U.S. & Global October Weather Summary

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Contact:        John Leslie                                                      FOR IMMEDIATE RELEASE
                        301-713-0214                                                  November 15, 2011
NOAA: Global temperatures 8th warmest on record for October
Strengthened La Niña conditions expected through winter
The globe experienced its eighth warmest October since record keeping began in 1880. Arctic sea ice extent was the second smallest extent on record for October at 23.5 percent below average. Additionally, La Niña conditions strengthened during October 2011. According to NOAA’s Climate Prediction Center, La Niña is expected to continue through the Northern Hemisphere winter.
This monthly analysis from NOAA’s National Climatic Data Center is part of the suite of climate services NOAA provides government, business and community leaders so they can make informed decisions.
Global temperature highlights: October
  • The combined global land and ocean average surface temperature for October 2011 was the eighth warmest on record at 58.14 F (14.58 C), which is 1.04 F (0.58 C) above the 20th century average of 57.1 F (14.0 C). The margin of error associated with this temperature is +/- 0.13 F (0.07 C).
  • The global land surface temperature was 1.98 F (1.10 C) above the 20th century average of 48.7 F (9.3 C), making this the 2nd warmest October on record. The margin of error is +/- 0.20 F (0.11 C). Warmer-than-average conditions occurred across Alaska, Canada, most of Europe and Russia, and Mongolia. Cooler-than-average regions included the southeastern United States, most of southern and western South America, parts of Algeria and Libya, part of Eastern Europe, and far southeast Asia.
  • The global ocean surface temperature was 0.70 F (0.39 C) above the 20th century average of 60.6 F (15.9 C), making it the 11th warmest October on record. The margin of error is +/- 0.07 F (0.04 C). The warmth was most pronounced across the north central and northwest Pacific, the northeast Atlantic, and portions of the mid-latitude Southern oceans.
  • The United Kingdom marked its warmest October since 2006 and eighth warmest in the last 100 years, at 3.6 F (2.0 C) above the 1971–2000 average.
  • Several locations in Argentina experienced their coolest October in five decades.
Global temperature highlights: Year to date
  • The combined global land and ocean average surface temperature for the January – October period was 0.95 F (0.53 C) above the 20th century average of 57.4 F (14.0 C), making it the 10th warmest such period on record. The margin of error is +/- 0.16 F (0.09 C).
  • The January – October worldwide land surface temperature was 1.53 F (0.85 C) above the 20th century average, the sixth warmest such period on record. The margin of error is +/- 0.34 F (0.19 C). The global ocean surface temperature for the year to date was 0.74 F (0.41 C) above the 20th century average and was the 12th warmest such period on record. The margin of error is +/-0.07 F (0.04 C).
  • La Niña conditions strengthened during October 2011. According to NOAA’s Climate Prediction Center, La Niña is expected to continue through the Northern Hemisphere winter 2011/2012.
  • Monthly rainfall across Spain was 35 percent below average, the driest October since 1998. 
Polar sea ice and precipitation highlights
  • The average Arctic sea ice extent during October was 23.5 percent below average, ranking as the second smallest October extent since satellite records began in 1979. The extent was 846,000 square miles (2.19 million square kilometers) below average and 127,000 square miles (330,000 square kilometers) larger than the record low October extent set in 2007.
  • On the opposite pole, the October Antarctic monthly average ice extent was 1.2 percent above the 1979–2000 average, the 12th largest on record.
  • Despite a record-breaking snowstorm in the US Northeast, Northern Hemisphere snow cover extent during October was below average, and ranked as the 15th smallest October snow cover extent in the 44-year period of record. The North America and Eurasian land areas both had below-average snow cover during the month. 
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* Included in this report: NOAA is now making it easier to find information about margins of error associated with its global temperature calculations. NCDC previously displayed this information in certain graphics associated with the report, but it will now publish these ranges in the form of “plus or minus” values associated with each monthly temperature calculation. These values are calculated using techniques published in peer-reviewed scientific literature. More information.
* In November, the GHCN-M version 3.1.0 dataset of monthly mean temperature replaced the GHCN-M version 3.0.0 monthly mean temperature dataset. Beginning with the October 2011 Global Monthly State of the Climate Report, GHCN-M version 3.1.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends. More information on this transition can be found at: ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3/techreports/
On the Web:
NOAA’s National Climatic Data Center: http://www.ncdc.noaa.gov            
NOAA Climate Services: http://www.climate.gov
October 2011 Release & Images:


