Weather Tidbits: The Omega Block

This Weather Tidbits will discuss about the omega block. This is an upper level weather pattern where a ridge of high pressure is sandwiched between two areas of upper level low pressure. This causes the jet stream to take on the shape of the Greek symbol omega (Ω). The high pressure blocks the main west to east flow across the country, which forces the air around the high. This pattern is usually stagnant and may stay put for several days. Under the high pressure, there will be an extended period of mainly sunny and warmer conditions. Under the low pressure, conditions will be cloudier, wetter, and cooler. If this pattern remains put for long enough, drought conditions and flooding concerns can arise under the high and low respectively.

In the given scenario shown in the video, Salisbury would be in a stretch of gloomy weather. However, the exact orientation does not need to be exactly as depicted here. This blocking pattern can easily have the high set up aloft Salisbury while one low remains over the Atlantic and the other low stays put closer to the center of the country.