Thursday, July 04, 2013

More Re Yarnell Hill Wildfire - II

Four regional radar plots are shown below - times are: 2 pm, 3 pm, 4 pm, and 6 pm MST. These charts are from NCAR RAL and are a bit hard to interpret, since the base-scan data are blended from or 5 NWS radars (brown plus signs show radar locations). I am not sure exactly how the software used blends these data together since the radar help page at the site provides minimal technical information. The radars blended together here are located at markedly different elevations (e.g., the Yuma radar is near sea level but the Flagstaff radar is above 7,000 ft MSL - more than a mile higher than the Phoenix radar).


At 2 pm (above) the radars were detecting the first signs that the fire was becoming more active - the arrow points to the echo from the smoke plume at the fire. A mesoscale outflow appears to be indicated by the narrow line of echo to the northeast of the fire. By 3 pm (below) a number of strong thunderstorm cells had developed along the outflow.



At 4 pm (above) the thunderstorm cells have weakened and the line of echoes and outflow boundary is approaching the wildfire area. By 6 pm (below) the outflow had moved rapidly southward and its position is indicated by the long line of weak echo that has moved into the northern part of Maricopa County.


The observations from the Stanton RAWS station, just south-southeast of the wildfire, on the 30th indicate that the mesoscale outflow reached Stanton between 4 and 5 pm with the averag hourly wind direction switching from southwest for the hour ending at 4 pm to north-northeast for the hour ending at 5 pm. Sometime during the hour ending at 5 pm the wind gusted to 41 mph. at the Stanton station.

A video of the fire taken from near Congress (see previous post) by Matt Oss can be viewed at

http://vimeo.com/69441733         there is also a link there to a photo gallery of the fire. The ouflow clearly passes over the wildfire during this video.

There is a satellited based overview of the fire at     http://cimss.ssec.wisc.edu/goes/blog/archives/13341





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