Drought, smoke and Haboob movies
Posted July 11, 2011
Kind of a grab bag of weather-related items to pass along this week. First, just noting that that for the first time since 2008, a portion of our state has gone into extreme drought status. While the specifics of the map may change a bit this coming week due to some beneficial showers and storms last week, the coverage was uneven and not especially heavy toward the coast, and as indicated by the red shading on the attached drought monitor map, central and southern coastal areas are the hardest hit in regards to agricultural and hydrological drought so far, though severe drought has also crept a bit westward, with most of our viewing area still in moderate drought (tan on the map).
One consequence of the dry conditions has been the formation of some significant wildfires in eastern parts of the state, all of which (the Pains Bay fire in Dare county, the Juniper Rd fire in Pender county and the Simmons Road fire in Bladen/Cumberland counties) are occurring in areas where unusually dry peat is burning, in addition to surface fire. The pet tends to smolder significantly, producing thick smoke that's heavy on very small particles that travel long distances. We continue to have some plumes and patches of smoke around the eastern half of the state associated with these fires, and today at least parts of our viewing area may experience some smoky conditions. I've included three modeled trajectory forecasts, one showing how air that starts in Raleigh, Fayetteville or Greenville early today will tend to move north or northeast, carrying smoke in that general direction, a second that shows where air has come from that arrives in those three cities this afternoon (called a "backward trajectory" that indicates some of the air originated off to our southeast yesterday), and a third showing that air leaving those three locations tomorrow morning will move much more toward the east-northeast, likely confining smoke at that time to areas east of our viewing area.
Finally, in the category of videos that make you go "wow," you may have seen pictures last week of the dust storm that hit the Phoenix, AZ area. They were the kind of sand/dust storm often called a "haboob," which is a specific type of dust storm that is produced by intense thunderstorm outflow winds, with gusts in the 60-80 mph range for the July 5th Phoenix event. These dust storms tend to be limited in duration and areal coverage, but also tend to be visually impressive due to the rapid generation of a "wall" of sand/dust that rapidly lofts to several thousand feet in height and advances forward at high speed. That whole process was captured nicely in a couple of time lapse videos that I've included links to. Note that in each case the video tends to load a bit slowly and may be very choppy the first time through. It is worth the wait to hit "replay" to see it play through smoothly. One thing that is especially noticeable in addition to the wall of sand/dust is that above that layer, you can see clouds being generated by warm, moist air being lifted up above the cool, dense thunderstorm outflow as it advances. It makes for a fascinating visualization of the complex processes at work. Enjoy!