The Philippine Atmospheric, Geophysical and Astronomical Services Administration ( Pagasa) said Monday the northeast monoon has begun.

Pagasa said that for several days ''strong to gale-force northeasterly winds have prevailed over Northern Luzon due to the strengthening of the high-pressure system over Siberia and enhanced by passing of low-pressure areas.''

''Gradual cooling of the surface air temperature over the northeastern part of Luzon has been observed. These meteorological conditions indicate the onset of northeast monsoon season in the country,'' said Pagasa.

Pagasa said the northeast wind flow is expected to gradually become dominant over Northern Luzon, bringing cold and dry air. Surges of cold temperatures may also be expected in the coming months.

it added that with the ongoing La Nina, northeast monsoon rainfall may be enhanced that could trigger floods, flash floods, and rain-induced landslides over susceptible areas. DMS