Tuesday, December 29, 2009

Heavy afternoon showers to continue for Coastal & south-Interior Karnataka till 1-Jan-10 .. http://yfrog.com/3nt9mp
Heavy cloud formation again over Lakshadweep & South Bay is very active .. http://yfrog.com/6mkpfj
ECMWF too agrees with the IMD outlook for end of 1st week - LOW over SW bay and wheeling into Chennai & South Andhra coast.
IMD: Forecast 1st Week of Jan, LOW over south-west Bay of Bengal may erupt, wheeling to cross the Chennai-south coastal Andhra Pradesh belt.
On Sunday, 27-Dec, the lowest minimum temperature of -1.0 deg Celsius was recorded at Adampur in Punjab.
Models had forecast the ongoing rains over the west coast and adjoining west-central peninsula, which could creep into central India
circulation tossed up by the easterly wave persisted over the Lakshadweep Islands on Monday supported at the ground level by the ‘warm pool'
IMD: strong northwesterly winds in the lower troposphere over the Indo-Gangetic plains would sustain themselves over the next two days.
IMD:: 10 per cent surplus the north-east monsoon season has notched up at the end of the penultimate week ending December 23.
South peninsular India is still being impacted by the easterly wave, though associated weather activity has shifted to the west coast.
North-East monsoon in surplus as more rain is forecast .. http://is.gd/5FeDd

North-East monsoon in surplus as more rain is forecast

Peninsular India and parts of central India are forecast to receive isolated to scattered rainfall during this week that would also witness the dawn of the New Year 2010.

South peninsular India is still being impacted by the easterly wave, though associated weather activity has shifted to the west coast and adjoining southeast Arabian Sea.

Sea-surface temperatures (SSTs) are still at elevated levels (up to 30 deg Celsius) over this region, which supports convection and cloud-building.

SURPLUS MONSOON

This is expected to help maintain, if not add to, the 10 per cent surplus the north-east monsoon season has notched up at the end of the penultimate week ending December 23.

Of the 36 Met sub-divisions, at least 24 received excess or normal rainfall thus far, while it was deficient in eight, an update by India Meteorological Department (IMD) said.

But, the four sub-divisions in the extreme northwest - west Rajasthan, Punjab, Haryana and Saurashtra-Kutch – continued to wallow in the ‘scanty' category.

The rain-bearing western disturbances have largely failed them since they lacked enough ‘spin' to wet the landscape. But the immediate east and south-east to these areas received adequate rainfall.

As for the south, outgoing long-wave radiation (OLR) is forecast to stay negative (a proxy for expected cloudiness) over equatorial Indian Ocean until mid-January if international model prognosis is to be believed.

This would go to support the case for a trough of low pressure around the area during the period and, by extension, associated weather activity.

This is exactly what the European Centre for Medium-Range Weather Forecasting (ECMWF) predicts for the rest of the month and into the New Year, with a likely weather system thrown in over Sri Lanka around January 6.

‘PHYAN' EFFECT

The US National Centres for Environmental Prediction (NCEP) has said that the week ending January 3, 2010, would see a warm south-east Arabian Sea push moisture into west-central and central peninsula supported by westerly flows (almost mimicking Cyclone Phyan flows earlier during this season).

The International Research Institute (IRI) for Climate and Society at the University of Columbia too tends to agree mostly with this outlook in its six-day forecast ending December 31.

The following week (January 4 to 12), according to the NCEP, is likely to see the scene once again shift to southwest Bay of Bengal. But the core of the rains would get pushed east-northeast over the open Bay of Bengal under westerly influence.

Meanwhile, the Chennai Met Centre said in its update on Sunday that rainfall was reported from a few places over Lakshadweep, coastal and south interior Karnataka during the 24 hours ending Sunday morning. Isolated rainfall occurred over Tamil Nadu and Kerala.

Forecast for the next two days said that rain or thundershowers are likely at a few places over Kerala, Lakshadweep, coastal and south interior Karnataka. Isolated rain or thundershowers has been forecast over Tamil Nadu and Puducherry.

CHILL IN NORTH

North and north-west India have been blanketed by a winter chill with minimum temperatures falling to below normal by 2 to 5 deg Celsius over parts of Punjab, Haryana, Uttar Pradesh, Bihar and Jharkhand. Cold wave conditions prevailed over isolated pockets of Punjab and Haryana where the minimum is below normal by 4 to 5 deg Celsius. The lowest minimum of 0.2 deg Celsius was recorded at Amritsar.

An IMD forecast has said that cold and strong northwesterly winds would prevail over the Indo-Gangetic plains for three more days.

