abhivassati

to rain, shed rain, pour; fig. rain down, pour out, shed DN.iii.160 (ābhivassaṃ metri causa); AN.iii.34; Thag.985; Ja.i.18 (Ja.v.100 pupphā a. stream down); Cp.iii.10#6; Mil.132, Mil.411. pp. abhivaṭṭa & abhivuṭṭha; (q.v.)
caus II. abhivassāpeti to cause (the sky to) rain Mil.132.

abhi + vassati from vṛṣ