Extreme Rainfall Hits Philippines
-South East Asia:
I spoke on Wednesday about two `hot spots` with respect to tropical weather over the western North Pacific basin, these being to the east and the west of the Philippines, respectively. As of Thursday, the JTWC have posted a `formation alert` relating to the potential for a tropical storm to form over the South China Sea (west of the Philippines). At this time, however, I want to talk about what has lately been happened over the Philippines. Owing to converging low-level winds, out-flowing winds aloft and the hilly nature of the Philippine landscape, there have been instances of torrential rain south and east of Manila.
On the eastern island of Catanduanes, our data shows 36-hour rainfall (through Thursday night (local time) of
697 mm, or 27.4 inches, at the weather radar site (north side of the island). Shrinking next to this, yet still dramatic, are these falls (within two to three days): Alabat -320 mm/12.5 inches, Daet (southern Luzon) - 335 mm/13.2 inches, Virac (southern Catanduanes) - 275 mm/10.8 inches. And the heavy rain is not done. The unsettled setting of converging moisture-laden wind over the archipelago will make for local excessive rainfall through at least early next week.
Now, as for the potential for a tropical storm, things are not so easy. Notwithstanding the JTWC plotting tropical low pressure off west-central Philippines, numerical weather forecasts are divergent as to what will happen--and when it may happen. My take is that no tropical storm will form within the next two days west of the Philippines. The low-level cyclonic swirl (weak low pressure) now over the eastern South China Sea may either dissipate and reform east of the Philippines, shift bodily east to the nearby Philippine Sea, or none of the above.
I am inclined to believe that a tropical storm will happen over the western North Pacific Basin within the next five days (give or take), but I do not know where.
-South Asia:
In South Asia, there was further weakening of the severe heat over Pakistan on Thursday. Thus, the highest temperature was `only` 44 degrees C at Pad Idan. Nawabshah had 42.5 degrees; the hottest at early week was 48 degrees C. Farther south and east, there was widespread 44- to 46-degree (111-115 degrees F) heat spread over northern and middle India. In eastern Maharashtra, Nagpur reached a full 47 degrees C on Thursday. Akola, with 46 degrees, was right behind in line.
The trimming of severe heat over Pakistan has happened owing to a weak low pressure aloft, not unlike a so-called `Western Disturbance` although I believe this may have reached Pakistan from the Arabian Sea and not from the west. Whatever it's path into the Subcontinent, this weak low will veer eastward as it slowly crosses the northern Subcontinent during the next few days. It may spark local heavy thunderstorms at the weekend in the highly storm-prone northeastern Subcontinent (near the Khasi Hills with its renowned rain-soaked town of Cherrapunji).
As the weak low pressure wave heads eastward through the end it the week, it will also trim the heat, if only a little, over the northern half of India.
Posted by Jim Andrews on Thursday, April 30, 2009 1:35 PM
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