Today, 173 years ago, in the year 1847, the eastern Polish area suffered from torrential rain.
Rabbi Yosef Shaul Nathanson, the Rav of Lemberg, notes that on the 20th of Av, the chazzan in his shul said the aforementioned prayer, but missed out the proper ending of the bracha of Sh’ma Koleinu. R’ Yosef Shaul is debating if in such a case, one has to return to the beginning of the bracha or not, and concludes, that not.
Source: Shulchan Aruch, Orach Chaim, 576:11 & 577:1, Shoel UMeishiv, 1st edition, vol. 3, siman 170