State of the Climate - Annual 2009
Issued January 15, 2010: The data presented in this report are final through July and preliminary from August-December. Ranks, anomalies, and percent areas may change as more complete data are received and processed.
Based on data from January through December, the average annual temperature for the contiguous U.S. was 53.1 degrees F (11.7 degrees C), which is 0.3 degrees F (0.2 degrees C) above the 20th Century average
As with most seasons, winter December-February 2008-09 featured regional variations in temperature, but the overall average temperature for the contiguous United States was officially "near-normal", or within the middle third of historic winter temperatures. The season was the 40th warmest such period on record (1896-2009), with above-normal temperatures across parts of the South and Southwest. Both the Central and East North Central regions experienced cooler-than-normal temperatures during the period. The monthly variations are illustrated in the statewide rank maps for December, January, and February.
The warm anomalies strengthened in the spring (March-May) period, ranking the contiguous U.S. 29th warmest overall. The warmer-than-average temperatures that were seen in the South and Southwest regions during the winter shifted to the West and Southwest regions during the spring.
Based on NCDC's ranking methods, the contiguous U.S. experienced a summer (June-August) that ranked 42nd coolest since 1895. A recurring upper level trough in the Central U.S. filtered in Canadian air that created below-normal temperatures throughout the Central and northern Plains, Midwest and Great Lakes areas. The cool anomalies peaked in July, when six states ( Ohio, Indiana, Illinois, Iowa, Pennsylvania, and West Virginia) experienced record cool temperatures for the month. This sharp cool feature was partially balanced by warmth in the South and West. For the summer period, the temperature averages in Florida, Texas, and Washington were much-above-normal. It is noteworthy that an El Niño emerged during early summer 2009. Preliminary attribution exercises performed by NOAA scientist indicated that cooler-than-normal temperatures in the central U.S. during summer and early autumn are not inconsistent with expectations during a developing El Niño episode.
Fall 2009 was a season of extremes for the contiguous United States. While September was about 1 degree F (0.6 degrees C) above the long-term mean (LTM), October was marked by an active weather pattern that reinforced unseasonably cool air behind a series of cold fronts, creating an average temperature that was 4 degrees F (2.2 degrees C) below the LTM and ranked the nation as the 3rd coolest, based on preliminary data. In October, 42 of the lower 48 states averaged temperatures that were below-normal. Florida was the only state with an above-normal temperature for October. The following month was something of a mirror image, becoming the 3rd warmest November on record, 4 degrees F (2.2 degrees C) above the LTM. Overall, the nationally-averaged temperature for the three month autumn period was above-normal, as the 31st warmest on record.
Annual averaged temperature for Alaska during 2009 was near the long-term mean. Winter temperatures in 2008-2009 were 1.9 degrees F (1.1 degrees C) below average. Spring temperatures were 0.7 degrees F (0.4 degrees C) below average, summer was 0.7 degrees F (0.4 degrees C) above average, and fall was 1.4 degrees F (0.8 degrees C) warmer than the 1971-2000 average. The Alaska data in this report is a composite of several preliminary datasets at NCDC.
One way to assess the magnitude of warm and cold episodes is to compute the percent area of the contiguous United States that was "very warm" and that which was "very cold". A figure that depicts these values for each month in the past 30 years is provided to the left. These percentages are computed based on the climate division data set. Those climate divisions having a monthly average temperature in the top ten percent (> 90th percentile) of their historical distribution are considered "very warm" and those in the bottom ten percent (< 10th percentile) are "very cold".
The U.S. experienced several warm and cold outbreaks during 2009. The first occurred in July, when 39 percent of the contiguous U.S. was "very cold". An abnormally strong and persistent upper-level pattern during the month helped produce a large number of record low temperatures east of the Rockies. In October, an active weather pattern reinforced unseasonably cool air behind a series of cold fronts. As much as 54 percent of the contiguous U.S. was "very cold". November was on the other end of the scale, when 45 percent of the U.S. was "very warm", according to the definitions provided above. The huge swings in variability continued in December when 36 percent of the contiguous U.S. experienced "very cold" temperatures. According to the National Snow and Ice Data Center, these cooler-than-normal temperature anomalies resulted from a strong negative phase of the Arctic Oscillation (AO), the strongest negative phase of the AO since 1950. A negative phase AO is often associated with a warm Arctic region and cooler conditions in the mid-latitudes of the Northern Hemisphere.
Based on data through December, above-average temperatures were measured in the lower troposphere during 2009. Data collected by NOAA's TIROS-N polar-orbiting satellites and adjusted for time-dependent biases by NASA and the Global Hydrology and Climate Center at the University of Alabama in Huntsville, indicate that temperatures in the lower half of the troposphere (lowest 8 km of the atmosphere) over the U.S. were slightly warmer than the 20-year (1979-1998) average.
Based on data from January through December, the average annual precipitation for the contiguous U.S. was 2.33 inches above the long-term average with a final annual amount of 31.47 inches. It was the 18th wettest in 115-years of record keeping.
Nationally, this was the 22nd driest winter (December-February) in the 1895-2009 record. Texas recorded its driest winter on record, while the state of North Dakota experienced its wettest winter on record. The contrast in rankings were the result of an active upper level pattern that shuttled systems rapidly across the northern tier states, while bypassing the deeper south. Some locations in North Dakota received more than 400 percent of their normal precipitation, breaking snowfall records not only for the month of December, but for any single month. Meanwhile, the persistent dry pattern in Texas led to further expansion of drought conditions.
It was the 18th wettest spring for the contiguous U.S. in 2009. Stagnant surface storm systems and surface fronts across the southern U.S. led to the above normal precipitation averages across the southeastern half of the United States and much above normal precipitation in the Southeast Climate Region in particular. Georgia experienced its second wettest such period. Several other states experienced a spring period that saw above average precipitation: Florida (5th wettest), Illinois (5th), Alabama (7th), and Arkansas (9th). The spring season was characterized by several extreme climatic events. In March, record breaking flooding occurred in parts of Minnesota and North Dakota along the Red River. The flooding was preconditioned by copious winter precipitation coupled with persistent precipitation-producing storms in the spring. Record-high flows were recorded along the Red River with peak levels exceding the 500-year return interval. In late March, a blizzard in the Southern Plains was responsible for three new state record 24-hour snowfall values in Texas, Oklahoma, and Kansas. During the same time, drought in southern Texas was at its peak. Much of the state was suffering from the lack of precipitation which led to 85 percent of Texas experiencing moderate-to-exceptional drought conditions during March and April.
