National Overview - August 2009
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
- Temperature Highlights - Summer
- For the 2009 summer, the average temperature of 71.7 degrees F was 0.4 degree F below the 20th Century average. The 2008 average summer temperature was 72.7 degrees F.
- The U.S. as a whole was below normal for the summer period (June-August). A recurring upper level trough held the June-August temperatures down in the central states, where Michigan experienced its fifth coolest summer, Wisconsin, Minnesota, and South Dakota their seventh coolest each, Nebraska its eighth, and Iowa its ninth coolest such period. In direct contrast, the temperatures in Florida averaged out to be fourth warmest, while Washington and Texas experienced their eighth and ninth warmest such periods, respectively.
- On a regional level, the East North Central experienced its sixth coolest summer in 115-years of record keeping. Only the Northwest averaged above normal readings during the period — their tenth consecutive summer with above-normal temperatures.
- Temperature Highlights - August
- For the contiguous United States the average August temperature of 72.2°F was 0.6°F below the 20th century average and ranked as the 30th coolest August on record, based on preliminary data.
- Temperatures were below normal in the Central and East North Central regions. Above-normal temperatures dominated the Northeast, areas in the Southwest, and in the extreme Northwest.
- Several northeastern states were much above normal for August, including Delaware and New Jersey, (eighth warmest), Maine (ninth), and Rhode Island and Connecticut (10th). In contrast, below-normal temperatures were recorded for Missouri and Kansas.
- For the year-to-date (January-August) period, the contiguous U.S. ranked 30th warmest. New Mexico and Texas recorded their ninth- and tenth-warmest, respectively, such periods on record.
- Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand was 1.7 percent above average in August. For the summer period (June-August), the model indicated that the national residential energy consumption was 2.5 percent below average.
- Precipitation Highlights - Summer
- For the summer season (June–August), the Northeast Region had its eighth wettest period on record. This contrasted with the South, Southeast and Southwest Regions, which were drier than average. Arizona observed its third driest summer, while both South Carolina and Georgia had their sixth driest.
- Precipitation Highlights - August
- This was the 28th driest August in the 1895–2009 record. Precipitation across the contiguous U.S. averaged 2.34 inches (59 mm), which is 0.26 inch (7 mm) below the 1901–2000 average.
- Above-normal averages were generally recorded across the northern U.S., west of the Great Lakes. The South and Southeast regions experienced below-normal precipitation.
- Precipitation across the Southwest region averaged 0.85 inches, which is 1.10 inches below normal and ranks as the 4th driest August on record. Arizona had its fourth driest, New Mexico its fifth, and it was the eighth driest August on record for Colorado, Utah and Texas.
- Lack of monsoonal moisture contributed to the near record dryness in the Southwest region. Tucson, Arizona experienced its driest August since 1976 and its third driest since 1948.
- Other Items of Note
- By the end of August, moderate-to-exceptional drought covered 14 percent of the contiguous United States, based on the U.S. Drought Monitor. Drought intensified in parts of the Pacific Northwest and new drought areas emerged in Arizona and parts of the Carolinas. Elsewhere, drought areas generally persisted, with minor improvements in Montana, Wisconsin, and Oklahoma.
- A total of 7,975 fires burned 1,646,363 acres in August, according to the National Interagency Coordination Center. August 2009 ranked fifth for the number of fires and sixth for acres burned in August this decade. For the year-to-date period (Jan-Aug), 64,682 fires burned 5.2 million acres across the nation. Late month fire activity, particularly in California, extending into September is likely to increase 2009 acreage burned relative to the 2000–2009 average. More detail information on U.S. wildfire activity can be found here.
- There were more than 300 record low minimum and maximum temperatures set across the Central and East North Central regions during the last two days of August as Canadian high pressure settled over the area at the end of the month.
- Several intense precipitation events occurred among generally wetter-than-normal conditions in the southern Appalachians and mid-Atlantic. Slow-moving thunderstorms in dropped 9.70 inches of rain at Cherry Point, NC, establishing the location's greatest one-day precipitation total in a record extending back 65 years. Most of the rain fell in three hours, representing a precipitation rate that equates with nearly a 500-year event.
