Saturday, January 23, 2010
Why "Vellore - Tamilnadu" records LOW temperature during Winter ??
Vellore during winter period draws wind from North Westerly direction. This dry cold continental wind originates from High pressure located in NW parts of India and passes through Punjab, Hariyana, NCR, West UP, Royalaseema and its eastern flange passes through Vellore. That is why Vellore and towns and cities to its West and NW locations will experience lower temperature in winter compare to Chennai. More over Vellore is inland and coastal effect is also influencing Chennai.
Posted by Mr. Anonymous
Posted by Mr. Anonymous
"Agumbe may be wet, but Hulikal is wetter" ... Mr.Anonymous responds.!!
For the interest of the general Public I must give certain points on how rainfall is measured. First of all according to WMO criteria
[1] There should be atleast one raingauge in every 250 Sq.Km area in plains and at least one raingauge for every 100 sq.km area in hilly areas.
[2] In India Fibre Glass Reinforced Polyester (FRP) Raingauge of diameter 159.6 mm and collector area 200 sq.cm is in use for the measurements of rainfall.
[3] This 200 sq.cm collector area raingauge must have relevant 20mm measure glass.
[4] Rainfall measurements should have to be taken at 0300Z [0830 hrs IST] daily without fail to enable comparison.
[5] The exposure of raingauge must be good.
Most of the raingauges maintained at vantage meteorological locations are NOT maintained by IMD. State government is maintaining such raingauges. Often the raingauge and measure glass combination may NOT be correct. Thus will lead to distorted or enhanced rainfall amount. {As happened in Chinna Kallar in 2007 ; in that year the annual rainfall was reported as 7000 mm because of the irrelevant measure glass.} In Agumbe too there were instances when the measurements were reported wrong.
In the light of the above I wish to state that Meteorologically vantage location should be properly assessed by scientific community and wish that Government should come out with rigid plans to deploy men and material at vantage locations to augment Disaster Management.
[1] There should be atleast one raingauge in every 250 Sq.Km area in plains and at least one raingauge for every 100 sq.km area in hilly areas.
[2] In India Fibre Glass Reinforced Polyester (FRP) Raingauge of diameter 159.6 mm and collector area 200 sq.cm is in use for the measurements of rainfall.
[3] This 200 sq.cm collector area raingauge must have relevant 20mm measure glass.
[4] Rainfall measurements should have to be taken at 0300Z [0830 hrs IST] daily without fail to enable comparison.
[5] The exposure of raingauge must be good.
Most of the raingauges maintained at vantage meteorological locations are NOT maintained by IMD. State government is maintaining such raingauges. Often the raingauge and measure glass combination may NOT be correct. Thus will lead to distorted or enhanced rainfall amount. {As happened in Chinna Kallar in 2007 ; in that year the annual rainfall was reported as 7000 mm because of the irrelevant measure glass.} In Agumbe too there were instances when the measurements were reported wrong.
In the light of the above I wish to state that Meteorologically vantage location should be properly assessed by scientific community and wish that Government should come out with rigid plans to deploy men and material at vantage locations to augment Disaster Management.
Rain, slight uptick in mercury seen for North
The International Research Institute for Climate and Society (IRI) at the University of Columbia has said that there is a 40 per cent probability of above-normal temperatures breaking out over northwest India during February-March-April.
This is the lowest on a five-grade probable temperature value scale plotted by the IRI in its seasonal weather outlook for this year.
West Rajasthan and adjoining central India could be relatively higher probability (50 to 60 per cent) of above normal temperatures during this period. But elevated probability for above-normal precipitation has been indicated for the North (Jammu and Kashmir, Himachal Pradesh, Uttarkhand, Punjab, Haryana and west Uttar Pradesh) through February to May.
The peninsular south is assessed as having the highest probability (70 per cent) for above normal temperatures during February-March-April.
This region would also have to contend with maximum possibility for below-normal precipitation during this period.
The trend is forecast to continue to hold as such during March-April-May, but probability for linearly regressive temperature values are seen over central India and to the further north.
Rainfall probability for the southwest coast (mainly Kerala) has been indicated to be below normal during this phase.
In what looks like a pleasant surprise, the traditional “hot plates” of Andhra Pradesh and adjoining Orissa may not exactly heat up to those levels during March-April-May and April-May-June.
Rainfall probability has been forecast to be less than normal over coastal Orissa and adjoining coastal areas of Gangetic West Bengal.
As for May-June-July, which coincides with the onset phase of the southwest monsoon, the IRI sees the peninsular south cooling, and the heating anomalies retreating to Gujarat and adjoining west Rajasthan.
ONSET PHASE
Precipitation, too, is seen to be normal for the entire country during the onset phase.
Similar forecast has come from Weather Trends International, a leading US-based private forecaster.
According to Dr Michael Ferrari, a forecast specialist with Weather Trends, initial signals indicate to “a better onset period”.
Last year's onset was delayed, and rains did not really pick up until later in the season.
But for 2010, the private forecaster sees a better start to the season.
“While the onset does look favorable, we are cautious when looking at the rainfall pattern for July through September,” Dr Ferrari wrote in his outlook statement.
