Wednesday, April 17, 2013

8:30pm, T.showers seen over Uttarakand, N,N-E Madhyapradesh, S.Bihar, S.Bengal, N-E states and S,central.Tamilnadu. http://ow.ly/i/1UBgn 
RT @shivaranjan: Room Temperature @ 7:09 PM #Chennai 32 C cc: @weatherofindia http://t.co/cT2CxyDQD7

HOT zones in India during next 3 days

Very HOT zones in India during next 3 days are going to be W,N-W India, N-E Madhyapradesh, S.Uttarpradesh and most of North Peninsula.

From Saturday, 20-Apr till 24-Apr, the HOT conditions along most of Peninsula and S-E India is expected to be below normal due to a strong low level Anti-cyclone to form over Central Bay.


Monsoon - update #1 - 17-Apr-2013

#Monsoon, 17-Apr - The Mascrene high is weak and there's a LOW pressure system East of Mauritius which is hindering the development!

#Monsoon, 17-Apr-2013 - Sea temperature is above 30 C over most of S.Bay and S,S-E Arabian sea ... http://ow.ly/i/1Utwg 

#Monsoon, 17-Apr-2013 - Seasonal heat LOW over N-central,N-W India is taking shape, today it was around 1002 mb.. http://ow.ly/i/1UtCo 
Yesterday, #Chennai - Airport recorded max temp. of 39.8 C. Now 2:10pm its around 37 C, feels like #WoW 47.7 C,Sea breeze slowly picking up!

7.8 earthquake in south eastern Iran on April 16, 2013



The ongoing collision of two enormous slabs of the Earth’s crust—the Arabian and Eurasian plates—caused a magnitude 7.8 earthquake in southeastern Iran on April 16, 2013. The quake was the largest to hit Iran in more than 50 years. Its epicenter was about 83 kilometers (52 miles) east of Khash, a city with a population of more than 70,000.
Earth’s crust is broken into giant plates that cover the surface of the planet like pieces of a puzzle. Individual plates constantly collide and grind against one another as they slide on top of a somewhat fluid layer of the Earth’s interior known as the asthenosphere, causing earthquakes in the process.
The Arabian plate is sliding north-northeast at a speed of about 37 millimeters (1.5 inches) per year relative to the larger Eurasian plate. Where the two plates collide in an area known as the Makran subduction zone, the Arabian plate plunges beneath the larger Eurasian plate. As it descends into the mantle where it will eventually melt, earthquakes occur deep beneath the surface, along the boundary between the two plates.
According to the U.S. Geological Survey, the earthquake was the result of faulting at an intermediate depth in the Arabian plate lithosphere, approximately 80 kilometers (50 miles) beneath Earth’s surface. The descending Arabian plate has caused quakes as deep as 160 kilometers (100 miles) beneath the surface in this area in the past, though most have been at much shallower depths.
This image, based on elevation data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER) on NASA’s Terra satellite, shows the area where the earthquake occurred. Land is shown with shades of green and beige. Higher elevations are lighter in color.
Global agencies forecast a normal South West monsoon this year ... http://ow.ly/k8O0H 

South-West monsoon is expected to break over the Kerala coast two to three days earlier !


The South-West monsoon is expected to break over the Kerala coast two to three days earlier than usual, says P.V. Joseph, eminent monsoon meteorologist and researcher.
Joseph has been a former director of India Meteorological Department (IMD) and is professor emeritus in the atmospheric science department at Cochin University of Science and Technology.


CLOUD BAND

He told Business Line on Tuesday that the long-term mean date of onset of monsoon over Kerala was June 1. A cloud band with rain-bearing thunderclouds had formed over extreme South Bay of Bengal.
This cloud band was expected to intensify and move northwards and give light to moderate rain in Kerala, Tamil Nadu and south Bay of Bengal during the next few days.
This cloud band is called the ‘pre monsoon rain peak,’ which is an indicator of the date of onset of South-West monsoon over the Kerala coast.


BAY ‘WARM’

The pre-monsoon rain peak is reached when surface temperature of seawater in the Bay of Bengal off India’s east coast rises about 35-40 days before the monsoon, and clouds near the Equator move north.
Joseph’s pre-monsoon rain peak is among the key parameters used for its own forecast by IMD. He is often consulted by the department while finalising its forecast.
Joseph said that last week’s average of sea surface temperature measurements obtained from Indian satellite Kalpana-1 as on April 15 had shown that the Central Bay of Bengal is ‘very warm.’
Sea surface temperatures have measured to more than 30 degree Celsius, a pre-condition for the formation of the pre-monsoon rain peak.


PAST TREND

It is the western edge of this rain band that normally gives moderate rainfall over Kerala and Tamil Nadu during this season. The Bay Islands have already been getting rain.
It has been noticed in the past that once central Arabian Sea too warms up to 31-32 degree Celsius, a rain band would form over south Arabian Sea as well.
This rain band would intensify to bring about the monsoon onset over Kerala. While doing so, it would also induce the formation of the low-level jet stream of monsoon, a current of strong south-westerly winds.

#HOT #Chennai - at 1:10pm, temperature = 38 C and feels like 45.9 C. Humidity around 45%.

Other #HOT places in India are ... Nagpur = 43 C, Hyderabad = 40 C.

Yesterday, highest maximum temperature of 44.1°C was recorded at Rentachintala (Andhra Pradesh)

1pm, W.D has cleared out from N,N-Central India. Showers continue over most of N-E states, Rest of India is #HOT... http://ow.ly/i/1UqHz 

1pm, http://ow.ly/i/1UqHz ... T.showers popping over N,central Tamilnadu.