National Overview - December 2016
NCEI added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
- Climate Highlights — December
- The average contiguous U.S. temperature during December was 32.9°F, 0.2°F above the 20th century average. This was the 54th coolest December on record for the Lower 48. The average maximum (daytime) temperature was 42.5°F, 0.3°F below the 20th century average, the 46th lowest maximum value on record. The average minimum temperature was 23.2°F, 0.6°F above average. This was the 59th warmest value on record. All three values — Average, Maximum and Minimum Temperature — are categorized as "Near Normal" for the month.
- Temperature patterns were roughly evenly dividen between above normal, near normal, and below normal across the country. The south and east were generally warmer than normal. Florida had its fourth warmest December on record. The northwest quarter of the country was generally cooler than normal. Oregon had its 11th coolest December on record.
- Alaska had a near-normal statewide temperature during December. Its average temperature of 5.7°F; was 2.0°F above its long-term average, which dates to 1925. It was the 38th warmest December record, a month that shows considerable variability over the period of record.
- During December, record warm daily maximum and minimum temperature records outpaced record cold daily maximum and minimum temperature records by about a 3-to-2 ratio. There were 2,889 warm daily temperature records (1,608 maximum and 1,281 minimum) compared to 1,994 cold daily temperature records (924 maximum and 1,070 minimum).
- Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during December was 44.4, the 40th lowest value of the 122-year record, owing largely to warmer-than-normal temperatures in the more populated eastern half of the country.
- The December precipitation total for the contiguous U.S. was 2.69 inches, 0.34 inch above the 20th century average, ranking as the 34th wettest December on record, categorized as "Wetter than Normal". Nine of the last eleven Decembers have been wetter than the 20th century average.
- Above-average precipitation was observed across the majority of the country, particularly in the intermountain West, Northern Plains, and Upper Midwest . North Dakota saw its 3rd wettest December, and South Dakora its 4th wettest.
- According to the January 3rd U.S. Drought Monitor report, 22.5 percent of contiguous U.S. was in drought, down from 31.5 percent at the end of November. Drought conditions improved significantly across the mid-South and Southeast, with the exception of peninsular Florida. More modest improvements were observed in parts of the West.
**A comparison of the national temperature departure from average as calculated by NCDC's operational dataset (nClimDiv), the U.S. Historical Climatology Network (USHCN), and the U.S. Climate Reference Network (USCRN) is available on our National Temperature Index 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)
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- Report not available at time of publishing.
- For further details on the weather and climate events in the Midwest, see the weekly and monthly reports at the Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- 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 )
- Report not available at time of publishing.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- Drought conditions over the month of December improved dramatically in the eastern states of Tennessee, Mississippi, Louisiana and Arkansas, while in Oklahoma, conditions worsened from the previous month. At the end of November, approximately half of the Southern Region was experiencing some type of drought, with much of Mississippi and Tennessee categorized under extreme drought. As of January 3, 2017, only 27 percent of the Southern Region was experiencing drought, with little to no extreme drought remaining. Much of the drought along the Gulf coast was also eradicated. Though precipitation totals in the eastern parts of the region were not high, they were much higher than in previous months. Due to below normal precipitation in Oklahoma, drought conditions deteriorated slightly with more counties now falling under severe drought.
- A tornado on December 5, 2016 in Ascension Parish caused some damage. The twister was rated EF1 with winds estimated to be 90 mph (145 kph). There were no reports of injuries or fatalities.
- On December 13, 2016, a tornado in Harrison County, Mississippi caused some damage along Bell Creek Road near the Harrison/Hancock County line. Although some structural damage was reported, much of the damage appears to be limited to trees. There were no reports of injuries or fatalities.
- A tornadic outbreak occurred on December 17. Several storms were reported in northern Mississippi and in southwestern Tennessee. Fortunately, damage was limited mostly to trees and power lines.
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Region Climate Center)
- December 1-5: Hawaii's Big Island peaks see heavy snow: Up to 35 in (89 cm) of snow was reported on Big Island volcanic summits. Sections of Hawaii Volcanoes National Park were closed above Red Hill Cabin.
