Stalled high pressure blamed for extreme weather

Since 1968, evidence suggests that we’ve been in a global cycle of wide weather extremes that’s been the strongest such cycle in more than 1,000 years. Based on climatological history, this cycle of extremes is not expected to peak until at least 2038. Until then, we should continue to see more weather records broken worldwide.

Last week, NASA announced that we’re seeing “unprecedented melting” of Greenland’s ice sheet. The recent decrease of ice has even surpassed the melting that occurred in 1889. This type of sudden melting in Greenland occurs about once every 150 years.

The melting of the Greenland ice was caused by a huge wave of warmer than normal air that moved across the island. It began on July 8 and ended four days later. It’s not uncommon to see some ice melting every summer on Greenland, but the 2012 melting has been unusually widespread. Nearly 97 percent of Greenland’s ice sheet was affected. However, there is still plenty of thick ice remaining several miles deep at the center of Greenland.

About the same time the melting peaked in mid-July, a giant iceberg broke off from the huge Petermann Glacier in northern Greenland.

It’s quite possible this Greenland melting is related to the worst drought and heat pattern in the Midwest over the last 50 years, and in some cases, since the Dust Bowl era of the 1930s. It was recently reported that a whopping 45 percent of the 2012 U.S. corn crop was rated “poor-to-very poor” by the U.S. Department of Agriculture. Soybeans were rated a record “33 percent poor-to-very poor.” The widespread crop damage in the nation’s midsection will likely lead to higher food prices over the next year.

The heat and drought pattern has been the result of two gigantic high pressure systems parked over the Northern Hemisphere this spring and summer. One has been locked in place in an “Omega pattern” over the central U.S., while the second high pressure ridge has been over Greenland, producing unusual warmth and abnormally rapid melting on the continent.

By contrast, between the two high pressure systems, there have been record rains, abnormally chilly temperatures and gusty straight-line winds called derechos that caused extensive property damage and power outages in late June and early July along the Mid-Atlantic coastline of the U.S. Our region also had an extremely wet June and early July.