Summer (June-August) precipitation was variable in 2009, which is typical for the season, but overall near normal, ranking 54th wettest out of 115-years worth of records. Regionally, the Northeast had its 2nd wettest summer ever, continuing a string of abnormally wet summer periods. Both the Southeast and Southwest were below normal. On the state level, the lack of monsoonal rains in the Southwest contributed to Arizona's 3rd driest summer. Precipitation averages in Georgia and South Carolina were also much below normal. Conversely, both Maine and Massachusetts experienced their 3rd wettest summer period.
It was the 13th wettest Autumn on record for the contiguous United States. Regionally, dry conditions continued in the West and Southwest where Arizona, Utah, and Nevada averaged much-below-normal precipitation for the three-month (Sep-Nov) period. This contrasted with the South, Southeast, and Central regions where precipitaton averages were above-normal to much-above-normal. Anomalously wet conditions in October led to a record wet month for the nation as a whole. The nationwide precipitation of 4.15 inches was nearly double the long-term average of 2.11 inches. Persistent precipitation during September and October made Arkansas' autumn precipitation its greatest ever. This punctuated the state's remarkable run of wetness in 2009, with four months of top three precipitation ranks ( May, 1st wettest; July, 3rd wettest; September, 2nd wettest; October, 1st wettest). Ten other states were much above normal in terms of precipitation for the autumn season. Interestingly, these high precipitation anomalies occurred despite only two tropical cyclones (Tropical Storms Claudette in August and Ida in November) making landfall during the Atlantic Hurricane season. Variable climatic extremes continued in the fall when, in November, the nationally-averaged precipitation ranked 18th driest, continuing the run of below-normal November precipitation in the contiguous United States.
Like similar values for temperature extremes (see above), the percent area of the contiguous United States considered "very wet" and "very dry" is based upon tenth percentile placement (i.e., those areas with the wettest or driest ten percent of precipitation for a period). The size of the footprint of "very wet" and "very dry" conditons during each month in the last 30 years is depicted in the adjacent figure. These percentages are computed based on the climate division data set.
During 2009, there were back-to-back months that had precipitation extremes of more than 25 percent. The first was October, as 40 percent of the U.S. was very wet. During October, substantial precipitation, nearly double the long-term average, created record wet conditions in contiguous divisions throughout the South and Midwest states. Iowa, Arkansas, and Louisiana all experienced their record wettest October. Fourteen other states had precipitation readings ranking in their top five. On the other hand, 27 percent of the country was categorized as very dry in November. The upper level jet stream was confined to the higher latitudes of North America, holding at bay major weather systems. Meanwhile, high pressure systems, which typically deliver very little precipitation, dominated much of the Western U.S. and Gulf states.
NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800.
NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts.
Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective September 2012, the GHCN-M version 3.2.0 dataset of monthly mean temperature replaced the GHCN-M version 3.1.0 monthly mean temperature dataset. Beginning with the August 2012 Global monthly State of the Climate Report, released on September 17, 2012, GHCN-M version 3.2.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends. For more information about this newest version, please see the GHCN-M version 3.2.0 Technical Report.
*The GHCN-M version 3.1.0 Technical Report was revised on September 5, 2012 to accurately reflect the changes incorporated in that version. Previously that report incorrectly included discussion of changes to the Pairwise Homogeneity Algorithm (PHA). Changes to the PHA are included in version 3.2.0 and described in the version 3.2.0 Technical Report. Please see the Frequently Asked Questions to learn more about this update.
Contents of this Section:
- Global land and ocean annual surface temperatures through October are the fifth warmest on record, at 0.56 °C (1.01 °F) above the long-term average.
- NOAA scientists project 2009 will be one of the 10 warmest years of the global surface temperature record, and likely finish as the fourth, fifth or sixth warmest year on record.
- The 2000-2009 decade will be the warmest on record, with its average global surface temperature about 0.54 °C (0.96 °F) above the 20th Century average. This will easily surpass the 1990s value of 0.36 °C (0.65 °F).
- Ocean surface temperatures (through October) were the sixth warmest on record, at 0.47 °C (0.85 °F) above the 20th century average.
- Land surface temperatures through October were the fifth warmest on record, at 0.80 °C (1.44 °F) above the 20th century average.
Please Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective with the July 2009 State of the Climate Report, NCDC transitioned to the new version (version 3b) of the extended reconstructed sea surface temperature (ERSST) dataset. ERSST.v3b is an improved extended SST reconstruction over version 2. This report uses the ERSST.v3b dataset to assess the entire year. Therefore, values for individual months of January-June presented in this report may differ slightly from those reported when ERSST.v2 was the operational dataset. For more information about the differences between ERSST.v3b and ERSST.v2 and to access the most current data, please visit NCDC's Global Surface Temperature Anomalies page.
The years 2001 through 2008 each rank among the ten warmest years of the 130-year (1880-2009) record and 2009 was no exception. The global combined land and ocean surface temperature was 0.56°C (1.01°F) above the 20th century average, tying with 2006 as the fifth warmest since records began in 1880. Globally averaged land temperature was 0.77°C (1.39°F) above average, resulting in a tie with 2003 as the seventh warmest on record. The ocean temperature was 0.48°C (0.86°F) above average—tying with 2002 and 2004 as the fourth warmest since records began in 1880. The 2000s decade (2000-2009) is the warmest on record for the globe, with a surface global temperature of 0.54°C (0.96°F) above the long-term (20th century) average. This shattered the 1990s value of 0.36°C (0.65°F). See the global time series.
|Global Top 10
Warm Years (Jan-Dec)
|Anomaly °C||Anomaly °F|
The 1901-2000 average combined land and ocean annual temperature is 13.9°C (56.9°F), the annually averaged land temperature for the same period is 8.5°C (47.3°F), and the long-term annually averaged sea surface temperature is 16.1°C (60.9°F).
