THURSDAY, MAY 10, 1979
ALTHOUGH THE COLD FRONT GRADUALLY MOVED SOUTH AWAY FROM HONG KONG, THE WEATHER REMAINED UNSETTLED WITH SHOWERS AND SOME THUNDERSTORMS.
CONDITIONS WERE RATHER COOL AND ON THE MORNING OF APRIL 4, THE ROYAL OBSERVATORY RECORDED A MINIMUM TEMPERATURE OF 14.1 DEGREES WHICH WAS THE LOWEST FOR THE MONTH. FRESH TO STRONG WINDS WERE EXPERIENCED OFF SHORE OVERNIGHT ON APRIL 4 AND 5 AND THE STRONG MONSOON SIGNAL WAS HOISTED ON BOTH OCCASIONS.
UNDER THE INFLUENCE OF AN AIRSTREAM FROM THE PACIFIC, CONDITIONS IN HONG KONG WERE WARM AND HUMID WITH WIDESPREAD FOG ON APRIL 6 AND 7.
VISIBILITY WAS REDUCED TO 100 METRES AT THE ROYAL OBSERVATORY AND WAGLAN ISLAND, 300 METRES AT CHEUNG CHAU AND 1,300 METRES AT THE HONG KONG INTERNATIONAL AIRPORT.
WATER TRAFFIC BETWEEN HONG KONG, MAÇAU AND GUANGZHOU (CANTON) WAS AFFECTED.
A FISHING BOAT SANK 80 NAUTICAL MILES SOUTH-SOUTHEAST OF HONG KONG AFTER COLLIDING WITH AN UNKNOWN VESSEL IN THICK FOG AROUND 1 A.M. ON APRIL 8.
THE PASSAGE OF A WEAK COLD FRONT ON APRIL 8 CLEARED THE FOG BUT CONDITIONS REMAINED CLOUDY WITH RAIN DURING THE FOLLOWING TWO DAYS. IT WAS FINE ON APRIL 11 AND 12 WHEN A RIDGE OF HIGH PRESSURE COVERED SOUTH CHINA BUT BECAME CLOUDY AGAIN THE FOLLOWING DAY WHEN ANOTHER COLD FRONT RAPIDLY APPROACHED HONG KONG.
THE COLD FRONT REACHED THE SOUTH CHINA COAST LATER IN THE EVENING AND WINDS OVER HONG KONG SOON FRESHENED FROM THE EAST. THE STRONG MONSOON SIGNAL WAS HOISTED FROM 1.10 A.M. TO 9.50 A.M. ON APRIL 14.
CONDITIONS WERE FINE AND SUNNY FROM APRIL 15 TO 17 BUT OVERNIGHT ON APRIL 17 MIST OR FOG DEVELOPED AND PERSISTED UNTIL THE ARRIVAL OF AN ACTIVE TROUGH OF LOW PRESSURE WHICH BROUGHT HEAVY SHOWERS AND THUNDERSTORMS, DURING THE AFTERNOON OF APRIL 19.
BETWEEN 3 P.M. AND 5 P.M. ON APRIL 19, THE ROYAL OBSERVATORY RECORDED 49.6 MM OF RAINFALL.
TRAFFIC WAS HELD UP ON BOTH SIDES OF THE HARBOUR WHEN MANY VEHICLES BROKE DOWN DURING THE HEAVY DOWNPOUR. MINOR FLOODS OCCURRED IN MANY LOCATIONS AND 70 PEOPLE WERE REPORTED TO HAVE EVACUATED FROM A VILLAGE IN WONG TAI SIN.
WINDS TURNED TO EASTERLY AFTER THE PASSAGE OF THE TROUGH FROM THE NORTH. THERE WAS A SHORT PERIOD OF STRONG WINDS OFF-SHORE OVERNIGHT AND THE STRONG MONSOON SIGNAL WAS HOISTED FOR A FEW HOURS.
THE WEATHER GRADUALLY IMPROVED DURING THE AFTERNOON OF APRIL 20 BUT REMAINED CLOUDY THE FOLLOWING TWO DAYS.
A RIDGE OF HIGH PRESSURE OVER SOUTH CHINA FROM APRIL 23 TO 26 GAVE RISE TO SUNNY AND HOT WEATHER IN HONG KONG, BUT THE WARM AND MOIST STREAM ALSO CAUSED MIST AND FOG DURING THESE FOUR DAYS.
/ON THE ALTEROON