Wednesday, August 11, 2010


The IMD 925 wind map shows that the westerly flows have started into north-west India by replacing the easterlies in connection with a ‘break monsoon' condition, weakening trend in rainfall.

Break monsoon condition occurs when the monsoon trough shifts from its normal position over central India, northwards towards the foot of the Himalayas. During a break monsoon, heavy rain is to be expected along the Himalayan foothills and Northeast India, as the eastern end of the axis moves into that region. "


Under the influence of an upper air cyclonic circulation, a feeble low pressure area is likely to form over northwest and adjoining westcentral Bay of Bengal today".- IMD bulletin today. This is also seen in the 925 wind map.
As discussed in yesterday's blog, this low would travel along the axis, and merge into it. As it moves, region around Delhi and western U.P. plains can expect heavy rains around this weekend. An extended forecast for this week would be rainfall with heavy falls over the Western Himalayan region. Resultantly,with heavy rains in the catchments of some rivers, we may witness some rivers overflowing into the Bihar plains from Sunday.

Along with this break monsoon, the days have started getting warmer, rather hotter. Yesterday's highs, as seen in this map, shows a 40c (Hissar), a 39c, (Ganganagar), and several 36s and 37s in the north.
Several places in the south have also started seeing higher day temperatures, with pockets recording 37c. As discussed in the "vagaries" on 9th. I would estimate Bangalore to cross 31c.

These hot conditions with moisture conditions would facilitate building up of thunder cells and thunder showers in the interiors of Gujarat/Maharashtra/Karnataka. These would be restricted, initially, meaning on Wednesday/Thursday, to interior Gujarat, and then thundershowers would pop up in interior Maharshtra and Karnataka from Saturday.However,thunder cells would not be widespread, and would be in pockets.


Mumbai: With the sun shining, the days have started getting to 32c. Likely to continue with such weather. With a daily average rain of less than 10 mms, till Sunday, one may tend to think the monsoon is over. But a shower to two will be a reminder that the rainy season is not over. Chances of a thunder cell drifting over Mumbai on Sunday from the east. But will not attempt to confirm that !

1 comment:

  1. Karnataka with nonstop mining and deforestation (in Kodagu, western ghats catchment area) has lead to extreme drought with no rain since june along with La-Nina effect(opposite of El-nino). It is estimated that in next coming years temperature of Bangalore will increase over 40c. Road widening, more added vehicles, dense glass buildings, metro-glass covering, no efforts being made for tree plantation will increase temperature by 4c. (2010 summer had high of 39c).

    On other hand all places over Maharashtra(as usual Mumbai exceptionally extreme rains), many in Gujarat, Rajasthan had heavy nonstop rains since june, july, august with all rivers, lakes, dams overflowing.

    Below is latest news about time bomb on which Karnataka is sitting.

    Karnataka encounters worst drought. No rain in south interiors nor in Malnad region.

    Cloudy skies, but no rain; state gropes in the dark

    Bangalore: Blame extended hours of unscheduled power cuts on paucity of rain and snags in the state’s major thermal power stations.

    Concerned by the dual crisis, the government has quietly asked all Escoms (electricity supply companies) to go ahead with unscheduled load-shedding till the situation improves.

    “Things are turning from bad to worse. Last week has pushed the state deeper into the red in terms of rainfall,” agriculture minister S A Ravindranath said.

    The state received area weighted-average rainfall of only 1.46 cm during the week that ended on Sunday, against the normal 19.87 cm, according to the agriculture department’s latest weekly rainfall update. Deficiency for the week is a staggering 95%, making it the driest first week of August in recent history.

    MORE BAD NEWS
    Rains will continue to elude most parts of Karnataka for some time. Though the meteorological department has predicted cloudy sky in many parts of the state, it has not forecast rainfall anywhere.

    So far, most districts in North Karnataka and the coastal belt have received good rain. Of the 30 districts, five have received below normal and deficit rainfall.

    What’s worrying is that catchment areas of three major hydel reservoirs — Linganamakki, Supa and Mani — have received deficient rainfall, while Raichur and Bellary thermal power plants are not generating to full capacity due to snags, depriving the state of at least 500 MW of power.

    Cities like Bangalore, Mysore and Hubli-Dharwar are facing 2 to 3-hour power cuts and rural areas five to eight hours.

    FARMING HIT
    The abrupt lull in monsoon is also threatening crops, especially paddy cultivation in over 1.5 lakh hectares in the state, officials said. Last year, cultivation covered 3.5 lakh hectares, and in all likelihood, it is going to be much less this season. “If monsoon continues to elude the state for one or two more weeks, the output will be just 25 per cent of the estimated,” said Raghavendra, senior agriculture officer.

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