Atmo Obs During Eclipse - Synoptic Pattern Miserable

Received the following email yesterday about Atmo observations during the eclipse. 
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Hi Bob,

I saw something that you might be interested in.  I was looking at weather chart summaries from the Department of Atmospheric Sciences here at the university and noticed that when we had a partial eclipse this morning, the air temperature stopped rising momentarily (the measured dewpoint also has a drop around that time, not quite sure if that is coincidental though).  Doesn't seem like a big effect given the short duration of the eclipse but interesting nonetheless.

Thanks,

Patrick Broxton

Researcher

Arizona Remote Sensing Center

School of Natural Resources and the Environment

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The incoming solar radiation was just what we'd expect (above), as was the temperature (just below). But what is surprising is the large drop in dewpoint temperature at the beginning of the eclipse - around 7 F (green below). The time series for RH is at bottom. This seems counter to what might be expected, i.e., with decreased mixing the dewpoint might even increase a bit during the eclipse.

I checked the observations at DM and TUS (note that observation time-series remain badly screwed up at TUS - this has continued for two weeks or so - not good) - and both sites experienced the drop in dewpoint also. So what was gong on? I also noted that winds at all three sites shifted to the west as the eclipse began. So, perhaps dry-air advection from west of metro caused the large drop in dewpoint. However, it is not clear to me why the winds shifted. Any other thoughts on this most appreciated.

As for August weather - the synoptic pattern remains miserable, with the dominant 500 mb anticyclone to our south and southeast and shifting only slightly north during next several days. The warm air, in the mostly southwesterly flow above 700 mb, is producing a nasty inversion just below 500 mb. Isolated storms likely to return to Cochise County but more grim here at low elevations. 

August has been a real bummer of a month, after the record setting character of July. Last and only significant rainfall here at house was on August 13th. With slightly more than a week left in the month, I am wondering if the pattern will change enough to bring another significant period of storms to the metro area. Most interesting thing in long-range models is forecast potential for a hurricane affecting south Texas by the weekend.