Monday, January 30, 2012

The Straw That Breaks the Camel's Back

After a brief flirtation with a more active storm pattern, change is coming to the Wasatch Mountains yet again.

As we discussed on Saturday, we have a chance for a snow on Wednesday night, after which we may be looking at an extended period of well below average snowfall.

The proverbial straw that breaks the Camel's back is a weak cyclone located over the north Pacific just west of the dateline.

The GFS and other computer models forecast this system to move northeastward into the Gulf of Alaska, where it develops into an intense midlatitude cyclone.  As is often the case during major cyclogenesis, strong warm advection and diabatic heating within the cloud shield downstream of the cyclone contribute to the development of a high-amplitude ridge over western North America.  This ridge builds over the western US following the passage of our storm on Wednesday night.

This sets the stage for persistent ridging and flow splitting over the western United States, as discussed in the previous post, and illustrated by the 8–10 day mean 500-mb height forecast from the ECMWF and GFS.

Looks like another tough stretch is coming for powderhounds, but great conditions, at least for a time, for those interested in bluebird corduroy.


  1. When you say a tough stretch, how long until the next snow system?

  2. There's a storm Wednesday night into Thursday AM. After that, forecast models are producing a very pronounced ridge and/or split flow for the next 3-16 days. Little point in saying more. A major storm in the 3-10 day time frame is not likely. After that, hope the models are wrong.

  3. Here's a question - From my observations, when the models show high pressure in the 10-16 day windown, they are correct more often than not. However, when they show snow during that time period, the models are probably wrong as often as they are right. Is my observation correct, or is it colored by my pessimistic view of the snow forecasts in this horrible season?