Notes From 9/6/11 Training Session

This image is from the simulated water vapor ABI imagery, band 8, forecast at 1800z on 9/6/11. This simulated water vapor image shows quite a bit of high clouds/moisture across the high plains and western Texas. This band usually shows moisture in the upper levels of the atmosphere, thus the cirrus clouds. It also shows a fair amount of dry air wrapping into the circulation of the remnants of Lee over the Ohio River Valley. Compare this to the image below:

This is a simulated water vapor ABI image, band 10, forecast at 1800z on 9/6/11. This simulated water vapor image shows moisture in the low to mid levels of the atmosphere. Thus, it shows a lot of dry air in the southern high plains and western Texas. It also shows this dry air wrapping around the circulation with the remnants of Lee over the Ohio River Valley. From these images, it can be concluded that just some high clouds were moving into the southern high plains and western Texas, with the dry conditions in the lower to mid levels continuing. One could also say that the dry air wrapping into the remnants of Lee may reduce the clouds and precipitation associated with it.

Example 2:

In this GOES-R probability of MVFR ceilings product, from 1115z on Tuesday, September 6, 2011, several areas of higher probabilities were noted. These areas included parts of northwest Wisconsin, southeast Wisconsin, north central Illinois and far northeast Minnesota. There was also a large area of higher probabilities over Minnesota back into the northern Plains. Let's compare with an operational GOES East image below:

This visible GOES East image was taken at 1125z on 9/6/11, 10 minutes later than the MVFR probability image earlier. The MVFR probability product did identify the clouds that were present across the area. This product showed probabilities of MVFR ceilings of generally 50 to 80 percent. However, the observations showed all of the ceilings were VFR (generally 3500 to 5000 feet above ground level). These values are on the lower end of the VFR ceiling spectrum, so even though the ceilings were not MVFR, they were close. This would give the forecaster more confidence that lower end VFR ceilings were occurring.

J. J. Wood
Meteorologist
National Weather Service
Milwaukee/Sullivan, WI