Blocking refers to atmospheric stagnation that can lead to many weather extremes like. floods, droughts, overly high or low temperatures along with other extreme weather conditions. Five different blocks occur with weather: Omega blocks, Rex blocks, Ring of Fire blocks, Split flows and Cut-off flows. Atmospheric blocks make a forecaster’s job easier because they last for days or weeks.
Omega blocks occur when high pressure dominates over the middle part of the United States, and low pressure is on both coasts. The weather under the Omega block is dry with light winds. The upper and lower areas of the block experience rain and colder weather. These blocks simplify forecasting.
Rex blocks set up next to strong high-pressure troughs creating strong low-pressure troughs usually in a coastal area. These blocks force air downward to lower areas and out to the east. They resemble figure-8s. The West Coast often experiences these.
A Ring of Fire pattern occurs often in the Southeast during the summer. A high pressure cell sets up over the Southeast. Rings of Fire refer also to cut-off highs. Air rotates around the cell. Thunderstorms are common in the afternoon because of this pattern. Meteorologists borrow the term, Ring of Fire, from geology.
Split flow blocks occur when two opposing jet streams run along the top and bottom parts of the country, respectively. The stagnant air remains in the middle of the country while the jet streams experience normal weather.
Cut-off lows occur often in California’s coastal areas. They bring many days of rain to the region. They are more intense than rex blocks. The winds move in a more northward direction, but the circulation of the system remains the same. They can occur anywhere.
Researchers at the University of Missouri report that planetary warming could lead to more days of blocking. This could lead to more health risks as what happened in 2003 when 40,000 Europeans died. Lupo, professor at the University of Missouri says that blocking last eight to 11 days each year. These researchers think that warmer days will lead to more blocking days and more storms.
Other results of blocking are long heat waves or numerous winter storms which can restrict and reduce the effectiveness of agriculture, commerce and the environment. The changes will affect how people and animals live. With more storms, the kinds of fruits and vegetables will change as they will not get the needed sun or water for effective growth.