But we can see in looking at a meteogram of weather variables since the beginning of the month that the high temperatures have been getting lower over the past few days:
|Meteogram from the KOUN station in Norman, Oklahoma since August 1, 2011. Temperature is in the top panel. From the Weather Underground site.|
So what's helping promote this cooldown? A roughly zonal pattern aloft has storms firing on the smallest shortwave perturbations. Here's a mosaic radar image from 17Z today:
|NEXRAD radar mosaic at 17Z, Aug. 11, 2011.|
|GFS analysis of 500mb heights and winds for 12Z, August 11, 2011.|
As I mentioned in an earlier post, MCSs (particularly MCCs) don't need strong upper-air support--just enough to get them going. However, their motion is still directed by the upper-level winds. In the pattern this morning, you can see that the flow at 500mb is generally southeastward across the southern plains. It's no coincidence that that's the direction the storms are moving.
However, while there's a relatively flat pattern with maybe some broad troughing aloft over the southeast, at the surface it's a slightly different story. Here's the surface analysis for 16Z this morning:
|RUC 16Z surface analysis of temperature (colors), winds (barbs) and mean sea-level pressure (contours) for August 11, 2011.|
|SPC day one convective outlook for August 11, 2011 as of 1630Z.|
So...enjoy the cool weather while it lasts. The CPC still has long-term outlooks indicating above-normal temperatures in the southern plains for the next month or so. I guess you just have to take what breaks you can...