- December 7-8: Ice storm and low elevation snow in Oregon: A strong storm brought a wintery mix to low elevations of Oregon. Accumulating snow and up to 0.75 in (19 mm) of ice accumulation was reported in Portland leading to power outages, traffic accidents, and airport delays.
- December 9-10: Atmospheric river impacts Sierra Nevada and western Nevada: A warm winter storm brought heavy snow and then rain to the Sierra Nevada, with snow levels rising to over 8,000 ft (2400 m). This created dangerous avalanche conditions and one death was reported at the Mount Rose ski resort (skier was in a closed area) in Nevada. The Truckee River reached minor flood stage and minor flood impacts were reported in Truckee, California and around the Reno, Nevada area.
- For more information, please go to the Western Regional Climate Center Home Page.
For the eighth consecutive month, the Northeast averaged out to be warmer than normal. The December average temperature of 29.3°F (-1.5°C) was 0.8°F (0.4°C) above normal. Maine was the only cooler-than-normal state at 1.0°F (0.6°C) below normal. Average temperatures for the other states ranged from 0.4°F (0.2°C) above normal in New Hampshire to 1.8°F (1.0°C) above normal in West Virginia.
The Northeast received 3.77 inches (95.76 mm) of precipitation, 108 percent of normal, in December. The twelve states were split between drier than normal and wetter than normal, with totals ranging from 81 percent of normal in Rhode Island to 131 percent of normal in West Virginia.
The U.S. Drought Monitor released on December 1 indicated 54 percent of the Northeast was in a moderate, severe, or extreme drought, with another 24 percent being abnormally dry. During the month, abnormally dry and drought conditions generally remained unchanged or improved across most of the region. Areas that saw conditions deteriorate included portions of southeastern Massachusetts, central Delaware, and southern and coastal New Jersey. The U.S. Drought Monitor released on December 29 indicated 44 percent of the Northeast was in a moderate, severe, or extreme drought, with another 27 percent being abnormally dry. Streamflow was generally near to below normal for the Northeast during December. As of December 29, the salt front on the Delaware River was 5 miles (8 km) upstream from its normal December location compared to 21 miles (34 km) on December 1. While water levels of some wells returned to near normal, many remained below normal in the drought-stricken areas. Some reservoirs saw an uptick in water levels, but overall they also remained below normal. For instance, Worcester, Massachusetts. reservoir was at 52.8 percent of capacity as of December 11, which is up from 52.1 percent on December 1, but below the December 1 average of 80.3 percent. As of December 30, the New York City reservoir system was at 64.8 percent of capacity compared to the normal 87.5 percent. Due to low streamflow and a drop in groundwater levels, western and central Maryland were placed in a Drought Watch. Mifflin, Juniata, Snyder, and Union counties in Pennsylvania were placed in a Drought Warning on December 16.
A lake-effect event dropped up to 25 inches (64 cm) of snow on portions of Pennsylvania and New York from December 14 to 15. Wind gusts up to 68 mph (30 m/s) accompanied the snow, creating poor visibility, especially in New York.s Wayne, Cayuga, and Oswego counties where blizzard warnings were in place. Numerous accidents occurred, including a pile-up involving nearly 60 vehicles on Interstate 80 west of Dubois, Pennsylvania. A storm system brought mixed precipitation and wind gusts of up to 60 mph (27 m/s) to the region from December 16 to 18. Storm totals included up to 9 inches (23 cm) of snow, up to 3 inches (76.2 mm) of rain, and up to 0.40 inches (1 cm) of ice accumulation. The rain contributed to flooding in portions of West Virginia and Pennsylvania, while icy conditions contributed to power outages, flight cancellations, and hundreds of accidents in Maryland. For instance, on December 17, there was a pile-up on Interstate 95 near Baltimore, Maryland involving 55 vehicles that killed two people and injured at least a dozen. In Massachusetts, the winds brought down trees and wires. A Nor.easter brought snow and wind gusts of up to 53 mph (24 m/s) to New England from December 29 to 30. Thundersnow was reported in some areas. Up to 27 inches (69 cm) of snow fell in Maine, where more than 100,000 customers lost power.
