by Jim Allsopp, Warning Coordination Meteorologist, National Weather Service, Chicago
Tuesday, February 5 is National Weatherman's Day, commemorating the birth of John Jeffries in 1745. Jeffries, a Boston physician and one of America's first weather observers, began taking daily weather observations in Boston in 1774. He took the first balloon weather observation over London in 1784. This is a day to recognize the men and women who collectively provide Americans with the best weather, water, and climate forecasts and warning services of any nation.
John Jeffries, an American physician, flew across the English Channel with Frenchman Jean Blanchard
Many of us take weather information for granted. Turn on a light switch, you get light. Turn on your television or radio, or check a web site and you get the weather forecast. It’s easy to forget that around the clock, dedicated meteorologists and weathercasters are vigilantly creating forecasts to help you plan your day, and issuing warnings to help keep you safe.
The men and women at your local National Weather Service (NWS) forecast office gather the raw weather data, analyze the data, and study numerical computer models in order to issue the weather and river forecasts and warnings to protect life and property. Specialized marine and aviation forecasts help enhance the Nation’s economy. Spot forecasts help firefighters control wildfires and emergency management officials contain hazardous chemical spills. Extensive climate records help engineers, architects, researchers, insurance companies and utilities.
The primary mission of the NWS is to provide the American public with the best possible warning service to save lives. Recent severe weather statistics show that we continue to improve our capability to warn the public of impending hazardous weather. Nationally, lead time for flash flood warnings improved from 22 minutes in 1993 to 59 minutes in 2011-12. Accuracy over the same time period increased from 71 percent to 79 percent. Lead time for tornado warnings has increased from 6 minutes in 1993 to almost 14 minutes today. Tornado warning accuracy increased from 43 percent to 73 percent. Winter storm accuracy in the last three years was 89 percent with an average lead time of 19 hours. Since 1990, the Tropical Prediction Center’s 24 to 72 hour tropical storm forecast track errors have been reduced by more than 50%. These more accurate and longer lead time warnings help communities stay safe.
Locally, the Chicago NWS forecast office, which serves 23 counties in northern Illinois and northwest Indiana, had an accuracy of 67 percent for tornado warnings over the last five years, with an average lead time of 11 minutes. For the stronger and more dangerous EF2 and greater tornadoes, the numbers improve to 93 percent and 18 minutes, respectively. Flash flood warning accuracy was 78 percent with an average lead time of 67 minutes. For winter storms, accuracy was 81 percent and average lead time 16 hours.
But the NWS couldn't accomplish its mission without a diverse group of partners helping in the process. Nationwide, more than 11,000 volunteer Cooperative Observers take regular measurements of temperature, precipitation and other data, which is used by forecasters and climatologists. Nearly 300,000 volunteer storm spotters are trained by the NWS to provide visual reports of severe weather conditions to forecast offices and local emergency management officials. Volunteer amateur radio operators provide critical emergency communications during severe weather.
The Chicago NWS office has a network of 78 dedicated volunteer Cooperative Observers throughout north central and northeast Illinois and northwest Indiana. In addition, there are about 20 supplemental snow observers and 20 supplemental rainfall observers in the area. Around 800 volunteer observers report through the Community Collaborative Rain, Hail, and Snow (CoCoRaHS) network. There are also about 30 volunteer ice spotters who provide forecasters reports of ice jam flooding on area rivers in winter. About 3000 people attend Skywarn severe storm spotter training classes in the local area each year.
Most of the colorful weather graphics seen on television and in newspapers come from another member of the America's weather team. Commercial weather companies enhance the presentation of the NWS data and information for their clients in the media and in many weather-sensitive industries. They also provide customized forecasts and services for clients.
Researchers, academia, and programmers who help us gain a better understanding of the atmosphere through new and better forecasting techniques, and better numerical modeling, also help advance the science.
And finally, television weathercasters are the most visible members of the America's weather team. They are the trusted faces many people turn to for weather information. The NWS depends of TV weathercasters to relay the NWS’s official watches and warnings for hazardous weather to the public.