Reference: Fataawa wa Rasaa.il Shaykh ‘Abdur-Razzaaq ‘Afeefee – Volume 1, Page 159, Fatwa No.23
Question: What is the qiblah (direction in which one should face) for supplicating?
Response: The sky is the qiblah, and raising the hands towards the sky is from the evidences of Ahlus-Sunnah affirming the Loftiness of Allaah (Subhaanahu wa Ta’aala). Even the creatures, if they are afflicted [with pain] they raise their heads towards the sky. And the Ka’bah is the qiblah for supplicating also as it is the qiblah for the salaah.