If you think the air has been unusually dry in Denver the last couple days, you are correct. In fact, Monday night’s measurement broke a record for October 16.
Only a tenth of an inch of water was measured in the whole atmosphere. This measurement is from a weather balloon that launches from Denver every day.
The National Weather Service has a contractor launch a weather balloon twice a day at 5 a.m. and 5 p.m. from a location in northeast Denver.
Attached to that balloon is an instrument called a radiosonde. It measures the temperature, wind, humidity and air pressure as it rises through the atmosphere, from the surface all the way up to about 60,000 feet.
The balloon will even reach high into the stratosphere before it pops and falls back to earth with a parachute.
The results of that measurement get transmitted back to the National Weather Service in Boulder. The data is arranged on a sheet called a sounding. One of the parameters that a sounding computes is precipitable water, the amount of water that could be strung out of the air at one location.
The .10 inches of water measured Monday was a record. Tuesday morning's sounding measured .11 inches of water.
It would be more likely to get readings like that in December or January, our two driest months for precipitable water.
The record driest air for all of October is .07 inches. There is one more weather balloon launch at 5 p.m. Tuesday, and the air is dry once again today. We will soon find out if we break that record for October.
By the way, these weather balloons can travel more than 100 miles away from it's launching point. If you happen to find one, the National Weather Service would love to get them back.
They have a self-addressed bag included on the radiosonde package. You can drop it in the mail to be reused, or you can drop it off at your local National Weather Service office