Inversions Rule

Conditions are ideal  for strong temperature inversions in the valleys of  Western Wyoming with snow cover, clear skies, very dry air, high pressure and the low sun angle of January.

Here are a couple of cam view this morning of the beautiful mid winter scenes.

North View from Snow King

North View from Star  Valley Ranch

The strong ridge of high pressure which has resulted in the extended period of clear skies and dry weather for this part of the country remains in place this Tuesday morning.

 Given the still low sun angle of January and very dry airmass, even with full daytime sunshine temperatures in the high valleys of Western Wyoming, from day to day are actually gradually cooling.  Illustrating this is the weather station at Thayne Elementary School which measures the amount of solar insolation along with temperatures.

Daily Minimum temperatures and daily solar insolation for January 2014 at Thayne ES

Note that once the sunny days began on the 15th nighttime temperatures became colder reaching a monthly low of -11 this morning. 

Riverton Balloon sounding this morning illustrates the strong inversions with the warmer air above.

Riverton Radiosonde 6am 01/21/14

Just a few hundred feet above the surface the temperature is above freezing and does not go below again until around 700 mb or 10,000 feet.

Following is a map of the observed minimum temperatures for Tuesday 1/21/14 across the region

Minimum temperatures 01/21/14

Quite the contrast from below zero in most valleys to generally teens in the higher elevations.

Here is a close look at minimums in both the Star Valley and Jackson Hole regions this morning.

Minimum temperatures 1/21/14

Minimums 01/21/14

 The skiers will find slope temperatures much milder than in the adjacent valleys, both day and night.

Here are the maximums observed on Monday 1/20/14

The higher elevations afternoon temperatures are in the 40s and some 20 or more degrees colder in the nearby valleys.

The classic example of the strong radiational cooling that occurs under this regime is at Peter Sinks near Logan Pass  in North Utah.  following is the graphic showing the dramatic day to night temperature change at this location.

While a short distance to the north, no more than a mile or so, another sensor is on the rim of the Peter Sinks site where little in the way of an inversion is able to develop.

A truly spectacular illustration of micro meteorology at the extreme.  Following is a map with the two stations plotted to show their proximity  to each other.

This pattern is expected to change very little through the coming weekend, so head to the mountains if you want to warm up!