Closer the cold comes, step by step by step. Sunday PM, the leading edge of the very cold air has made it into Wyoming and the Dakotas (those poor people – Figure 1). We will see the typical pre-storm warmth with westerly down-slope winds (gusty at times) and compression heating. The cold air begins to slide in later Tuesday with almost 24 hours of snow on Wednesday (Figure 2).
The longer range forecast:
By Wednesday (Figure 3) air that is around 25°F below normal is sliding into Denver. This will feel like quite a shock after our mild week. The weatherunderground model has 1-3 inches of snowfall. The GFS model (Figure 4) gives us 1-2 inches. The NAM has us at about 2-3 inches (though it is hard to read in Figure 5). Those are too far off of most of this winter’s storms and all models agree that a trough takes over for the ridge in the west and we stay below normal to normal, temperature-wise, for the rest of the 10 day window. Yes, get the coats ready again.