<P> A Western Disturbance is an extratropical storm originating in the Mediterranean region that brings sudden winter rain to the northwestern parts of the Indian subcontinent . It is a non-monsoonal precipitation pattern driven by the westerlies . The moisture in these storms usually originates over the Mediterranean Sea and the Atlantic Ocean . Extratropical storms are a global phenomena with moisture usually carried in the upper atmosphere , unlike their tropical counterparts where the moisture is carried in the lower atmosphere . In the case of the Indian subcontinent , moisture is sometimes shed as rain when the storm system encounters the Himalayas . </P>
with reference to the climate of india the western disturbances originate over
the Mediterranean Sea the Atlantic Ocean