UN
5
SUNDAY, JANUARY 13, 1991
YEAR
TROPICAL CYCLONE SIGNALS WERE HOISTED FOR THE FIRST TIME IN THE MAY 17 FOR TYPHOON MARIAN, BUT MARIAN FAILED TO COME CLOSE
ON
ENOUGH TO BRING ANY SIGNIFICANT RAIN TO THE TERRITORY.
IN JUNE, TROPICAL CYCLONE WARNING SIGNALS WERE HOISTED DURING THE PASSAGE OF SEVERE TROPICAL STORM NATHAN AND TYPHOON PERCY BUT THE MONTHLY RAINFALL TOTAL OF 448.1 MILLIMETRES WAS ONLY SLIGHTLY ABOVE NORMAL.
OF
ON JUNE 30, AN UNSTABLE SOUTHWESTERLY AIRSTREAM IN THE WAKE PERCY BROUGHT ABOUT PERIODS OF HEAVY RAIN AND THUNDERSTORMS, RESULTING IN THREE INCIDENTS OF LANDSLIPS AND OVER 30 REPORTS OF FLOODING IN KOWLOON AND THE NEW TERRITORIES.
JULY WAS HOTTER AND DRIER THAN NORMAL. THE WEATHER WAS BASICALLY FINE EXCEPT FOR SHOWERS AND PERIODS OF RAIN BROUGHT BY AN UNSTABLE SOUTHWESTERLY AIRSTREAM IN MID-JULY AND BY SEVERE TROPICAL STORM TASHA WHICH NECESSITATED THE HOISTING OF THE STRONG WIND SIGNAL NO. 3 TOWARDS THE END OF THE MONTH.
THE MONTHLY RAINFALL TOTAL WAS 268 MILLIMETRES, 15 PER CENT BELOW THE NORMAL FIGURE OF 316.8 MILLIMETRES.
AUGUST 1990 WAS THE HOTTEST MONTH AND THE DRIEST AUGUST EVER EXPERIENCED IN HONG KONG. THE MONTHLY MEAN TEMPERATURE OF 29.5 DEGREES AND THE MONTHLY MEAN MINIMUM TEMPERATURE OF 27.4 DEGREES WERE. THE HIGHEST ON RECORD, WHILE THE MONTHLY MEAN MAXIMUM OF 32.1 DEGREES WAS THE SECOND HIGHEST FOR AUGUST.
WITH A DAILY MEAN TEMPERATURE OF 31.9 DEGREES AND A DAILY MINIMUM TEMPERATURE OF 30.1 DEGREES, AUGUST 18 WAS THE HOTTEST DAY ON RECORD. THE MAXIMUM TEMPERATURE OF 36.1 DEGREES ON THAT DAY EQUALLED THE ABSOLUTE MAXIMUM SET 90 YEARS AGO.
THE
ITS MONTHLY MEAN RELATIVE HUMIDITY OF 75 PER CENT WAS ALSO LOWEST FOR AUGUST. THE MONTHLY TOTAL RAINFALL OF 150.1 MILLIMETRES WAS 64 PER CENT BELOW NORMAL.
SEPTEMBER WAS RELATIVELY CLOUDY AND WET. THE MONTHLY RAINFALL OF 409.9 MILLIMETRES WAS 28 PER CENT ABOVE NORMAL. OVER HALF OF THE MONTH'S RAINFALL COULD BE ATTRIBUTED TO THE PASSAGE OF TYPHOON DOT OVER SOUTHERN CHINA.
DURING THE FIVE-DAY PERIOD FROM SEPTEMBER 8 ΤΟ 12, 230 MILLIMETRES OF RAINFALL WERE RECORDED AT THE ROYAL OBSERVATORY. THE HEAVIEST DOWNPOUR OCCURRED ON SEPTEMBER 10 AND TRIGGERED OFF FLOODING AND LANDSLIP OVER VARIOUS PARTS OF THE TERRITORY.
OCTOBER WAS SUNNIER THAN NORMAL. THE MEAN ATMOSPHERIC PRESSURE OF 1,015.7 HECTOPASCALS WAS THE SEVENTH HIGHEST FOR THE MONTH OF OCTOBER. THE MONTHLY RAINFALL OF 100.7 MILLIMETRES WAS. 17 PER CENT BELOW NORMAL.
THE
NOVEMBER WAS ON THE WHOLE WINDY AND RELATIVELY CLOUDY. STRONG MONSOON SIGNAL WAS HOISTED ON THREE SEPARATE OCCASIONS. HOWEVER, IT WAS STILL COMPARATIVELY WARM WITH A MONTHLY MEAN MINIMUM TEMPERATURE OF 20.4 DEGREES, THE FIFTH HIGHEST ON RECORD.
/THE MONTHLY