Mean temperatures ranged from near average to well above average across the Southeast region during December. The greatest departures in mean temperature were found across Florida, as well as central and southern portions of Alabama and Georgia. Monthly departures were 4 to 8°F (2.2 to 4.4°C) above average in these areas. At least 18 long-term (i.e., period of record equaling or exceeding 50 years) stations in Florida observed December mean temperatures that were ranked within the top 3 warmest values on record. Fort Myers, FL (1892-2016), Miami, FL (1895-2016), and Key West, FL (1873-2016) observed their second warmest December mean temperature on record, while Tampa, FL (1890-2016) and Vero Beach, FL (1942-2016) observed their third warmest December mean temperature on record. Unseasonably warm daytime maximum and nighttime minimum temperatures were recorded at numerous locations in Florida during the month. Clermont 9 S, FL (1948-2016), located about 20 miles southwest of Orlando, observed its highest daily maximum temperature on record for December, reaching 90°F (32.2°C) on two days during the month (5th and 18th). Fort Myers, FL and Miami, FL recorded their highest December count of 16 and 12 days, respectively, with a maximum temperature at or above 85°F (29.4°C). Miami also tied its third highest December count of 21 days with a minimum temperature at or above 70°F (21.1°C). Temperatures were well above average in Puerto Rico and the U.S. Virgin Islands during the month, as San Juan, PR (1898-2016) observed its warmest December mean temperature on record (80.8°F; 27.1°C). Across the Southeast, the warmest weather of the month occurred on the 18th, as unseasonably warm, moist air surged northeastward ahead of a vigorous cold front. Daytime maximum temperatures exceeded 70°F across much of the region, with several locations in Florida reaching 85 to 90°F. Augusta, GA (1874-2016) observed its highest daily maximum temperature on record for December (84°F; 28.9°C), and Miami, FL tied its highest daily minimum temperature on record for December (79°F; 26.1°C). In contrast, the coldest weather of the month occurred on the 16th, as an Arctic high pressure system ushered in unusually cold air across the northern portion of the region. Nighttime minimum temperatures fell below 32°F (0°C) across much of the region north of Florida, but the coldest air was confined to Virginia, where several locations reached the single digits F (-17.2 to -12.8°C).
Precipitation was highly variable across the Southeast region during December, with several extremes recorded. The driest locations were found across much of central and northern Florida, as well as portions of a broad area extending northeastward from central Alabama to northern Virginia. Monthly precipitation totals were between 5 and 50 percent of normal in these areas. Venice, FL (1955-2016) observed its driest December on record, with only 0.04 inches (1.0 mm) of precipitation. Naples Municipal Airport, FL (2002-2016) recorded its longest streak of 60 days with no measurable precipitation, ending on the 5th of the month. In contrast, the wettest locations were found across southeastern Florida, a narrow strip of northern Florida, and a broad area extending northeastward from coastal Alabama to southeastern North Carolina. Monthly precipitation totals ranged from 150 to 400 percent of normal in these areas. Camilla 3 SE, GA (1938-2016) observed its wettest December on record, with 11.09 inches (282 mm) of precipitation. Over 60 percent of the monthly total was recorded on the 6th, as Camilla observed its wettest day for any month on record, with 6.75 inches (171 mm) of precipitation. Chipley, FL (1939-2016) also observed its wettest day for any month on record, with 9.60 inches (244 mm) of precipitation on the 6th. Early on the 17th, an ice storm produced numerous transportation impacts across portions of northern Virginia and the Washington, D.C. area. Freezing rain accumulations up to a quarter of an inch caused Washington Dulles Airport and segments of Interstate 95 and the Beltway to close for several hours, with one fatality occurring in a 23-vehicle pileup in Fairfax, VA. While freezing rain accumulations were much less (0.01.0.05 inches; 0.3.1.3 mm) in the Triangle region of North Carolina (i.e., Raleigh, Durham, and Chapel Hill), over 200 vehicle accidents were reported in Raleigh, with at least 26 involving injuries. Very little snowfall was observed across the region, with the greatest monthly total of only 4.0 inches (102 mm) recorded on Beech Mountain, NC. Precipitation was highly variable in Puerto Rico and the U.S. Virgin Islands during December, with monthly departures ranging from less than 25 percent of normal in southwestern Puerto Rico to more than 400 percent of normal in the west-central portion of the island.