El Niño-Southern Oscillation (ENSO) began 2009 in a cold (La Niña) phase, but by April some anomalous warming took place in the sea surface temperature (SST) of all Niño regions across the equatorial Pacific Ocean. Such conditions are indicative of a transition from cold phase ENSO (La Niña) to ENSO-neutral conditions. By June 2009, warm phase (El Niño) conditions had entrenched across the equatorial Pacific basin, and persisted through the end of the year. In conjunction with the developing ENSO warm phase, the worldwide ocean temperatures increased relative to the long-term average during late spring. The presence of an El Niño in the tropical Pacific Ocean contributed to the warmest global ocean temperatures for the June-August season. Above average SST remained present in all Niño regions at the end of November and by December El Niño strengthened, and Oceanic Niño Index values exceeded the El Niño threshold for the year's last five months, ensuring that 2009 was recorded as an El Niño year. According to the end-of-year outlook from NOAA's Climate Prediction Center, El Niño was expected to continue through the Northern Hemisphere spring 2010. For more information on the state of ENSO during 2009, please visit NOAA's Climate Prediction Center (CPC).
Warmer-than-average temperatures occurred during the year (January-December) for most of the world's surface. The warmest above-average temperatures occurred throughout high latitude regions of the Northern Hemisphere including much of Europe and Asia, also across Mexico, Africa, and Australia. Cooler-than-average conditions occurred across the southern oceans, parts of the northeastern Pacific Ocean, central Russia, and a region spanning southern Canada and the north central contiguous United States.
The map, above left, is created using data from the Global Historical Climatology Network (GHCN), a network of more than 7,000 land surface observing stations. Temperature anomalies are with respect to the 1961-1990 average. The map, above right, is a product of a merged land surface and sea surface temperature anomaly analysis developed by Smith et. al (2008). For the merged land surface and SST analysis, temperature anomalies with respect to the 1971-2000 average for land and ocean are analyzed separately and then merged to form the global analysis. For more information, please visit NCDC's Global Surface Temperature Anomalies page.
Notable temperature extremes in 2009 include southern Australia's record-breaking heatwave during their summer months of January-February. January's heatwave brought numerous new temperature records across the region. Southern South Australia and most of Victoria experienced their highest maximum temperatures since 1939. However, unlike the southern states, Queensland and Northern Territory had their coolest January since 1984. A second heatwave impacted the area during early February. The second time around, extreme heat was accompanied by very dry conditions that contributed to the development of deadly wildfires. The wildfires claimed over 200 lives. Please see February 2009 U.S. Wildfire page for a Special Summary of Bushfire Activity in Southeastern Australia.
In Europe, bitter cold temperatures gripped the northern and eastern region at the beginning of January. Temperatures plummeted to -9.9 °C (14.2 °F) in Farnborough, Hampshire, U.K., the lowest temperature since January 1991. The United Kingdom experienced its coolest winter since the winter of 1996-1997. The United Kingdom's mean temperature during winter 2008-2009 was 3.2 °C (37.8 °F).
Temperatures across Ontario, Canada, were well below average during the month of July, with an overall anomaly of 2.2 °C (4.0 °F) below average. Several locations experienced their lowest temperatures since 1992. Several locations set new monthly low mean temperatures for the month of July. This was part of a larger pattern that brought much-cooler-than-normal temperatures to the U.S. Midwest.
Australia and New Zealand had their warmest August since national temperature records began 60 and 155 years ago, respectively. The August 2009 average temperature for Australia was 2.47 °C (4.45 °F) above the 1961-1990 average, shattering the previous record by 0.98 °C (1.76 °F). The national August 2009 average temperature for New Zealand of 10.2°C (50.4 °F) was 1.7 °C (3.1 °F) above the August average. However, in October 2009 New Zealand experienced its coolest October since 1945.
Global precipitation in 2009 was near the 1961-1990 average. Precipitation throughout the year (January-December) was variable in many areas. Regionally, drier than average conditions were widespread across the Hawaiian Islands, Alaska's panhandle, Australia, southern South America, and parts of western Europe and southern Asia. Southeastern Brazil, parts of eastern and southeastern Asia, and most of Europe and the eastern half of the contiguous United States experienced wetter than average conditions.
Notable precipitation extremes in 2009 include the notably weak Indian Monsoon. The country as a whole reported just 77 percent of normal monsoon season rainfall, according to the India Meteorological Department, the lowest such total of the decade. The Philippine Islands had well-above-average precipitation, mainly due to the combined effects of typhoons that impacted the islands during 2009. During the month of June, central Europe had heavy rains that triggered floods and mudslides. The floods were reported to be central Europe's worst natural disaster since 2002.
Australia had its twelfth wettest January since records began in 1900; however, the southern states experienced very dry conditions during January 2009. Victoria had its driest January since 1956 and sixth driest January on record with 82 percent below-normal precipitation. South Australia and New South Wales had 80 percent and 67 percent below normal precipitation, respectively. In contrast, Queensland had its sixth wettest January (80 percent above normal) and January 2009 was the wettest since 1991.
Ottawa's International Airport set an all-time monthly record when 243.4 mm (9.6 in) of rain fell in July 2009, surpassing the previous all-time record of 224.8 mm (8.8 in) in June 2002. This value also shattered the previous July rainfall record of 186.4 mm (7.3 in) set in 1972. Earlton, Ontario, Canada experienced its wettest July since 1969.
Across the United Kingdom, precipitation was 133 percent of average in August 2009. Western Scotland received over twice its average August rainfall. It tied with 1985 as the wettest August since national records began in 1914. Dumfries and Galloway had their wettest August on record.
