 miles southeast of the mouth of the Mississippi, heading due west at around 6mph. The official forecast is for TD5 (or proto-Edouard) to track roughly WNW over the course of tonight and tomorrow, before making landfall on the upper Texas Gulf Coast on Tuesday. The UKMET model (compiled in my hometown of Exeter, Devon) appears to be the eastern outlier, calling for landfall in western Louisiana.

Here (courtesy of Google Earth) is a close-up of the NHC's forecast track passing over Galveston Island, Texas - nearly 108 years after that infamous storm:

(click to enlarge)

With maximum sustained winds of 35mph, TD5 is right on the precipice of tropical storm strength. Indeed its minimum central pressure of 1007 is already indicative of a TS, and I would be astonished if we hadn't said hello to Edouard by lunchtime tomorrow.

The official NHC forecast calls for proto-Edouard to peak at TS strength before making landfall but, as noted in the 1opm discussion, the GFDL model predicts that it will reach hurricane strength.

More tomorrow (hopefully!).

Another strong tropical wave...

...moving off the coast of west Africa.

Hat-tip: Brendan Loy

Hello Dolly

94L has leap-frogged over TD status and is now a 40 knot Tropical Storm.

The system was already close to tropical storm strength yesterday, but lacked a closed circulation until today.

According to the first NHC Discussion on Dolly, issued a few minutes ago:

"THIS IS CURRENTLY A SPRAWLING SYSTEM WITH 34-KT WINDS AND HEAVY RAINS EXTENDING WELL AWAY FROM THE CENTER ... ALTHOUGH VERY RECENTLY CONVECTION HAS BEGUN TO CONSOLIDATE OVER THE CIRCULATION CENTER."

It looks much more impressive on the satellite imagery than last night:


The official NHC forecast, supported by all the computer models, calls for Dolly to pass over the Yucatan Peninsula during the course of tonight and early tomorrow. The precise point of landfall indicated by the NHC track appears to be the town of Tulum in the Mexican state of Quintana Roo. The models also agree that, after leaving the Yucatan, Dolly will travel roughly NW over the southwestern Gulf of Mexico.

There is less agreement about Dolly's second landfall, although all the models currently predict that it will occur somewhere in the Mexican state of Tamaulipas (ranging from the far north to the far south of the state). None of the models currently call for a Texan landfall - although the official NHC track puts it as close as 20 miles south of the Mexico/Texas border. The official forecast is now at the far north of the guidance envelope, and I would be surprised if it wasn't revised southwards in fairly short order, nearer to the model consensus.

Dolly's next big test is how well it survives its sojourn over the Yucatan tonight and tomorrow. After that, there is not a whole lot that can prevent it from intensifying - except, perhaps, for some wind shear courtesy of an upper-level low that lies in Dolly's path (although even this appears to be moving out of the way).

Here's the official view, delivered in the most recent Discussion:

"THE OFFICIAL INTENSITY FORECAST IS CLOSE TO THE SHIPS MODEL SOLUTION OF A STRONG TROPICAL STORM OVER THE WESTERN GULF...ALTHOUGH THE GFDL FORECAST OF A HURRICANE IN THAT AREA IS CERTAINLY POSSIBLE."

PS: According to Google, I am far from the only blogger to have chosen "Hello Dolly" as their headline this evening. And I didn't even make the first page! Apologies for such a lack of originality....

Cristobal's centre to pass 36 miles from North Carolina?

The last few updates to the official NHC forecast have called for the centre of Cristobal to pass closer and closer to the coast of North Carolina. This shift is illustrated by the 3-day cone archive on the NHC website.

The latest NHC Bulletin reports that:

"THE CENTER OF THE TROPICAL STORM IS EXPECTED TO MOVE PARALLEL AND VERY CLOSE TO THE COAST OF NORTH CAROLINA TODAY AND BEGIN TO MOVE AWAY FROM THE COAST BY MONDAY."

Through the magic of Google Earth, I have calculated that the latest forecast track (issued as part of the 10am BST Discussion) will take the storm within 36 miles of Cape Hatteras, North Carolina, sometime between 10pm Sunday and 10am Monday (BST).*

There has not been any significant change to Cristobal's intensity overnight, with maximum sustained winds around the 45mph mark. Its satellite presentation remains unimpressive:

I'll post a further update later today.

* I'd like to post an image from Google Earth to illustrate this, but I suspect that doing so would be a breach of copyright.....

94L update

94L has entered the western Caribbean Sea. It remains a strong tropical wave, with winds of up to 35mph. However, the system continues to lack a closed circulation. According to the 10.35pm BST Tropical Weather Discussion:

"AN AIR FORCE RECONNAISSANCE AIRCRAFT INVESTIGATED THE SYSTEM THIS AFTERNOON AND DETERMINED THAT THE CIRCULATION WAS NOT CLOSED AT THIS TIME."

Nevertheless, conditions appear favourable for development. Wind shear of 5-10 knots won't be sufficient to arrest its development; neither will SSTs of 28°C plus (illustrated by my very rough plot of the computer model spread below):

These warm waters are also of a sufficient depth to permit development (see chart above).

94L is currently heading NW at around 15-20mph. All of the computer models call for two Mexican landfalls - the first in the Yucatán Peninsula, and a second in the Mexican state of Tamaulipas. The most northerly model (GFDL) forecasts that the second landfall will occur right on the border with Texas.

Watch this space....

Cristobal

A bulletin issued by the NHC at 7pm BST confirmed that Tropical Depression 3 has become Tropical Storm Cristobal, with maximum sustained winds of 40mph.

