Alaska’s coldest February and winter in 21 years; Sixth warmest winter on record for contiguous U.S.
During February, the average contiguous U.S. temperature was 36.2°F, 2.4°F above the 20th century average. This ranked among the warmest one-third of the 126-year period of record. Despite being on record pace for warmest winter on record in January, the winter (December–February) average contiguous U.S. temperature was 36.0°F, 3.8°F above average, ranking sixth warmest winter on record.
The February precipitation total for the contiguous U.S. was 2.40 inches, 0.27 inch above average and ranked among the wettest one-third of the historical period of record. The winter precipitation total was 7.71 inches, 0.92 inch above average, and ranked among the wettest one-third of the 125-year period of record. For the 12-month period March 2019–February 2020, the precipitation total was 34.12 inches, 4.16 inches above average and the sixth wettest March–February period on record.
This monthly summary from NOAA National Centers for Environmental Information is part of the suite of climate services NOAA provides to government, business, academia and the public to support informed decision-making.
Much-above-average temperatures were observed across parts of the Mid-Atlantic and Northeast as well as portions of California and Florida. New Jersey and Rhode Island ranked third warmest, while Maryland, Delaware and Connecticut ranked fifth warmest.
Below-average temperatures were observed across portions of the central Rockies to western Texas during February. No state ranked below average for the month.
The Alaska February temperature was 1.5°F, 3.3°F below the long-term average. This ranked among the coldest one-third of the 96-year period of record for the state and was the coldest February since 1999.
The North Slope had its coldest February in 31 years.
It was the coldest February since 1984 in Utqiaġvik (Barrow).
Utqiaġvik had seven days in February with low temperatures as cold or colder than −40°F — the most in any February since 1984 and in any calendar month since January 1989.
Cold temperatures across the region were a catalyst for rapid ice growth across the Bering Sea in February, where sea ice extent expanded to 100% of average for the month. This was the first February since 2013 where the Bering Sea ice extent was not below average.
Much-above-average to record wet conditions were present across much of the Southeast during February, as flooding rainfall on multiple days caused landslides and severe damage to roads and other infrastructure. In Jackson, Mississippi, the Pearl River crested at its highest level since 1983, inundating many homes. Several other rivers across Alabama and Mississippi were near-to or above flood stage. Georgia ranked second wettest, while Alabama and North Carolina ranked third wettest for the month.
After a dry January across southwestern California, February brought little to no relief, with many locations reporting less than 5% of average rainfall. California ranked driest on record for February with 0.20 inch of precipitation, besting the previous record of 0.31 inch set back in 1964.
Stations across the San Francisco Bay area and interior parts of northern California tied or set records for driest February on record. San Francisco, San Jose, Sacramento, Oakland and many other stations received no precipitation during the month, setting local records for the driest February.
Air temperatures during the winter were warm enough across the Great Lakes to keep surface water temperatures above freezing across a large portion of the basin. As a result, enhanced lake-effect snow events occur much later in the season than on average, which lead to higher seasonal snowfall totals. This was indeed the case during February 27–29, as heavy lake effect snowfall impacted portions of the Tug Hill Plateau region of upstate New York. Cold and blustery winds blew across the length of Lake Ontario, over the relatively warm waters, lifting moisture and dumping several feet of snow along the downwind communities. Carthage, New York, received 48 inches of snowfall from this event while Croghan and Redfield observed 42.5 inches and 31.2 inches, respectively. Other communities south of Buffalo received between one and two feet of snow from this event and lesser amounts across the Upper Peninsula of Michigan According to the March 3 U.S. Drought Monitor report, 11.5% of the contiguous U.S. was in drought, up slightly from 11% at the end of January. With the extremely dry conditions during January and February across California, moderate drought blossomed across 34% of the state over the last three weeks and expanded across Oregon and into Nevada. In Texas, the drought footprint contracted, yet intensified as extreme drought expanded across parts of south Texas. Drought conditions improved across Hawaii. as well as the northern Lower Peninsula of Michigan.
The Arctic Oscillation (AO) was strongly positive for most of the winter, particularly in January and February. Twice in February, it set all-time records for its highest values.
The positive phase of the AO is associated with enhanced troughing of the upper-air jet stream in the Arctic and enhanced ridging of the jet stream in the midlatitudes. This strengthens the jet stream and traps the colder temperatures in the Arctic, leaving warmer conditions to the south, including across the contiguous U.S.
During January, February and the latter half of December, the jet stream was stronger than normal and upper-air troughs were strongest near Alaska, Greenland and central Russia, leading to persistently cold anomalies in those regions. The ridges were strongest over Europe, East Asia and the northeastern Pacific, allowing warmer anomalies to persist.
As a result of this positive AO, winter temperatures were above average across most of the contiguous U.S. and much-above-average across the eastern U.S. West Virginia and Rhode Island each had their fourth warmest December–February on record. Twenty-two additional states had a top 10 warmest winter.
The Alaska December–February temperature was 0.7°F, 2.9°F below the long-term average, ranking among the coldest one-third of the 95-year record and the coldest winter in 21 years. Much-below-average temperatures were concentrated in parts of the Central Interior region with below-average temperatures across much of mainland Alaska. Above-average temperatures were present across portions of the Panhandle.
For the first time in 21 years, Fairbanks remained below freezing during all of climatological winter (December–February).
Much-above-average to record precipitation was observed from the Southeast into the Great Lakes. Alabama and Georgia ranked wettest on record for winter precipitation, while South Carolina ranked second wettest. Parts of the West and northern Rockies received below-average precipitation for the season.
Much of the Rockies, northern Plains, western Great Lakes and northern New England received average to above-average snowfall during winter. The Sierra Nevada Mountains, the southern Great Lakes and from the Ohio Valley to the Mid-Atlantic region and into the Northeast saw below-average to near-record low snowfall totals for the season. This was due in part to the northward deviation of the polar jet stream, which brought colder air to the West and warmer air across much of the eastern U.S. As a result, very few cold winter storms traversed the south-central portions of the Lower 48 and up the East Coast during the winter season.
Climatologically speaking, winter is the wet season in California and across much of the West. If March and April do not produce adequate precipitation to make up for the dry conditions experienced during winter, there will be increased concerns regarding sufficient water resources to get through the dry season (summer) and also for the increased potential for wildfires this coming fall.
While much of interior and northern Alaska was drier than average during the winter, portions of the Alaskan Panhandle were wetter than average. Petersburg, Alaska, received 40 inches of precipitation — the wettest winter since 2006–2007.