Typhoon Ketsana claimed nearly 500 lives across the Philippines, Cambodia, Laos and Vietnam. The storm struck the Philippines on September 26th, lashing the islands with strong winds and torrential rains. Approximately 80 percent of Manila was submerged during its worst flooding in 40 years. The heaviest precipitation fell in a short time: 424 mm (16.7 inches) in a 12-hour period, with 340 mm (13.4 inches) in a six-hour period. Each value exceeded the existing 24-hour record (335 mm or 13.2 inches) set in 1967, as well as the average September monthly rainfall (391 mm or 15.4 inches).
Over 200 mm (8 inches) of rain fell in a three-hour period on October 2nd in Sicily, Italy. The heavy downpours triggered mudslides that claimed the lives of 20 people with 40 others missing. These were Italy's worst mudslides in over a decade. India's southern states—Karnataka and Andhra Pradesh—had their heaviest rainfall in over six decades in October 2009. The effects of the copious rainfall were responsible for the deaths of 286 people and for leaving 2.5 million people homeless.
Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849.
Quayle, R.G., T.C. Peterson, A.N. Basist, and C. S. Godfrey, 1999: An operational near-real-time global temperature index. Geophys. Res. Lett., 26, 333-335.
Smith, T.M., and R.W. Reynolds (2005), A global merged land air and sea surface temperature reconstruction based on historical observations (1880-1997), J. Clim., 18, 2021-2036.
Smith, et al (2008), Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate., 21, 2283-2293.
National Snow & Ice
The Arctic sea ice reached its annual maximum extent on February 28, 2009, at 15.14 million square kilometers (5.85 million square miles). This is 720,000 square kilometers (278,000 square miles) below the 1979-2000 average of 15.86 million square kilometers (6.12 million square miles), marking the fifth-lowest maximum extent in the satellite record. The six lowest maximum extents have all occurred in the last six years (Source: National Snow and Ice Data Center). The Arctic sea ice reached its annual minimum extent on September 12, 2009, at 5.10 million square kilometers (1.97 millions square miles). This marks the third-lowest recorded extent since 1979, larger than the minimum extents of September 2007 and 2008. The 2009 minimum extent is 1.61 million square kilometers (620,000 square miles) below the 1979-2000 average minimum. The sea ice began its annual growth in Autumn, but at a slower rate compared to previous years. For the first weeks of November, the sea ice extent dropped below the 2007 record low extent, setting a new record for the month. However, by month's end the sea ice had grown above 2007 levels.
For the 2008-09 winter (Dec-Feb) the Northern Hemisphere experienced slightly below average snow cover, and had the 20th lowest snow cover extent on record. The 43-year mean Northern Hemisphere winter snow cover extent for the 1967-2009 period of record is 45.5 million square kilometers (17.6 million square miles).
Across North America, snow cover for the 2008-09 winter was above average, with the 12th largest extent since satellite records began in 1967. The 43-year mean North America winter snow cover extent is 17.1 million square kilometers for the 1967-2009 period of record. A series of large snow and ice storms struck the U.S. during the winter months. The 2008-09 snow season brought numerous daily, monthly, and seasonal snowfall records across the contiguous United States.
Snow cover extent during spring 2009 was the sixth-lowest spring snow cover extent on record. The 43-year average Northern Hemisphere spring snow cover extent for the 1967-2009 period of record is 30.8 million square kilometers (11.9 million square miles).
Across North America, snow cover for spring 2009 was the 17th largest extent since satellite records began in 1967. The average North America spring snow cover extent is 12.9 million square kilometers (5.0 millions square miles) for the 43-year period of record.
In 2009, the contiguous U.S. experienced nearly the same amount of snowfall for the month of October as the month of November. October 2009 ranked as the snowiest such period for the contiguous U.S. with 538,000 square kilometers (207,720 square miles) of snow cover extent, 385,000 square kilometers (148,650 square miles) above the long-term mean. The U.S. in November observed 585,000 square kilometers (225,870 square miles) of snow cover extent, 512,000 square kilometers (197,680 square miles) below the long-term mean. November 2009 ranked as the 6th smallest snow extent since the satellite record began in 1965. Cool temperatures in October and warm temperatures in November contributed to the snow cover extent anomalies across the contiguous United States.
Analysis provided by the Global Snow Laboratory, Rutgers University.
On December 11th 2008, southwest Louisiana and southeast Texas experienced a rare accumulating snowfall event. A cool upper level low pressure system interacted with rainfall lingering from a previous storm leading to the snow. Snowfall amounts up to six inches were reported in the region. On the following day in the Northeast, the same storm coated trees and wires with ice, causing an estimated 1.4 million customers to lose power. The damage from the storm was so severe that President Bush declared a state of emergency across much of the New England area.
On December 17th 2008, the mountains of Southern California received as much as 30 inches (76 cm) of snow while the Las Vegas, Nevada airport reported a new daily record of 3.6 inches (9 cm). It was the most snow for Las Vegas during any month since 7.5 inches (19 cm) fell in January 1979. More than 200 additional records were set on the 18th and 19th, when the same system moved northeast into the Great Plains. The snow totals from this system ranged from 6 to 10 inches (15 cm to 15 cm).
December 2008 snowfall broke historical monthly records in many locations across the Upper Midwest. La Crosse, Wisconsin had their snowiest December on record with 32.7 inches (83 cm) of snowfall. This also ranked as their fourth snowiest month on record. A December record of 45.6 inches (116 cm) of snow fell in Green Bay, Wisconsin, topping their previous record of 36.4 inches (92 cm) which was set in 1887. Madison, Wisconsin also experienced their snowiest December on record with 40.4 inches (103 cm). Grand Forks received a record 30.1 inches (76 cm) of snow for the month, which was also their second snowiest month on record. In Bismarck, North Dakota, the National Weather Service office recorded an all-time monthly snowfall record of 33.3 inches (85 cm). Fargo also recorded an all-time record snowfall amount for any month with 33.5 inches (85 cm).
In the northwestern U.S., Portland, Oregon experienced their snowiest December with 18.9 inches (48 cm) observed at the airport. This monthly total was their second snowiest month ever on record, bested only by the 41 inches (104 cm) that fell in January 1950. Spokane, Washington also set a December record with 46.2 inches (117 cm) of snow. The old record of 42.7 inches (108 cm) was set in 1996.
