Warm modified Circumpolar Deep Water (mCDW) from the Southern Ocean is able to intrude onto the continental shelf in many regions around Antarctica. These intrusions transport great amounts of heat to the continental shelves, affecting basal melting of ice shelves and sea ice formation in coastal polynyas. In Prydz Bay, the largest embayment in East Antarctica, the strongest intrusion of mCDW over the inner continental shelf in March-July is significantly associated with the variability of westerly winds north of the shelf break in January-May. This is the period when the westerly winds over the Southern Ocean move southward, driving the mCDW to become shallower near the shelf break and allowing more warm water to access the inner shelf. Deep convection in winter can entrains sensible heat of this intruded mCDW at mid-dephts into the surface layer, reducing 45% of the potential sea ice production in the coastal polynya. Our findings provide insight into how seasonal variability of atmospheric forcing in the open ocean will affect warm water inflow and heat transport onto continental shelves, and indicate potential impacts on the Antarctic Bottom Water formation.