Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 24. joulukuuta 2010 klo 15:50 (GMT)
November 2010 was the globe's second warmest November on record, according to the National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center (NCDC). NASA's Goddard Institute for Space Studies rated November 2010 the warmest November on record. Both NOAA and NASA rated the year-to-date period, January - November, as the warmest such period on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere for November were the 5th or 3rd warmest on record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. UAH rates the year-to-date period, January-November, as the 2nd warmest such period in the satellite data record, behind 1998. The record or near-record November global warmth is remarkable, given that we are in the midst of a moderate strength La Niña episode in the Eastern Pacific. The large amount of cold water that upwells to the surface during a La Niña typically causes a substantial cool-down in global temperatures, making a monthly temperature record difficult to set. November 2010 is the only "warmest month on record" as rated by NASA to occur during La Niña conditions. The November temperature record is all the more remarkable since we are near the minimum of the 11-year solar sunspot cycle. Global temperatures are cooler by about 0.1°C for the two years following a solar minimum, compared to global temperatures two years after solar maximum. Our current minimum in solar energy makes it much more difficult to set monthly global temperature records.
An average November for the U.S.
For the contiguous U.S., November was near-average in temperature, ranking as the 46th warmest November in the 116-year record, according to the National Climatic Data Center. The year-to-date period, January to November, was the 19th warmest such period on record. No states had a top-ten warmest or coldest November on record. November 2010 precipitation was also near average. Only Montana had a top-ten wettest November on record, and no states had top-ten driest November.
La Niña in the "moderate" category
The equatorial Eastern Pacific Ocean is currently experiencing moderate La Niña conditions. Sea surface temperatures (SSTs) over the tropical Eastern Pacific in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", were 1.4°C below average as of December 20, according to NOAA. The Australian Bureau of Meteorology put this number at 1.29°C below average (as of December 19.) Moderate La Niña conditions are defined as occurring when this number is 1.0°C - 1.5°C below average. Temperatures colder than 1.5°C below average qualify as strong La Niña conditions. NOAA is maintaining its La Niña advisory, and expects La Niña conditions to last through the coming winter into spring.
Both El Niño and La Niña events have major impacts on regional and global weather patterns. La Niña typically causes warm, dry winters over the southern portion of the U.S., with cooler and wetter than average conditions over the Pacific Northwest. The Ohio and Mississippi Valleys states typically have wetter winters than usual during La Niña events.
November 2010 Arctic sea ice extent 2nd lowest on record
Northern Hemisphere sea ice extent in November 2010 was the 2nd lowest in the 31-year satellite record behind 2006, according to the National Snow and Ice Data Center. As of December 24, ice extent was the lowest on record for this time of year. Ice volume in November was the lowest on record, according to University of Washington Polar Ice Center.
Figure 1. Sea ice extent in the Arctic as measured by satellites. Beginning in mid-December, ice extent was at record low levels for this time of year. Image credit: University of Bremen.
Major atmospheric pattern shift coming
The unseasonably cold weather over Europe and the Eastern U.S. is due to break between Christmas and New Year's, as the atmosphere undergoes a major shift in its circulation. The very unusual high pressure region over the Arctic is forecast to break down and be replaced by the typical low pressure region we expect to see in winter. After recording some of its coldest temperatures in 17 years this week, the UK may well see record highs on New Year's Eve as a result of the pattern shift. The pattern shift should bring the Eastern U.S. above-normal temperatures during the last few days of 2010, and a major New Year's Eve snowstorm to Iowa, Minnesota, and Wisconsin.
The ZombieSat saga ends?
Last week, I blogged about ZombieSat, the rogue Galaxy-15 communications satellite that failed during a solar storm. ZombieSat has been spewing noise in the C-band microwave region that has been interfering with broadcasts from satellites in its path, including the key SES-1 satellite that relays most of the weather data wunderground and the National Weather Service uses. Within the next week, ZombieSat will close in on its sister satellite, Galaxy-16, which hosts the Public Radio Satellite Service (PRSS) feeds, among others. A few weeks ago, PRSS warned its customers (who include commercial stations as well as the nation's public broadcasters) that there would be a possibility of disruption to its services on or about December 26. But on Friday December 17, Intelsat announced that ZombieSat had lost its "lock" on Earth, resulting in a loss of power that caused the satellite's main interfering transponders to shut down. So it appears the ZombieSat saga is over, and a whole bunch of engineers and operations directors can enjoy Christmas weekend without worrying about a zombie satellite hanging 23,000 miles over their heads.
Happy holidays, everyone!
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