Tuesday, April 14, 2015

Weather Update

Here I am stuck on the Frontrunner after an incident causing an hour or longer delay. I'm late for class, so I'll just look at the weather and take a closer look at this cold front moving in. 

Currently, it is 61 degrees and sunny at the airport. The southerly winds have also contributed to the warm morning.
Looks like it's going to be a nice day, but don't be fooled.

An approaching cold front is expected to reach Utah this afternoon. I would expect some big changes in the weather around 3:00 PM. In the radar image below you can see the front over Nevada this morning.

Looking at the NWS point forecast for this afternoon and evening. Our high temperature of the day will be at 11:00 AM. Then, in the afternoon when we usually keep warming due to solar heating, the temperature drops steadily to evening. Looks like temperatures behind the cold front are about 25 degrees colder than it is right now. Brrrrr! Oh, and it will be pretty windy, too.

Since yesterday, the precipitation ensembles is forecasting slightly more rain and snow. The ensemble mean suggests 0.5 inches of water. There is one outlier model that thinks we'll only get a sprinkling, but I would say that case is pretty unlikely today. Many of the individual members are predicting a bit more, about 0.7 inches of water. Safer to expect a half inch of water.
It doesn't look Provo will get this much water. 

Since the cold front will bring much colder this rain will turn into snow as we approach the evening hours. By morning we could wake up to an inch or two. The thirsty mountains will sure love this spring storm.

UPDATE: April 14, 2015 2:00 PM
The cold front is at our doorstep. Look at the shift in winds between Dugway and the Salt Lake Valley. Numbers on the map are wind gusts in miles per hour. I-80 has been closed due to tipped over semi trucks.

Below is a time lapse showing the blowing dust in the valley. It looks kind of nasty out there.

Where is the dust coming from? It's from the west desert. I'm still waiting for the TERRA satellite to pass over Utah to get another look at the dust, but by the next orbit we might be socked in with clouds.

From the University of Utah, it's pretty difficult to see anything in the distance. Plus, here is a "storm selfie" of me and some of my classmates:

In the TRAX air quality measurements show unhealthy levels of PM 2.5.

The front is about to reach the University of Utah. If you thought it was dusty two hours ago (12:45 PM), look outside now (2:45 PM)!
William Browning Building 12:45 PM

William Browning Building 2:45 PM
And now we can look at the cold front passage at the airport. Yay!

The best way to classify a cold front is by cold air. In the last half hour, temperatures at the airport have dropped 20 degrees.

 Also, note that winds at the airport have shifted from the south to the west, northwest. It's incredible that winds are gusting at 65 miles per hour!

An an updated view of PM 2.5 in the valley: at the Neil Armstrong Academy concentrations are almost at 250!!! Downtown is also extremely polluted. This air is not good to breathe. 

Compare the camera image at 3:17 PM with the one at the top of this post from this morning...

Update 4:16 PM
Now with the front passage and some rain, the dust has cleared out quite a bit. Visibility has improved at the Neil Armstrong Academy.

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