Thursday, April 15, 2010

Another squally thunder storm over North-W.Bengal at around 8:30pm and now 11:30pm its over North Bangladesh ..
7:30pm, a Super thunder cell over the tornado hit zone of North W.Bengal sweeping fast into North Bangladesh now ..
RT @soumiks: Sight of first rain at kerala. Just beautiful. Have to wait for this 3 months in mumbai.
Chennai - From now on thunder storms will come from south-west, west or North-west.. till August.
Chennai - threat of rain has been removed.!.. we have to wait till NOON of 16-Apr for the next RAIN window.
Heavy thunder squalls over S_E corner Nepal, North extreme Bengal, North Bangladesh and into N-E states..
More thunder cells along Kerala western ghats, south Karnataka and over North Karnataka ..
Got the confirmation from South Kerala .. it's Raining there.
RT @intorpidire: @weatherofindia Its raining in adoor, pathanamthitta.. . Wid lightning and thunder. kerala weatherofindia
RT @dipsubha8: praying for norwester,its too hot here at kolkata
Raining in south extreme Kerala ?? we need "twits" from there to confirm. Thanks
"India's indigenous GSLV-D3 rocket fails in mission along with GSAT 4 satellite" .. .. Weather problem ??
4:30pm, we are witnessing a minor thunder cell over South Maharastra bordering with Karnataka. And more heavy showers over S-W Bengal.
4pm, Heavy thunder squalls over North-east Orissa, and into bordering S-W Bengal ..
4pm, Thunder cells visible over South extreme western ghats (kerala), central Andhra and one over north Karnataka.
Some isolated and minor (at this time) thunder cell formation is seen over south extreme end of western ghats.
Some isolated and minor (at this time) thunder cell formation is seen over south extreme end of western ghats.
Some isolated and minor (at this time) thunder cell formation is seen over south extreme end of western ghats. ... isolated thunder storms with HIGH winds over North and SOuth Orissa. ... isolated thunder storms with HIGH winds over North and SOuth Orissa.
ALERT :: Chennai - is experiencing more cloud formation now 3:37pm, these are signs of RAIN..!
Cloud cover over North Tamilnadu and South-east Andhra is keeping afternoon temperatures to moderate..
Medium high cloud cover over North Tamilnadu, we might have a thunder storm in these zone in next 5 hrs..
1pm, already we have thunder showers over North and South Orissa ..
IMD: A strong western disturbance around April 20, which is expected to dig its heels into northwest India before moving further east.
northeast is shown to ‘light up' yet again thanks to raised level of thunderstorm activity from Nor'westers..
Seasonal thunderstorms have announced their arrival with a vengeance over Bihar and West Bengal ..
Western forecasts signal good monsoon in India ...

Rain to continue in the North-East

Seasonal thunderstorms have announced their arrival with a vengeance over Bihar and West Bengal with typically destructive gale-force winds wreaking havoc in the contiguous border areas of the States late on Tuesday night.

Brute force

Thunderstorms during this time of the year are seasonal in nature and are called Nor'westers, thanks to the trigger in the westerlies blowing from northwest India.

Nor'westers can at times pack a deadly punch with accompanying high winds, lightning and thunder activity. Moisture incursion over heated land sets up the ideal conditions for the storms to take shape.

India Meteorological Department (IMD) said in its update on Wednesday that the causative land-based trough ran down from Bihar to south Chhattisgarh across Jharkhand and Orissa.


Another trough ran down from north Karnataka to Tamil Nadu with an embedded cyclonic circulation over Karnataka and neighbourhood.

Satellite cloud imagery showed the presence of low to medium clouds (partly clouded conditions) over parts of peninsular India, the north-eastern States, south-east Arabian Sea and south Bay of Bengal.

Meanwhile, international weather models indicate that the westerlies would hold sway over the region during this week and possibly the next, with western disturbance activity picking up once again.

The first of the series may enter the northwest as early as Thursday (tomorrow) and may get particularly accentuated over east and northeast India due to the presence of the trough. The wind strength and the depth of the trough are mutually complimentary, with one feeding the other. Since the Nor'westers have drawn first blood in the Bihar/West Bengal region, it is likely that the latter could witness continued activity over the next few days as well.

The IMD has forecast scattered to fairly widespread rain or thundershowers over the north-eastern States during the next 24 hours but may decrease thereafter.

Isolated rain or thundershower is likely over West Bengal, Sikkim, Jharkhand and Orissa during the same period.

Widespread showers

Forecast until Monday hinted at the possibility of scattered to fairly widespread rain or thundershowers with isolated thunder squall over the Northeastern States. According to the US National Centres for Environmental Prediction, the week ending April 21 would see isolated rains over parts of northwest India, scattered over northeast India and the southwest coast (mainly Kerala, south-coastal Karnataka).

But the proceedings would likely get a leg-up during the week that follows (April 22-30) with showers activity being indicated from southwest Rajasthan to the rest of the northwest India, east India and northeast India.

The northeast is shown to ‘light up' yet again thanks to raised level of thunderstorm activity from Nor'westers.

