National Overview - December 2011
NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
A preliminary list of select cities breaking annual temperature and precipitation records during 2011 can be found here.
- Climate Highlights — December
- The average contiguous U.S. temperature for December was 35.0 degrees F, or 1.7 degrees F above the 1901-2000 long-term average. Precipitation averaged across the nation during December was 2.08 inches or 0.15 inch below average. This monthly analysis is based on records dating back to 1895.
- During December the eastern third of the nation, as well as the Northern Plains, experienced above-average temperatures. The warmest temperature anomalies (the temperature compared to the 20th century average) occurred across the Northern Plains, the Great Lakes and into the Northeast. A total of 15 states had December temperatures ranking among their ten warmest.
- Cooler-than-average temperatures were present for the Pacific Northwest, the West, and Southwest climate regions. New Mexico tied its fourth coolest December on record, with monthly temperatures 5.3 degrees F below average.
- December's weather pattern established two major precipitation regimes across the contiguous United States. Below-average precipitation was present across the West, Northwest, and Northern Plains. Above-average precipitation was present in a swath of states from Arizona to Pennsylvania, through the central part of the country.
- Seven states had December precipitation totals among their ten driest — California (2nd driest), Nevada (2nd), Oregon (2nd), Washington (3rd), Idaho (4th), South Dakota (9th), and Montana (10th) . The Pacific Northwest and West regions had their second driest Decembers on record. Drier-than-average conditions were also present for the southeastern coastal states.
- Much of the central part of the country was wetter than average, as a persistent storm track brought above-average precipitation to 18 states. Kansas (5th wettest), Arkansas (8th), and Ohio (8th) had December precipitation totals among their ten wettest.
- The state of Alaska was warm and wet during December 2011. According to data back to 1918, this was the third warmest December on record with a temperature anomaly of 8.7 degrees F above the 1971-2000 average. The warmest December on record for Alaska occurred in 1985, when the monthly temperature anomaly was 11.0 degrees F above average. It was also the fifth wettest December on record for Alaska, with a precipitation anomaly of 39.4 percent above the 30-year average.
- According to the U.S. Drought Monitor, as of January 3rd 2012, about 3.3 percent of the contiguous U.S. was experiencing the worst category of drought, called D4 or exceptional drought, a decrease from the nearly six percent at the beginning of the month. Drought conditions lessened across the Southwest and Southern Plains, where above average precipitation was observed during December. Moderate Drought conditions developed across parts of California, Nevada, and Oregon, where below-average precipitation was observed for several months.
- A list of select December temperature and precipitation records can be found here.
- Climate Highlights — 6-month period (July-December)
- During the last six months of 2011 (July-December), the average U.S. temperature was 59.1 degrees F or 1.9 degrees F above average, ranking as the fourth warmest such six-month period on record. The contiguous U.S. was drier than average for the period, with some regional variability.
- Only five states had July-December temperatures near-normal, with all other state across the contiguous U.S. being warmer than average for the 6-month period. A total of 23 states had July-December temperatures among their ten warmest on record. Delaware, Massachusetts, New Hampshire, New Jersey, Rhode Island, and Vermont were record warm for the period.
- The July-December period was wetter than average for much of the Ohio Valley and into the Northeast, consistent with long-term precipitation trends across these regions. Twelve states had six-month precipitation totals ranking among their ten wettest. Pennsylvania and New Jersey were record wet with precipitation anomalies of 16.85 inches and 11.34 inches, respectively.
- States across the Southeast, Southern Plains, West Coast, and Upper Midwest had below-average precipitation during July-December. Oregon (3rd driest), Idaho (5th), California (7th), Texas (7th), and Minnesota (9th) had a top ten dry 6-month period.
- Climate Highlights — Annual Period (January-December)
- During 2011, the contiguous U.S. was warmer than average, with a temperature anomaly of 1.0 degree F, ranking in the top third of the historical distribution. The U.S. as a whole had an average precipitation 0.36 inch below the 20th century average, ranking near the median of the historical distribution.
- The South and Northeast had annual temperatures which were much-above average, having their 8th warmest and 9th warmest years on record, respectively. Sixteen states had annual temperatures among their ten warmest. Delaware was record warm for the period, with an annual temperature of 58.2 degrees F, or 3.5 degrees F above average. Texas had its second warmest year on record, with an annual temperature anomaly of 2.2 degrees F, just shy of the annual record of 2.5 degrees set in 1921.