There were only 18 severe weather reports across the Southeast during the month, which is well below normal (based on the median frequency of 52 reports for December during 2000.2015). All but three of the reports were for thunderstorm wind gusts. Late on the 17th, thunderstorm winds estimated at 65 mph damaged trees and power poles near Waterloo, AL, as a squall line moved through the area. Only three tornadoes (2 EF-0s and 1 EF-1) were confirmed across the region during the month, which is well below the median frequency of 9 tornadoes observed during December. An EF-0 tornado touched down in Vina, AL on the 18th, resulting in damage to several buildings and athletic fields at the local high school. Early on the 29th, a nocturnal EF-1 tornado touched down near Jefferson, GA and caused minor damage to several homes. On the 12th, a man was killed by a lightning strike while standing outside his home near Molino, FL. This is the first December lightning fatality in the United States since 1998, when a man was struck inside a home under construction in Paradise Valley, AZ.
Drought conditions improved significantly across the western half of the region during December. The coverage of extreme-to-exceptional (D3.D4) drought across the Southeast decreased from 36 percent on November 29th to 21 percent on December 27th. Indeed, extreme-to-exceptional drought in Alabama and Georgia decreased by nearly 45 and 13 percent, respectively, during the month. Exceptional drought conditions were removed from the Carolinas, while severe-to-extreme (D2.D3) drought was eliminated from the Florida Panhandle and southwestern Virginia. While the rainfall during December suppressed lingering wildfires, streamflow and lake levels were slower to respond in some areas from the long-term effects of the drought. Some improvement in pasture conditions was reported in drought-stricken portions of the region, but many pastures reached dormancy before the arrival of beneficial rainfall. Livestock producers continued to provide a supplemental feeding for their herds, with many producers concerned about the potential for severe hay shortages later this winter. Small grains and forage were not able to be planted in many areas due to insufficient soil moisture and a persistent lack of rainfall during the planting window. A prevalence of foggy mornings during mid-December increased disease pressure on vegetable crops across portions of southern Florida.
With the exception of north and central Oklahoma, December was the fourth consecutive warmer than normal month for the Southern Region. In fact, all states except for Oklahoma this past month, experienced a warmer than normal month from September through December. Temperature anomalies did vary spatially across the region in December, with the southern half of the region averaging between 2-4 degrees F (1.11-2.22 degrees C), and the northern half of the region averaging between normal and 2 degrees F (0 and 1.11 degrees C) above normal. The statewide monthly average temperatures were as follows: Arkansas reporting 42.30 degrees F (5.72 degrees C), Louisiana reporting 54.70 degrees F (12.61 degrees C), Mississippi reporting 49.80 degrees F (9.89 degrees C), Oklahoma reporting 38.60 degrees F (3.67 degrees C), Tennessee reporting 40.90 degrees F (4.94 degrees C), and Texas reporting 49.60 degrees F (9.78 degrees C). The state-wide temperature rankings for May are as follows: fiftieth warmest for Arkansas, nineteenth warmest for Louisiana, thirtieth warmest for Mississippi, fifty-second coldest for Oklahoma, forty-second warmest for Tennessee, and twentieth warmest for Texas. All state rankings and records are based on the period spanning 1895-2016.
December precipitation totals in the Southern Region varied spatially bringing with them a mixed bag of wetter than normal conditions in some counties, and drier than normal conditions in other counties. Along the south western Texas coast, precipitation totals varied between 150 to 200 percent of normal. To the north in central Texas and in Oklahoma, precipitation was scarce, with most stations only reporting between 5 to 50 percent of normal precipitation. This was also the case throughout most of northwestern Arkansas. Although precipitation was slightly below normal in the northern half of the state of Mississippi, the amount of precipitation was enough to help alleviate drought conditions. Near normal precipitation in western and central Tennessee, combined with above normal precipitation in eastern Tennessee also helped alleviate drought. The state-wide precipitation totals for the month are as follows: Arkansas reporting 3.58 inches (90.93 mm), Louisiana reporting 6.01 inches (152.65 mm), Mississippi reporting 4.93 inches (125.22 mm), Oklahoma reporting 0.75 inches (19.75 mm), Tennessee reporting 6.79 inches (172.47 mm), and Texas reporting 2.05 inches (52.07 mm). The state precipitation rankings for the month are as follows: for Arkansas it was the forty-sixth driest, for Louisiana it was the thirty-fifth wettest, for Mississippi it was the fifty-seventh driest, for Oklahoma it was the twentieth driest, for Tennessee it was the twenty-third wettest, and for Texas it was the forty-second wettest. All state rankings are based on the period spanning 1895-2016. `Significant Events for December 2016
Much of the West saw above normal precipitation for the month of December, with the main exceptions being Washington, interior Montana and coastal sections of California and Oregon. The Pacific Northwest and northern Rockies experienced well below normal temperatures, while temperatures in much of Arizona and New Mexico were well above average.
