Sunday, July 24, 2011

Tropical Update

We are still watching two invests in the Western Pacific and one of them is about to become a tropical depression.

Invest 93W, last located approximately 450km east of Catarman, Samar, now has improved convective activity over the last 6 hours. A partially exposed low level circulation center can be seen on the VIS image. The corresponding IR image shows cooling cloud tops, mainly to the west and south portions of the system due to light to moderate easterly wind shear of 10-20kts. An ASCAT pass also reveals surface winds of up to 25kts located on the southern half. Because of these developments, JTWC, has now upgraded 93W's chances to "High" and is also issuing a Tropical Cyclone Formation Alert (TCFA). If it becomes a cyclone, PAGASA will assign the local name "Juaning."

Right now, light to moderate rains are now making their way towards Samar and Eastern Visayas, as well as the Bicol Region. Rain will continue for these areas for the next 2-3 days as 93W tracks parallel the archipelago.

Computer models initialized well with the system although they diverge a bit on the medium term. The consensus, though, will bring this future storm near the Northeastern part of Luzon. GFS is the southern outlier bringing the storm to Aurora while the NOGAPS misses the Philippines and brings it towards Taiwan. Projected landfall time is around Wednesday or Thursday (if it does happen). Residents along the eastern seaboard from Samar/Leyte all the way up to Cagayan must closely monitor the progress of Invest 93W.

Another area of interest we are watching is 94W, near Chuuk in the Eastern Micronesia. Satellite and microwave images also show cooling cloud tops and improved banding. 94W is in an area of light to moderate wind shear although it currently has a lesser chance compared to 93W mainly because of its proximity to the equator. Nevertheless, computer models are also keen on developing 94W to a storm in 2-4 days' time. It could pass south of Guam early next week and move north of Yap by the middle of next week.

 If necessary, we will put up another update by 12 midnight tonight (Philippine Time).
Issued (08 UTC) 4pm PhT 072411

No comments:

Post a Comment