When someone says that climate science shows that the
latest cold air outbreak was partly driven by climate change, people need to know what's wrong with that statement.
When someone says that the
latest cold air outbreak is evidence that global warming is false, people need to know what's wrong with that statement, too.
They can also explain more than half of the warming recorded over the Antarctic Peninsula, because «anomalously strong westerlies should act to decrease the incidence of
cold air outbreaks from the south and lead to increased warm advection from the Southern Ocean.»
Thus instead of a strong zonal wind that keeps cold polar air locked in the Arctic, there is a tendency for
more cold air outbreaks to middle latitudes.
Vavrus, S., J. Walsh, W. Chapman, and D. Portis, 2006: The behavior of extreme
cold air outbreaks under greenhouse warming.
During the cool season, the Ridge brought long stretches of cloudless days, which caused daytime temperatures during winter to be well above average (and, at the same time, the position of the ridge also prevented
major cold air outbreaks from occurring after December 2013).
A report from Climate Central's World Weather Attribution team analyzed the current
cold air outbreak for signs of a climate change signal, indicating:
Negative values indicates high pressure in the polar region and thus a tendency for weak zonal winds that
facilitate cold air outbreaks to middle latitudes.
In the negative phase of the AO, the polar vortex becomes disturbed, and
cold air outbreaks become more likely over the mid-latitudes, including the United States.
Such cold air outbreaks are, in fact, decreasing in intensity both in observations and climate models primarily because the source of the cold air, the Arctic, is warming strongly.
At times, some tentacles of it will slip southward and
bring cold air outbreaks into the U.S., but this year, we're seeing a huge chunk of it, most of it descending into the U.S.»
You can examine some of the extreme heat and
cold air outbreaks dating back to 2000, and can watch events unfold during the course of a month using the «Play Month» option.
So how the jet stream will change in the future, and how those changes will affect storminess or severe
winter cold air outbreaks, is far from simple.
In other words, take these
same cold air outbreaks and project them on the climate of the 1800s, and they'd be more severe.
The polar vortex can lead to
major cold air outbreaks in any portion of the Northern Hemisphere — North America, Europe and Asia.
Thus instead of a strong zonal wind that keeps cold polar air locked in the Arctic, there is a tendency for a less zonal flow and thus
more cold air outbreaks to middle latitudes.
There is likely to be a decline in the frequency
of cold air outbreaks (i.e., periods of extreme cold lasting from several days to over a week) in Northern Hemisphere] winter in most areas.
There are going to be shifts in storm tracks and the intensity of
the cold air outbreaks that you get in the winter.
Atmosphere - Ocean General Circulation Models are able to simulate extreme warm temperatures,
cold air outbreaks and frost days reasonably well.
The cold air outbreak of the next few days is nothing unusual, and neither inconsistent with an overall picture of a warming world, nor evidence that global warming is making cold weather more extreme.
A tornado is an extreme event, but one whose causes, sensitivity to change and impacts have nothing to do with those related to an ice storm, or a heat wave or
cold air outbreak or a drought.
If the putative Arctic magnification of global warming prevents
the cold air outbreaks from cooling the northward moving saline water, it may not cool enough to become convectively unstable.
When the NAO is in its negative phase, the low and high are weaker than normal, and
cold air outbreaks and snow are more likely in the eastern U.S..
There is likely to be a decline in the frequency of
cold air outbreaks (i.e., periods of extreme cold lasting from several days to over a week) in NH winter in most areas.
The US east coast experiences more
cold air outbreaks and hence snowy weather conditions.
The 1912 United States cold wave (also called 1912
cold air outbreak) remains one of the coldest winters yet to occur over the northern United States.