- Wetter-than-average conditions were present for the Northeast (wettest year on record) and the Ohio Valley [(Central Climate Region) 2nd wettest year). Seven states across the two regions — Connecticut, Indiana, Kentucky, New Jersey, New York, Ohio, and Pennsylvania — had their wettest year on record.
- Drier-than-average conditions were present across the southern tier of the country. Georgia (5th driest) New Mexico (6th), Louisiana (7th), and South Carolina (8th) had annual precipitation totals among their ten driest. Texas was record dry for the year, with 14.89 inches of precipitation — 13.03 inches below the 20th century average. The year 2011 surpassed 1917 as the driest year on record for Texas, when 14.99 inches of precipitation was observed across the state.
- An in-depth report on the climate and weather of 2011 will be forthcoming in the NCDC’s 2011 Annual Report, scheduled to be released on January 19th.
Alaska Temperature and Precipitation:
- Alaska had its 3rd warmest December on record, with a temperature 8.7°F (4.8°C) above the 1971–2000 average.
- Alaska had its 35th warmest October-December on record, with a temperature 1.3°F (0.7°C) above the 1971–2000 average.
- Alaska had its 38th warmest January-December period on record, with a temperature 0.4°F (0.2°C) above the 1971–2000 average.
- Alaska had its 5th wettest December since records began in 1918, with an anomaly that was 39.4 percent below the 1971–2000 average.
- Alaska had its 24th wettest October-December on record, with an anomaly that was 7.8 percent above the 1971–2000 average.
- Alaska had its 36th wettest January-December period on record, with an anomaly that was 5.4 percent above the 1971–2000 average.
For additional details about recent temperatures and precipitation across the U.S., see the Regional Highlights section below. For information on local temperature and precipitation records during the month, please visit NCDC's Records 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)
- December’s average temperature of 34.1 degrees F (1.2 degrees C) was 5.3 degrees F (2.9 degrees C) above normal and 9.0 degrees F (5.0 degrees C) warmer than December 2010. It was the warmest December since 2006 (2006 was the warmest December since 1895) and the sixth warmest December since recordkeeping began in 1895. In addition, it was the ninth consecutive month to average warmer than normal. Each of the states in the Northeast was warmer than normal, with departures that ranged from +4.5 degrees F (+2.5 degrees C) in Maryland and West Virginia to +6.3 degrees F (+3.5 degrees C) in Delaware. This month was the 2nd warmest December since 1895 in Delaware and Rhode Island, and the 3rd warmest in Connecticut, Massachusetts, and New Jersey. Temperatures in the remaining states ranked within the 5th to 15th warmest on record. With nine of the twelve months averaging above normal, the yearly average was also warmer than normal. The Northeast’s average annual temperature in 2011 was 49.0 degrees F (9.4 degrees C), which was 1.5 degrees F (0.8 degrees C) above normal and only one degree F (0.6 degrees C) less than the warmest year, 1998. This year was the Northeast’s 9th warmest since 1895. Each of the states in the region ranked within the top 12 warmest since 1895, with Delaware posting its warmest year on record. Departures among the states ranged from +1.2 degrees F (+0.7 degrees C) in Massachusetts to +2.5 degrees F (+1.4 degrees C) in Delaware.
- December’s precipitation total of 3.64 inches (92.5 mm) was 104 percent of normal. While this month’s total was 0.17 inches (4.3 mm) above normal, it was 0.32 inches (8.1 mm) less than December 2010. This was the fifth consecutive wetter-than-normal December. None of the state’s precipitation totals departed far from normal Delaware, at 94 percent of normal, was the driest state; and Pennsylvania was the wettest, with 113 percent of its normal precipitation amount. The Northeast’s annual precipitation total of 55.14 inches (1400.6 mm) sent 2011 into the record book as the wettest year since 1895, surpassing 1996’s total of 54.60 inches (1386.8 mm). This year’s total was 10.97 inches (278.6 mm) wetter than normal. Four of the states hit hard by the tropical storms in August and September - Connecticut, New Jersey, New York, and Pennsylvania - also had their wettest year on record. Vermont saw its 2nd wettest year since 1895 and Massachusetts, its 3rd. The region averaged 124 percent of normal in 2011; state departures ranged from 109 percent in Delaware to 136 percent in New Jersey and Pennsylvania.
