Thursday, October 01, 2009

Could another "Onil" be in the making?

The storm track of T.C. Onil can be found at this link. More on 2004 North Indian Ocean cyclones here.

Onil began as a tropical depression on Oct. 1, 2004. It became a tropical cyclone on Oct. 2. Dry air then "killed" the storm as it drifted northeast to westernmost Gujarat state, India, on Oct. 3. The low-level center, drifting southward over the Arabian Sea, spun for another week, however.

Ali writes in the comments that T.C. Onil yielded heavy rain at Badin, Sindh, Pakistan, along with nearby Gajarat. I believe that I recall, ever so distantly, this storm, but not any details.

--Could another "Onil" be in the making? I do not know, but the makings of an Arabian Sea depression or even cyclone can be found over peninsular India now, It has already triggered a burst of heavy rain at Ratnagiri. The GFS numerical forecast scenario shows a center of low pressure emerging along the west coast (Karnataka) during the next few days. With it heavy falls of rain over a fairly small area along/west of the Ghats.

Next, the wandering low is tracked along an erratic path towards the north and west to become a full-blown cyclonic low early next week. It is all forecast to end with a swoop towards the northeast and landfall upon Gujarat.

-What to make of this? Well, there will be some low pressure along the west coast of India during the mid to late week with local heavy falls of rain nearby. If the low shift far enough away from land, tropical cyclone status could be reached. At the start of next week, enough moisture for scattered thunderstorms will reach as far north as Sindh.

-By the way, the latest (1200 UTC on Tuesday) run of the GFS drops heavy rain over Karachi. This idea of extremely abnormal heavy rain over Karachi simply will not "go away." I would be more apt to believe this idea were it to be forecast for the same days, rather than shifting randomly from run model run to the next.

--Quickly, on Typhoon Ketsana. Landfall was apparently near Binh Son, south of Danang. Far from angling northwestward to skirt the Vietnam coast, Ketsana in truth jogged southward to landfall south of the JTWC forecast track (of Monday). Top winds at landfall were reckoned at 90 knots, or 165 kph -- a Category 2 (Saffir-Simpson) hurricane.

Rainfall owing to Ketsana was over 35 cm at Danang and at least 45 cm at Hue.

-And now, there are three more tropical cyclones (depressions and storms) lined up eastward from Philippines: 18W, 19W (Parma) and 20W. More on these later.

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