- The Climate Prediction Center (CPC) reported that El Niño was present in the equatorial Pacific Ocean during the month of August. Equatorial sea surface temperatures (SSTs) remained +0.5 to +1.5°C above average across the region at the end of the month. Observations and model forecasts by the CPC indicate El Niño conditions will continue to intensify and are expected to continue through the winter of 2009-2010. For additional information on ENSO conditions, please visit the NCDC ENSO Monitoring page and the latest NOAA ENSO Advisory.
had its 46th warmest August since records began in 1918, with a
temperature 0.9°F (0.5°C) below the 1971—2000
had its 13th warmest June—August on record, with a
temperature 0.9°F (0.5°C) above the 1971—2000
- Alaska had its 28th warmest January—August on record, with a temperature 0.4°F (0.2°C) above the 1971—2000 average.
For additional details about recent temperatures and precipitation across the U.S., see the Regional Highlights section below and visit the May Climate Summary page. For information on local temperature and precipitation records during the month of July, please visit NCDC's Extremes page. For details and graphics on weather events across the U.S. and the globe please visit NCDC's Global Hazards page.
These regional summaries were provided by the six Regional Climate Centers and reflect conditions in their respective regions. These six regions differ spatially from the nine climatic regions of the National Climatic Data Center.
- Northeast Region: (Information provided by the Northeast Regional Climate Center)
- Temperatures during August averaged above normal, breaking the cool trend of the previous two months. The Northeast average of 69.9°F (21.1 °C) was 1.9 degrees F (1.1 °C) above normal. Departures among the states ranged from 0.7 degrees F (0.4 °C) above normal in West Virginia to 2.9 degrees F (1.6 °C) above normal in Maine, where it was the 10th warmest August since 1895. Other temperature rankings are below. In general, the eastern half of the region saw the greatest positive departures; farther west, the departures were closer to normal. Most locations saw their highest temperatures during the third week of the month and the lowest at the end of August.
- Rainfall in the Northeast averaged 100% of normal, but there was a great disparity in the totals throughout the region. Five states (Rhode Island, Connecticut, West Virgina, Vermont, Maine) saw below normal rainfall. Of these states, Rhode Island was the driest, with only 50% of the normal August amount. Delaware was the wettest state this month with 207% of normal rainfall. In addition, Delaware's total of 9.61 inches (24.41 cm) made this month the 9th wettest in 115 years. These two states also had the rainfall extremes last month, but in the opposite direction - Delaware had its 3rd driest July on record, while Rhode Island had its 2nd wettest July.
- On August 9, a line of thunderstorms spawned an EF-1 tornado and a derecho that caused widespread damage in Allegany County, NY. Later on the 9th, up to 5 inches (12.7 cm) of rain in a 2-hour time period flooded parts of northern Chautauqua and northwestern Cattaraugus Counties, NY. Significant damage occurred in Silver Creek and Gowanda, NY as creeks and streams turned into raging torrents. More information on the western New York severe weather can be found at this web site: http://www.erh.noaa.gov/buf/svrwx/web_090810_Flashflood/indexflood.html. Other reports of severe weather this month include straight-line winds that downed over a hundred trees in Central Park, NY on the 19th and an EF-1 tornado in Oxford County, ME on the 21st that snapped or uprooted thousands of trees and damaged or destroyed a few buildings.
- It was the 9th wettest summer in the Northeast. The total of 14.44 inches (36.68 cm) was 119% of normal. West Virginia, the only state to average below normal rainfall, received 92% of the normal summer total. At the other end of the spectrum, Massachusetts saw 152% of normal rainfall. It was the 3rd wettest summer in Massachusetts, and the 6th wettest in Maine and New Hampshire. Among individual locations, it was the wettest summer in Portland, Maine, Concord, New Hampshire and Albany, New York.
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- The unseasonably cool weather of July continued into the month of August throughout the Midwest. Temperatures in August were near normal in eastern Ohio, dropping to 3°F (1.7°C) below normal in western portions of the region. The 10-day period from August 8-17 was the only substantially warm period during the month, with temperatures averaging near normal across Missouri to 5°F (2.8°C) above normal in the northern portions of the Midwest. Average daily low temperatures during the month were near to slightly above normal in eastern Ohio decreasing to 2°F to 3°F (1.1°C to 1.7°C) west of the Mississippi River. The cool weather was dramatically seen in the average daily maximum temperatures, which were near normal in eastern Ohio but as much as 6°F (3.3°C) below normal in western portions of the region. Based on preliminary August temperature data, this was the 21st coolest August on record for the Midwest. There were more than 300 record low minimum and maximum temperatures set across the region the last two days of August as Canadian high pressure settled over the area at the end of the month.
