142 thoughts on “Light rain possible

  1. KAR,

    What happenned last night after I slept? I expected 3-4 cm looking at the radar, but we got only 6 mm here.
    Foreca is predicitng 35 mm for early morning monday. Looking at the radar we could get max 1 mm

  2. hey guys see radar animation…clouds near karaikal..pondi movin east into ocean..n clouds fom east of nellore comin to chennai

  3. Rainfall around chennai for august till 24.8.10

    Stations where exact values are availabable(mm)

    Redhills – 295.6
    Cholavaram – 293
    Korattur anaicut – 289
    Chembarambakkam – 273
    Tamaraipakkam – 227
    Poondi – 202.2

  4. Rainfall around chennai for august till 24.8.10

    Stations where exact values are availabable(mm)

    Redhills – 295.6
    Cholavaram – 293
    Korattur anaicut – 289
    Chembarambakkam – 273
    Tamaraipakkam – 227
    Poondi – 202.2
    Chennai – 185.2
    Chennai AP – 153.3

  5. Stations from IMD daily report till 24 august

    Ponneri – 38cm
    Poonamalle- 29.7cm
    Sriperumbudur – 21.2cm
    Tambaram – 18.82cm
    Marina – 14.4cm
    Guindy – 13.5cm

  6. Overall rainfall for august(mm)
    Ponneri – 380
    Poonamallee – 297
    Redhills – 295.6
    Cholavaram – 293
    Korattur anaicut – 289
    Chembarambakkam – 273
    Tamaraipakkam – 227
    Sriperumbudur – 212
    Poondi – 202.2
    Tambaram – 18.82
    Chennai – 185.2
    Chennai AP – 153.3
    Marina – 144
    Guindy – 135
    Kelambakkam – 60

  7. Guys lets move on. This system is coming to an end and don’t think we can expect anything worthwhile here.. Even a localized thunderstorm in the evening can give better rainfall to us.

  8. Taking a look at the Chepauk
    Stadium, Chennai forecast over
    the coming week and the
    average daytime maximum will
    be around 32°C, with a high of
    33°C expected on Saturday
    afternoon. The average minimum
    temperature for the week ahead
    will be around 27°C, dipping to
    its lowest on Thursday morning
    at 25°C. Wednesday is expected
    to see the most precipitation
    with around 97mm, or about
    3.8inches anticipated. The
    strongest wind will be felt on
    Friday evening, coming from the
    south, and reaching around
    13mph, that’s about 21kph.

  9. we ll get nothing..the better this clears the better for thunderstorms during late august and into september

  10. As per radar readings, we could see a strong cloud pattern slowly moving towards chennai from south east and east from bay of bengal.

    it covers nearly 200 KMS and we could expect contineous showers at least for 4 hours from 10.30.

    let us see. In anna salai no drizzling for the past 90 minutes.

  11. as per latest radar readings, chennai would get sunshine in another one hour. system is moving away from chennai coast. we could expect late evening thunderstorms if we get good sunshine.


  12. Chennai is always higher than bangalore in terms of overall rains in a year..only during SWM or summer rains it loses to bangalore during some years..

  13. Dear All,

    If we want to get a right reading of Radar, we must see plan position indicator diagram (V) which gives an indication of cloud pattern for 250 KMS less than 3000 meters.

    if you view the other product, only cloud above 3,000 meters are visibel. So only thunder clouds can be seen above 3000 meters. for sea based systems, the plan postion indicator diagram is more reliable and give accurate cloud pattern.

    as per that we could see just 25 KMS south & east of chennai there were huge cloud mass building up. ( please see the diagram plan position indicator (v) and not max product which can only reflect high clouds availability.

    interested readers may see and comment upon.


  14. Dear Karthik / John.

    There are vairous doppler products available for various distances above surface. The max ( z) product can give better clarity for thunderstorm clouds.

    for sea disturbance always better to rely on Plan position indicator (v) under doppler products option. you can see for yourself.

    if you follow the max ( z product) in doppler, chennai at present should have bright sunshine, whereas it is still cloudy at a lesser height. So plan position indicator diagram can give better accuracy. As per latest diagram, we could see 2 coloured portions of rainfall in sea. east /south east of chennai hardly 25 Kms away from chennai.


  15. @suresh..that is not rianfall..it is something else..may be temperature of clouds…ppi-z only predicts rain very correctly…

  16. karthik.

    If you follow PPi ( z) chennai would have sun shine from 12 Noon, but still cloudy.

    What i feel only for high clouds rain this PPI ( Z) product works correctly.

    if you see the plan position indicator diagram (v) it gives you a right cloud pattern, which says now chennai is totally cloudy which is a reality. Certainly that is not the temperature of clouds why i say because it narrates m/s. which means milli meters of rain fall.

    any other views on this pl. from any one who knows in depth about radar findings.


  17. John.

    That is not cloud temperature. the white dot denotes mild drizzle where the rating are between -3 and + 3. All dots given in the table above white denotes rains with intensity.

    towards east of chennai and south east of chennai contineous drizzling for about 50 KMS which is visible in radar diagram which also singify the correctness as chennai is still cloudy.

    we can get a right pictures if we see plan position indicator digram (v) and of course for thunderstorms we can still rely on the othe rproduct.


  18. The percentage of days with a sea breeze over Tambaram
    was slightly higher than observed over Meenambakkam. One would expect the
    number of sea-breeze days at these two locations to be the same. This difference
    may be because of weakening of the winds over and close to the city, because of
    increased friction.

  19. 1987-1997 averages


    June – 58mm
    July – 68mm
    August – 39mm


    June – 66mm
    July – 108mm
    August – 145mm


    June – 95mm
    July – 95mm
    August – 102mm

  20. some inputs from me…

    PPI V is planned position indicator velocity data. Using the Doppler Theory, the radar uses a Doppler Shift to determine the velocity of a reflector.

    Unit for this is m/s , which for me looks like meters/second.

    Negative values indicate reflectors moving towards the radar, while positive values indicate reflectors moving away from the radar.

  21. john,

    blue spots nothing but mild clouds and its negative ratings, no rainfall. if dbz exceeds 38.7 mild showers. you have to identify the colour and match with the table.


  22. Dear Mr. Kumar,

    To a certain extent, i agree with your explanation. but if you see both the diagrams, the one with Max ( Z) product says chennai is totally cloudless whereas it is still cloudy.

    so it would be appropriate to go with PPI ( V)

    we may also get some opinion from other readers.


  23. Mr. John.

    Though clouds do generate rains, but still if it reaches surface, it normally evaporates. Hence we have to ascertian the ratings 38.7 DBZ is the right rating for the surface to get wet. Any rating above 38.7 in line with the colour in the diagram indicates intensity.


  24. oh k the colors r meant to be taken frm max z in tat case u r ri8 mild drizzles en se but movin away since no -ve, thanks ss

  25. Karthi.

    u r right only satellite reveals clouds and radar always rains or winds. but then why there is a difference in Max ( Z) product and plan position indiactor ( v) diagram which slightly confuses.

    let us debate it further when i find time.


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