Current and Weather

 

Big Falling Current

Screenshot 2021-03-31 at 4.49.29 PM.png

  • Generally (for East coast and Sentosa area) when the tide is falling, the current is going to right to left (from shore)

  • And when tide is rising, the current is going left to right (from shore)

  • However, on days with big tidal change like the image on the right, the rising currents (left to right) force may no be strong enough to change the direction of the currents, the current would slow slow around 1.00pm to 3.00pm and would resume a strong right to left current from 4.00pm to 6.00pm.

 

balanced Tidal change

Screenshot 2021-03-31 at 5.01.59 PM.png

  • when the rising and falling tides are about the same, you can expect the slowest times to be 30 min to 1 hour after the highest or lowest tides, and a subsequent change in current direction.

 

Big Rising Currents

Screenshot 2021-03-31 at 5.08.19 PM.png

  • When the force of the rising currents is much stronger than the force of the falling currents, the direction of the currents wont change, it may slow down a little, then resume a fall left to right current when the tide ride again.

 

Speed of Current & Rate of Change

Screenshot 2021-07-21 at 6.29.21 PM.png
Screenshot 2021-07-21 at 7.07.23 PM.png

  • How to know when is the fastest or slowest current of the day?

    Let’s take 10 July as an example: 0500 to 1600

  1. Calculate the rate of change per hour (difference in tide/time), we give it the pueno units N to take is as the tidal force.

    5 to 6 : 1N (rise)
    6 to 7: 3N (rise)
    7 to 8: 4N (rise)
    8 to 9: 5N (rise)
    9 to 10: 5N (rise)
    10 to 11: 4N(rise)
    11 to 12: 3N(rise)
    12 to 1: 1N (rise)
    1 to 2: 2N (fall)
    2 to 3: 3N (fall)
    3 to 4: 6N (fall)

  2. Calculate the relative force of the current.

    Next, we would assume that the current at 8 to 9 and 9 to 10 at 5N would be the fastest, but that is not true, we need to put into account the momentum of the current in the previous hours. If this was east coast area, we need to account for the last 2 hours too. (Real force at 7 to 8 = 1N + 3N +4N = 8N)

    At 7 to 8: 4N (rise) with 8N of relative force applied, the Current would move towards the right and the speed is increasing because the relative force is larger than 6 to 8: 3N (rise) with 3N relative force. (3N + 1N - 1N = 3N)

    At 8 to 9: 5N (rise) with 12N of relative force to the right, the Current would move towards the right and the speed is increasing because the relative force is larger than the previous hour


    At 9 to 10: 5N (rise) with 14N of relative force to the right, the Current would move towards the right and the speed is increasing because the relative force is larger than the previous hour

    At 10 to 11: 4N (rise) with 14N of relative force to the right, the Current would move towards the right and the speed will remain the same because the relative force is similar to the previous hour

    At 11 to 12: 3N (rise) with 12N of relative force to the right, the Current would move towards the right and the speed will decrease because the relative force is smaller than the previous hour

    At 12 to 1: 1N (rise) with 8N of relative force to the right, the Current would move towards the right and the speed will decrease because the relative force is smaller than the previous hour

    At 1 to 2: 2N (fall) with 6N of relative force to the right, the Current would move towards the right and the speed will decrease because the relative force is smaller than the previous hour

    At 2 to 3: 3N (fall) with 4N of relative force to the Left, the Current would move towards the Left and the speed will increase because the relative force is Bigger than the previous hour

    At 3 to 4: 6N (fall) with 11N of relative force to the Left, the Current would move towards the Left and the speed will increase because the relative force is Bigger than the previous hour

  3. Predict when is the fastest and slowest current.

    We will know that the current at the start of the trip at 8N relative force would be mild and towards the right side, it will increase in speed all the way till 11am.

    The fastest current will be from 9 to 11 am with similar relative force of 14N

    The current will start to slow down at 11am and will be at the slowest between 2pm to 3pm as the relative force changes from right to left. (current is not slowest at the highest tide around 1200)

 

Windy Weather App

windy0108_01.jpg

  • Use the Windy Weather app to check the wind conditions for the day. Extra caution is needed for winds above 12 knots, may need to put more outriggers

  • Use the app will give a rough gauge of the currents at a specific spot

  • The app is very accurate when is comes to wet weather predictions.

 

Rain clouds

Screenshot 2021-04-28 at 3.58.10 PM.png

  • Save the NEA webpage to your phone’s internet favourite.

  • http://www.weather.gov.sg/weather-rain-area-240km

  • You can also download the NEA app, but its not so good, the website gives us more information