Hi Everybody!!
Winter is in full swing today (January 9, 2014)! Blowing in on the north wind is "Winter Weather" which varies in extremes in different years. Currently North America is in the grips of a Polar Vortex with strong effects. I am happy to see public weathercasts explaining weather systems more this year and issuing more warnings. For any of you not up to speed: Google Search and Wikipedia to the rescue with excerpts and links shared below in regard to "Winter Weather". Tonight's photostudy is of a cold winter day with blue skies (and my big birds!) Thanks to G+ Auto Backup, we have highlights of the albums. Enjoy!

Winter

From Wikipedia, the free encyclopedia

Winter (/ˈwɪntər/) is the coldest season of the year in temperate climates, between autumn and spring. It is caused by the axis of the Earth in the respective hemisphere being oriented away from the Sun. Different cultures define different dates as the start of winter, and some use a definition based on weather, but when it is winter in the Northern Hemisphere it is summer in the Southern Hemisphere, and vice versa. In many regions, winter is associated with snow and freezing temperatures. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.

Ecological reckoning and activity[edit]

The snowshoe hare is one animal that changes color in winter

Ecological reckoning of winter differs from calendar-based methods by avoiding the use of fixed dates. It is one of six seasons recognized by most ecologists who customarily use the term hibernal for this period of the year (the other ecological seasons being prevernal, vernal, estival, serotinal, and autumnal).^[15] The hibernal season coincides with the main period of biolological dormancy each year whose dates vary according to local and regional climates in temperate zones of the Earth. The appearance of flowering plants like the crocus can mark the change from ecological winter to the prevernal season as early as late January in mild temperate climates.

To survive the harshness of winter, many animals have developed different behavioral and morphological adaptations for overwintering:

Migration is a common effect of winter upon animals, notably birds. However, the majority of birds do not migrate—the cardinal and European Robin, for example. Somebutterflies also migrate seasonally.
Hibernation is a state of reduced metabolic activity during the winter. Some animals "sleep" during winter and only come out when the warm weather returns; e.g., gophers, frogs, snakes, and bats.
Some animals store food for the winter and live on it instead of hibernating completely. This is the case for squirrels, beavers, skunks, badgers, and raccoons.
Resistance is observed when an animal endures winter but changes in ways such as color and musculature. The color of the fur or plumage changes to white (in order to be confused with snow) and thus retains its cryptic coloration year-round. Examples are theRock Ptarmigan, arctic fox, weasel, white-tailed jackrabbit, and mountain hare.
Some fur-coated mammals grow a heavier coat during the winter; this improves the heat-retention qualities of the fur. The coat is then shed following the winter season to allow better cooling. The heavier coat in winter made it a favorite season for trappers, who sought more profitable skins.
Snow also affects the ways animals behave; many take advantage of the insulating properties of snow by burrowing in it. Mice and voles typically live under the snow layer.

Some annual plants never survive the winter. Other annual plants require winter cold to complete their life cycle, this is known as vernalization. As for perennials, many small ones profit from the insulating effects of snow by being buried in it. Larger plants, particularlydeciduous trees, usually let their upper part go dormant, but their roots are still protected by the snow layer. Few plants bloom in the winter, one exception being the flowering plum, which flowers in time for Chinese New Year. The process by which plants become acclimated to cold weather is called hardening.

Humans and winter[edit]

Humans evolved in tropical climates, and met cold weather as they migrated into Eurasia, although earlier populations certainly encountered Southern Hemisphere winters in Southern Africa. Micro-evolution in Caucasian, Asiatic and Inuit people show some adaptation to the climate.

(See link above for more info)

Fat Sissy wanted to roll us into the winter photostudy!

study 1
LINK TO PHOTOSTUDY IN G+ PHOTO ALBUMS:
https://plus.google.com/u/0/photos/117645114459863049265/albums/5960262394253885361

LINK TO PHOTOSTUDY IN G+ PHOTO ALBUMS:
https://plus.google.com/u/0/photos/117645114459863049265/albums/5960264111333848785

study 3

LINK TO PHOTOSTUDY IN G+ PHOTO ALBUMS:
https://plus.google.com/u/0/photos/117645114459863049265/albums/5960265848515626353

http://en.wikipedia.org/wiki/Polar_vortex

Polar vortex

From Wikipedia, the free encyclopedia

A polar vortex (also known as a polar cyclone, polar low, or a circumpolar whirl^[1] ) is a persistent, large-scale cyclone located near either of a planet's geographical poles. On Earth, the polar vortices are located in the middle and upper troposphere and thestratosphere. They surround the polar highs and lie in the wake of the polar front. Thesecold-core low-pressure areas strengthen in the winter and weaken in the summer due to their reliance upon the temperature differential between the equator and the poles.^[2] They usually span less than 1,000 kilometers (620 miles) in which the air is circulating in a counter-clockwise fashion (in the Northern Hemisphere). As with other cyclones, their rotation is caused by the Coriolis effect.

