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Upper atmospheric high pressure and dry air keeps things quiet on Saturday. Moisture in place and a shifting of the high center allows for afternoon storms and seasonable high temperatures for many days to come.
1am update 8/6:
A bunch of work and home stuff crowded out the forecast discussion today (8//6) but the story is pretty simple. The high that either blocks the moisture and convection or pumps it into the state is in a no-so-great location for storms Tuesday and (somewhat) on into Wednesday. After that it does drift to the southeast of Colorado again. Moisture will return Thursday-Saturday (at least) and short waves will be able to interact with this moisture to really kick off some better thunderstorm coverage Thursday +. More later!
End 1am udpate.
There is quite a big blob of tropical moisture over the southwest U.S., (Figure 1) but the high has wobbled over Colorado Saturday which will keep things quiet except for a few isolated thunderstorms up in the mountains and on the Palmer Divide (Figure 2). For Sunday, the high center drifts to Arizona which will allow some afternoon storms to form and drift east off the mountains.
The Longer Range Forecast:
Little changes in the longer range - you can watch the animation of the 500mb pattern and the closed set of circles that is the high (like a mountain with lines of equal elevation) drift this way and that around the southwestern U.S. over the next 5 days (Figure 3). The upper atmospheric relative humidity gives an indication of the moisture flow around this high - the animation in Figure 4 shows blobs of moisture getting pulled into the circulation. Because of this, we'll see varying amounts of afternoon convection over the next 10 days with peak activity occurring when the high is more distant or to the southeast of us, and when the higher moisture values are in place at the time of maximum daytime heating (Figure 5).