The first six months of 2012 have been the hottest on record across the contiguous United States.
According to the National Oceanic and Atmospheric Administration, more than 40,000 daily heat records have been broken so far this year. In 2011, there were 25,000 daily heat records broken. Overall, the ratio for high temperature records compared to cold temperature records is a whopping 7-to-1.
Over the past 12 months, every state in the lower 48 was warmer except for Washington.
La Niña, the cooler than normal sea-surface temperature event, has waned, and ocean waters along the equator have been warming up in recent weeks. This is likely one of the contributors to the increase in temperature.
The big heat in June east of the Rockies has led to widespread crop damage in the central United States. A recent report from the U.S. Department of Agriculture states that about 30 percent of the corn crop was considered to be in poor or very poor shape. It was 22 percent the prior week. Corn is now pollinating in many areas and the extreme heat at this time of year can hurt the formation of ears and kernels.
The intense heat has been caused by a huge high pressure system that has been moving from the intermountain West and eastward across the Midwest and parts of the Southeast. This ridge has been stubborn because of the slowdown of the North Atlantic Oscillation, a pattern that pushes weather systems across the country. This same high pressure system has also expanded to the West Coast, giving us very warm to hot weather.
While the much of the country was sweltering in June, we were cooler than average by 2.5 degrees. We were also wetter last month with a total of 2.86 inches at the airport, which was 1.61 inches above normal. Since Jan. 1, 12.99 inches of rain and melted snow has accumulated in Spokane. That’s 3.88 inches more than normal. In northwestern Coeur d’Alene, 27.23 inches of moisture has been recorded.
It looks like we’ll see more very warm to hot weather between now and early September. Overall, temperatures are expected to be higher than normal with precipitation below normal for the rest of the summer season. However, there may be a few isolated thunderstorms, but the activity should be centered over the mountains.
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