The Arctic vortex in the Northern Hemisphere has two centers, one near Baffin Island and the other over northeast Siberia.^[1] In the southern hemisphere, it tends to be located near the edge of the Ross ice shelf near 160 west longitude.^[3] When the polar vortex is strong, the Westerlies increase in strength. When the polar cyclone is weak, the general flow pattern across mid-latitudes buckles and significant cold outbreaks occur.^[4] Ozone depletion occurs within the polar vortex, particularly over the Southern Hemisphere, which reaches a maximum in the spring.

Polar vortex over Quebec and Maine on the morning of January 21, 1985

History[edit]

The polar vortex was first described as early as 1853.^[5] The phenomenon sudden stratospheric warming (SSW) appears during the wintertime in the Northern Hemisphere and was discovered 1952 with radiosonde observations at altitudes higher than 20 km.^[6]

Identification[edit]

Polar cyclones are climatological features that hover near the poles year-round. Since polar vortices exist from the stratosphere downward into the mid-troposphere,^[1] a variety of heights/pressure levels within the atmosphere can be checked for its existence. Within the stratosphere, strategies such as the use of the 4 mb pressure surface, which correlates to the 1200K isentropic surface, located midway up the stratosphere, is used to create climatologies of the feature.^[7] Due to model data unreliability, other techniques use the 50 mb pressure surface to identify its stratospheric location.^[8] At the level of the tropopause, the extent of closed contours of potential temperature can be used to determine its strength. The horizontal scale of the vortex is frequently less than 1,000 kilometres (620 mi).^[9]

Duration and power[edit]

This section requires expansion. (June 2013)

Polar vortex and weather impacts due to stratospheric warming

Polar vortices are weaker during summer and strongest during winter. Individual vortices can persist for more than a month.^[9] Extratropical cyclones that occlude and migrate into higher latitudes create cold-core lows within the polar vortex.^[10] Volcanic eruptions in thetropics lead to a stronger polar vortex during the winter for as long as two years afterwards.^[11] The strength and position of the cyclone shapes the flow pattern across the hemisphere of its influence. An index which is used in the northern hemisphere to gauge its magnitude is the Arctic oscillation.^[12]

The Arctic vortex is elongated in shape, with two centers, one normally located over Baffin Island in Canada and the other over northeast Siberia. In rare events, when the general flow pattern is amplified (or meridional), the vortex can push farther south as a result of axis interruption, such as during the Winter 1985 Arctic outbreak.^[13] The Antarctic polar vortex is more pronounced and persistent than the Arctic one; this is because the distribution of land masses at high latitudes in the Northern Hemisphere gives rise to Rossby waves which contribute to the breakdown of the vortex, whereas in the Southern Hemisphere the vortex remains less disturbed. The breakdown of the polar vortex is an extreme event known as a sudden stratospheric warming, here the vortex completely breaks down and an associated warming of 30–50 °C (86–122 °F) over a few days can occur.

Sudden stratospheric warming events, when temperatures within the stratosphere warm dramatically over a short time, are associated with weaker polar vortices. These changes aloft force changes below in the troposphere. Strengthening storm systems within the troposphere can act to intensify the polar vortex by significantly cooling the poles. La Niña-related climate anomalies tend to favor significant strengthening of the polar vortex.^[14]

Climate change[edit]

Meanders of the northern hemisphere's jet stream developing (a, b) and finally detaching a "drop" of cold air (c); orange: warmer masses of air; pink: jet stream

A study in 2001 found that stratospheric circulation can have anomalous effects on the weather regimes.^[15] In the same year researchers found a statistical correlation between weak polar vortex and outbreaks of severe cold in the Northern Hemisphere.^[16]^[17] In more recent years scientists identified interactions with Arctic sea ice decline, reduced snow cover, evapotranspiration patterns,NAO anomalies or weather anomalies which are linked to the polar vortex and jet streamconfiguration.^[15]^[17]^[18]^[19]^[20]^[21]^[22]^[23] However, because the specific observations are considered short-term observations (since ~13 years) there is considerable uncertainty in the conclusions. Climatology observations require several decades to distinguish natural variability from climate trends.