The ‘rain trail' from the northeast will sneak down south-southeast to east India, east-central India and adjoining peninsular India before linking up with the weather activity along the southwest coast.

This is being mainly attributed to the arrival of strong western disturbance around April 20, which is expected to dig its heels into northwest India before moving further east.

Given this context, the heat wave in the northwest and east India might scale down during the last 10 days of the month. But this could also interfere with the heating process necessary to set the stage in the northwest for monsoon to drive in.

Meanwhile, overnight on Wednesday, heat wave conditions prevailed over many parts of Northwest India, north Gujarat, Chhattisgarh, interior Orissa, Jharkhand and isolated pockets of northeast Madhya Pradesh, Vidarbha, costal Andhra Pradesh and costal Orissa.

The highest maximum temperature of 45.5 deg Celsius was recorded at Hirakud in Orissa. Rain or thundershowers have occurred at many places over the Northeastern States and at a few places over Karnataka and at isolated places over Kerala during the past 24 hours.

Earthquake : Sumatra Subduction Zone

A magnitude 7.7 earthquake struck deep beneath the Selat Mentawai (Mentawai Straight), between Sumatra and the nearby Simeulue and Nias Islands on April 6, 2010. Although it was stronger than any earthquake in the continental United States since the Great San Francisco Earthquake of 1906 (magnitude 7.8), it was modest by Indonesian standards. Two recent great earthquakes—a magnitude 8.6 on March 28, 2005, and a magnitude 9.1 on December 26, 2004—occurred within 125 kilometers of the recent quake. The structure of the region’s sea floor and the topography of the islands give clues about the source of the geological violence: Sumatra is part of an island arc along the boundary where the Australia and Sunda tectonic plates collide.
This map shows the location of the magnitude 7.7 earthquake (red star) and the series of weaker aftershocks that occurred over the next several days (red circles). The aftershocks ranged up to magnitude 5.1. The depth of the ocean is shown in blue, with darker colors representing deeper water. Elevation is shown in shades of brown; lighter areas are higher. The boundary between the Australia Plate and the Sunda Plate is a thick black line. Arrows represent the relative direction of motion of the two plates, which are colliding at a rate of about 60 millimeters (2 inches) per year. Most of the time, friction between the plates causes them to stick together, and stress increases over time. When enough stress builds to fracture the stuck rocks, the plates jump past each other, releasing energy in the form of earthquakes.
The map reveals typical features of a subduction zone: an oceanic trench, a fore-arc ridge, a fore-arc basin, and an island arc. The location of the plate boundary is marked by the Sunda Trench, a narrow band of very deep water that parallels the Sumatran coast. Along the trench (lower left), the Australia plate is moving underneath (represented by a curved arrow) the Sunda Plate, forming a deep trough. On the edge of the Sunda Plate, approximately 100 kilometers (60 miles) from the Sunda Trench and 180 kilometers (100 miles) from Sumatra, are a series of islands that are the crest of a fore-arc ridge. The ridge is formed primarily from marine sediments scraped off the top of the Australia plate and piled up on top of the leading edge of the Sunda Plate. These sediments are called an accretionary wedge.
Simeulue and Nias are separated from Sumatra by the Selat Mentawai. This sea is a fore-arc basin, a depression between the fore-arc ridge and island arc. Sediments washed into the basin from both the fore-arc ridge and island arc weigh down the crust in this area, creating the depression. Sumatra itself is part of an island arc. The island is raised above sea level by the upwelling of hot, buoyant magma, derived from partially melted rocks along the boundary between the subducting (Australia) plate and the overriding (Sunda) plate. Active volcanoes and calderas fed by the rising magma parallel Sumatra’s west coast. Among these is Toba Caldera, the site of the largest eruption in the past 2.5 million years.
Active subduction off the Indian Ocean coast of Sumatra is responsible for both the region’s geography and its earthquakes. Although rare on human timescales, over geologic time earthquakes are frequent in the area. The same forces that produce the earthquakes also created Sumatra, its volcanoes, the nearby islands, and shaped the sea floor.
Chennai - Now 12:35pm is having a partial High cloud cover, less heat, good stiff sea breeze and High percentage of Humidity.
Rain on 14-Apr, Heavy showers over South interior Karnataka, South-west Andhra and N-E states as usual..
On 14-Apr, highest maximum temperature of 45.5°C was recorded at Sambalpur (Orissa).
IMD: "It is clarified that this was not a cyclonic storm as has been reported by some of the media"
120 killed as Nor'wester (Tornado) strikes Bihar, West Bengal ...
Freak storm kills 96 in Bihar, Bengal ...
Thousands wait for help in storm-hit (Tornado) India ...
Deadly Indian storm a tornado .. kills more that 116 ..
Mangalore: Cyclone Upsets Fishing Activity, Causes a Boat to Capsize‎ ...
On 14-Apr, Bangalore: Heavy rains, strong winds ..
RT @aatheena: in B'lore such a nice weather RT@TwaddlingRicha @aatheena where in india is it raining?? We punjab ppl are craving for rain :|
Chennai - is having some low cloud formation at this time.. No rain prediction yet.!
Skies clearing up over south peninsula after yesterday evening's massive electric showers..