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Building Omega Block Scorches Southern California

May 27, 2020

May 27, 2020

Image of water vapor

On May 27, 2020, NOAA’s GOES-West satellite used its water vapor imagery to spy this donut-shaped low-pressure system spinning off of the West Coast. This is currently pumping up very hot temperatures into the Southwestern U.S. and will set up a weather pattern known as an Omega Block across the continental United States later in the week.

An Omega Block happens when areas of low pressure (around the omega edges) gradually transition to areas of higher pressure in the middle, mimicking the shape of an omega symbol (Ω). Lower pressure usually means cooler, wetter conditions; higher pressure usually produces drier, warmer weather.

Parts of the Western and Southwestern U.S. are currently experiencing a heatwave with temperatures in the upper 90s and 100s degrees Fahrenheit. According to the San Joaquin NWS page , the heatwave will intensify as the upper-level ridging persists, pushing temperatures to be 20 degrees above average for Central and Southern California.

The GOES-R satellites are equipped with Advanced Baseline Imager (or ABI) bands that allow scientists to read and classify atmospheric moisture and temperatures in a satellite’s coverage area. Here, you can see water vapor with different moisture levels interacting off of the West Coast, creating residual weather conditions for the rest of the country.

The GOES-West geostationary satellite keeps watch over most of North America, including the continental United States and Mexico, the Pacific, as well as Central and South America. The satellite’s high-resolution imagery provides optimal viewing of severe weather events, including thunderstorms, tropical storms, and hurricanes.