31 Day Accurate Weather Forecasts

A dream you say, maybe not, according to this article from Scientific American.

An excerpt.

“Hey, Google, what’s the weather? We have become comfortable with the idea that we can make decisions based on accurate weather forecasts for the next three, five or seven days. Families plan cookouts for the upcoming weekend. Citrus farmers protect orange trees if a freeze is coming. Emergency managers evacuate towns that will be downwind of wildfires. Communities along rivers prepare sandbags to line homes and businesses if heavy rain looms.

“But all kinds of decisions could benefit from accurate prediction that stretched as far as three or four weeks out. Farmers could determine how safe it is to plant crops in early spring by finding out whether a late-season frost is expected. Ski-resort operators could choose to wait to start making snow if temperatures were likely to warm again before they could set a base. Water managers could draw down reservoirs in anticipation of spring flooding—or store water if drought were expected. And, of course, you could plan for what your vacation might be like next month.

“In the past several years atmospheric scientists have started to publish “subseasonal” weather forecasts that extend to three and four weeks. A typical seven- to 10-day outlook provides daily high and low temperatures, the percent chance of rain or snow, and wind conditions. A subseasonal projection predicts whether temperatures will be warmer or cooler than average for a given date, based on historical data, and whether it will be wetter or drier than normal. It also foretells hazardous and extreme weather. This time frame fills a big gap between short-term weather reports and seasonal forecasts that anticipate broad trends such as whether El Niño conditions in the Pacific Ocean will bring a warm summer to North America.

“Subseasonal forecasts are improving. For example, a set of weather models known as SubX (the Subseasonal Experiment), led by me at George Mason University and one of my colleagues at the University of Miami, accurately predicted several weeks in advance the increased rainfall associated with Hurricane Michael in 2018, a bitterly cold air outbreak in the Midwestern U.S. in late January 2019, and the July 2019 heat wave in Alaska. The SubX project, begun three years ago, combines forecasts from seven major climate and earth research centers in the U.S. and Canada.

“As an exercise for this article, on February 27 I used SubX to create forecast maps for the U.S. and for the world for March 21 through March 27—a time span 23 to 29 days out. The maps predicted warmer-than-normal temperatures in the Eastern U.S. and colder-than-normal temperatures in the West. They indicated that early spring conditions would prevail along the East Coast and that prolonged winter would persist in the West. The Southeast would continue to be wetter than usual, following a wet February. Several of the predictions were spot-on. A couple were not.


“The seven- to 10-day weather projections we depend on are based on computer models that simulate how the atmosphere evolves. They contain mathematical equations that estimate how temperature, winds and moisture will change second by second and day to day. Since the birth of weather models in the 1950s, forecasts have steadily improved thanks to better scientific understanding of these variables and to advances in computing power. In 1990 only three-day forecasts were 80 percent accurate or better. Today the three-, five- and seven-day outlooks are at that level.

“Many more factors must be considered in a week 3–4 forecast. Like a seven-day projection, this exercise begins with the current weather. Every day large national meteorological and space agencies around the world, including the National Oceanic and Atmospheric Administration and NASA, provide about four million observations of air temperature, atmospheric pressure, winds and humidity from weather balloons, weather stations, airplanes and satellites. Atmospheric scientists combine all these data in a weather model.”

Retrieved July 24, 2020 from https://www.scientificamerican.com/article/accurate-weather-forecasts-28-days-out/

Be well everyone!

About David H Lukenbill

I am a native of Sacramento, as are my wife and daughter. I am a consultant to nonprofit organizations, and have a Bachelor of Science degree in Organizational Behavior and a Master of Public Administration degree, both from the University of San Francisco. We live along the American River with two cats and all the wild critters we can feed. I am the founding president of the American River Parkway Preservation Society and currently serve as the CFO and Senior Policy Director. I also volunteer as the President of The Lampstand Foundation, a nonprofit organization I founded in 2003.
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