- Unlike December 2010, when most of the Northeast saw above normal snowfall, this December was noteworthy for its lack of snow. In a normal December, the northern half of the region gets at least a foot (30.5 cm) of snow. This month, a few areas in northern Maine and Vermont had totals of up to a foot (30.5 cm) and only a small section of New York east of Lake Ontario saw over 24 inches (61.0 cm). Normally snowy Syracuse, NY didn’t see its first inch (2.54 cm) of snow until the 15th; Buffalo, NY’s seasonal total of 3.8 inches (9.65 cm) was 32.9 inches (83.57 cm) below normal. Both Buffalo and Syracuse had their 3rd least snowy October through December on record. The lack of major snow events this month had its blessings and its curses. Local and state snow removal costs were minimal, holiday shoppers could get to the malls with ease, and weather related travel delays were few and far between, especially during the holiday season. On the flip side, the winter tourism industry was suffering financially due to the lack of snow and cold temperatures.
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- December temperatures averaged 3 to 10 degrees F (2 to 6 degrees C) above normal across the Midwest with the largest departures in Minnesota. Temperatures were below normal early in December but well above normal for the last two-thirds of the month. Daily temperature records were almost exclusively record highs with 629 record highs and just 7 record lows. Annual temperatures were very close to normal for the entire region with all locations within 2 degrees F (1 degree C) of normal for the year.
- December precipitation ranged from less than 0.25 inches (6.4 mm) in parts of Minnesota to more than 7 inches (177.8 mm) in southeast Missouri and southwest Kentucky. The low totals in Minnesota were less than 25% of normal in some locations. In northwest Missouri and southern Iowa, precipitation totals of 2.5 to 3 inches (63.5 to 76.2 mm) more than doubled normal. Annual precipitation ranged from less than 20 inches (508.0 mm) in northwest Minnesota, 75% of normal, to more than 70 inches (1778.0 mm) along the Ohio River Valley, 150% of normal. Indiana, Ohio, and Kentucky recorded their wettest year statewide in 2011 (1895-2011 period). Ten cities along the Ohio River and northward to Lake Erie set new records for annual precipitation. Cincinnati, Ohio, with 140 years of data, broke its old record of 57.58 inches (1462.5 mm) in 1990 by 15.70 inches (398.8 mm) with 73.28 inches (1861.3 mm) in 2011. Cleveland, Ohio, with 141 years of data, broke its previous record of 53.83 inches (1367.3 mm) in 1990 by 11.49 inches (291.8 mm) with 65.32 inches (1659.1 mm) in 2011. Many other stations in this area set annual precipitation records including several in Ohio that topped the old state record of 70.82 inches (1798.8 mm) including Cheviot, Ohio with an unofficial total of 76.24 inches (1936.4 mm).
- Snow totals were unusually low across the Midwest in December. Monthly totals were just 0 to 2 inches in the southern half of the region and topped 12 inches only in northern Wisconsin and Upper Michigan. Those totals were below normal by 0 to 5 inches (0 to 127 cm) for most of the region and 5 to 10 inches (127 to 154 cm) for the northern third of the region and as much as 24 inches (610 cm) below normal for parts of northern Michigan along the Great Lakes. By the end of the month, snow was on the ground only in parts of Minnesota, Wisconsin, and Michigan. . Winter sports in the upper Midwest have been hampered by the lack of snow and warmth which has melted much of what did fall. An upside has been lower heating costs for residential customers and reduced snow removal cost for municipal budgets.
- Despite the lack of snow overall, hundreds of accidents have been reported in December, some in snow events with just an inch or two (3 to 5 cm) of snow. Freezing rain spread across a wide swath of the Midwest on the 29th and 30th. Dozens of accidents were reported in each of numerous cities from southern Wisconsin to northern Ohio.
- Heavy rains in Indianapolis, Indiana led to one death on the 21st. The fatality was a drowning in a ditch.
