Typhoon Dolphin

[Somerset Squall]

After a month of inactivity, a tropical depression has formed about 400 miles east of Guam. 27W is currently packing sustained winds of 25kts, but is expected to strengthen over the coming days as waters are warm and shear continues to decrease. 27W is quite far out to sea so is no threat to land... yet. 27W is forecast to move generally westwards throughout the next few days whilst slowly gaining strength. I'm not going to say whether 27W will become a typhoon in the future but it certianly has plenty of water to cross before reaching any land. But will the shear remain low enough? The system was being buffeted by 40kts of shear yesterday and this could easily happen again. One to watch.

[Cookie]

as somerset was saying miles from land!

[Somerset Squall]

Intensity has increased to 30kts. However, the satellite appearance of 27W is far from amazing. A small area of convection lingers near the centre but is limited in coverage. Convectional banding is weak. Shear is now expected to become very strong in the next day or so. So the long term future for 27W now looks quite bleak, however, the shear forecast is fairly uncertain so things may still change. The one thing 27W has on it's side are sea temps.

[Cookie]

thanks for the updates mate :lol:

[Somerset Squall]

27W has slowly become better organised over the last day or so, and has now strengthened to 40kts and been named Dolphin. Dolphin will continue westwards towards the Philippines and continue to intensify. Initially, dry air was hampering development, but Dolphin is moving into a moist environment now with low shear and improving outflow. Dolphin is forecast to peak at 60kts before landfall in Philippines so it easily could become a typhoon. Dolphin has a good central dense overcast feature which should help it intensify more quickly. Dolphin is certainly looking better than it did last night, the more moist environment has really helped this system along. The Philippines need to keep a close eye on Dolphin over the next few days. Landfall is expected to occur in around 5 days time- as mentioned above Dolphin still has a lot of ocean to cross as it formed so far east out to sea.

(Interesting to note that JMA now forecasts a peak of 75kts in the latest advisory just out- typhoon now looks quite likely.)

[Somerset Squall]

Dolphin has slowed down but is still moving westwards towards the Philippines. Intensity remains at 40kts and the storm has potential for further strengthening. However, the track forecast has changed. Dolphin is expected to continue to slow to a crawl to the east of the Philippines as it approaches a weakness in the subtropical steering ridge to the north. This will allow Dolphin to push northwestwards, meaning it may miss the Philippines. Another possibilty highlighted in the most recent JTWC forecast discussion is a trough picking up Dolphin and sending the storm northeastwards. Either way, landfall in the Philippines is less likely.

Dolphin will also weaken as it nears the Philippines in a day or so as shear is now forecast to increase again and another cold, dry surge of air is expected to impact the storm. This should induce the weakening trend at around 60hrs so Dolphin still has that time to intensify in generally favourable conditions.

[Cookie]

thanks for the updates, an interesting choice in name,

[Somerset Squall]

thanks for the updates, an interesting choice in name,

Indeed, it seems out of place with the other West Pacific names! It's a weird name for a tropical cyclone in any basin I think!

[Cookie]

can you see this system becoming a cat 1 system?

[Somerset Squall]

can you see this system becoming a cat 1 system?

Possibly, it certainly has enough time over water, it just has to stay away from the dry, cold air which will inevitably affect the storm again soon. It is certainly a well organised storm currently, intensity has now increased to 45kts so yes, I'd say Dolphin has a good shot at cat1 typhoon status. Not certain though of course

[Somerset Squall]

Dolphin has continued to intensify overnight and is now a 55kt tropical storm. The storm still shows off an impressive central dense overcast feature with some fairly good banding. Dolphin has 48 more hours in which to strengthen. Thereafter, a cold, dry surge of air and increasing shear will weaken the storm. It now looks more likely that the trough swinging in to the northwest of Dolphin will create a bigger weakness in the subtropical steering ridge and allow Dolphin to make a sharper turn to the north beyond 48hrs. The Philippines look to come off largely unscathed with this storm.

