La Nina 2020: Weather system set to bake the US with heat and humidity, here's what you need to know
Looks like we will have to stock up on sunblock and Kool-aid because it is about to get hot this summer. The Weather Channel's forecast from this weekend predicts that this summer is going to be hotter than usual across the US, beginning from June through August. It also noted that north-eastern areas are expected to face particularly high temperatures.
The hot-above-average temperatures are possible to set in from central Texas into the Pacific north-west, from eastern Washington and eastern Oregan into Idaho, and from western Montana, western Wyoming, northern Utah, and north-eastern Nevada. The same could apply for the Gulf Coast spanning over the mid-west and upper Mississipi Valley, part of Southern California, Southern Nevada and south-western Arizona, where the temperature could either be nearly average or mildly warmer.
This new hot weather forecast could be because of the cooling sea-surface temperatures that were discovered in the Pacific ocean and could result in a La Nina, later in the year. La Nina is a phenomenon that is hard to come by, but it corresponds with floods, droughts and is marked by the onset of a hot, scorching, and humid summer weather. "We do think the idea of La Nina developing does happen this year," AccuWeather meteorologist Tyler Roys told New York Post.
The warm waters from the Gulf of Mexico will contribute to the warm and humid air that will blow along the east coast. "The Gulf of Mexico waters are extremely above normal this year so that will be a leading enhancer for weather systems that lead through the south this summer," said Roys. "It can also play a factor in any tropical storms. There may be a few of those days where you get outside and sweat immediately."
June may see a few pleasant days before the heat and humidity turns it into a hot summer. In the western US, California, Washington and Oregon, chances are that their draughts will persist. The temperatures in the Northern and Central Plains will likely be warmer than usual, but the mixture retained in soil could help with lessening the humidity.
What is La Nina?
La Nina is a natural phenomenon that deals with climate patterns. It involves fluctuating oceanic temperature, that is the cooling of the sea temperature along the tropical west coast of South America and also results in changes in the atmospheric pressure. It is the antithesis of El Nino, which is characterized by warmer oceanic temperatures in the equatorial region of the Pacific Ocean. Together, La Nina and El Nino form the 'cold' and 'warm' phases of the El Nino-Southern Oscillation (ENSO).
How does La Nina occur?
El Nino ushers warmer temperatures, which are above the normal sea temperature, to the southern Pacific ocean around northern Australia, New Guinea and the islands of Indonesia. La Nina is detected when the sea-surface temperature decreases by more than 0.5 degrees Celsius (0.9 degrees Fahrenheit) for approximately five continuous three-month seasons.
The cooler sea-surface temperature brought about by La Nina arises in the southern Pacific, just off the coast of South America. Unusually strong, upward-moving trade winds and ocean currents shift the cold water to the surface through a process known as upwelling, which can also cause a drastic drop in sea-surface temperatures. The temperature of the coastal sea-surface along Ecuador and Peru dropped by nearly 4 degrees Celsius (7 degrees Fahrenheit) during the La Nina event in 1988-1989.
What are the effects of La Nina?
Both contrasting phenomenons El Nino and La Nina affect patterns of rainfall, atmospheric pressure and global atmospheric circulation. Changes in atmospheric circulation, that is movement of air across the globe coupled with ocean currents and distribution of thermal energy on the earth's surface, lead to variations in the world's climate. La Nina is particularly characterized by lower-than-normal air pressure over the western Pacific which leads to a spike in rainfall levels.
This benefits Southeast Asian countries like India and Bangladesh, where summer monsoons help boost the agriculture industry and in turn increase the country's GDP. However, La Nina causes devastating floods and damages in Northern Australia as reports from the 2010 La Nina event entails. It is also associated with incessant rains over southeastern Africa and northern Brazil.
On the other end of the spectrum, La Nina is also characterized by higher-than-normal pressure over the central and eastern Pacific, which leads to decreased cloud production and scarce rainfall in that region. Across the coast of tropical South America, the Gulf Coast of the United States, and the pampas region of southern South America, the areas experience drier conditions spurned by less rainfall.
When does La Nina occur and how long does it last?
La Nina and El Nino tend to peak during the Northern Hemisphere Winter. La Nina events could last anywhere between one to three years, but El Nino lasts no more than a year.