The Black Hills of South Dakota experienced a powerful blizzard on March 23rd through 24th. As much as 43 inches (109 cm) of snow fell in western South Dakota. The Rapid City airport received 11.5 inches (29 cm) of snow from the event. The airport also recorded consecutive record highs of 73°F and 77°F on the 21st and 22nd. Fargo, North Dakota received a record amount of snow for the month of March. The 28.1 inches (71 cm) shattered the previous record of 26.2 inches (67 cm) set in 1997. Just to the west, 29.7 inches (75 cm) at Bismarck tied with March 1950 for its highest amount of snow for March and its 5th highest amount for any month.
Another strong storm affected the middle of the country the last week of March, leaving heavy snow accumulations across the Southern Plains. The states of Texas, Oklahoma, and Kansas set new all-time 24-hour snowfall records during the blizzard on March 27th and 28th. A National Weather Service cooperative network observer in Follett, Texas reported a 24-hour snowfall total of 25 inches (64 cm). A cooperative observer in Kansas measured 30 inches (76 cm) in 24-hours in the town of Pratt. Two separate cooperative stations observed 26 inches (66 cm) of snowfall in 24-hours at Freedom and Woodward, Oklahoma, both breaking the previous 38 year-old record of 23.0 inches (58 cm). Snow drifts as high as 20 feet (6 meters) were reported across the Southern Plains.
During the 2008-09 winter season, several seasonal snowfall totals were noteworthy. International Falls, Minnesota, recorded 125 inches (318 cm) of snow, which broke a season snowfall record. The previous record of 116 inches (295 cm) was set during the 1995-96 season. The 97.7 inches (248 cm) of snow in Spokane, Washington, surpassed the previous record of 93.5 inches (238 cm) set in 1915-16. Bismarck, North Dakota received 100.3 inches (255 cm) of snow, only 1.3 inches (3 cm) shy of the record set during the 1996-97 season. The annual snowy trend continued in Youngstown, Ohio, which recorded 86.5 (220 cm) inches. Based on records that date back to 1948, the northeastern Ohio town has experienced its three snowiest seasons in the past three years (90.2 inches (229 cm) in 2006-07 and 102.8 inches (261 cm) in 2007-08).
The unusually cool and wet conditions experienced across the middle of the U.S. in October led to several locations setting snowfall records. Cheyenne, Wyoming experienced 28 inches (71 cm) of snow for the month, making October 2009 the city’s snowiest October on record. North Platte, Nebraska observed 30.3 inches (77 cm) of snowfall, making October 2009 the snowiest month of all months on record for the city. The previous record was 27.8 inches (71 cm) recorded in March 1912.
The 2009 tornado count at the end of December was 1,156. June was the most active month of the year with 268 confirmed tornado reports. This ranks 2009 as the 9th quietest month since 1990 and the 5th quietest month this decade. The only months to experience more tornadoes than the past 3-year average was April, June, July, and December.
The highest concentrations of tornado reports were clustered in the Southeast and into the Midwest. The Plains States and “Tornado-Alley” had a relatively calm tornado year relative to their historical records. 2009 was the busiest year of the decade for Louisiana and Alabama in terms of the number of tornadoes, with 82 and 103 tornadoes, respectively. Conversely, Texas and Kansas had their second calmest year of the decade with 108 and 87, tornadoes respectively. According to the SPC, November 2009 had only 4 preliminary tornado reports marking the calmest November since 1980, and the 3rd quietest (tied: 1950,1962,1969) since extensive records began in 1950. November, in the past, has been a fairly active month for parts of the southeastern United States.
The number of fatalities this year is down compared to the last four years, with 22 reported deaths. The number of killer tornadoes was also down for the year with only 10 fatal tornadoes. The deadliest single tornado for the year occurred on February 10th when an EF4 tornado caused 8 fatalities near Lone Grove, Oklahoma. This was the first February EF4 tornado for Oklahoma and was the deadliest February tornado in the state’s history.
The largest outbreak for 2009 occurred on April 10th with 73 preliminary reports of tornadoes across the southeastern U.S., killing 2 people. Arkansas, Missourri, Mississippi, Tennessee, Alabama, Kentucky, and Georgia all experienced killer tornadoes during 2009.
Hurricanes & Tropical Storms
2009 Season Summary:
The 2009 North Atlantic hurricane season had nine named storms, three hurricanes, and two major hurricanes. This is the fewest number of hurricanes for a North Atlantic season since 1997. An average season has 11 named storms, six hurricanes, and two major hurricanes. Only two tropical storms and no hurricanes made landfall in the U.S. for the season. This is only the 13th time that no hurricanes have struck the U.S. during a hurricane season (June-November) since 1943.
The ACE index of hurricane activity also indicated a below-average season, with a preliminary value of approximately 46x104 knots2. The 1949-2008 ACE average is 106x104 knots2, with 2009 having the 12th lowest ACE since 1949. The below average conditions are attributable to higher than average wind shear and lower than average relative humidity in the middle atmosphere suppressing tropical cyclone development across the basin. These conditions are expected during an El Niño, similar to the one that developed over the course of the 2009 hurricane season. Of the 11 seasons with a lower ACE index, nine occurred during El Niño events.
The 2009 season got off to a late start with Ana forming on August 15th; this is the latest date for the first named tropical storm in the Atlantic since Hurricane Andrew formed on August 17th, 1992.
Hurricane Bill became the strongest tropical cyclone of the Atlantic season with sustained winds of 135 mph (217 km/hr) and a central minimum pressure of 943 mb. Bill was also a very large storm with tropical storm force winds extending 230 miles (370 km) from the storm's center. This is the fifth largest diameter of tropical storm force winds on record for the basin. Bill made landfall along Newfoundland, Canada as a tropical storm on August 24th.
