Is Av Harachamim recited prior to Musaf on Shabbos Mevarchim Tishrei? On one hand we don’t actually recite the blessing over the new month and hence perhaps it should be recited as usual, although on the other hand it still is Shabbos Mevarchim and hence perhaps it should not recited as we rule by all Shabbos Mevarchim?
One recites the paragraph of “Av Harachamim” prior to Musaf on Shabbos Mevarchim Tishreiy.
Although on a regular Shabbos Mivarchim the paragraph of Av Harachamim is omitted, nevertheless since on this Shabbos the month is not verbally blessed in Shul therefore one is to recite this paragraph.
Sources: See regarding not reciting in the paragraph of Av Harachamim on a regular Shabbos Mivarchim: Admur 284:14; Admur in Siddur; Rama 284:7; Sefer Minhagim Tirana; See regarding not recited in the paragraph of Av Harachamim on a regular Shabbos Mivarchim: Mateh Efraim 581:47; Shaareiy Efraim 10:35; Toras Menachem 1990 4:299 [Sichas Netzavim Vayeilech; brought in Shaareiy Halacha Uminhag 5:68; Shulchan Menachem 3:75]; Piskeiy Teshuvos 284:17