"And it is He who sends the winds as heralds before His mercy," meaning: He spreads them out before the rain.
Muhammad said: The reading according to this interpretation is (nashran) with a fathah on the nun, and the meaning is: dispersing/spread out.
﴿وَهُوَ الَّذِي يُرْسِلُ الرِّيَاحَ نَشْرًا بَيْنَ يَدَيْ رَحْمَتِهِ﴾ أَيْ: يَبْسُطُهَا بَيْنَ يَدَيِ الْمَطَرِ.
قَالَ مُحَمَّدٌ: الْقِرَاءَةُ عَلَى هَذَا التَّفْسِيرِ (نَشْرًا) بِفَتْحِ النُّونِ، وَالْمَعْنَى: مُنْتَشِرَةً