The groundhog Punxsutawney Phil may have seen his shadow today, but the prospect of six more weeks of the mild winter of 2011/12 doesn't seem so terrible. In fact, now that we're past the typical coldest period of the year, the days are already getting longer, and the typical average temperatures are warming up day by day across the country.
In many areas, this tame winter has been unusual but not unheard of. For example, in the Northeast, the winter has been one of the warmest and least snowy on record, but it has been warmer during past winters. (The Weather Channel has a nice comparison between snow cover charts from February 2011 vs. 2012.)
While winter temperatures have been increasing, on average, due to global warming, the mild winter this year is likely mainly due to natural climate variability, including a La Niña event in the Pacific Ocean and the orientation of the upper air jet stream.
Temperatures in the Northeast have averaged at least 5°F above average since December, with very little snow cover, according to Art DeGaetano, a Cornell University climatologist and the director of the Northeast Regional Climate Center.
“Although December 2011 and January 2012 have been warm, you do not have to go back too far to find a warmer period. The early winter of 2001-02 was the warmest at many Northeast U.S. stations. Over a longer time frame, the early winter of 1931-32 stands out as the warmest at the majority of Northeast U.S. sites,” DeGaetano said i...
While Alaska continues to to suffer from record cold and snow, much of the rest of the country continues to experience a year without winter.
This week, it's likely that warm temperature records will be broken throughout the eastern U.S., with forecast highs in New York City approaching 60°F on Tuesday and Wednesday, and reaching the mid-60s in Washington, D.C. According to the National Weather Service (NWS), record highs may also be set today in Islip, N.Y., and Bridgeport, CT.
It has also been unusually warm in the mid-section of the country. As Paul Douglas wrote for the Minneapolist Star-Tribune, the Twin Cities missed setting a record high by just four degrees on Monday, topping out at 44°F, about 20°F above average for the date. Douglas wrote that there have been just three subzero nights so far this winter in Minneapolis-St. Paul, down from the average of 19 to date.
"It's been one of the mildest winters on record; at the rate we're going this will easily be a "Top 10 Warmest Winter" in the Twin Cities," Douglas wrote.
The contrast from what Alaska is experiencing is a consequence of the prevailing weather pattern that has set up so far this winter, with high altitude winds preventing Arctic air from spilling down into the continental U.S. for extended periods.
Thanks in large part to the interplay of weather patterns in the northern Pacific Ocean and North Atlantic, frigid air has been stuck in the Far North for nearly the en...
In a dramatic reversal of fortune compared to last year, an unusually dry winter is causing the level of Lake Mead, Nevada, to decline, making water managers increasingly anxious about supplying water to the thirsty Southwest.
During the past three years, the level of Lake Mead has followed a boom and bust cycle, dropping to a record low in 2010 during an intense drought, then recovering during 2011 thanks to record mountain snowfall, and now dropping again in the midst of a dry winter.
According to an article in the Las Vegas Review-Journal, water managers are forecasting the lake level to drop by about 13 feet due to the dry winter so far. As the newspaper reported:
"In December, the U.S. Bureau of Reclamation was predicting a roughly 11-foot rise in Lake Mead over the next year. Now the bureau expects the nation's largest man-made reservoir to shed about 13 feet by January 2013.
One acre-foot equals about 326,000 gallons, which is enough water to supply two average valley homes for one year. At current consumption levels, the 2.45 million acre-foot reduction in Lake Mead's forecast since last month represents enough water to supply the entire Las Vegas Valley for a decade."
During the past 11 years, a particularly dry and warm climate has lingered in Utah, Nevada, Arizona and Southern California, leading to reduced flow along the Colorado River. In fact, scientists have already shown that the stress on the water resources in the Southwest reg...
NASA released a new, high-resolution "Blue Marble" image of Earth this week, taken from instruments aboard the recently launched Suomi NPP satellite. The image is actually a composite of many pictures from Jan. 4, 2012 that were stitched together, and shows North America in stunning detail. One feature that is notably absent from the picture is snow cover, which is confined to parts of the Rocky Mountains and Sierra Nevada.
In many parts of the country, snowfall has been running well below average so far this year.
The image was taken by one of the five instruments aboard the NPP satellite, known as the Visible/Infrared Imager Radiometer Suite or VIIRS. According to an article in the LA Times, the image was put together by a NASA oceanographer named Norman Kuring, as a favor to a NASA scientist who asked for a visual image to use for a talk at a scientific conference.
The LA Times explained how the image was put together:
"VIIRS is not really a camera — rather it has a scanning telescope that measures the difference between the amount of light coming down to the surface of Earth from the sun as compared to the amount of light that is reflected back to the telescope. Kuring made the image above by running code that translates that data into an image.
"VIIRS only scans one swatch of Earth at a time, measuring about 1,900 miles across. Kuringer says you can think of it as if you were walking down the street with a broom and sweeping as you go...
If you're on the Left Coast and like snow, it may be time to rejoice. If you're on the East Coast, though, don't hold your breath.
The winter weather pattern is finally changing, steering long-awaited storms into California, Oregon, and Washington, while still failing to excite snow lovers along the East Coast. Aside from a light-to-moderate snow event on Saturday, the Washington-to-Boston corridor is likely to see milder than average conditions heading into early February, according to recently released long-range outlooks from the National Oceanic and Atmospheric Administration (NOAA).
Heavy rains and mountain snows, along with strong winds, are expected through the weekend and into next week in northern California, parts of Oregon, and Washington. The arrival of winter storms in California is good news, since the entire state has been experiencing much drier than average conditions. In some cases, higher elevations were running snowfall deficits of more than 150 inches.
The Western storms that struck earlier this week have eased the snow drought in Oregon and Washington. Mt. Hood, Ore., picked up 50 inches of snow during the course of this week, and Seattle saw a daily record of 6.8 inches on January 18, an inch more than the city sees in typical year.
Unfortunately for those in the West, though, they're making up for lost time too quickly, leading to serious problems.
In Seattle, freezing rain fell on top of the snow, contributing to power o...