April 28 - Dust storm 'Helen' event summary
A particularly deep upper level trough has caused a couple of exceptional dust events to the border region this past weekend.
Below is a longwave difference animation that I recorded from the RAMSDIS webpage that shows the dust this morning looping around the low. Areas of dust show up as the deep red to violet.
The dust source area also shows up on the VIIRS dust product from SPoRT. This was image was captured at 3pm mountain time.