![\"\"](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2021\/06\/revised_three_skewts.png\")
<\/a>Three skew-T plots from around Madison, Wisconsin, showing an increase in instability.<\/p><\/div>\n
Of course, surface conditions don\u2019t tell the whole story, and this is where the NUCAPS profiles prove their worth. The dashed line on each sounding represents the temperature of the near-surface mixed layer air parcels as they ascend. These air parcel trajectories were calculated by the SHARPpy package, a free and open-source tool designed to analyze atmospheric soundings.\u00a0 As air rises, it cools, but it cools at different rates depending on if the air is saturated or not. If air from the surface is warmer than the air that surrounds it, it will continue to rise all on its own, but air that\u2019s cooler is going to sink. Note that the 3rd and the 6th\u00a0 are stable days. The dashed line is to the left of the red temperature line. On those days, an ascending air parcel is always colder than its environment and since cold air sinks, no surface-based air is going to rise high enough to make deep convective clouds and the rain that accompanies them.\u00a0 However, on the 8th the situation is reversed: the dashed line is to the right of the temperature sounding which means that air from the surface is warmer than its environment and will rise on its own.<\/p>\n
The instability isn\u2019t that large on the 8th; rising air parcels aren\u2019t substantially warmer than their environment and so there\u2019s not a lot of buoyant energy.\u00a0 Still, it has been enough to contribute to some localized showers. \u00a0That’s evident on the CMORPH satellite-based precipitation estimates over the midwest (available on SSEC RealEarth), which shows virtually no rain on the 6th but the results of some scattered showers in south-central Wisconsin on the 8th. \u00a0It’s not much, but right now the area needs every drop it can get.<\/p>\n