The Weather of April 2002

    April 2002 was warmer, sunnier and drier than usual.  It was the third warmest April with a mean temperature of 24.6 degrees, 2.4 degrees above normal.   The total bright sunshine duration of 176.8 hours was more than 60 percent above normal.  The monthly rainfall amounted to 12.4 millimetres, a mere 8 percent of the normal figure.  The accumulated rainfall for the first four months of the year was 280.7 millimetres, near the normal figure of 299.8 millimetres for the same period.

    As the northeast monsoon gradually weakened on 1 April, a warm maritime airstream set in and prevailed over the south China coast for the next eight days.  Coupled with plenty of sunshine, it was unseasonably warm during the period with the daily maximum temperatures reaching the high twenties.   The maximum temperature of 28.6 degrees recorded at Ching Ming Festival was the highest ever for the festival.

    A trough of low pressure meandering the coast brought some squally thunderstorms and about 9 millimetres of rainfall in the morning of 6 April.  It became mainly fine later in the day and the fine weather persisted for the next three days.

    A surge of the northeast monsoon reached the coast of South China on 10 April.  The temperature fell gradually to a minimum of 17.8 degrees on 11 April amidst continuous light rain, the lowest in the month. The rain ceased that evening, but the weather remained cloudy until 13 April.

    The northeast monsoon weakened on 14 April and the temperature began to climb in the next three days until another replenishment of the northeast monsoon reached the coast on 18 April.  Cooler weather with light rain and sunny periods ensued for three days.  As a warm maritime airstream replaced the northeast monsoon on 21 April, the temperature was on the rise again and reached 29.7 degrees on 24 April, the highest of the month.

    Another cold front reached the coast on 25 April and brought cloudy weather and light rain for two days.  Apart from some light rain in the morning, the weather for the rest of the month was fine and sunny.

    There was no tropical cyclone over the South China Sea and the western North Pacific in the month.

    Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1-1.2.  Monthly meteorological figures and departures from normal of April are tabulated in Table 2.