The same bulletin states that "SOME STRENGTHENING IS FORECAST DURING THE NEXT COUPLE OF DAYS." As far as I can see, any such intensification is likely to be limited by SSTs that are - at best - only marginally favourable for development (see my post earlier today), and by the higher wind shear that Cristobal will probably encounter once it passes north of the NC/VA border.

The storm is currently located around 100 miles east of Charleston, South Carolina. The official forecast track has not changed since my earlier post.

Time-lapse images of the Moon

Take a look at this awesome video over on the BBC website.

TD3 update

The latest satellite view indicates that the effects of Tropical Depression 3 are being felt along the coast of South Carolina:


This is confirmed by the local weather radar from Charleston, SC:


With maximum sustained winds now reaching 30 knots, TD 3 really is on the precipice of TS strength. Here's the headline from the 4PM discussion:

"THE TROPICAL DEPRESSION IS CONTINUING TO ORGANIZE AND IS NEARING TROPICAL STORM STRENGTH."

A US Air Force reconnaissance plane will pay TD3 a visit at around 6pm BST today - it may well be designated as a TS very soon after that.

Encouragingly, the NHC track has shifted to the right since my last post, due to the centre of the depression reforming to the east. The official forecast no longer calls for TD3 to make landfall anywhere on the US East Coast (although the coasts of North and South Carolina remain well within the 3-day forecast cone).

Updates on 94L and Bertha will follow later today.

New Weather Blog

One of these days, I really must set up a links sidebar. Once I do, Brendan Loy's new weather blog (hosted on Pajamas Media) will be right up there.

It's called The Weather Nerd. It's not clear whether this title was PJM's choice or Brendan's (I'd bet on the latter). Either way, I'm sure it will be terrific - so do check it out.

PS: Brendan's more general blog is also very good - see here.

Introducing Tropical Depression 3

On the off chance that anyone is reading this, I apologise for the lack of updates over the last couple of days. My time has been monopolised by other (less interesting) things. Normal service resumes as of now.

Much has happened since I last posted on Wednesday evening. Most notably, Tropical Depression 3 has formed - but not where I thought it might! It has not formed from 94L, the tropical wave that travelled over the Atlantic, across the Windward Islands and into the Caribbean. Instead, it has formed from 96L - an area of thunderstorm activity that started out just off the west coast of Florida on Wednesday. I pretty much ignored 96L, because it seemed so unlikely to develop before reaching Florida (which, in retrospect, was rather short-sighted).

By Thursday afternoon, 96L's journey had taken it roughly NE over Florida and into the Atlantic, just off the coast of Georgia. It continued to move NE during the course of Friday, alongside the coasts of Georgia and South Carolina. 96L became better organised during this period, and was finally designated as a TD at 4AM BST this morning.

The centre of TD3 is believed to be about 65 miles SE of Charleston, South Carolina, heading roughly NE at around 5mph (although the latest NHC bulletin reports that it has been moving rather erratically today). This motion should take it parallel to the coasts of South and North Carolina. The GFDL model then calls for TD3 to take a sharp left into Pamlico Sound, followed by landfall near Engelhard, North Carolina on Sunday afternoon/evening. None of the other model tracks take TD3 much closer to the east coast than it is now. The official NHC track is in the middle of the guidance envelope. It calls for TD3 to cross over the Outer Banks, but no further inland. Unsurprisingly, a tropical storm warning has been issued from the South Santee River in South Carolina all the way up to the NC / VA border.

I predict that TD3 will become Tropical Storm Cristobal within the next 24 hours. Its current intensity is only just shy of the minimum TS threshold, with maximum sustained winds of 35mph. Moreover, its minimum central pressure of 1007mb is already indicative of tropical storm strength, based on the rule of thumb that W = 1375-(1.315 x P) [where W denotes maximum sustained winds, and P denotes minimum central pressure].

However, it's fair to say that conditions are only just favourable for development. Wind shear is in the 10-20kt range, and my crude plot of the NHC forecast track over current SSTs below illustrates that TD3 is expected to stay within the 26°C zone (although very close to warmer waters):


I think these conditions, together with the current minimum central pressure, are sufficient to support my prediction that we will be saying hello to Cristobal by this time tomorrow. Here's the official view, delivered in the 10AM BST discussion this morning:

"ONLY A SLIGHT INCREASE IN INTENSITY IS INDICATED IN THE FORECAST. NEVERTHELESS...THE SYSTEM COULD BECOME A 35-KNOT TROPICAL STORM."

Holiday season underway

I can report that the 4.30 to Brighton is absolutely jammed.....

94L may be a Tropical Depression

94L has taken a bit longer to develop than many observers had expected (including me). Indeed, it spent quite a bit of yesterday becoming less organised. That trend was reversed somewhat today, with some convection developing but still no sign of a closed circulation. The visible satellite presentation is not particularly impressive:


A Hurricane Hunter reconnaissance aircraft is currently checking 94L to see whether it has become TD3. This is possible, but I wouldn't put much money on it (it just doesn't look like a TD on the satellite imagery). I'll report back on this later.

For now, the disturbance is moving roughly westwards at around 20-25mph. I can't find any local radar images for the islands of Barbados, St Vincent or Grenada but, judging by the water vapour satellite loops, I'd wager that they are experiencing heavy rainfall at the moment.

UPDATE: This just in from the NHC:

"ALTHOUGH THE SYSTEM HAS A BROAD CIRCULATION...DATA FROM THE AIRCRAFT INDICATE THAT THE SYSTEM LACKS A SINGLE WELL DEFINED CIRCULATION CENTER. IN ADDITION...THUNDERSTORM ACTIVITY ASSOCIATED WITH THE LOW HAS BECOME LESS ORGANIZED THIS AFTERNOON. CONSEQUENTLY...THE SYSTEM IS NOT BEING CLASSIFIED AS A TROPICAL DEPRESSION AT THIS TIME."