The Prophet ﷺ never raised his hands for any invocation except for that of Istisqa' and he used to raise them so much that the whiteness of his armpits became visible. (Note: It may be that Anas did not see the Prophet ﷺ raising his hands, but it is narrated that the Prophet ﷺ used to raise his hands for invocations other than Istisqa. See Hadith No. 807 & 808 and also see Hadith No. 612, Vol. 5).  

كَانَ النَّبِيُّ ﷺ لاَ يَرْفَعُ يَدَيْهِ فِي شَىْءٍ مِنْ دُعَائِهِ إِلاَّ فِي الاِسْتِسْقَاءِ وَإِنَّهُ يَرْفَعُ حَتَّى يُرَى بَيَاضُ إِبْطَيْهِ