Saturday, October 25, 2008

2 hr Heavy rain

Yesterday (24-oct-08) very heavy electric shower lashed almost all parts of the city
Chennai airport reported 122 MM
Showers lashed for 2 hrs.

Some comments from Accuweather blog

My sights having been turned elsewhere, I missed the exceptional heat over southern Pakistan at Karachi. This heat wave has seen 8 of the last 14 days (as of Thursday) reaching 100 to 102 degrees F/about 38-39 C.

The normal average daily high for October in Karachi is 92 degrees, or about 33 degrees C. October is the heart of a "second summer" in Karachi owing to the onset of offshore winds (related to the North East Monsoon) before lingering summer heat has faded.

About the NE Monsoon, I see that rains have gained ground northward along the east (Andhra) coast. At Nellore, a lull in the rain followed about 10 inches/25 cm since Sunday. To the west, weak tropical low pressure over the Arabian Sea has spurred rainfall of 9.2 inches since Tuesday on Amini, one of the small Lakshadweep Islands.

As of Thursday, that weak tropical low seems less likely to become a tropical depression given the trend in numerical forecasts. More emphatic are forecasts of a tropical depression or tropical cyclone east of India during the early week.

MJO - Madden-Julian Oscillation

A good insight into MJO - by Ahmed,
For more on MJO click here
Forecasts based on the movement of the periodical Madden-Julian Oscillation (MJO) wave of alternating enhanced and suppressed phases of rainfall suggest that the ongoing wet session over the southern peninsula would weaken towards the month-end. This is based on the assessment that the current phase of the MJO wave, travelling periodically from West Africa into Indian Ocean and further east into the equatorial Pacific and beyond, would be followed up by the suppressed phase from November 1.

This weakened rain phase would last until November 22, according to the ensemble forecast system of the US National Weather Services. The successor MJO phase of enhanced rains is expected to get anchored over equatorial Indian Ocean and the southern Indian peninsula from December 2.

A long-term outlook by the UK Met Office and the European Centre for Medium-Range Weather Forecasts suggested ‘above normal’ rain for southern peninsula through December, January and even early into February.

"I think this happenned last year too. We had a good rain in October, then Nov was very dry and again rains picked up in December"