- Frontal systems repeatedly moved out of the Northern Plains and into the Midwest in August, providing a focus for showers and thunderstorms. These systems frequently slowed or stalled across the central Midwest, resulting in an axis of heavy rain from northwestern Missouri through southwestern Iowa into northern Illinois. Rainfall in southeastern Iowa exceeded 13 inches (330 mm) for the month at some locations. Clutier, Iowa reported 13.65 inches (347 mm), Cedar Rapids 13.05 inches(331 mm), and there were a number of other reports of more than 10 inches (254 mm) for August. Monthly rainfall was from 175 percent to 300 percent of normal in this band. Outside of this band, rainfall in August was spotty, with some areas receiving normal to above normal rainfall and surrounding areas less than 50 percent of normal. Significant rain fell in central Minnesota and northwestern Wisconsin toward the end of the month, providing some improvement in the drought situation there. However, at the end of the month drought was still classified as severe in northwestern Wisconsin and the southern Michigan U. P.
- All nine Midwestern states experienced severe weather during August. The majority of the severe reports this month came on August 4 and on August 19-20. The storms on August 19 included 30 tornado reports in seven Midwestern states, including at least one twister that touched down in downtown Minneapolis, Minnesota.
- For details on the weather and climate events of the Midwest during May, see the weekly summaries in the MRCC Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- Mean temperatures for August 2009 were above normal across much of the region, especially eastern Virginia, North Carolina, and portions of Florida where temperatures were 2 to 4°F above normal. There were 79 daily maximum temperature records set or tied, and more than half of these were observed in Florida. There were no heat waves during the month, although several metropolitan areas experienced daily maximums near 100 F (38°C), including Columbia, South Carolina, Raleigh-Durham, North Carolina, Richmond, Virginia, and Washington, DC. Much of Puerto Rico recorded above normal temperatures for the month. San Juan, Puerto Rico registered a mean temperature of 84 F (29°C), which was 2°F above normal. Temperatures across portions of Georgia and most of Alabama were slightly below normal. There were 97 daily minimum temperatures broken or tied across the region with a majority of them recorded in Alabama and Florida. Mobile, Alabama recorded a minimum temperature of 60°F (16°C) on the 24th, which ranks as the third coolest minimum in August for a record extending back to 1872. Also, Troy, Alabama recorded a minimum temperature of 58°F (14°C) on the 10th of the month.
- Much of the region displayed below normal precipitation totals for the month of August. This was especially the case across SC where some locales received less than 25% of the normal precipitation for the month. Greenville-Spartanburg, South Carolina recorded only 1.21 inches (31 mm) of precipitation during the month, which ranks as the 10th driest August in a record that extends all of the way back to 1893. This dry streak that began in June is most revealed in the modest June-August precipitation total of 6.28 inches (160 mm), which ranks as the 4th driest on record. Monthly precipitation totals were above normal across portions of Alabama, western Georgia, South Carolina, and portions of southwest and far eastern Virginia. Norfolk, Virginia recorded a monthly precipitation total of 13.22 inches (336 mm) making it the 3rd wettest August for a record extending back to 1874. Over 5 inches (127 mm) of this precipitation fell in a 3-hour period on the 22nd, which caused major urban flooding. Slow-moving thunderstorms in Craven Co. North Carolina dropped 9.70 inches (246 mm) of precipitation over Cherry Point, which is the greatest one day precipitation total in a record extending back 65 years. Most of this precipitation fell in 3 hours resulting in a precipitation rate that equates with nearly a 500-year event. In Savannah, Georgia, locally heavy rainfall exceeding 4 inches (102 mm) caused major flash flooding that involved the rescue of people from vehicles caught in the floodwaters. The early evening deluge coincided with the occurrence of high tide thus making the floodwaters higher.
- The continued dry conditions in portions of the Carolinas resulted in the development of moderate drought (D1) conditions in NW South Carolina and a small portion of east-central North Carolina. This was circumscribed by a broader area of abnormally dry conditions extending from the eastern half of North Carolina southwestward through northern South Carolina and portions of northeast Georgia. Tropical Storm Claudette made landfall in western Florida on 8/17 with relatively modest winds and precipitation totals. Coastal North Carolina experienced rough surf associated with the offshore passage of Hurricane Bill and Tropical Storm Danny in August. The rough surf and strong undertow were blamed for the loss of a 12-year old boy near Corolla as Tropical Storm Danny passed. Lightning from thunderstorms caused house fires in a number of locations during the month, including Atlanta, Georgia and Surry, Co. North Carolina, where several firefighters were injured.
