I love this Saakhi and apparently such incident as the above has occurred more than once. Professor Udai Singh jee, who is currently a resident of Toronto Canada, narrated a Saakhi which he witnessed himself. It was Bhai Sahib's Haveli (mansion) at his village Narangwal and Professor Udai Singh jee was visiting a Samagam that was going on there. Diwan was outside in the frontyard and all of sudden it started raining. Professor Udai Singh jee said that he can still see the scene in front of his eyes. Some Singhs started moving towards the covered Verendah. Then Bhai Sahib raised his arm towards the sky, as if challenging it, and uttered a Gurbani Pankiti (that I can't remember now but will find out from Professor jee). The rain stopped falling at the Samagam location.
Kulbir Singh