Temperatures on this Tuesday morning are starting off similarly to yesterday. Yesterday morning, all signs were pointing to a warm-up in the Helena Valley which did not come to pass. Temperatures remained below zero all day on Monday because of the persistent dense, cold air trapped in the valley. Additionally, clear skies overnight last night allowed for radiational cooling, so the modest warm-up that we did see yesterday afternoon quickly dropped after sunset. So now, that inversion is still firmly in place this morning, and the Helena Valley is waking up to temperatures in the 20s below zero yet again.
When will things start to warm up? Warmer air is moving into Montana today, but the strong inversion in the Helena Valley means that the afternoon high will be significantly lower than nearby locations.