OMEGA BLOCK
*It resembles the Greek letter Omega and is best analyzed at 500-mbs are adjacent pressure surfaces. The basic pattern of the Omega block is show below:
Air over the Southwest U.S. in forced to the north into Canada and then back south into the Southeast U.S. by the huge high-pressure ridge in the center of the country. The region under the omega block experiences dry weather and light wind for an extended period of time while rain and clouds are common in association with the two troughs on either side of the omega block. Omega blocks make forecasting easier since you can pinpoint areas that will be dominated by dry or rainy weather for several days. The right side of the omega block will have below normal temperatures while the region to the left will have above normal temperatures in this case.
