Although the level of moisture flowing through the sky doesn’t have a one-to-one relationship with rainfall amounts, having more moisture can boost the odds for rainfall extremes, if there’s a force to squeeze that moisture out, such as the cluster of thunderstorms that hit the #GrandCanyon. This weekend, there was an additional force at play. Moisture from the remnants of #TropicalStorm #Iselle was flowing across the West, siphoned inland by a #HeatDome & further waterlogging the atmosphere.