Monday, July 4, 2011

Tropical Update

Still tracking three low pressure areas today, and two of them are less than 1000km apart. Invest 97W and Invest 96W are in the Philippine Sea (east of the country), while 95W is in South China Sea, near Palawan.

Invest 97W is a new LPA that popped up today. It was last located just 280km east southeast of Virac, Catanduanes. ASCAT pass reveals a small and weak circulation with winds of about 20-30kph. Latest weather reports around the country also hints at a broad cyclonic circulation. Furthermore, pressure reports in Luzon range from 1008-1010mb. Satellite and IR images show weak convective activity, with the majority of it displaced to the west and is now affecting Catanduanes and the Bicol Area. JTWC is giving a "Low" mainly due to the moderate wind shear in the area of 20-30kts. Computer models are not picking this system up either.

Invest 94W, meanwhile, has a higher chance of developing, and JTWC has re-upgraded it back to "Medium". With the dissipation of 96W, 94W can now develop more easily, although the presence of a TUTT in the Philippine Sea continues to bring subsiding air and thus impedes 94W's development. Furthermore, its proximity to 97W won't help; if one of them develops, one has to rob the other off of energy. With that said, wind shear is somewhat favorable and the TUTT cell is forecast to move northeast allowing 94W to intensify slowly. Computer models are are still having a hard time, however; although most of them are now picking up this LPA, forecasting it to be a weak cyclone by the middle of this week.

Invest 95W, is drifting in the South China, embedded in the active monsoon trough. Development for this system is unlikely, however.

Satellite image from NRLMRY showing the three LPA's position, as well as that of the monsoon's.And here's an ASCAT image showing the surface winds and the circulation of Invests 97W and 96W.
As for the weather in the Philippines in general, the ITCZ is very active at the moment, affecting large parts of Visayas and Mindanao. Rainfall amounts continue to range from 100-200mm which can result to flash floods and landslides. Furthermore, the presence of two LPA's and the potential for a cyclone this week, it looks like rain will continue for the Philippines throughout this week. Although, parts of Northern Luzon are actually enjoying nice, dry weather, which could turn wet if a cyclone does form.
Issued (0730 UTC) 330pm PhT 070411

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