Monsoon Low Leaves Torrential Rain in North India

Jun 21, 2011; 2:13 PM ET

MONSOON LOW SHIFTS LOCUS OF SUBCONTINENT RAIN

A deep cyclonic low drifted ashore in the Sundarbans southeast of Kolkata late last week, then set out westward over northeastern and north-central India.

Tropical low centered over mid-northern India on June 21, 2011 (IMD satellite image).

As of late Tuesday, local time, the still-well-marked center of low pressure lay near the Madhya Pradesh/Uttar Pradesh line.

This low has yielded some very heavy falls of rain in West Bengal and Jharkhand, and into northern Chattisgarh and eastern Madhya.

Rainfall was about 35 cm at Bankura, West Bengal; in Jharkhand, Ranchi got more than 30 cm.

Needless to say, rainfall has gotten a fast start “out of the gates” with amounts well above normal, a slightly slow Monsoon onset notwithstanding. The India Meteorology Department (IMD) called the SW Monsoon onset a few days later than average in northeastern India, but the onset has accelerated to near-average status in the middle north.

In apparent compensation for all of the rising air tied to rains with the strong low, there has been a marked lessening in coverage and intensity of rains in the south and west; most have fallen between the Arabian Sea and the Western Ghats, owing to uplift of the SW Monsoon flow over the hills.

As the low continues to track westward, weakening, during the next few days, the overall pattern of rainfall may stay little changed. The SW Monsoon advance will be on hold for Gujarat even as it proceeds across the north.

IMD GIVES SCHEDULED UPDATE OF LONG RANGE MONSOON FORECAST

Today, June 21, the Long Range Forecast Update is posted on the IMD website.

In a nutshell, there is little new in the forecast, as near-normal rainfall is forecast for India as a whole. The forecast of 98 percent of long-term average rainfall is about the same as that forecast in the preliminary outlook.

TYPHOON IN THE MAKING

There is good reason to believe that the next typhoon or strong tropical storm is in the works east of the Philippines. Numerical forecast models show a significant tropical low east of Philippines by Thursday. First landfall could be anywhere from Taiwan east to Okinawa on or about Friday.

It is too early for me to know whether this would-be tropical cyclone will stay well east of China or strike the east following a hit upon Taiwan.