The winter NW Pacific SSTA effect on the Pacific storm track is investigated in detailin the context of the T₂₁L₅ GCM. Results show that warm SSTA can give rise to dramatically in-creased baroclinicity on the north side of the anomaly area and downstream of it and to cause syn-optic scale perturbation variance,disturbance kinetic energy and eddy heat flux to be intensifiedat the entrance of the storm track,thereby revealing the important role of thermal forcing in themaintenance and development of the track.