Tuesday, December 12, 2017

Valley Fog, Hoar Frost, and Inversion

Fog has settled thick in the Salt Lake Valley. Cache valley has had days of fog.

December 7th, 2017

December 12th, 2017

Freezing fog often causes hoar frost which is the thick white frost that deposits on trees. If the fog droplets are supercooled, meaning the liquid water is below freezing, it will freeze on contact to surfaces. My brother took this picture from Logan:
Photo Credit: Nathan Blaylock

Oh, and the air is getting pretty bad out there. Check out the PM 2.5 trends across northern Utah. Yuck.

Monday, November 27, 2017

Golden Sunrise

I have never seen a sunrise like this before. When I stepped off the train in Salt Lake at 7:20 AM, the sky was on fire. The light was like pure gold and it filled the sky. What made it so gold? Partially because of blowing dust. Wind's have been quite strong from the south.

Winds throughout the valley were strong from the south all night long. The south wind and associated mixing caused the temperatures in the area to stay warm throughout the night. At MTMET the temperatures never fell below 60 last night. Very unusual for the last week of November.
The PM 2.5 concentration took a spike at the same time as sunrise. The dust in the air scatters the light, and gave us the pretty sunrise.

Thursday, November 9, 2017

Doppler on Wheels Returns

A Doppler on wheels came back to the University of Utah. Here is a picture of me today, and from 2011 when I first saw one of the storm-chasing machines.

19 November 2017

27 October 2011

Thursday, September 14, 2017

Rainbow to the West

My mother sent me this picture this morning. It's not often you see a rainbow to the west!

A radar image at 13:05 UTC

Thursday, July 13, 2017

Spanish Fork HRRR terrain

If you live at the mouth of a canyon you know that it can get windy. One challenge in numerical weather prediction is the inability to resolve small scale features, such as terrain (well, we could run models at ultr-fine scale, but we don't have the computational capacity to do that). The HRRR model has a 3-km grid spacing, which is great, but still too coarse to simulate the actual depth of Spanish Fork Canyon. See the examples below:

Model terrain in the HRRR at Spanish Fork. You are looking south east towards Spansih Fork Canyon

Below is the actual terrain, from a 30 m Digital Elevation Model, is shown below. Again you are looking towards the southeast towards Spanish Fork Canyon.

Finally, a Google Earth image showing the area we are looking at...