“Looking ahead, we are not anticipating a recovery to a normal rainfall distribution for the entire season. Regarding a recovery in the Indian crop as a whole, we are looking towards 2011.”
Scientists with the Research Institute for Global Change in Tokyo have assessed that the prevailing El Nino conditions may have peaked and could give way to a late season La Nina during this year.
They expected precipitation trends through August and September to be likely influenced by the La Nina conditions in the equatorial Pacific that have traditionally favoured the Indian monsoon though without direct cause-effect relationship.
Meanwhile, an update from India Meteorological Department said on Friday that minimum temperatures continued to stay below-normal over many parts of east Uttar Pradesh, central, east and peninsular India and isolated pockets of Punjab. Cold wave conditions prevailed over many parts of Chhattisgarh and some parts of east Uttar Pradesh, east Madhya Pradesh, north interior Karnataka, Punjab, Jharkhand, Gangetic West Bengal, interior Maharashtra and Telangana.
Amritsar recorded the lowest minimum temperature of -1.2 degree Celsius during the 24 hours ending Friday morning.
Forecast for the next two days said that dense fog conditions will continue in the morning hours over parts of Indo-Gangetic plains. Cold wave conditions would occur over parts of central and adjoining east India.
Minimum temperatures may increase over parts of northwest India. Isolated to scattered rain or snow will occur over western Himalayan region. Isolated light rain has also been forecast over Punjab and Haryana mainly on Sunday
This is the lowest on a five-grade probable temperature value scale plotted by the IRI in its seasonal weather outlook for this year.
West Rajasthan and adjoining central India could be relatively higher probability (50 to 60 per cent) of above normal temperatures during this period. But elevated probability for above-normal precipitation has been indicated for the North (Jammu and Kashmir, Himachal Pradesh, Uttarkhand, Punjab, Haryana and west Uttar Pradesh) through February to May.
The peninsular south is assessed as having the highest probability (70 per cent) for above normal temperatures during February-March-April.
This region would also have to contend with maximum possibility for below-normal precipitation during this period.
The trend is forecast to continue to hold as such during March-April-May, but probability for linearly regressive temperature values are seen over central India and to the further north.
Rainfall probability for the southwest coast (mainly Kerala) has been indicated to be below normal during this phase.
In what looks like a pleasant surprise, the traditional “hot plates” of Andhra Pradesh and adjoining Orissa may not exactly heat up to those levels during March-April-May and April-May-June.
Rainfall probability has been forecast to be less than normal over coastal Orissa and adjoining coastal areas of Gangetic West Bengal.
As for May-June-July, which coincides with the onset phase of the southwest monsoon, the IRI sees the peninsular south cooling, and the heating anomalies retreating to Gujarat and adjoining west Rajasthan.
ONSET PHASE
Precipitation, too, is seen to be normal for the entire country during the onset phase.
Similar forecast has come from Weather Trends International, a leading US-based private forecaster.
According to Dr Michael Ferrari, a forecast specialist with Weather Trends, initial signals indicate to “a better onset period”.
Last year's onset was delayed, and rains did not really pick up until later in the season.
But for 2010, the private forecaster sees a better start to the season.
“While the onset does look favorable, we are cautious when looking at the rainfall pattern for July through September,” Dr Ferrari wrote in his outlook statement.
“Looking ahead, we are not anticipating a recovery to a normal rainfall distribution for the entire season. Regarding a recovery in the Indian crop as a whole, we are looking towards 2011.”
Scientists with the Research Institute for Global Change in Tokyo have assessed that the prevailing El Nino conditions may have peaked and could give way to a late season La Nina during this year.
They expected precipitation trends through August and September to be likely influenced by the La Nina conditions in the equatorial Pacific that have traditionally favoured the Indian monsoon though without direct cause-effect relationship.
Meanwhile, an update from India Meteorological Department said on Friday that minimum temperatures continued to stay below-normal over many parts of east Uttar Pradesh, central, east and peninsular India and isolated pockets of Punjab. Cold wave conditions prevailed over many parts of Chhattisgarh and some parts of east Uttar Pradesh, east Madhya Pradesh, north interior Karnataka, Punjab, Jharkhand, Gangetic West Bengal, interior Maharashtra and Telangana.
Amritsar recorded the lowest minimum temperature of -1.2 degree Celsius during the 24 hours ending Friday morning.
Forecast for the next two days said that dense fog conditions will continue in the morning hours over parts of Indo-Gangetic plains. Cold wave conditions would occur over parts of central and adjoining east India.
Minimum temperatures may increase over parts of northwest India. Isolated to scattered rain or snow will occur over western Himalayan region. Isolated light rain has also been forecast over Punjab and Haryana mainly on Sunday
Cyclone Magda Comes Ashore
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this true-color image of Magda over the Indian Ocean in the northwest and Western Australia in the southeast. Lacking a distinct eye, the storm nevertheless spans several hundred kilometers.
On January 22, The Sydney Morning Herald reported that Magda might have damaged some buildings along the Kimberly coast, but no injuries had yet been reported.
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