The general assumption is that reduced snow cover and sea ice reflect less sunlight and therefore evaporation and transpiration increases, which in turn alters the pressure and temperature gradient of the polar vortex, causing it to weaken or collapse. This becomes apparent when the jet stream amplitude increases (meanders) over the northern hemisphere, causing Rossby waves to propagate farther to the south or north, which in turn transports warmer air to the north pole and polar air into lower latitudes. The jet stream amplitude increases with a weaker polar vortex, hence increases the chance for weather systems to become blocked. A recent blocking event emerged when a high-pressure over Greenland steered Hurricane Sandy into the northern Mid-Atlantic states.^[24]

Ozone depletion[edit]

Southern Hemisphere Ozone Concentration, February 22, 2012

The chemistry of the Antarctic polar vortex has created severe ozone depletion. The nitric acid in polar stratospheric clouds reacts with chlorofluorocarbons to form chlorine, whichcatalyzes the photochemical destruction of ozone.^[25] Chlorine concentrations build up during the polar winter, and the consequent ozone destruction is greatest when the sunlight returns in spring.^[26] These clouds can only form at temperatures below about −80 °C (−112 °F). Since there is greater air exchange between the Arctic and the mid-latitudes, ozone depletion at the north pole is much less severe than at the south.^[27]Accordingly, the seasonal reduction of ozone levels over the Arctic is usually characterized as an "ozone dent", whereas the more severe ozone depletion over the Antarctic is considered an "ozone hole". This said, chemical ozone destruction in the 2011 Arctic polar vortex attained, for the first time, a level clearly identifiable as an Arctic "ozone hole".^{[citation needed]}

study 4

LINK TO PHOTOSTUDY IN G+ PHOTO ALBUMS:
https://plus.google.com/u/0/photos/117645114459863049265/albums/5960267216351801953

Check out the following link and excerpt from NOAA. Another tool to help you with your winter planning, (join on Social Media):
http://www.noaanews.noaa.gov/stories2013/20131121_winteroutlook.html

NOAA- National Ocean and Atmospheric Administration

Drought likely to persist or develop in the Southwest, Southeastern U.S. this winter

No strong climate pattern influence anticipated through upcoming winter season

November 21, 2013

Download here. (Credit: NOAA)

Winter is likely to offer little relief to the drought-stricken U.S. Southwest, and drought is likely to develop across parts of the Southeast as below-average precipitation is favored in these areas of the country, according to NOAA’s annual Winter Outlook announced today.

Drought has been an ongoing concern across parts of the Southwest and Texas for nearly three years, and after some relief during the past few months, drought is likely to redevelop during winter.

Sea surface temperatures across the equatorial Pacific have been near average since spring 2012, and forecasters expect that to continue through the winter. This means that neither El Niño nor La Niña is expected to influence the climate during the upcoming winter.

“It’s a challenge to produce a long-term winter forecast without the climate pattern of an El Niño or a La Niña in place out in the Pacific because those climate patterns often strongly influence winter temperature and precipitation here in the United States,” said Mike Halpert, acting director of NOAA’s Climate Prediction Center. “Without this strong seasonal influence, winter weather is often affected by short-term climate patterns, such as the Arctic Oscillation, that are not predictable beyond a week or two. So it’s important to pay attention to your local daily weather forecast throughout the winter.”

Download here. (Credit: NOAA)

The Precipitation Outlook favors:

Below-average precipitation in the Southwest, Southeast and the Alaskan panhandle.
Above-average precipitation in the Northern Rockies, particularly over Montana and northern Wyoming and in Hawaii.

The Temperature Outlook favors:

Below-average temperatures in the Northern Plains and the Alaskan Panhandle.
Above-average temperatures in the Southwest, the South-Central U.S., parts of the Southeast, New England and western Alaska.

The rest of the country falls into the “equal chance” category, meaning that there is not a strong or reliable enough climate signal in these areas to favor one category over the others, so they have an equal chance for above-, near-, or below-normal temperatures and/or precipitation.

The Climate Prediction Center produces the U.S. Winter Outlook to give American communities the best possible scientific prediction of how the winter may shape up across the nation. This outlook supports local and state governments in their effort to plan for public needs during the winter, and large and small businesses as they plan for winter impacts on things like transportation, market demand for goods and services, and finances. Building a Weather-Ready Nation is a collective effort to improve America’s resilience to extreme weather and climate by empowering the public to make fast, smart and life-saving decisions.

This seasonal outlook does not project where and when snowstorms may hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon the strength and track of winter storms, which are generally not predictable more than a week in advance.

NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter, Instagram and our other social media channels.