Hurricane Ida was the most destructive storm of the 2009 hurricane season contributing to hundreds of deaths in El Salvador, Honduras, and Nicaragua. Ida is also notable because it was the first November hurricane to make landfall during an El Niño event since 1925. Ida intensified rapidly off the Nicaragua coast to a Category 1 hurricane on November 4th in less than 24 hours after the first National Hurricane Center advisory was issued. This is the second fastest hurricane intensification on record, behind Humberto in 1970 which intensified to hurricane status in less than 18 hours. Ida emerged into the Caribbean and strengthened to a Category 2 hurricane on November 8th. Ida eventually weakened and made a second landfall as a tropical storm near Dauphin Island, Alabama on November 10th making Ida the second latest tropical cyclone to make landfall along the Gulf Coast, trailing only Hurricane Kate in 1985 which made landfall on November 21st
2009 Season Summary:
The 2009 Eastern Pacific hurricane season had 17 named storms, seven hurricanes, and four major hurricanes. An average season experiences 16 named storms, nine hurricanes, and four major hurricanes, putting the 2009 season near normal. For the first time in 10 years, no tropical depressions formed during the month of May. The first named storm of the season, Hurricane Andres, did not develop until June 21st, marking the latest start to a Pacific hurricane season in 40 years. The basin made up for a late start with the most active August since 1968, with eight named storms.
The developing El Niño produced conditions which are more favorable for tropical cyclone development in the Eastern Pacific basin. A developing El Niño often leads to decreased wind shear across the basin. The only two seasons with above-normal number of storms since 1995 have been years with an El Niño event.
The ACE index of hurricane activity in the basin had a preliminary value of approximately 106x104 knots2. The 1970-2008 ACE average is 132x104 knots2. In terms of energy, this places the 2009 season in the near-normal category.
Hurricane Jimena formed off the western Mexican coast on August 29th and strengthened to a Category 4 storm on August 31st with maximum sustained winds of 155 mph (250 km/hr) and a minimum central pressure of 931 mb. Jimena weakened and made landfall as a Category 2 on September 2nd near Cabo San Lazaro. At least three deaths are blamed on Jimena in Mexico.
Hurricane Rick formed on October 15th. On October 17th Rick strengthened to a Category 5 storm with maximum sustained winds of 180 mph (285 hm/hr) and a minimum central pressure of 906 mb. Rick was the first Category 5 storm in the basin since Hurricane Kenna in 2002. Rick was also the second strongest hurricane ever recorded for the basin, behind Hurricane Linda in 1997, and the strongest October hurricane for the basin. Rick’s impressive strength was not long lived as it weakened to a tropical storm on the 20th, and made land-fall on the 21st near Mazatlan, Mexico with 55 mph (90 km/hr) winds.
The data presented in this drought report are preliminary. Ranks, anomalies, and percent areas may change as more complete data are received and processed.
Contents Of This Report:
National Drought Overview
As with temperature extremes during the year, widespread precipitation extremes occurred during 2009, with large areas of the country very dry and large areas very wet from month to month. About a fifth to a fourth of the contiguous U.S. had monthly precipitation totals very dry (at the tenth percentile of the historical record or drier) during January, February, and November, while roughly one- to two-fifths of the country was very wet (monthly precipitation totals at the 90th percentile of the historical record or wetter) during May, June, October, and December. Based on early analysis of data, November 2009 ranked as the 18th driest November, nationally, in the 1895-2009 record, February 2009 ranked as the eighth driest February, and January 2009 ranked as the fifth driest January.
Dry conditions occurred during much of the year across parts of the Southwest, Upper Mississippi Valley, and southern Texas. Below-normal precipitation occurred intermittently in portions of a ring around the country -- from the northern Rockies, Far West, and Southwest, to the southern Plains and Southeast, then up along the East Coast and back across the Great Lakes. This precipitation pattern is evident in the January-November precipitation anomalies. The year was dominated by weather patterns which brought large areas of wetness to the central parts of the country and to other regions at various times. The wettest October on record occurred during 2009, bringing drought relief to many areas. Rains during December brought additional relief to the south Texas drought areas and virtually eliminated drought from the eastern United States.
The percent area* of the contiguous U.S. experiencing moderate to extreme drought contracted from about 27 percent in February to 16 percent by July, expanded in late summer and early autumn to about 22 percent, then contracted late in the year (reaching about 12 percent by the end of December). According to U.S. Drought Monitor statistics, the percent of the U.S. (including Alaska, Hawaii, and Puerto Rico) experiencing moderate (D1) to exceptional (D4) drought was about 16 percent at the beginning of the year, peaked at 22 percent in late March, then progressively declined during the rest of the year to about 10 percent by the end of December.
*This drought statistic is based on the Palmer Drought Index, a widely used measure of drought. The Palmer Drought Index uses numerical values derived from weather and climate data to classify moisture conditions throughout the contiguous United States and includes drought categories on a scale from mild to moderate, severe and extreme.
Regional Drought Overview
The drought epicenters during 2009 were southern Texas, the southern Appalachians, California, and Hawaii. Severe agricultural impacts were felt, especially in Texas. Low streams, reservoirs and stock ponds, and depleted soil moisture combined to ravage agricultural (pasture, range and crop) lands early in the growing season. Nationally, short to very short (i.e., dry to very dry) topsoil moisture conditions reached a peak area in early July, with dry soils persisting in some areas through September. The percent area of the nation with below-to-much-below normal streamflow peaked in February, but low streams occurred in various areas as the year progressed.
Parts of south central and southern Texas (map) have been drier than normal for most of the last two years. Beneficial rains since September brought drought relief, but not before these areas turned in their driest September-August on record (climate divisions seven and nine).
Parts of the Southeast began 2009 with lingering moderate to extreme drought, with drought peaking in southern Florida in April. But by the beginning of summer, drought in the Southeast was mostly gone. Below normal precipitation during August-October brought areas of moderate to severe drought back to parts of the Carolinas.
Parts of the West, especially California, have suffered through three years of drought. Northern California began the year with moderate to extreme drought. Conditions improved throughout the year, but the state ended 2009 with areas of moderate to severe drought remaining.
Parts of the Upper Mississippi Valley and adjacent western Great Lakes have been in some level of dryness or drought for most of the last seven years. Northwest Wisconsin (climate division 1) had the driest 12-month October-September period on record in 2009 (October 2008-September 2009).