Contact:        John Leslie                                          FOR IMMEDIATE RELEASE
                        301-713-0214                                       November 8, 2011
NOAA: October warmer than average in the United States
Early season storm breaks October snowfall records across the Northeast, while record drought continues across the Southern Plains
During October, a persistent upper-level weather pattern brought below-normal temperatures to the southeastern United States and above-normal temperatures from the Southwest, across the northern tier of the United States, and into parts of the Northeast. Near-normal precipitation during October across the Southern Plains made little change in long-term drought conditions. The drought stricken areas of the Southern Plains still need at least 18 inches of rain in a single month to end the on-going drought.
The average U.S. temperature in October was 55.7 degrees F, 0.9 degrees F above the 1901-2000 long term average. Precipitation, averaged across the nation, was 2.04 inches. This was 0.07 inch below the long-term average, with variability between regions. This monthly analysis, based on records dating back to 1895, is part of the suite of climate services NOAA provides.
U.S. Climate Highlights – October
The Southwest, much of the Northeast, and states along the U.S.-Canadian border experienced above-normal temperatures. Eighteen states had October temperatures above their long-term averages.
Eleven states from Louisiana to West Virginia had October temperatures below their long-term averages. Meanwhile, states in the Pacific Northwest, the Central and Southern Plains, and parts of the Midwest had near average October temperatures.
An early season storm brought heavy snow accumulations to the Northeast on October 29-31. Several locations broke October snowfall records, including New York City’s Central Park, where 2.9 inches of snow accumulated. The highest snowfall amounts were further inland, with more than 30 inches accumulating in western Massachusetts and southern New Hampshire. The heavy, wet snow falling on the autumn foliage, combined with strong winds, caused havoc across the region. The storm received a preliminary rank of Category 1 on the Northeast Snowfall Impact Scale (NESIS), which takes into account snowfall accumulation in populated areas, making it the only ranking storm to occur during October on record. NOAA continues to assess the economic impact of this early season snow storm.
Several storms impacted the interior western states during October, bringing above normal precipitation totals to Idaho, Montana, Nebraska, Nevada, and Wyoming. Storms also impacted the eastern seaboard, causing wetter than normal conditions in Florida and the Northeast.
A string of states from Minnesota southward along the Mississippi River to Louisiana observed below normal precipitation. Eight states were drier than normal during October with Iowa, Louisiana, and Missouri each having their ninth driest October on record.
Dry and warm weather the first few weeks of October created ideal wildfire conditions across the Great Basin and Pacific Northwest, contributing to record acreage burned during the month. More than half a million acres burned nationwide during October, more than double the long-term average.
As of November 1, about nine percent of the contiguous United States remained in the worst category of drought, called D4 or exceptional drought, smaller than nearly 12 percent of the country experiencing exceptional drought at the beginning of the month. Slight improvement of drought conditions occurred across the Southern Plains during October, where near-normal precipitation was observed.
August-October and Year-to-Date
During the August-October period, the United States as a whole experienced much above normal temperatures with the nationally averaged temperature of 66.0 degrees F ranking as the 10th warmest August-October on record.
This same three month period brought very warm temperatures to the western half of the country, where 10 states experienced temperatures among their 10 warmest for the period, including Texas, which was record warm. The Northeast was also particularly warm, where eight states had a top 10 warm August-October. Below-normal temperatures were present for parts of the Ohio Valley and Gulf Coast.
Precipitation was a mixed bag during the August-October period, with record wet conditions across the Northeast, and much drier than normal conditions across the central United States. Maryland, New Jersey, New York, Pennsylvania, and Vermont had a record wet August-October period, and seven other states in the region had precipitation totals among their 10 wettest.
For the first 10 months of 2011, the contiguous United States was warmer than average. Above-normal temperatures were present across the southern tier of the country, and along the eastern seaboard. Texas was record warm for the 10 month period, while Delaware, Maryland, New Jersey, New Mexico, and Oklahoma had temperatures ranking in their top 10 warmest.
As a whole, the January-October period brought near normal precipitation to the United States, but there was significant regional variability. States across the Northeast were record wet, including Connecticut, Massachusetts, New Jersey, New York, Ohio, Pennsylvania, and Vermont. Drier than normal conditions prevailed across the southern tier of the country, with record dry conditions reported for Texas.


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