- For details on the weather and climate events of the Midwest, see the weekly summaries in the MRCC Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- Monthly average temperatures for December were above normal across the Southeast region. The greatest departures were found across the northern half of the region, where monthly temperatures were between 5 and 6 degrees F (2.8 to 3.3. degrees C) above average, while temperatures across the southern half of the region were between 2 and 4 degrees F (1.1 to 2.2 degrees C) above normal. Monthly temperatures were slightly above normal across much of Puerto Rico and the U.S. Virgin Islands. December ranked among the top 10 warmest on record at several locations across the region, including Tampa, FL, Miami, FL, Columbus, GA, Raleigh-Durham, NC, Greenville, SC, and Richmond, VA. Overnight temperatures were especially warm during the month, as over 200 daily high minimum temperature records were tied or broken across the region. Many of these occurred in the days before Christmas, which was in stark contrast to the cold and snow that struck the region one year earlier.
- For the third straight month, precipitation was highly variable across the Southeast region. Monthly totals were between 100 and 150 percent of normal across western portions of Virginia and North Carolina and across sections of Alabama and North Georgia. Some locations across the Southern Appalachians recorded between 150 and 300 percent of normal precipitation for the month. Heavy precipitation connected with a slow-moving frontal system produced 4.28 inches (108.7 mm) at Meadows of Dan, VA on the 7th of the month, setting a monthly record 24-hr rainfall total. In contrast, the driest locations across the Southeast were found across the eastern Carolinas and the Florida Peninsula, where monthly precipitation totals were less than 25 percent of normal. Charleston, SC recorded only 0.65 inches (16.5 mm) of precipitation, making it the second driest December in a record extending back to 1938. Elsewhere across the region, monthly precipitation was between 25 and 75 percent of normal, including the western slopes and interior mountains of Puerto Rico. In contrast to last December, there was very little snowfall reported across the Southeast region. Trace amounts of snow were reported in northern Alabama and in the mountains of North Carolina and Virginia from the 7th to the 8th of the month in the wake of a frontal passage. Additionally, up to 2 inches (50.8 mm) of snow was reported across the higher elevations of North Carolina and Virginia as a low pressure system tracked across the eastern U.S. from the 27th to the 29th of the month.
- The calendar year 2011 was exceptionally warm across a large portion of the Southeast region. Miami, FL and Cape Hatteras, NC recorded their warmest year ever in records extending back to 1895 and 1893, respectively. It was the second warmest year ever in Richmond, VA and Tampa, FL, while Columbia, SC and Norfolk, VA tied their second warmest year ever. Several other locations recorded one of their top 10 warmest years ever in 2011, including Atlanta, GA, Washington, D.C., Raleigh-Durham, NC, Charleston, SC, and Roanoke, VA. In terms of precipitation, it was the second driest year on record in Gainesville, FL and Tallahassee, FL, with preliminary annual totals of 33.28 inches (845.3 mm) and 34.81 inches (884.2 mm), respectively. One year after recording its wettest year ever, San Juan, PR recorded its second wettest year on record in 2011 with 88.16 inches (2239.3 mm).
- There were 79 reports of severe weather across the Southeast in December, including an outbreak of 13 tornadoes on the 21st and 22nd of the month. Six of these tornadoes occurred in Georgia, including an EF-3 that tracked for several miles across Floyd, Gordon, and Bartow Counties northwest of Atlanta. One home was completely destroyed and several others were damaged. An EF-2 tornado was also reported in nearby Rome, GA, resulting in three injuries and significant damage to more than 20 homes. The remaining seven tornadoes were reported across central Alabama, including an EF-1 that tracked across Elmore, Coosa, and Tallapoosa Counties. This tornado destroyed a metal building and uprooted a 100 year old oak tree in Kellyton, AL. In total, between 400 and 500 trees were uprooted along its 25 mile (40.2 km) path.
- Drought conditions continued to persist across more than half of the Southeast region in December. The lack of rainfall across the Florida Peninsula contributed to the re-emergence of D0 (abnormally dry) conditions by the end of the month, forcing several communities to consider implementing additional water restrictions. The warm, dry weather facilitated the planting and growth of winter grains and vegetables, as well as the transport of harvested crops across the region. A rare Code Orange air quality dsignation (considered unhealthy for sensitive groups according to the EPA) occurred across parts of central Georgia beginning on New Year’s Eve. Preliminary analyses by the Georgia State Climate Office suggest that the event was caused at least partly by local fireworks displays under ideal meteorological conditions (i.e. a strong nocturnal inversion, shallow boundary layer, and calm winds).
