ES2015 written script, use with caution.

Probability-v4.js

/* NOTICE: This file is written in ES2015.
 *  Please use the --harmony flag for nodejs environment.
 *
 * License: CC BY-SA 4.0 by Ivan Ip<m@lifeho.me>
 */

var iconv = require('iconv-lite'),
    request = require('request'),
    cheerio = require('cheerio'),
    cheerioTableparser = require('cheerio-tableparser'),
    selectr = '#containercontent > table:nth-child(15) > tbody > tr > td > table:nth-child(3) > tbody > tr:nth-child(22) > td > table:nth-child(1)',
    probability = {};

module.exports = function(callback){
  request({url:'http://www.hkww.org/weather/latesttc.html', encoding:null}, function (error, response, html) {
    if (!error && response.statusCode == 200) {
      var html = iconv.decode(html, "big5");

      if(html.indexOf("There are currently no active warning bulletins.") > 0)
        return callback({ info: 'No active warning bulletins.'});
      var $ = cheerio.load(html);

      // Let TableParser parse the table
      cheerioTableparser($);

      var rawdata = $(selectr).parsetable(true, true, true);
      var data = Object.values(rawdata);

      var title = rawdata[0][0];
      var probability = {
        'standBy_signal': {
          // tau = +6
          '+6-inforce': data[1][3],
          '+6-cancel': data[1][4],
          // tau = +12
          '+12-inforce': data[2][3],
          '+12-cancel': data[2][4],
          // tau = +18
          '+18-inforce': data[3][3],
          '+18-cancel': data[3][4],
          // tau = +24
          '+24-inforce': data[4][3],
          '+24-cancel': data[4][4],
          // tau = +30
          '+30-inforce': data[5][3],
          '+30-cancel': data[5][4],
          // tau = +36
          '+36-inforce': data[6][3],
          '+36-cancel': data[6][4],
          // tau = +42
          '+42-inforce': data[7][3],
          '+42-cancel': data[7][4],
          // tau = +48
          '+48-inforce': data[8][3],
          '+48-cancel': data[8][4]
        },
        'strongWind_signal': {
          // tau = +6
          '+6-inforce': data[1][6],
          '+6-cancel': data[1][7],
          // tau = +12
          '+12-inforce': data[2][6],
          '+12-cancel': data[2][7],
          // tau = +18
          '+18-inforce': data[3][6],
          '+18-cancel': data[3][7],
          // tau = +24
          '+24-inforce': data[4][6],
          '+24-cancel': data[4][7],
          // tau = +30
          '+30-inforce': data[5][6],
          '+30-cancel': data[5][7],
          // tau = +36
          '+36-inforce': data[6][6],
          '+36-cancel': data[6][7],
          // tau = +42
          '+42-inforce': data[7][6],
          '+42-cancel': data[7][7],
          // tau = +48
          '+48-inforce': data[8][6],
          '+48-cancel': data[8][7]
        },
        'Gale-or-Storm_signal': {
          // tau = +6
          '+6-inforce': data[1][9],
          '+6-cancel': data[1][10],
          // tau = +12
          '+12-inforce': data[2][9],
          '+12-cancel': data[2][10],
          // tau = +18
          '+18-inforce': data[3][9],
          '+18-cancel': data[3][10],
          // tau = +24
          '+24-inforce': data[4][9],
          '+24-cancel': data[4][10],
          // tau = +30
          '+30-inforce': data[5][9],
          '+30-cancel': data[5][10],
          // tau = +36
          '+36-inforce': data[6][9],
          '+36-cancel': data[6][10],
          // tau = +42
          '+42-inforce': data[7][9],
          '+42-cancel': data[7][10],
          // tau = +48
          '+48-inforce': data[8][9],
          '+48-cancel': data[8][10]
        }
      };

      var info = title.concat(probability);
      return callback(info);
    } return callback({ info: 'No statistic data has been found.' });
  });
}