[Cookie]

yup dose looks like quiet a sharp turn!

[Cookie]

quite a small sytem really, big low pressure behind the storm as can be seen by somersets first post.

also can be seen in post below

[Somerset Squall]

Indeed, clearly shows the difference between an extratropical cyclone and a tropical cyclone. Tropical cyclone being more intense but smaller. I wouldn't say Dolphin was really that small but I can see your point in comparison to the very large extratropical cyclone to the northeast.

Dolphin strengthened to 60kts this morning, but since then convection decreased and intensity is back down at 55kts. Dolphin is still forecasted to become a typhoon though (maybe tonight) before being dragged north into a more hostile environment.

[Somerset Squall]

Intensity is back up to 60kts and Dolphin is perhaps on the brink of becoming a typhoon. Good banding features persist along with impressive outflow and CDO feature. There is no eye as yet but Dolphin has about 12hrs in which to strengthen further. Beyond this, a trough will drag Dolphin northwards into a highly sheared environment which will induce a fast weakening trend. It is possible Dolphin may have peaked in intensity and may not become a typhoon at all, but it is certainly very near...

[Somerset Squall]

Dolphin is now a 65kt, cat 1 typhoon. I'll have an update later when I have more time.

[Cookie]

looks a good typhoon, gusts of over 100 mph

up to a cat 2!

[Somerset Squall]

Indeed Cookie, Dolphin has surprised me a little this afternoon. Intensity has leapt up to 90kts and the typhoon has a well formed eye with excellent spiral banding. Dolphin has made use of the superb outflow and low shear to rapidly strengthen this afternoon. After a slow start, Dolphin has certainly proved the West Pacific can definitely support a strong typhoon in late season.

Because Dolphin has become stronger than anticipated, it will respond more to the trough swinging by to the north. In fact, this is already occuring as Dolphin has made a sharp turn to the north and is expected to accelerate northeastwards. This motion will take Dolphin over colder waters and higher shear so weakening will commence very soon.

[Cookie]

yup surprised me as well, seemed to really get its act together and fast.

[Cookie]

correct me if im wrong appears to be going through an eye wall replacement!

[Somerset Squall]

correct me if im wrong appears to be going through an eye wall replacement!

Possibly Cookie, it's a little difficult to tell but if you are referring the eye dissapearing then that's more likely due to it becoming cloud obscured. Take a look at this satellite loop and you can see the eye dissapear behind clouds. Also, take note of the southwest moving clouds to the northwest of Dolphin- this is the cold, dry airflow previously mentioned which will weaken Dolphin:

http://cimss.ssec.wisc.edu/tropic2/real-ti...sirbbmjava.html

A classic way on satellite imagery to pick out an eye wall replacement cycle is if a second wall (or double eye) appears. The two walls battle for dominance before the inner wall collapses, the outer wall becomes dominant and contracts. EWRC's are often preceded by weakening followed by re-intensification (sometimes rapid if conditions are right).

Dolphin has weakened to 85kts. The eye is re-emerging on satellite imagery but isn't looking quite as well defined. However, banding still remains very impressive and weakening will be slow, at least at first.

[Cookie]

thanks somerset, wasn't 100% sure wanted to get an experts thoughts!

[Somerset Squall]

Dolphin has steadily weakened today and is now a minimal typhoon with intensity of 65kts. Dry air is penetrating the system, reducing the convection and weakening the core. The eye has dissapeared along with the excellent banding features and all that remains is a small area of deep convection over the centre. Further weakening will occur whilst the typhoon moves northeastwards, and dissipation is expected to occur in a few days time.

[Somerset Squall]

The slow weakening continues. Dolphin also continues to march northeastwards in a high shear environment. Thus, further weakening can be expected until dissipation- forecasted to occur in 36hrs time.

[Somerset Squall]

Dolphin has dissipated. The LLC is no longer discernable and has been absorbed into the cold front associated with a large extratropical low to the northeast. All deep convection has also dissipated.