- 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)
- December was an interesting month across the High Plains Region. The northern areas of the region were generally drier and warmer than normal and many areas did not experience a White Christmas. The lack of snow cover, not just in the High Plains Region, but also in areas north into Canada, contributed to the unseasonably warm temperatures. The Dakotas had the largest temperature departures in the region, ranging from near normal in the southwest corner of South Dakota to over 12 degrees F (6.7 degrees C) above normal in northern and northeastern North Dakota. These warm temperatures caused many locations in the Dakotas to be ranked in the top 15 warmest Decembers on record. For instance, Fargo, North Dakota had an average temperature of 25.3 degrees F (-3.7 degrees C), which was 12.8 degrees F (7.1 degrees C) above normal. Fargo’s average temperature for December was ranked as the 3rd warmest and was just shy of the record which occurred in 1959 with 25.9 degrees F (-3.4 degrees C) (period of record 1881-2011). Meanwhile, the western areas of the Region were generally colder than normal with temperature departures at least 6 degrees F (3.3 degrees C) below normal occurring in areas of southern Colorado and Wyoming. A few locations in southern Colorado ranked in the top 10 coolest Decembers on record. Lamar, Colorado had its 3rd coolest December on record with an average temperature of 21.8 degrees F (-5.7 degrees C). While this was 8.5 degrees F (4.7 degrees C) below normal, it was not cool enough to beat the old December record of 18.1 degrees F (-7.7 degrees C) which occurred in 1924 (period of record 1893-2011).
- Precipitation was varied across the Region this month. The Dakotas were generally drier than normal, with a few isolated pockets receiving above normal precipitation. The ongoing dry conditions in eastern North Dakota led to the expansion of moderate drought conditions (D1). Meanwhile, heavy rain and snow across Kansas and southern Colorado helped alleviate and in some cases eliminate drought conditions. Precipitation was a welcome sight in drought-stricken areas of Colorado, Kansas, and southeast Nebraska. This month, the heaviest precipitation in the Region fell in a large swath that stretched from southeastern Colorado, through Kansas, and into southeastern Nebraska. The majority of the locations in this swath received 200-400 percent of normal precipitation, while clusters of locations in Kansas and Colorado received 400-800 percent of normal precipitation. Numerous locations ranked in the top 10 wettest Decembers on record and many had precipitation totals which were ranked second and third wettest. Wichita, Kansas had its 5th wettest December with 3.69 inches (94 mm) of liquid equivalent precipitation (period of record 1888-2011). The wettest December occurred in 1984 with 4.71 inches (120 mm) of liquid equivalent precipitation. Snowfall totals for the month of December also ranked in the top 10 across some areas of Kansas and Colorado. At least one location had its snowiest December on record - Pueblo, Colorado. Pueblo received 18.6 inches (47 cm) of snow this month, which beat out the old record of 18.2 inches (46 cm) set all the way back 1913 (period of record 1888-2011). December 19-20 was an active period as a major winter storm brought heavy rain, sleet, and snow to Colorado and Kansas. Heavy snow was accompanied by strong winds which created blizzard conditions in some locations. According to the National Weather Service in Dodge City, Kansas, snow drifts of 8 to 10 feet (243 to 305 cm) were also reported. Some of the heaviest snow fell in southeastern Colorado where some interesting records were set. Lamar, Colorado received 19.0 inches (48 cm) of snow on December 20th and set an impressive new daily snowfall total for that day. This snow total well exceeded the old record of 10.0 inches (25 cm) set in 2006 (period of record 1893-2011). The snowfall on the 20th also set a new record as the highest one-day snowfall total for any day in December. Interestingly, the 19.0 inches (48 cm) of snow on the 20th was also the second highest one-day snowfall total for any day of the year in Lamar. The record one-day snowfall occurred October 26, 1997 when 22.0 inches (56 cm) fell in Lamar. 2011 ended on a windy note as damaging winds affected Wyoming, Colorado, Kansas, and Nebraska. Wind gusts over 60 mph (97 km/hr) were widespread and there were even reports of winds over 100 mph (161 km/hr) in some of the mountainous areas of Colorado. The high winds led to dangerous driving conditions on the open highways and some structural damage. According to the National Weather Service in Cheyenne, Wyoming, vehicles, buildings, and signs were damaged as a result of the high winds.
