Category Archives: Climate

What is the National Climate Assessment?

The U.S. National Climate Assessment is mandated by the Global Change Research Act of 1990. The assessment is conducted about every four years and is an authoritative scientific analysis of climate change risks, impacts and responses in the U.S.

The nation this month completed the Fifth National Climate Assessment, or NCA5. The National Oceanic and Atmospheric Administration is the administrative agency for NCA5 and certifies that the report meets Information Quality Act and Evidence Act standards. The assessment is an extensive process that includes internal and external review from federal agencies, the general public and external peer review by a panel of experts. Continue reading

Category: Climate, History, Seasons, Severe Weather

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Higher overnight lows led to warm September

As we enter the month of October and the traditional end of the warm season, it’s interesting to note that the average temperature last month, through Sept. 28, was 4.0 degrees above normal in Madison.

That is by far the biggest deviation among traditional warm-season months — June, July, August and September. All were warmer than average this year: June was 0.8 degrees, July just 0.5 degree and August only 1.2 degree above the respective norm. Continue reading

Category: Climate, History, Seasons

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Are daily weather forecasts affected by climate change?

As it turns out, predictions of the coming weather are nearly exclusively dependent on the observed conditions of the atmosphere in the day prior to the forecast period. Continue reading

Category: Climate, Meteorology, Uncategorized

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Are computers used in weather forecasting?

Weather forecasting is a challenging and fascinating aspect of meteorology. An accurate forecast requires a thorough knowledge of all the variables of the atmosphere. There are also conservation principles of momentum, mass, energy and moisture, combined with the ideal gas law from chemistry that forecasters must consider.

The physical principles are represented as equations, and with current weather conditions, are used to solve for variables meteorologists care about — wind, temperature and precipitation. Computers are used in numerical weather prediction to solve these mathematical models to predict the weather based on current weather conditions. Continue reading

Category: Climate, Meteorology

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Why are cities hotter than the surrounding rural areas?

On average, the city is warmer than the countryside. This difference in temperature is referred to as the urban heat island effect. A number of factors contribute to the relative warmth of cities, such as heat from industrial activity, the thermal properties of buildings and the evaporation of water.

For example, the heat produced by heating and cooling city buildings, and running planes, trains, buses and automobiles contributes to the warmer city temperatures. Heat generated by these objects eventually makes its way into the atmosphere, adding as much as one-third of the heat received from solar energy. Continue reading

Category: Climate, Meteorology, Seasons

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