Tuesday, June 22, 2010
2:30pm, Scattered monsoon showers all along west coast from N.Maharastra to S.Kerala coast... http://ow.ly/i/2bza
10-day lag seen in June rains, may not hit sowing
A 10-day outlook for monsoon suggests that seasonal rains might just make it to Bihar and eastern Uttar Pradesh, but only with a lag of as many days.
“The normal date for onset over east Uttar Pradesh is June 18, which means that the monsoon caravan is already late by three days,” said Dr Akhilesh Gupta, leading operational forecaster and Advisor to the Ministry of Science and Technology.
NO MAKING UP
And there is no possibility of this delay being made up if initial conditions as obtaining on Monday are any indication, Dr Gupta told Business Line on Monday. This would mean that June would end up with a cumulative delay of eight to 10 days before monsoon rains can reach parts of northwest India beyond east Uttar Pradesh.
Crucially enough, the delay is not seen as pausing a major threat to sowing operations despite the crop (rice, pulses, oilseeds and maize) being largely rain-fed. This is because the transplanting operations in the region are usually taken up between the first week and third week of July only. Rains falling during the intervening period, though, are a blessing for the nurseries.
By the same token, the monsoon may not reach west Uttar Pradesh until July 1, done in by the ‘lag effect.' The big difference is that west Uttar Pradesh is entirely irrigated, and is in a position to cope with the likely delay in onset of monsoon.
STRONG REVIVAL
According to Dr Gupta, forecast beyond a 10-day period is fraught with risk and it may not be fair to comment on how things would pan out during the rest of July.
For now, however, forecasts indicate a reasonably strong revival of monsoon from Wednesday/Thursday. This active phase may last the whole of the next 10-day period.
A reviving monsoon approaches the mainland always from the south, and triggers activity over the Bay of Bengal as well. Thus, the new monsoon pulse would cover Kerala, Karnataka, Tamil Nadu and parts of Andhra Pradesh before hitting Konkan and the rest of the west coast in phases.
By Saturday, there is a possibility that some kind of a circulation may show up over the Andhra Pradesh coast, which may move inland.
This would bring rains over the north peninsula and central India. Some rains are also likely over Bihar and Uttar Pradesh from a weak interaction of the Bay system with an incoming western disturbance.
It may not bring the monsoon into the northwest, but it would lead to abatement of the severe heat wave conditions in the region.
India Meteorological Department (IMD) said on Monday that heat wave to severe heat wave conditions were prevailing over Rajasthan, Delhi and parts of Haryana.
Heat wave conditions were also reported from many parts of west Uttar Pradesh, northwest Madhya Pradesh and isolated pockets of Gujarat region and Jammu. The highest maximum temperature of 48.1 deg Celsius was recorded at Sri Ganganagar in Rajasthan during the 24 hours ending Monday morning. The heat wave is being anchored by a seasonal trough over northwest India (northwest to southeast), which is aligned slightly north of its normal position.
The northward bias brings a barrage of hot northwesterlies into play over the region, crowding out cooler easterlies from the Bay of Bengal. This is what sustains the heat wave.
But from Thursday onwards, the brewing system in the Bay would allow the easterlies to start filling the plains of the northwest. The resulting cloudiness would gradually help cap the heat.
By July 1, the entire north-west India, except west Rajasthan, would see the heat abate completely as cool easterlies make headway as far northwest as Punjab.
Meanwhile, India Meteorological Department (IMD) sees renewed wet spell along the west coast during the next two days in what is projected as a revival of monsoon.
Seasonal rains had gone into a lull over the last week, delaying the progress of the monsoon into east and east-central India. Fairly widespread rain or thundershowers have been forecast over Konkan, Goa, coastal Karnataka, Andaman and Nicobar Islands, Kerala and Lakshadweep during next 24 hours and may scale up thereafter.
A warning valid for the next two days said that isolated heavy to very heavy rainfall may unfold over Assam, Meghalaya, and Arunachal Pradesh. Heavy rainfall is likely over Nagaland, Manipur, Mizoram, Tripura, Konkan, Goa and coastal Karnataka during this period.