- The U.S. Drought Monitor had many changes this month. Storm systems bringing beneficial rain and snow to Colorado and Kansas have led to the erasure of all exceptional drought conditions (D4) in those states. In addition, extreme drought conditions (D3) were also erased in Colorado. Other major changes occurred in Kansas as well, as all drought conditions were eliminated in the north and the drought conditions that remain have contracted to the south somewhat. Southeastern Nebraska also benefitted from the December precipitation as drought conditions were erased for a large portion of that area. Meanwhile, due to an ongoing lack of precipitation in North Dakota, moderate drought conditions (D1) have expanded northward in the eastern side of the state. Drought conditions in South Dakota remained largely the same since last month, with the exception of a slight expansion of abnormally dry (D0) and D1 conditions in the southeast. According to the U.S. Seasonal Drought Outlook drought conditions in portions of the Dakotas, Nebraska, Colorado, and western Kansas were expected to persist, while drought conditions in eastern Kansas were expected to improve.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- The month of December, was generally cooler than normal in Texas, northern Louisiana and in the Oklahoma panhandle. Though it was cooler than normal, temperatures averaged only 0-4 degrees F (0 to 2.22 degrees C) lower than expected. Elsewhere, conditions were generally slightly warmer than normal, with temperatures averaging between 0 to 6 degrees F (0 to 3.33 degrees C) above expected values. The highest departures were observed in Tennessee, where most stations averaged between 4 and 6 degrees F (2.22 to 3.33 degrees C) above normal. The state of Tennessee had an average temperature of 42.20 degrees F (5.67 degrees C) for the month, and it was the thirty-second warmest December on record (1895-2011). On the flip side, Texas averaged only 45.40 degrees F (7.44 degrees C), which was the twenty-sixth coolest December on record (1895-2011). Other state average temperatures include: Arkansas at 42.60 degrees F (5.89 degrees C) , Louisiana at 50.80 degrees F (10.44 degrees C), Mississippi at 47.20 degrees F (8.44 degrees C), and Oklahoma at 38.90 degrees F (3.83 degrees C). The state rankings for these states all fell well within the two middle quartiles.
- With a few exceptions, December was generally a wet month for the Southern Region. Dry areas included southern Louisiana and southern Mississippi, eastern Oklahoma, and parts of western Texas. These areas generally averaged approximately five to twenty five percent of normal precipitation for the month. The wettest part of the region included Arkansas, parts of southern and northern Texas, and western Oklahoma. Stations in these regions averaged between 150 and 400 percent of normal precipitation. Texas averaged 2.88 inches (73.15 mm) of precipitation, making it the nineteenth wettest December on record (1895-2011). It is also the second month in the year where precipitation for the state exceeded two inches (50.80 mm). Oklahoma experienced its twenty-eighth wettest December on record (1895-2011) with a state average precipitation total of 2.35 inches (59.69 mm). For Arkansas, it was the eighth wettest December on record (1895-2011) with a state average precipitation total of 7.47 inches (189.74 mm). Stations in the northeastern and southern areas of the state averaged between 150 and 250 percent of normal. Louisiana averaged 5.49 inches (139.45 mm) of precipitation, while Mississippi, averaged 5.99 inches (152.15 mm) of precipitation. Tennessee averaged 5.91 inches (150.11 mm) of precipitation for the month. State rankings for Louisiana, Mississippi, and Tennessee were all in the middle two quartiles.
- Drought conditions in the Southern Region improved slightly from the previous month. Above normal precipitation over much of the region has led to improvements over western Louisiana, northwestern Texas, and northern Texas. As of January 3, 2012, only 17.24 percent of the Southern Region is experiencing exceptional drought, which is approximately a twelve percent improvement over the end of November. The amount of extreme drought was also reduced by approximately eleven percent. Drier than normal conditions in southeastern Louisiana, however; has led to the introduction of extreme drought over much of the Florida Parishes.
- A snowstorm over December 19 to December 21, dumped up to 15 inches (381 mm) of snow across the great plains affecting areas from new Mexico to Kansas. In Oklahoma, and northern Texas, snow drifts were so high that many roads and interstates had to be temporarily closed.
- On December 20, 2011, a tornado in Calcasieu Parish, Louisiana caused the roof of a patient care facility to be blown off.
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Regional Climate Center)
- Dry and generally cool conditions were observed in much of the West this month as high pressure dominated the region. Several systems made their way across the Southwest, bringing above normal precipitation to the area. Montana experienced a very warm month. Many locations in the West experienced damaging high winds this month associated with passing cold fronts or Santa Ana conditions.
