Thursday, February 18, 2016

Cold Front

On days like today the atmospheric sciences department cancels classes and graduate students abandon work. Students lined up against the window of the 8th floor conference room in the William Browning Building today as a massive cold front, the strongest one in years, approached. The cold front hit the University of Utah at 11:35. Temperatures dropped 20 degrees in fifteen minutes.

Notice the crane turned to the north. This is before the frontal passage with winds still strong from the south.

The crane turned south after the frontal passage.

Strong Winds

Strong winds in northern Utah this morning preceding a winter storm. Shown below is wind speed and wind gusts in mph.

Looks like the cold front and precipitation is on it's way...

Right now the Cold Front is at Dugway. Look at the drastic temperature contrast! On the east side of the front temperatures are at 10 C, warm enough to get away with a jacket. On the west side of the front in the cold air, temperatures are at 2 C, near freezing!

From the HRRR, looks like the front is expected to reach the Salt Lake Valley between 12:00 and 1:00.

Wednesday, February 10, 2016

This is bad...

Have you taken a look outside? You can't see much. This morning we were socked in with dense fog, plus the pollution levels are in the unhealthy range. PM 2.5 concentrations in downtown Salt Lake are over 100 micrograms/m3. That's bad.

Utah county has been quite a bit cleaner than Salt lake County, but I looks like the pollution from Salt Lake is being transported south. Winds are light from the north. This may explain the sudden spike in PM 2.5 concentrations at the Lindon air quality site.

This mornings sounding shows how strong this inversion really is. The ground is cold, below freezing, while the air temperatures in the mountains are above 10 C. Since cold air sinks, all that pollution we emit at the surface stays at the surface. 

Wednesday, February 3, 2016

Windy Balloon Launch: Reno, NV

High Wind Release Reno
Here is the balloon release by our OPL (Observation Program Leader) from Friday, January 29th during a high wind event in Reno. Wind gusts were around 60 MPH. A couple of things to note. (1) The radiosonde did not hit the ground towards the end of the video. (2) More importantly, this data is directly fed into weather models that help to predict weather downstream, like for the midwest blizzard occurring right now.
Posted by US National Weather Service Reno Nevada on Tuesday, February 2, 2016