Tuesday, October 4, 2011

Omega block continues to bring pleasant fall weather to the Mid-South

Looking at the upper level weather maps this morning, the pattern that has controlled our weather for the past several days is still in firm control of our weather.  The upper level pattern we are under the influence of is termed an omega block. The term comes from the fact that the pattern represents the Greek letter omega (picture at left). An omega block is characterized by three pressure systems - low, high, low (from west to east).  The pattern also tends to be very stagnant, due to the strength of the high pressure system, resulting in days to weeks of the same weather over an area. The Mid-South has fortunately been under the high pressure portion of the block, resulting in an extended period of dry and sunny weather.

An omega block resides over the continental U.S. with low pressure on the coasts and high pressure dominating the central U.S. The omega block gets its name from the contouring of the upper-level pressure systems, which resemble the Greek letter omega. This map shows the 500mb layer (about 18,000 feet).
As the week progresses, the omega pattern will slowly shift east and weaken by the end of the weekend, allowing a more progressive pattern to return, meaning fronts will make steadier progress across the United States as we head into the middle of October.

For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

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