Monday, February 7, 2011

Something Out of Nothing

Numerical Weather Prediction is quite remarkable.  Indeed we've had a decent front develop over northern Utah.  Note how it is presently near 50F at locations along I-80, but 40F at Locomotive Springs and in the mid 30's upstream of the lake.  It's also remarkable how cool it is (mid-to-low 30s) beneath the solid precipitation shield that extends from roughly Promontory Point eastward across the Cache Valley and into the Bear River Range.  I suspect diabatic cooling is contributing to these lower temperatures.

The "frontal passage" shows up quite nicely at Gunnison Island on the Great Salt Lake.  Not a huge temperature drop, but abrupt nonetheless.

Nevertheless, there's plenty as well to be confused about.  Note the northwesterly flow at Dugway Proving Grounds, yet temperatures are in the mid 50's?  Looks like the temperature gradient and wind shift may not be collocated.  Simplistic views of frontal evolution may not apply to this case.  

1 comment:

  1. It looked like a dry line was moving through the west desert ahead of the cold front earlier today. Many of the stations from Wendover eastward saw an abrupt warming and drying with a wind shift to strong westerlies. You can follow this event eastward through the day well before the cold front moved in. Hence, that shift in winds wasn't due to the cold front, but rather mixing out along the dry line. At least that's my hypothesis.