Deadly cold weather has spread across central and eastern Europe, and is expected to continue through the end of the week. At least 60 people have died from the bitter cold overnight temperatures, which reached as low as -20°C (-4°F) Monday night. The BBC is reporting that "more than 600 people have sought treatment for frostbite and hypothermia." Typically, the elderly and low-income population are hardest hit by extreme temperatures (cold or heat), and such is the case in Europe this week.
Alaska has also been in weather news, after a wave of extremely cold temperatures over the weekend (even for our northern-most state). This past Friday and Saturday nights were record-setting for Alaska, as Jeff writes in his blogs:
Friday night and Saturday night, temperatures plummeted to -50°F and -51°F in Fairbanks, marking the first time since 1999 the city had seen back-to-back minus fifty nights. The low temperature so far today at the Fairbanks International Airport has been -44°F, giving the city sixteen days of -40°F temperatures so far this month. Since 1906, there have only been three years (1906, 1934, and 1971) with more 40 below days during the month of January. At forty below zero, the air is so cold that the water vapor condenses out into ice crystals, which float in the air creating a low-visibility fog.
According to the Fairbanks weather office, here are the likely final rankings for January temperatures at select locations in Alaska during 2012:
Kotzebue: 2nd coldest
Barrow: not in top ten coldest
Fairbanks: 5th coldest (coldest since 1971)
Our Weather Historian Christopher C. Burt also wrote a blog
on the -79°F controversy from Jim River, Alaska.
In December, we were reporting
that the lower-48's unseasonably warm weather and lack of snow was due to a particularly positive Arctic Oscillation (AO) index. The Arctic Oscillation is a measure of the jet stream's strength. A positive AO is a stronger than average jet stream, and it tends to keep cold air bottled up in the Arctic. During a positive AO, the Arctic is colder than average, and the mid-latitudes are warmer than average. In December and early January, the AO was positive. In mid-January, the AO went negative (Figure 1), which we expect to have the opposite impact. A weak jet steam means cold, Arctic air can escape to the south, and that's what we've been seeing in Europe this week.Figure 1. The Arctic Oscillation index has been extremely positive for most of this winter, until it made a dramatic shift to negative in mid-January.Figure 2. The 8-14 day temperature forecast from NOAA's Climate Prediction Center. Blue is below-normal, orange/red is above normal.
So what does this mean for the rest of winter? Hard to say. To add another acronym to the mix, I introduce the Pacific/North American oscillation (PNA). The PNA, which is a measure of the strength of highs and lows over the Pacific Ocean and North America, also changed in mid-January from negative to positive. A positive PNA tends to favor winter-like weather in the South, Southeast, and Eastern United States. In terms of precipitation, it's a mixed bag. In a positive PNA, the Pacific Northwest sees above-average precipitation, but the Midwest tends to see below-average precipitation.
NOAA's Climate Prediction Center (Figure 2) is guessing that over the next few weeks, the Southeast will see below-average temperatures, and the Northwest, including Alaska, will see above-average. This is more of the same for most of the Western states, but Alaska will probably enjoy the reprieve. Whether the U.S. will see a big snow event before winter ends is still up in the air. It will probably get cold enough for a little while, but the question will be whether a moisture-rich storm comes along to take advantage of wintry temperatures that could appear in the east and southeast states.Mixed emotions on this year's Winter weather
As expected, there are mixed emotions about this year's Winter weather. Some love it, some hate it. Personally, I love a good snow storm. However, being in San Francisco, I know I'm not going to get that in any year.