PUNXSUTAWNEY — National Weather Service meteorologist Jared Rackley, stressed the importance last week of weather spotters, calling them the first line of defense when severe weather threatens.
Rackley’s came during the training of area residents training to become weather spotters through the Skywarn program at the Punxsutawney Weather Discovery Center.
Rackley said the NWS needs everyday people to be weather spotters to enhance the accuracy of the warnings issued and spotters help verify reports received. He said the United States averages 650 severe weather related deaths and sustains $15 billion in losses. He said the NWS is the sole entity that issues severe weather warnings in the United States for the public.
“What we do does impact the economy in the U.S. The National Weather Service plus you equals a credible warning. Without you, we can’t do this. You are the ground truth,” Rackley said.
He said if a tornado is spotted on radar, a tornado warning is issued. The warning is then upgraded to a confirmed tornado warning when the NWS receives a spotter report and their media partners can spread that information. He said while radar technology has improved in recent years, the NWS can’t see everything on the radar, which makes local weather spotters imperative. He said the radar beam spreads higher the further away it travels, which means the NWS can’t see what is happening on the ground at a distance from the radar. The beam also gets wider the further from the radar, which hurts resolution.
He said spotters are needed after the fact to verify the warnings sent out and to analyze the lead time of the warning
“We want to know how we are doing so we can do better,” Rackley said.
Rackley explained the differences between a severe weather watch and a severe weather warning and gave examples of the criteria needed for a warning to be issued. He said that a severe weather watch means all the ingredients for severe weather are present and a warning means the weather event is already under way.
He said individuals should seek safety if a severe weather warning is issued.
Rackley said a severe thunderstorm warning is issued when the NWS receives reports of wind that exceeds 58 miles per hour and hail that is greater than one inch in diameter. A tornado warning is issued when Doppler radar indicates a tornado or a weather spotter confirms that a tornado has touched down in an area. A flash flood warning is issued when six inches or more water flowing over a roadway is reported.
Rackley said good weather spotters are well versed in safety and preparedness when reporting storms, where to get weather information before and during the weather event, know how to identify features of an event and know how to accurately convey what they are seeing to the NWS. He advised spotters not to attempt to go out in the middle of a severe weather event to make a report and to always be safe.
“Don’t put yourself in harm’s way. You can wait until after the storm to send us a report,” Rackley said.
He said safety after the weather event is important as well, warning that spotters should avoid fallen power lines and debris from the storm.
Rackley stressed the importance of the NWS’s T.E.L system for weather reporting, which stands for Time, Event and Location. Rackley said spotters need to report what time they saw the event, the exact event details and where the event occurred. For severe thunderstorm winds, spotters should report winds that are 58 mph or higher, downed power lines or trees and any structural damage. For tornados and funnel clouds, report any observed rotation in the clouds, damage on the ground, the direction the cloud or tornado is moving and how long has the tornado been on the ground. Hail size and damage should be reported. For significant flooding, report closed or impassable roads and any water entering homes. Reports can sent to the unlisted weather spotter number at 800-242-0510, to firstname.lastname@example.org, http://weather.gov/pittsburgh or to the NWS Pittsburgh’s Facebook and Twitter.
Rackley spoke of some of the features and hazards associated with thunderstorms, saying a thunderstorm needs three prerequisites to occur: moisture to form clouds, a lifting mechanism to lift the moisture up and instability in the atmosphere. He said wind shear is needed to form severe thunderstorms. He said wind shear allows the updraft to tilt, which results in stronger thunderstorms and allows for rotation. He said supercell thunderstorms are the most dangerous form of thunderstorms as they produce unusually large hail and tornados. He said super cells are responsible for the EF 2 and 3 tornados.
He said hail is formed when rain droplets are sucked into the storm and crystalize when they spend time below the freezing level. They continue to grow larger until the updraft cannot contain them.
“The stronger your thunderstorm is, the bigger hail you have,” Rackley said.
Flash flooding occurs when heavy rain from thunderstorms is localized. Rackley said flash flood warnings are issued when an inch to up to three inches are expected in a matter of hours. He said flash flooding is a bigger problem in urban areas as they are susceptible to landslides and other damages. Rural areas are safer during a flash flood because the terrain allows the water to travel rather than collect. Some threats for flash floods include landslides and washed out roads. Tornados were the final large threat that could occur during a storm. He said a tornado is a violently rotating column of air that must be in contact with the ground.
For more information on how to be a weather spotter, visit www.weather.gov/pbz/skywarn.