Moderate to extreme drought afflicted parts of Hawaii throughout 2009. Below-normal precipitation departures for the year were widespread across the islands. The U.S. Drought Monitor (USDM) depicted abnormal dryness across parts of Alaska during most of the year, with a small area of moderate drought along the southern coast during the summer months. Annual precipitation departures were below normal at many southern Alaska and central Alaska stations, with the USDM abnormally dry depiction expanding into central Alaska by year end. While drought was not depicted on the U.S. Drought Monitor map for Puerto Rico during 2009, annual precipitation was below normal for the southeastern third of the island.
Tree ring records provide a useful paleoclimatic index that extends our historical perspective of droughts centuries beyond the approximately 100-year instrumental record. Several paleoclimatic studies have shown that droughts as severe or worse, both in magnitude and duration, than the major 20th century droughts have occurred in the U.S. during the last thousand years. The following paleodrought report was prepared by the NOAA/NCDC Paleoclimatology and Climate Monitoring branches during 2009:
Contacts & Questions
Global Snow & Ice
NH Snow Cover Extent
Analyses of NOAA data were provided by the Global Snow Laboratory, Rutgers University. Period of record is 1967-2009 (43-years).
As shown in the time series to the right, the mean Northern Hemisphere snow cover extent during winter 2008-2009 was slightly below average. The Northern Hemisphere had the 20th lowest snow cover extent on record. The 43-year mean Northern Hemisphere winter snow cover extent for the 1967-2009 period of record is 45.5 million square kilometers.
Across North America, snow cover for winter 2008-2009 was above average; the 12th largest extent since satellite records began in 1967. The 43-year mean North America winter snow cover extent is 17.1 million square kilometers for the 1967-2009 period of record.
Snow cover extent during spring 2009 was the sixth-lowest spring snow cover extent on record. The 43-year average Northern Hemisphere spring snow cover extent for the 1967-2009 period of record is 30.8 million square kilometers.
Across North America, snow cover for spring 2009 was the 17th largest extent since satellite records began in 1967. The average North America spring snow cover extent is 12.9 million square kilometers for the 43-year period of record.
Sea Ice Extent
Arctic sea ice extent, which is measured from passive microwave instruments onboard NOAA satellites, usually expands during the cold season to a March maximum, then contracts during the warm season to a September minimum. According to NOAA's National Snow and Ice Data Center, the September Northern Hemisphere average sea ice extent was 5.4 million square kilometers (23.8 percent or 1.7 million square kilometers below the 1979-2000 average)—the third lowest since satellite records began in 1979, behind 2007 and 2008. The past five years have had the five smallest minimum sea ice extent on record. The September 2009 Arctic sea ice extent was 1.1 million square kilometers greater than 2007's record low and 690,000 square kilometers greater than September 2008, the second-lowest extent. This was the 13th consecutive September with sea ice extent below average. September 1996 was the last year with above-average sea ice extent.
The image to the right depicts Northern Hemisphere sea ice extent from July-October, the five-month period centered on the regular annual minimum of Arctic Sea Ice. It shows that, over the course of the months spanning the late melt season, the annual minimum and the early recovery season, 2009 had either the second or third least ice extent (smallest "footprint" of ice), behind 2007 and, occasionally, 2005 or 2008. The annual minimum extent in September 2009 was the third smallest of the 31-year record. The average September rate of sea ice decline is 11.2 percent per decade. A complete summary of the 2009 Northern Hemisphere sea ice extent is available, courtesy of the National Snow and Ice Data Center.
Arctic sea ice conditions are inherently variable from year to year in response to wind, temperature and oceanic forcings. Quite often a "low" ice year is followed by recovery the next year. But increasing surface temperatures in high latitudes have contributed to progressively more summer melt and less ice growth in the fall and winter. While natural variability is responsible for year-to-year variations in sea ice extent, three extreme minimum extent years along with evidence of thinning of the ice pack suggest that the sea ice system is experiencing changes that may not be solely related to natural variability.
In contrast, the 2009 Southern Hemisphere sea ice extent had its second largest sea ice extent for April and August 2009, behind 2008 and 2000, respectively. It was also the third largest sea ice extent for September, behind 2006 and 2007.
During the past century, global surface temperatures have increased at a rate near 0.06°C/decade (0.11°F/decade), but this trend has increased to a rate of approximately 0.16°C/decade (0.29°F/decade) during the past 30 years. There have been two sustained periods of warming, one beginning around 1910 and ending around 1945, and the most recent beginning about 1976. Temperatures during the latter period of warming have increased at a rate comparable to the rates of warming projected to occur during the next century with continued increases of anthropogenic greenhouse gases.
Temperature measurements have also been made above the Earth's surface over the past 52 years using balloon-borne instruments (radiosondes) and for the past 30 years using satellites. These measurements support the analyses of trends and variability in the troposphere (surface to 10-16 km) and stratosphere (10-50 km above the earth's surface).
The best source of upper air in-situ measurements for studying global temperature trends above the surface is the Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC) dataset.
Data collected and averaged between the 850-300 mb levels (approximately 5,000 to 30,000 feet above the surface) indicate that 1958-2009 global temperature trends in the middle troposphere are similar to trends in surface temperature; 0.12°C/decade (0.22°F/decade) for surface and 0.15°C/decade (0.26°F/decade) for mid-troposphere. Since 1976, mid-troposphere temperatures have increased at a rate of 0.17°C/decade (0.31°F/decade). For 2009, global mid-troposphere temperatures were 0.40°C (0.72°F) above the 1971-2000 mean and the seventh warmest.
Since 1979, NOAA's polar orbiting satellite measurements have also been used to measure temperatures in the troposphere and stratosphere. Microwave Sounding Unit (MSU) data are analyzed for NOAA by the University of Alabama in Huntsville (UAH), Remote Sensing Systems (RSS, Santa Rosa, California) and the University of Washington (UW). These observations show that the global average temperature in the middle troposphere (the layer which is centered at an altitude of 2 to 6 miles, but which includes the lower stratosphere) has increased, though differing analysis techniques have yielded similar but different trends (see below).
