Brihat Samhita
तीव्रदिवाकरकिरणाभितापिता मन्दमारुता जलदाः । रुषिता इव धाराभिर्विसृजन्त्यम्भः प्रसवकाले ॥ २१-२४ ॥
If the pregnant clouds should be exposed to the hot rays of the Sun, if they should be accompanied by gentle winds and appear as if covered by drops of rain, they will yield abundance of rain.
english translation
tIvradivAkarakiraNAbhitApitA mandamArutA jaladAH । ruSitA iva dhArAbhirvisRjantyambhaH prasavakAle ॥ 21-24 ॥
hk transliteration by Sanscript