- For more information, please go to the Southeast Regional Climate Center Home Page.
- High Plains Region: (Information provided by the High Plains Regional Climate Center)
- A persistent upper air pattern continued to keep the High Plains Region cool this August. Most locations had average monthly temperatures that were 2°F to 4°F (1.1°C to 2.2°C) below normal and isolated areas of the Region were 4°F to 8°F (2.2°C to 4.4°C) below normal. Monte Vista, Colorado recorded its coolest August with an average temperature of 57.8°F (14.3°C), which broke the old record of 58.2°F (14.6°C) recorded in 1956. Interestingly, many locations recorded average temperatures that were nearly identical to those recorded in July. For instance, Lincoln, NE had an average temperature of 72.6 (22.6°C) in July and 72.3 (22.4°C) in August. Lincoln's normals for July and August are 77.8 (25.4°C) and 75.4 (24.1°C), respectively. For the summer, temperature departures of 2°F to 5°F (1.1°C to 2.8°C) below normal dominated the Region and many locations ranked in the top 15 coolest summers on record. The only exceptions to the mild weather were isolated pockets of Wyoming, Colorado, and Kansas. Casper, Wyoming recorded its coolest summer with an average temperature of 63.9°F (17.7°C). The previous record of 64.3°F (17.9°C) occurred in 2004.
- This August, some areas of the region received ample precipitation, while other areas were dry and saw either the development of abnormally dry conditions or little relief to ongoing drought. Precipitation totals exceeding 200% of normal were confined to pockets of Wyoming, South Dakota, Nebraska, and Kansas. Within these regions of heavy precipitation, many locations recorded the wettest August on record. The driest areas in the region were Colorado and North Dakota where precipitation totals less than 50% of normal were common. This month?s wet spot is Columbia, South Dakota. Not only did this location record its wettest August, it also recorded its wettest summer. Columbia received 7.22 inches (183.4 mm) of precipitation, or 313% of normal, this month which smashed the old record of 5.84 inches (148.3 mm) recorded in 1957. For the summer, Columbia received 17.90 inches (454.7 mm) of precipitation which is 9.45 inches (240.0 mm) above normal and 212% above normal. The old record of 14.45 inches (367.0 mm) was recorded in 1993.
- The two areas of moderate drought (D1) remain largely unchanged this month as drought persists in eastern North Dakota and southeast Nebraska. Both areas have seen crop stress however, impacts should be only short term as streamflows are above normal and the long term outlook is good. Due to a weak monsoon season, abnormally dry conditions (D0) have developed in southwest Colorado. Elsewhere in the Region, only minor changes were observed in the U.S. Drought Monitor. According to the U.S. Seasonal Drought Outlook, the drought conditions in south central Nebraska and east central North Dakota are expected to improve through November 2009.
- According to the National Weather Service Weather Forecast Office in North Platte, Nebraska, Lake McConaughy is making a recovery from low lake levels. Lake McConaughy is the largest reservoir in Nebraska and is located in the western part of the state north of Ogallala, Nebraska. The lake, originally constructed for irrigation, supplies water for irrigation to over 200,000 acres of land in the southwest and south central areas of the state. Between the 1960s and 1990s, Lake McConaughy had high lake elevations with 3227 ft as the lowest elevation recorded during this time. However, recent drought lasting from 2000-2006 brought the lake to a new historic low elevation of 3197.5 feet on September 14, 2004. Over the last few years, rain and limited irrigation have improved lake levels and as of September 1, 2009 the lake had an elevation of 3229 feet. Lake levels are expected to continue to rise through winter and spring.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- With the exception of southern Texas, northern Arkansas, and eastern Oklahoma, most of the Southern Region averaged near-normal mean daily temperatures for the month of August. That is, for most of the Southern Region, mean daily temperatures for the month averaged within 2° F (1 °C). In northern Arkansas and eastern Oklahoma, mean daily temperatures for the month averaged approximately 2-4 ° F (1-2 °C) below normal. Conversely, mean daily temperatures were above normal in drought ridden southern Texas, with values ranging approximately 2-4 ° F (1-2 °C) above normal. Anomalously high temperatures in this region could be amplifying drought conditions, which have persisted in southern Texas for several weeks.
