Aloha from Beautiful Honolulu,
We are still nearly a month away from the official start of the 2009 Atlantic hurricane season, but the Western Pacific, as you may expect, is already off to a boisterous start with several newly named storms.
Although there is no official 'Season' in the Western Pacific (they have been observed in every month, if conditions are favorable), most cyclones do occur between April and December.
Already, a Major Typhoon, KUJIRA (01W), has rapidly spun up from a tropical storm after a series of well-organized inner-core convective bursts supported by an excellent outflow channel to the NE. It has a small, compact and very well organized structure with a 150 mile-wide Central Dense Overcast (CDO) sporting a tiny, 10 mile-wide eye.
Typhoon Kujira has exhibited 'explosive intensification' on it's way to it's current 115 Kts., (Hurricane Category 4), with central pressures lowering down to 937 mb, presumably with the help of that superb outflow channel. Very impressive signature on the animated satellite loops.
Interestingly, for being at severe hurricane 'Cat 4' strength, it's typhoon-strength winds (65 Kts.) only extend out to 30 miles from the center, a sure indicator of a small, compact cyclone with an extremely tight pressure gradient in it's eyewall structure, similar to Florida's 'Hurricane ' from 5 years ago.
The Joint Typhoon Warning Center (JTWC), located here at Pearl Harbor, has the typhoon intensfying still a little more, just before making a rendezvous with the island of Iwo To and vicinity. (How far is that from Iwo Jima?)
Meanwhile CHAN-HOM (02W) has also formed, this one well to the SW of the Phillipines, but on a path of slow recurvature taking it into those islands in 3 or 4 days, probably as a weakening tropical storm after peaking briefly as a minimal typhoon a day or so before landfall. Flash flooding in mountainous regions is, perhaps, the greatest danger with this type of scenario. An all-too-common occurance in this part of the world.
Both 'storms' are already on paths of recurvature, a behavior commonly seen with early season tropical cyclones in many basins, including the Atlantic (NW Caribbean or BOC storms recurving, immediately upon formation, into the GOM, for example).
And the Official start of the Eastern Pacific Basin is on May 15th.
The National Hurricane Center in Miami starts making official Tropical Weather Outlooks (TWO) for the Eastern Pacific area fully 2 weeks before the start of the Atlantic hurricane season, due to the frequent early-season tropical cyclones that form in the very warm waters just off the western coasts of Mexico and Central America.
I'll be updating these 2 'WestPac' storms over the next few days and see what effects, especially Kujira, has on any of the islands in their projected paths.
Further info and imagery at the excellent Navy Research Lab website: http://www.nrlmry.navy.mil/tc_pages/tc_home.html