Monday, November 18, 2013
A weak wave traverses our state on late Tuesday into Wednesday leading to some showers producing only a few inches on the hill and light rain in the valleys.
A strong wave entering the west coast on Wednesday splits, with the southern portion forming a cutoff low moving southward along the coast while the northern portion moves along the US border with Canada.
By Thursday, cold air from the northern wave will be over our area as energy begins to eject to the northeast from the cutoff low now forecast to be just off the coast of southern California. The interaction of this ejecting energy and the cold air from the north could create significant snows lasting into Friday.
Current forecasts have a nice but chilly weekend for northern Colorado as the cutoff low moves across the desert southwest. These cutoffs are notoriously difficult to forecast as their movement depends upon upstream energy that is difficult to measure in the data sparse Pacific. If the cutoff low moves further north than forecast, the nice weekend forecast may be in jeopardy.
There is a lot of cold air lurking to our north after next weekend, and some models want to build a ridge over the Gulf of Alaska which will shunt this cold air over our region. Timing is uncertain, but confidence is growing that an active wet and cold storm track will grace our area around the end of the month.