- August precipitation in the Southern Region was highly variable during the month of August. The driest area of the Southern Region was once again in southern Texas. In southern Texas, almost all stations reported less than 50% of normal precipitation for the month. This was also the case in west central Texas, the Oklahoma panhandle, central Louisiana, southeastern Arkansas, and northwestern Mississippi. Dry conditions were also observed throughout most of Tennessee, with the exception of the eastern quarter of the state, where precipitation totals varied between 150-200% of normal. In the remainder of Tennessee, conditions were relatively dry with most stations only reporting between 50 and 90% of normal. In central and north central Oklahoma, higher than normal precipitation values were observed, with many stations reporting between 150 and 200% of normal August rainfall. Similar conditions were also observed in northwestern and northeastern Arkansas, and central Mississippi.
- August drought conditions in the Southern Region have not significantly changed since the end of July. One area of improvement occurred in north central Oklahoma, where anomalously high August precipitation totals have helped to eradicate moderate and severe drought conditions. Moderate drought conditions remain in southeastern Louisiana, southern Mississippi and central Texas. As was the case last month, a large portion of southern Texas (approximately 25 % of the state of Texas) remains in extreme or exceptional drought. The persistence of drought in southern Texas is mainly due to low August precipitation totals and positive August temperature anomalies.
- On the 3rd of the month, several wind reports were documented for eastern Texas. Reports indicated that strong winds resulted in many downed trees and damaged power lines. This was also the case in central Mississippi on the 7th of the month. On the 8th, a tornado touched down in New Iberia, LA. One injury was reported. According to 2theadvocate.com, several car windows were shattered and the roof on a funeral home was partially blown off. On the 12th of the month, over a dozen wind reports were filed in southern Mississippi and southeastern Louisiana. Damage included the downing of trees and power lines. Two days later, on the 14th of the month, 57 knot (105.5 km/h) winds were reported in Edinburg, TX. Strong winds near Dawn, TX were also reported. Wind speeds there ranged from 60-70 mph (96.6-112.6 km/h). A tornado touched down in Houston, TX on the 16th of the month. A brick wall was reported to be blown over and an 18 wheeler in a parking lot was also blown over. Another tornado was reported in Laredo, TX on the 22nd of the month, however; no damage or injuries were mentioned in the report. On the 23rd of August, wind damage occurred in Chouteau, OK, with reports of downed power lines, downed tree limbs, and metal sheeting blown off a roof of a building. One day later, wind damage was reported in New Iberia, LA, with damage consisting of downed trees and power lines.
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Regional Climate Center)
- Temperatures were near normal for much of the West. Only the extreme eastern portion of Montana had significantly lower than normal temperatures while pockets of the Southwest had higher than normal temperatures. Douglas, Arizona, reported their warmest August on record dating back to 1948 and Tucson recorded their 2nd warmest August. Tucson also noted a string of 29 consecutive days, starting July 10th, with minimum temperatures of 75°F (23.9°C) or higher, the longest such streak in their record, topping the previous record of 18 such days set in 2003 and tied in 2006. An odd anomaly occurred in Ely, Nevada, as they recorded their coolest August in 41 years. Surrounding areas had no such anomaly. Casper, Wyoming, recorded their 4th coolest August dating back to 1948.
- Precipitation was also near normal for the region with the notable exceptions of the southwest (dry) and portions of Idaho and Montana (wet). The lack of monsoonal moisture led Tucson to their driest August since 1976 and third driest on record dating back to 1948. Missoula, Montana, recorded 3.08 inches (78.2 mm) for their 2nd wettest August on record while Boise, Idaho, recorded their 3rd wettest August with 1.79 inches (45.5 mm).
- On August 26th a large fire (the Station Fire) began in the Angeles National Forest just north of Los Angeles. Due to very hot and dry conditions the fire had exploded to over 105,000 acres with only 5% containment by September 1st. Two firefighters have been killed and at least 53 structures destroyed and 6,600 homes under mandatory evacuation orders.
- For more information, please go to the Western Regional Climate Center Home Page.
See NCDC's Monthly Extremes web-page for weather and climate records for the month of May. For additional national, regional, and statewide data and graphics from 1895-present, for May, the last 3 months or other periods, please visit the Climate at a Glance page.
PLEASE NOTE: All of the temperature and precipitation ranks and values are based on preliminary data. The ranks will change when the final data are processed, but will not be replaced on these pages. Graphics based on final data are provided on the Climate Monitoring Products page and the Climate at a Glance page as they become available.