June 23, 2022 - Clouds of the Day - Cirrus over the Prairie

Cirrus clouds were smeared over the southern sky this morning. These clouds are cirrus fibratus (fibers) and cirrus spissatus (clumps of dense cirrus), all with streamers (fall streaks) of ice crystals. The clouds moved quickly eastward in a strong flow aloft leaving the deep blue sky that is seen in the background. In many urban areas the deep blue-sky color is seldom seen like it is here. The air over Iowa this morning moved from over the Pacific Ocean across the Central and Southern Rockies and the Great Plains. Scroll down to see the sky clear of clouds.

Photo by Craig Johnson, Weatherbriefing L.C.

Cirrus clouds are made of mostly of ice crystals and stand out in the pristine clear air. Temperatures at cloud level above 18,000 feet were near 16 degrees F. The cirrus below looked like clumps and thin delicate strands of hair. They are also ice crystals.

Photo by Craig Johnson, Weather Briefing, L.C.

Below is how the sky looked after the cirrus clouds moved east. The sky was a deep blue from horizon to horizon with temperatures rising through the 80s to near 90 F.

Photo by Craig Johnson, Weather Briefing, L.C.

Some Science

And finally, the map below shows weather balloon data collected this morning. The upper air station model plots include the temperature in degrees Celsius (upper left of station location) with the dew point depression plotted just below it. For example, the temperature at Omaha, Nebraska, was -9 C and the dew point depression was 24 degrees C. The dew point depression is the difference between the temperature and the dew point. The larger the difference the drier the air. A depression of 24 degrees is very dry air. Look to the east at Davenport, Iowa. The dew point depression was 46 degrees - even drier than Omaha.

The photo above shows the result of the dry air - nothing but blue sky. The upper air over Iowa today is very dry. The cirrus clouds were remnants of cloudiness that was coming out of the southern Plains across Iowa. Dew points reported from balloon measurements west and south of Omaha indicated moisture at high altitude. Some of that moisture, in a small patch, was briefly visible early today over Iowa but it moved east, and the ice crystals sublimated (turned to vapor) into the dry air.

The map below includes the data plotted from balloon (radiosonde) soundings and isotherms (dashed lines of the same temperature. The 16-degree isotherm crosses Iowa.

This map was plotted using Digital Atmosphere, software available from www.weathergraphics.com. Users are able to try out the software at no cost.