A feeble western disturbance is likely to affect Jammu and Kashmir during the next two days. But the warmth that it carries in front would not be sufficient to cause any large change in minimum temperatures over the plains of northwest India.

Given this, cold wave conditions are likely over isolated places over Punjab and Haryana.

Heavy rains in south as chill spreads over north-west India

An easterly wave active over the southern peninsula, especially over south-east Arabian Sea, has ramped up the north-east monsoon to ‘vigorous' status over Kerala.

In contrast, a relentless barrage of cold and dry northwesterlies sustained the chill over north and northwest India during the last 24 hours with no sign of abating anytime soon.

COLD WINDS

The strong northwesterly winds in the lower troposphere over the Indo-Gangetic plains would sustain themselves over the next two days as well, an India Meteorological Department (IMD) update said on Monday.

A feeble western disturbance would affect Jammu and Kashmir during this period and cause rain or snow over adjoining Himachal Pradesh also. But no large change in minimum temperatures is likely over plains of north-west India.

Given this, cold wave conditions are likely to continue over isolated places over Punjab, Haryana and East Uttar Pradesh during this period.

An update from the Chennai Met Centre said that heavy to very heavy overnight rainfall has been reported from many places over Kerala and south interior Karnataka during the last 24 hours ending Monday morning.

A few places over Lakshadweep, coastal and north interior Karnataka too received moderate rainfall while it was isolated over Tamil Nadu.

RAINS IN SOUTH

International models had forecast the ongoing rains over the west coast and adjoining west-central peninsula, which could gradually creep over to parts of central India and adjoining east India.

The causative cyclonic circulation tossed up by the easterly wave persisted over the Lakshadweep Islands on Monday supported at the ground level by the ‘warm pool' (28 to 30 deg Celsius) in the south-east Arabian Sea hugging the Kerala/Karnataka coast.

Prevailing westerly winds are sweeping moisture from this part of the sea into the hinterland where it is being dumped as rain. Kerala and adjoining south interior Karnataka benefited the most from these rains during the last 24 hours.

An IMD update on Monday has, however, said that a trough of low lay stretched from south-east Arabian Sea into the Karnataka coast.


This meteorological feature would allow moisture to be piped in and the rains to sustain over the mainland.

Forecast for the next two days said that rain or thundershowers are likely at many places over Lakshadweep and at a few places over Kerala and Karnataka. Isolated rain or thundershowers are likely over Tamil Nadu and Puducherry.

Another trough of low was located over south-west Bay of Bengal with a cyclonic circulation over coastal Tamil Nadu and adjoining south-west Bay. But the seawaters had cooled down considerably over this area curbing convection and rainfall.

The IMD has forecast isolated rainfall activity along the west coast and over central and adjoining east India and south peninsula during the next three days.

The US National Centres for Environmental Prediction (NCEP) has said in its outlook for the next seven days that rainfall up to 600 per cent above normal for this time of the year may get recorded over the southwest coast and the immediate interior.

Forecast for the following week suggested that south-west Bay of Bengal may erupt with activity once again with a likely low-pressure area wheeling in to cross the Chennai-south coastal Andhra Pradesh belt.

The European Centre for Medium-Range Weather Forecasts (ECMWF) too agrees with the outlook though it found the ‘low' mostly active around south-east Tamil Nadu and adjoining Sri Lanka.

The activity is shown as peaking around January 5 with the entire extreme south peninsular India and entire Sri Lanka getting ensconced within a trough of low pressure, with or without a ‘low'.

In the north, severe cold wave conditions prevailed in some parts of Haryana and Punjab while cold wave conditions were reported from isolated places in Jharkhand and east Uttar Pradesh.

Minimum temperatures are below normal by 4 to 6 deg Celsius over parts of Punjab and Haryana and by 2 to 4 deg Celsius over East Uttar Pradesh, Bihar, adjoining West Bengal, Orissa and Chhattisgarh, an IMD update said.

On Sunday, the lowest minimum temperature of -1.0 deg Celsius was recorded at Adampur in Punjab. A feeble western disturbance has been persisting over Jammu and Kashmir and neighbourhood.

IMD forecast until January 2 spoke about the possibility of isolated rainfall over parts of north-eastern states and extreme south peninsular India.
Chennai - will witness more low cloud formation today & day time temperature will be +1 or +2 deg above yesterday.
Satellite shows subdued Arabian sea activity over lakshadweep & Heavy showers continue over maldives .. http://ping.fm/M9F58
Showers for Coastal Karnataka & North Kerala to continue till 2-Jan-10 .. http://yfrog.com/4f3j8p
Entire south Bay is active now .. http://yfrog.com/3n2ljj