December was an active weather month over the West characterized by a persistent stronger than normal jet stream over the northern half of the US and two major atmospheric river events during the first half of the month. These were both inland penetrating atmospheric rivers that brought widespread heavy rain and snowfall from California all the way to the Rocky Mountains of Wyoming and Montana. Jackson, Wyoming, had its sixth wettest December since records began in 1905 with 3.22 in (81.79 mm), 210% of normal. Elko, Nevada had its eighth wettest December on record with 2.83 in (71.88 mm), 236% of normal. Records for Elko began in 1888. Above average precipitation was also found in the Sierra Nevada. Blue Canyon, California, received 15.39 in (390.91 mm), 134% of normal, This brought some improvement of drought conditions to the region; however, the warm nature of the atmospheric river storms produced high snow levels and snow water equivalent actually decreased in mid-to- low elevation locations over the course of the month. For example, the Tahoe Basin went from 119% of normal snow water equivalent on December 1 st 2016 to 62% of normal on January 1 st 2017.
Precipitation was generally below normal in Washington, most notably east of the Cascade Range. Ephrata, Washington, recorded 0.32 in (8.13 mm) of precipitation, 26% of normal. A small region in southwest Nevada, east of the White Mountains, did not benefit from the atmospheric river storms and reported drier than normal conditions. Dyer, Nevada, recorded only 0.08 in (2.03 mm) for the month, 24% of normal.
A cold, and somewhat dry, continental polar air mass was in place over much of the Pacific Northwest and Montana during early and mid-December, producing below normal temperatures. Many locations had one of their top-10 coldest Decembers on record. Baker City, Oregon recorded its coldest December at 14.7 F (-9.6 C), 10.1 F (5.6 C) below normal. Records at Baker City date back to 1943. Great Falls, in north-central Montana, saw its 5 th coldest December in an 80-year record at 14.3 F (-9.8 C), 10.5 F (5.8 C) below normal, Much of Arizona and New Mexico, as well as sections of coastal California observed above normal temperatures. Albuquerque, New Mexico, observed an average temperature of 49.7 F (9.8 C), 2.9 F (1.6 C) above normal, and San Diego, California, recorded 66.3 F (19.1 C), 2.4 F (1.3 C) above normal.
Temperatures in Alaska were well below normal during the first half of the month and above normal the second half of the month. Interior and southern portions of the state were 3-6 F (1.7 C to 3.3 C) below normal, while the west coast and North Slope were 3-8 F (1.7-4.4 C) above normal. Temperatures at Utqiaġvik, on the North Slope, were 7.9 F (4.4 C) above normal, while at the other end of the spectrum, Kenai saw a departure of 6.1 F (3.4 C) below normal. December in Alaska was quite dry in the southern and southeastern portions of the state and for the Interior and North Slope precipitation was well above normal. Fairbanks led the way with 1.96 in (50 mm) precipitation, 306% of normal and the 4 th wettest December since records began in 1904. Unlike previous winters, the precipitation in the mainland all fell as snow. In Hawaii, Maui and the Big Island experienced well above normal precipitation with Hana recording 19.4 in (492.8 mm), 278% of normal and the wettest December since records began in 1950. Oahu and Kauai saw significantly below normal precipitation; Lihue recorded 1.17 in (30 mm) rainfall, 23% of normal and the 10 th driest December since records began in 1950.Significant Events for December 2016