Thursday, September 4, 2014
Currently, monsoonal moisture has once again invaded the area from the south, leading to high clouds this afternoon. Additionally, a cool front is moving across our northern Colorado border, and that may help some afternoon or evening showers to develop.
The upper level low associated with this front is currently splitting, with some of the energy being left behind on the central west coast. Pieces of this lagging part of the trough will keep the chance of showers for Friday and Saturday as the energy moves either over us or just north of us, as there is model disagreement on exactly how this lagging trough will evolve.
There may be a break on Sunday and early Monday as transient ridging crosses the area ahead of another trough forecast to be over the Pacific northwest by late in the weekend. Not only will this wave pick up whatever energy remains from the lagging trough off the central west coast as it moves eastward, but the remnants of Tropical Storm Norbert, currently of the coast of Baja, will also be entrained as that storm moves north.
This may lead to another very wet period late Monday through Tuesday night before the westerly flow associated with the Pacific northwest trough moves over our area by Wednesday. Dry and cool air behind this trough will likely produce some great early fall weather through the end of the workweek before another trough looks to threaten next weekend’s weather. However, there is considerable model disagreement by then, so the forecast is uncertain.