Monday, September 4, 2017
The cool front for today I mentioned in the last forecast has weakened for the Steamboat Springs area as most of the energy will travel to our east along the west side of a deep, closed low pressure system over Hudson Bay. The minimal cloudiness we see now represents the leading edge of the front, but it now appears no rain will be produced from this weak surge of cooler air.
Probably the most significant impact of the front will be cooler temperatures for Tuesday and Wednesday morning with slightly cooler afternoon highs.
Upstream Pacific energy combined with some energy loitering off the California coast will conspire to nudge the western ridge of high pressure eastward and allow moisture to modestly increase over Colorado by around Thursday in weak southwest flow.
It looks like our best chance for showers will be Thursday and Friday before additional Pacific energy splits as it approaches the West Coast near the end of the work week. The northern portion of the split travels across the northern U.S. border during the weekend, reducing the atmospheric moisture a bit for a downturn in rain chances for the weekend, but increasing them early in the next work week as another shallow cool front is forecast to move through northern Colorado.
The gorilla in the room is Atlantic hurricane Irma, and though it won’t directly affect our weather, it will certainly be national news as the week wears on. Current forecasts have the major hurricane affecting Florida by mid-weekend, validating the earlier trends of the European ECMWF model over the American GFS model.
And even though forecasting the track of the hurricane over a week out is very low probability, current non-hurricane specific models bring the hurricane north through Florida and along the southern East Coast early in the work week before turning it northwestward towards the Ohio River Valley by midweek.