In all cases these trends are positive. The analysis performed by RSS reveals a trend of 0.09°C/decade (0.16°F/decade) while the UAH analysis reveals a lower trend of 0.04°C/decade (0.08°F/decade). When adjusted by University of Washington scientists to remove the stratospheric influences from the RSS and UAH mid-troposphere average, the trends increase to 0.15°C/decade (0.26°F/decade) and 0.11°C/decade (0.20°F/decade), respectively. (A journal article is available that describes the University of Washington adjustments to remove the stratospheric influence from mid-troposphere averages.) Trends in these MSU time series are similar to the trend in global surface temperatures, which increased at a rate near 0.16°C/decade (0.29°F/decade) during the same 30-year period.
While middle tropospheric temperatures reveal an increasing trend over the last three decades, stratospheric temperatures (14 to 22 km / 9 to 14 miles above the surface) have been below average since the warming effects from the 1991 Mt. Pinatubo eruption dissipated in 1993. January-December 2009 was the 17th consecutive year with below-average temperatures (an anomaly of -0.53°C/-0.95°F), the eighth coolest year on record. The below-average stratospheric temperatures are consistent with the depletion of ozone in the lower stratosphere and the effects of increasing greenhouse gas concentrations. The large temperature increase in 1982 is attributed to the volcanic eruption of El Chichon, and the increase in 1991 was associated with the eruption of Mt. Pinatubo in the Philippines.
Christy, John R., R.W. Spencer, and W.D. Braswell, 2000: MSU tropospheric Temperatures: Dataset Construction and Radiosonde Comparisons. J. of Atmos. and Oceanic Technology, 17, 1153-1170.
Free, M., D.J. Seidel, J.K. Angell, J. Lanzante, I. Durre and T.C. Peterson (2005) Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series, J. Geophys. Res., 10.1029/2005JD006169.
Free, M., J.K. Angell, I. Durre, J. Lanzante, T.C. Peterson and D.J. Seidel(2004), Using first differences to reduce inhomogeneity in radiosonde temperature datasets, J. Climate, 21, 4171-4179.
Fu, Q., C.M. Johanson, S.G. Warren, and D.J. Seidel, 2004: Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429, 55-58.
Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003a), Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology, J. Climate, 16, 224-240.
Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003b), Temporal homogenization of monthly radiosonde temperature data. Part II: trends, sensitivities, and MSU comparison, J. Climate, 16, 241 262.
Mears, CA, FJ Wentz, 2009, Construction of the RSS V3.2 lower tropospheric dataset from the MSU and AMSU microwave sounders. Journal of Atmospheric and Oceanic Technology, 26, 1493-1509.
Mears, CA, FJ Wentz, 2009, Construction of the Remote Sensing Systems V3.2 atmopsheric temperature records from the MSU and AMSU microwave sounders. Journal of Atmospheric and Oceanic Technology, 26, 1040-1056.
Mears, Carl A., M.C. Schabel, F.J. Wentz, 2003: A Reanalysis of the MSU Channel 2 tropospheric Temperature Record. J. Clim, 16, 3650-3664.
Issued: 8 January 2010
While significant fire activity early in the year threatened to set 2009 above average for both number of fires and acres burned, wetter conditions across many parts of the nation as the year progressed, coupled with effective fire management, helped to restrain fire activity by mid-year. Despite the largest fire in Los Angeles County's (California) recorded history (Station fire), by the end of August the nationwide acreage burned by wildfire was very near the 2000–2009 average and thereafter declined below average. Based upon data provided by the National Interagency Fire Center (NIFC) fire activity in 2009 ranked fifth highest (sixth lowest) out of the past decade in terms of number of fires — about 1 percent below the 2000-2008 average. Acres burned in 2009 were 14.5 percent below the 2000-2008 average, ranking seventh highest (fourth lowest) since 2000. Average fire size also ranked seventh highest out of the 2000-2009 period, at about 14 percent below average.
2009 Wildfire Statistics(Source: NIFC)
|2009–Annual Totals||Nationwide Number of Fires||Nationwide Number of Acres Burned|
(2005 – 2009)
(2000 – 2009)
The year 2009 finished with a total of 77,315 fires having burned 5,914,821 acres (2,393,463 hectares). The number of fires was 966 fires below the 2000 – 2008 average of 78,281. Acreage burned across the nation in 2009 was 1,002,554 acres (405,719 hectares), or about 15 percent, below the 2000 – 2008 average. Average fire size in 2009 was 76.5 acres (40.0 hectares) per fire, which was 11.9 acres (4.8 hectares) per fire below the 2000 – 2008 average, or about 14 percent smaller than average. The data used in this assessment is from the National Interagency Fire Center (NIFC).
Special Summary of the Los Angeles County "Station" Fire
NASA JPL photo of the Station fire in Los Angeles County on Friday, August 28, 2009 – Click for larger image
Los Angeles' Station fire, which began on August 26th, burned an estimated 160,577 acres, making it the largest fire in Los Angeles County's recorded history, and the tenth largest fire in California history since 1933. The fire was also among the most destructive of 2009 — destroying 209 structures, including 89 homes, and claiming the lives of two fire fighters. At its height early in September, the fire threatened an estimated 12,000 structures, including the historic Mount Wilson observatory and dozens of critical communications towers. According to an InciWeb report, as of September 19th just under $100 million USD had been spent battling the blaze. Nearly 40 miles (64 km) of the Angeles Crest Highway was closed indefinitely due to fire damage, with repair estimates of $12 million USD, according to the California Department of Transportation. At the end of September, the fire was 98 percent contained, but continued to burn until it was finally declared 100 percent contained at 7 PM on 16 October, making it the longest lived fire of the 2009 season. Fire investigators have determined that arson was the cause of the Station fire.
Additional Wildfires Links
- NOAA Fire Products
- NOAA Fire Imagery
- NOAA Economics
- U.S. Drought Monitor
- National Interagency Fire Center
- U.S. Forest Service Fire Maps
- Wildland Fire Assessment System
- Alaska Interagency Coordination Center
- Canadian Interagency Forest Fire Center