Knowing astronomical data, including sun and moon position, can also be helpful. Austin was once asked to determine what the lighting conditions were the night that a couple had been murdered. A witness said he saw the defendant enter the home on the night of the murder. To establish what the lighting would have been like then, Austin measured the terrain, looked at cloud cover, humidity, temperature, and sun and moon positions. She explains there are different twilights (twilight, civil twilight, nautical twilight and astronomical twilight). Each lasts 20 to 35 minutes.
Astronomical data can be obtained from the Navy. The United States Naval Observatory, reporting to the Navy Oceanography and Meteorology Command, determines the positions and motions of the Earth, sun, moon, planets, stars and other celestial objects; provides astronomical data; determines precise time; measures the Earth’s rotation; and maintains the U.S. Master Clock. The U.S. Naval Observatory makes its products available to the public through the Naval Oceanography Portal (see box on Page 47).
Standard data for law enforcement
Even if law enforcement doesn’t look up weather using the various sites available online, Austin suggests law enforcement officers have standard weather data that they gather. Like Ashby, she suggests officers note current weather conditions, as well as surface conditions (wet, icy, dry, etc.), atmospheric conditions (lighting, visibility, winds and so on).
“You never know at the beginning what’s going to be important,” she says. “Even after the occurrence of an event, this information is still very valuable, as are photographs taken on scene.”
Certified consulting meteorologists
When law enforcement has questions about what’s important or how to find the answers to important questions, forensic meteorologists can help.
Harned estimates there are several hundred forensic meteorologists in the country, but notes just over a hundred of them, including himself, are AMS certified consulting meteorologists.
“Meteorology is an unregulated profession,” Harned says. “A lot of people don’t realize that. There are no state licensing boards or exams meteorologists take to call themselves consulting meteorologists.”
AMS recognized a need for a professional certification with qualifications for the CCM program centered in knowledge, experience and character.
“The program is pretty rigorous,” Harned says, adding it’s a good way for people to ensure they have a reputable consulting meteorologist — in any kind of weather.