Widespread rainfall activity has been forecast over the west coast during the four to five days. Fairly widespread to widespread rainfall will occur over the Northeastern States while being scattered to fairly widespread central and east India and the rest of peninsular India and Maharashtra.
North-west may have to wait beyond July 6 for monsoon
Northwest India may have to wait beyond July 6 to see the onset of monsoon rains, according to latest updates by international models.
The US National Centres for Environmental Prediction (NCEP) is of the view that entire Rajasthan, parts of west Madhya Pradesh, Punjab, Himachal Pradesh, Uttarkhand and Jammu and Kashmir may be denied timely onset of the rains.
However, west Uttar Pradesh, Delhi and Haryana may just be able to slip themselves under cover during this period.
NON-SEASONAL RAIN
Northwest India, however, is shown in positive territory, assessed at 25 per cent above normal rainfall for the season (June 1-17) until now. This was largely due to non-seasonal rains dumped over west Rajasthan and adjoining areas by an incoming circulation from erstwhile super cyclone, Phet, early this month, as also by passing western disturbances.
South peninsula is shown at +22 per cent and central India -3 per cent in terms of cumulative rainfall received during this period but northeast India lagged at -22 per cent.
The normal timeline for monsoon to cover the entire landmass is June 30, but this could now get stretched by at least a week, if not more, according to NCEP. The monsoon covers south peninsula, east and central India in calibrated movements mandated by helpful churns mostly in the Bay of Bengal. It then turns west-northwest to head into Rajasthan, Punjab and Haryana, among others, forming part of northwest India.
WEAK LINK
The Bay of Bengal appears to be the weakest link for now in the vulnerable monsoon chain underpinning its spatial and temporal spread.
India Meteorology Department (IMD) too accepts this fact saying in its latest forecast update that a monsoon-boosting ‘low' might take shape only late this week (around Friday).
But the European Centre for Medium-Range Weather Forecasts sees northwest Bay of Bengal (as against Head Bay), which is not ideal for monsoon to move west-northwest.
Instead, the system might cross the Andhra Pradesh-Orissa coast and head west (as against west-northwest) into east-central and adjoining central India, Maharashtra and Mumbai-south Gujarat, before slipping into the Arabian Sea by June 30.
In a marked deviation from this outlook, though, the NCEP says the system in the northwest Bay might initially track a little east-northeast along the coast and cross the West Bengal coast.
This (around the head Bay) is the ideal position for it to swing the monsoon current west-northwest into east India, covering West Bengal, Jharkhand, Chhattisgarh, Uttar Pradesh and Madhya Pradesh during the week ending July 6.
NCEP weather chart also shows a counterpart spinning up from the Arabian Sea and setting up a rendezvous with the incoming Bay system over land. Even this would not be enough to take the rains into Rajasthan and other places in the northwest.
According to monsoon experts here, they would not be surprised to find on retrospect that these areas have had to wait until July 10 to see the monsoon unfold. These areas would probably need to wait for the next system to get initiated in the Bay of Bengal, of which no clear forecasts were available from any model on Sunday.
The International Research Institute for Climate Prediction at Columbia University sees possibility of heavy to very heavy rains over coastal Karnataka, Konkan and northeast India during the six days ending Thursday.
The IMD too has said in its outlook for the week that the monsoon would be weak over the country except these two regions mentioned by the IRI. In a warning valid for the next two days, the IMD said that isolated heavy to very heavy rainfall would occur over Assam, Meghalaya and Arunachal Pradesh. Heavy rainfall is likely over Nagaland, Manipur Mizoram, Tripura, Konkan, Goa and coastal Karnataka also during this period.
The outlook valid until Wednesday spoke about the possibility of widespread rain or thundershowers over Konkan, Goa and coastal Karnataka.
Fairly widespread rain or thundershowers are likely over the Northeastern States, West Bengal, Sikkim, coastal Andhra Pradesh, Kerala, Lakshadweep and Andaman and Nicobar Islands. The rains would be scattered over Vidarbha, interior Karnataka, Telangana and Rayalaseema, the IMD said.
Starting with the developments aliong the West coast of India,we see the UAC (Upper Air Circulation) in the trough has become less marked.
Now, this development means that there is no UAC present to cross the coast near Mumai as estimated earlier, and as a result, I would scale down the quantum of rainfall estimated earlier.
