Friday, December 10, 2010

IOP2 Ends

Despite my forecasting thinking to the contrary, heavy rain, strong winds, and a potent frontal passage have removed the cold pool from the Salt Lake Valley bringing and end to IOP2. The lake tried to hold onto a shallow lens of cold air for a bit longer, but it too succumbed to the exchange of momentum from aloft. The differences in mix out time can be seen in the following figure:

The sharp temperature rise at the airport occurred about 6 hrs prior to the mix out at Hat Island in the middle of the (not so) Great Salt Lake. The temperature then crashed shortly later as a well defined surface front pushed south across the lake and into the Salt Lake Valley bringing heavy rain and then ice pellets and snow. Strong NW winds with gusts to 43 mph helped to ensure that any residual pockets of cold air at the surface were completely eradicated.

The view across the valley is now as clean as it ever is in the winter and we're all breathing a bit deeper this afternoon. Out next cold pool event looks to be a shorter lived episode (maybe around 72 hrs) starting on Saturday night or Sunday morning and persisting until sometime Wednesday.

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