Changes in the weather?

In the previous post on the 30th (read it here), I discussed the overall typical summer time pattern.  The North American Monsoon had been ongoing, and strongly, for 2 to 3 weeks and that has continued until just a few days ago.  More on that....but first...

In that previous post I mentioned that because of the weak summertime flow, that only a "only subtle changes in the flow aloft and at the surface can bring a change."  Just enough of a shift allowed for at least some areas of plains and central U.S. to receive a pretty good amount of rainfall (this past weekend) and then a few spots benefited last evening (the 4th).  Here is a map of the rainfall this past 7 days ending this Thursday morning...

The latest drought monitor map shows the improvement across Colorado...

Now - additional changes are showing up across the northern hemisphere.  Look at the jetstream map from this morning....

Those Upper lows (the red L's) across the higher latitudes are a big change and they are pretty strong for this time of year!  However, the only real impact for the high plains is shifting the westerlies (the wind aloft) east into the U.S. with the first indication of the upper system entering the west coast.  This has shut off the North American Monsoon and is poised to warm up the central plains to around 100 or a little more.  Unfortunately it will also strengthen the Elevated Mixed Layer (warming aloft) and will decrease the threat of thunderstorms.  There will probably still be some (primarily Saturday) but it appears that areas of storms would favor locations mainly east of the high plains.

The hot temperatures may not last "that" long depending on the evolution of the jet stream.  I'll have to reevaluate what this shift will do for the remainder of August and I'll take a look later next week so look for an update.  For now, here is the outlook for rainfall through late next week (notice the change across the Rockies).

If you're down at the PRCA rodeo in Dodge this week, I'll be around most days - at the Ford county Emergency Management booth, wondering around, or at the ticket gate.  Stop by and say howdy.