Since the coastal trough still hangs on (see IMD map),we can expect rains on a lesser scale to continue along the coast North of Karnataka this week.
As mentioned yesterday, I personally think that the Monsoon axis trough running west-east along the Northern plains of India, has had some role to play in the vanishing of the UAC. I have always been sceptical when this axis shifts northwards, as it heralds a "break" period for the peninsula regions, and can weaken the trough, or any embedded low in it.
With the trough intact, as it will be till Friday 25th. at least,rainfall to some extent will continue along the coast and in the interior areas of Maharashtra and Karnataka thru this week.
If, after this week, the axis of the monsoon shifts further north towards the Himalayas, and deepens,then the entire peninsula region is in for an unwanted "break". This may delay the monsoon progress into the Northern regions and subsequently into the North-West corner.
Though nobody wants a break now, the MJO forecast (see this link) shows the "unwanted negative" MJO waves during the next 15 days. When positive, it creates the "lows" and the depressions, and the rain bearing systems into the monsoon currents. When forecasts show a negativity, it reads as less systems in the regions.It is one of the few aspects of the weather that can be skilfully predicted beyond about 2 weeks into the future.
But, I really hope that things change for the better, and Nature eventually ridicules man's forecasting. We will keep our observations updated and monitor the same.
Meanwhile, the extreme in the Northern belt continues with a special mention of a minimum of 33.8c at Gwalior last night, and 32.6c as the low at New Delhi.
Mumbai: Will continue to get the passing showers on Tuesday, with about 10 mms of rain. Wednesday's forecast may have to be scaled down due to the reasons discussed. City can expect a few more showers, with rainfall during the day totaling 20mms. Thru Friday, Mumbai can get passing thunder rain, and with the rainfall scaled down, city may just about recieve 25-30mms till Friday.
Now, this development means that there is no UAC present to cross the coast near Mumai as estimated earlier, and as a result, I would scale down the quantum of rainfall estimated earlier.
Since the coastal trough still hangs on (see IMD map),we can expect rains on a lesser scale to continue along the coast North of Karnataka this week.
As mentioned yesterday, I personally think that the Monsoon axis trough running west-east along the Northern plains of India, has had some role to play in the vanishing of the UAC. I have always been sceptical when this axis shifts northwards, as it heralds a "break" period for the peninsula regions, and can weaken the trough, or any embedded low in it.
With the trough intact, as it will be till Friday 25th. at least,rainfall to some extent will continue along the coast and in the interior areas of Maharashtra and Karnataka thru this week.
If, after this week, the axis of the monsoon shifts further north towards the Himalayas, and deepens,then the entire peninsula region is in for an unwanted "break". This may delay the monsoon progress into the Northern regions and subsequently into the North-West corner.
Though nobody wants a break now, the MJO forecast (see this link) shows the "unwanted negative" MJO waves during the next 15 days. When positive, it creates the "lows" and the depressions, and the rain bearing systems into the monsoon currents. When forecasts show a negativity, it reads as less systems in the regions.It is one of the few aspects of the weather that can be skilfully predicted beyond about 2 weeks into the future.
But, I really hope that things change for the better, and Nature eventually ridicules man's forecasting. We will keep our observations updated and monitor the same.
Meanwhile, the extreme in the Northern belt continues with a special mention of a minimum of 33.8c at Gwalior last night, and 32.6c as the low at New Delhi.
Mumbai: Will continue to get the passing showers on Tuesday, with about 10 mms of rain. Wednesday's forecast may have to be scaled down due to the reasons discussed. City can expect a few more showers, with rainfall during the day totaling 20mms. Thru Friday, Mumbai can get passing thunder rain, and with the rainfall scaled down, city may just about recieve 25-30mms till Friday.
N. Bay LOW along Orissa coast will deepen in another 48hrs, this'll boost the Monsoon showers along W.coast & Bay wing. http://ow.ly/i/2bom
10:30am, Heavy Monsoon showers along Maharastra coast, scattered along Karnataka & Kerala coast... http://ow.ly/i/2bnN
RT @EcoSeed: No more coal by 2024 http://bit.ly/9EEJn3 reuters coalpowerplants dirtycoal industrialemissions europeanparliament eu
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