- December temperatures were below normal in much of the West with the notable exception of the upper Missouri River Basin. During the second half of the month, many locations in Montana saw positive temperature departures from normal in the double digits. Glasgow, Montana airport experienced its 11th warmest December monthly average at 23.8 F (-4.5 C) in a record beginning in 1955. A number of locations in New Mexico and southern Colorado experienced cold conditions, many 6-10 F (3-6 C) below normal. Roswell, New Mexico averaged 34.5 F (1.38 C), the 8th coolest in a record dating from 1894. With clear skies in western portions of the region, daytime highs were well above average, and nighttime lows were well below average.
- Precipitation was below normal in much of the West this month. A series of storms passed through the Pacific Northwest during the last week of the month, staving off near-record dryness, but still only about half the average. A series of cutoff low-pressure systems moved across the Southwest during the first half of the month, bringing above normal precipitation to Arizona, New Mexico, and Southern Colorado. Pueblo, Colorado airport recorded its 5th wettest December with 0.84 in (21.3 mm) on a record beginning in 1954. Albuquerque, New Mexico recorded their 9th wettest December with 1.2 in (30.5 mm).
- Many locations in California and Nevada experienced record or near-record dry conditions. Reno, Nevada reported its lowest December total (not even a trace) in 129 years (1883 and four prior years also had no precipitation). Fresno, California reported no measurable precipitation for the 2nd time since 1878 (tied with 1989). Downtown San Francisco received 0.14 in (3.6 mm), the 3rd driest December since 1849, behind only the 0.00 readings of 1876 and 1989. San Jose (2nd driest since 1874) and Sacramento (6th driest since 1849) also had a notably dry month, and an index of 8 Sierra Nevada stations recorded its second lowest December total since 1920, and 4th lowest July-December.
- December 1-2: Santa Ana Wind Event: A strong wind event affected much of the Southwest. Gusts of 140 mph (225 kph) were recorded at the crest of the southern Sierra Nevada. Gusts to 80 mph (128 kph) were recorded in the Los Angeles area. Many power lines and trees were downed in Southern California, and on the 1st, 200,000 people were without power in the Los Angeles area. Pasadena, California declared a state of emergency following the wind event. Several wildfires broke out with the dry, warm air created near the coast. Albuquerque, New Mexico, Las Vegas, Nevada and Salt Lake City, Utah were also affected by this wind event and recorded high gusts.
- December 3-5: Snowstorms in West: The low pressure system that helped to generate high winds over the Southwest moved northeast, bringing snowfall to the southern Rockies and plains. Most basins in northern Arizona and New Mexico and Colorado received 4-8 in (10-20 cm). Higher altitude locations like Taos, New Mexico received up to 18 in (45.7 cm) of snowfall.
- December 11-12: Southwest Precipitation Event: Another cutoff low moved down the West Coast and then inland on December 11-12, bringing significant precipitation and snowfall to Southern California, eastern Nevada, southern Utah, and northern Arizona and New Mexico. Several inches of snow were received throughout the area, with highest storm totals of up to 8 in (20 cm) along the Arizona/New Mexico border. San Diego received a storm total of 0.67 in (17 mm), one-third of the location’s average December total of 1.78 in (45.2 mm).
- December 19th: New Mexico/Southeast Colorado Snowstorm: New Mexico and Southeast Colorado received several inches of snow with totals up to 1 foot (30.4 cm) at high elevations. High winds and low visibility associated with the storm caused road closures and travel difficulties on several major travel routes.
- December 30-31: Colorado/Wyoming High Wind Event: Damaging wind gusts up to 75 mph (120 kph) occurred in southern Wyoming and northern Colorado. High profile vehicles and tractor-trailers were knocked over on some Wyoming highways. A roof was torn of a warehouse in Cheyenne, Wyoming injuring two people, and a falling tree branch killed a man in Boulder, Colorado. Localized power outages were also experienced throughout the region.
- For more information, please go to the Western Regional Climate Center Home Page.
See NCDC's Monthly Records web-page for weather and climate records for the most recent month. For additional national, regional, and statewide data and graphics from 1895-present, for any period, 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 Temperature and Precipitation Maps page and the Climate at a Glance page as they become available.