WEATHER By Jack Williams MORE THAN 75 percent of derechos occur between April and August. AVOIDING DERECHO DRAMA PROTECTION FROM DEADLY DOWNDRAFTS A NINETEENTH-CENTURY NAME STILL USED TODAY A ny pilot who's thinking of flying more than a few miles from his or her home airport between March and September should look at the Day 1 Convective Outlook from the National Weather Service's Storm Prediction Center (www. spc.noaa.gov/products/outlook/day1otlk.html). Physics professor Gustavus Hinrichs first used the term derecho in 1888 in a paper published by the American Meteorological Society. "Derecho" is Spanish for "straight ahead"-Hinrichs used the word to distinguish straight-line wind damage from that produced by tornadoes. 44 / FLIGHTTRAINING.AOPA.ORG The center, in Norman, Oklahoma, is the NWS's source of outlooks and forecasts for convective weather. Meteorologists use "convection" to describe thunderstorms and the violent weather they sometimes create, such as tornadoes, squall lines, and mesoscale convective systems-which are large, long-lasting, organized collections of thunderstorms. "Day one" refers to the day you look at the web page. The center also has outlooks for days two and three-if you' re planning to fly tomorrow or the day after tomorrow, you should take a look at thesehttp://spc.noaa.gov/products/outlook/day1otlk.html http://spc.noaa.gov/products/outlook/day1otlk.html http://FLIGHTTRAINING.AOPA.ORG