Gov't: La Nina Returning For Winter
September 10, 2011
UPDATED By WeatherBug Meteorologist, Andrew Rosenthal
The upcoming winter looks to be a familiar one, as the same climate pattern as last winter appears to be making a return.
The U.S.`s Climate Prediction Center reported on Thursday that a strengthening La Nina is returning and could drive this winter`s weather across much of the U.S. La Nina, opposite of the warm-phase El Nino, is a periodic cooling of the equatorial Pacific waters west of South America. It influences weather patterns throughout the world and often triggers common weather pattern that produce weather extremes in the U.S.
This is the same weather pattern that was responsible for some extreme weather both in the U.S. and around the world during the winter and spring of 2010-11. The Sierra Nevada saw a record snowpack that lasted well into the summer, and heavy rain flooded the Mississippi and Missouri valleys. On the flip side, La Nina-driven extreme droughts have dominated Texas and New Mexico as well as much of equatorial Africa.
While El Nino and La Nina typically cycle back-and-forth in alternating years or every 3 years, it is not all that unusual to see the climate pattern repeat itself. In fact, this happens as much as 50 percent of the time.
The return of La Nina "means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico," said Mike Halpert, deputy director of the Climate Prediction Center. Halpert also noted that "La Nina also often brings colder winters to the Pacific Northwest and the northern Plains, and warmer temperatures to the southern states."
In a typical La Nina winter, heavy mountain snow and rain are found from the Pacific Northwest eastward across the northern Intermountain West and into the northern Rockies and the northern high Plains. La Nina produces drier and warmer weather from southern California all of the way to Florida and the Southeast. Thus, the return of La Nina this fall and winter could worsen the drought throughout the southern tier and increase wildfire risk in California and the Southwest.
for more information on the differences between El Nino and La Nina.
NOAA`s full, detailed winter outlook will be released in mid-October.
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