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Posts Tagged ‘Polar Vortex’

Return Of The Polar Vortex: Coldest Of The Cold En Route To U.S.; Warmer In Alaska Than South Carolina

In Uncategorized on January 28, 2014 at 6:46 pm

Visualization of surface winds (lines and black arrows) and temperatures (shaded colors) on Monday morning, as the latest Arctic blast swept from the Midwest to the South and East.

Click image to enlarge. Credit: earth.nullschool.net.

 

Oldspeak: “While the lower 48 states freeze — every state in the contiguous U.S. is expected to see a low temperature at or below 32°F on Tuesday morning — this weather pattern also has a flipside, with unusually mild conditions affecting Alaska and the Western U.S. At 10 p.m. local time on Sunday, it was warmer in Homer, Alaska than anywhere in the contiguous U.S., except for Southern Florida and Southern California. The high temperature in Homer of 55°F broke their all-time monthly high temperature record…” -Andrew Freedman

“Sooooo its pushing 60 in some parts of the arctic, while its negative 40 in the Midwest of the U.S. Again. And expected to be so, through February…. While record heat bakes Australia. AGAIN.  Yeahhhhh, that’s normal. SMDH… We’re sooo fucked. :-O ” -OSJ

By Andrew Freedman @ Climate Central:

The polar vortex is back, and for many suffering through an already frigid winter, the Arctic air barreling into the lower 48 states may be the coldest of the cold yet.

Temperatures may plunge well below zero in the Upper Midwest, and could potentially last as long as three days in some areas. Cities such as Chicago, Minneapolis, and Madison are already enduring extreme cold, with two consecutive days of subzero high temperatures expected. In addition, a rare snow and ice storm is slated to develop along the Gulf Coast on Tuesday and Wednesday. Computer model projections show the potential for more than 6 inches of snow to fall in parts of the Southeast, particularly in Southeast South Carolina, Georgia, and North Carolina, areas that are not accustomed to such heavy snowfall and ice.

The frigid temperatures in the Central and Eastern U.S. come courtesy of a jet stream pattern that has kept the door to the Arctic, which is the Northern Hemisphere’s freezer, wide open, allowing dangerously cold air to repeatedly move southward into the lower 48 states in distinct waves.

As happened in early January, the now infamous polar vortex has something to do with the latest cold snap, with its southernmost extent clipping the northern tier of the U.S.

The persistence of the cold during January has set the month on course to be the second coldest winter month in the contiguous U.S. since December 2000, coming up about a degree shy of the monthly average temperature in January 2011, according to Ryan Maue of WeatherBell Analytics, a private weather forecasting firm.

 

Of course, blaming this all on the polar vortex isn’t entirely accurate. The true polar vortex exists at upper levels of the atmosphere, and what’s been causing January’s bitter cold — and soon to be February’s — is a result of the interaction between the vortex and events in the more chaotic lower atmosphere.

The polar vortex exists at the upper levels of the atmosphere at and above the typical cruising altitude of commercial jetliners, and is an area of frigid air and relatively low air pressure surrounded by a strong west-to-east jet stream that circles the Arctic during the winter.

When the upper level winds encircling the vortex are strong, the cold air tends to stay locked in the Arctic. But when those winds slow, as has occurred this winter, the polar vortex can wobble and split, with pockets of extremely cold air getting pinched off and shunted southward, into the U.S., Europe, and Asia. According to many computer models, this is likely to happen throughout much of February.

Visualization of wind speed and direction in the lower stratosphere, looking from the top of the Northern Hemisphere down. The polar vortex is highlighted within the black rectangle, with its circulation extending south above the U.S.
Click image to enlarge. Credit: earth.nullschool.net.

Ultimately, the distinction between the upper level vortex and its lower level reflections is of interest mainly to meteorologists, since most Americans are more concerned with staying warm than with looking up “polar vortex” in a textbook.

Charts of the middle of the troposphere, which is the layer of the atmosphere where most weather occurs, show that several areas of unusually cold temperatures are currently affecting the U.S. and parts of Europe and Asia, while an unusually mild region stretches from Alaska across the Arctic and extending into northern Siberia.

While the lower 48 states freeze — every state in the contiguous U.S. is expected to see a low temperature at or below 32°F on Tuesday morning — this weather pattern also has a flipside, with unusually mild conditions affecting Alaska and the Western U.S. At 10 p.m. local time on Sunday, it was warmer in Homer, Alaska than anywhere in the contiguous U.S., except for Southern Florida and Southern California. The high temperature in Homer of 55°F broke their all-time monthly high temperature record, according to Weather Underground.

On Jan. 27, the temperature in Nome, Alaska reached 51°F, which was not only the warmest temperature on record there for January, but was also the warmest temperature observed at that location between the dates of Oct. 17 and April 9, according to Weather Underground’s Chris Burt.

On Jan. 25, the headquarters of Denali National Park, Alaska, where Mt. McKinley is located, reached a high temperature of 51°F, which tied the record high temperature for the month of January, according to the National Weather Service.

In Nome, the temperature climbed to 45°F on Jan. 26, which was the second warmest January day there since recordkeeping began in 1907. Numerous daily high temperature marks and records for highest overnight low temperatures have also been set in Alaska, and computer model projections show continued unusual warmth is likely to affect the state for much of February.

Unusually mild conditions have also affected the Western U.S., as the jet stream has steered storms well north of the area into Canada, pumping warm air into the region from the southwest.

For example, Sacramento, Calif., reached 79°F on Jan. 25, breaking the high temperature mark there for the month of January. A monthly temperature record was also broken at Sacramento Executive Airport on the same day.

For the lower 48 states during the period from Dec. 28 to Jan. 26, 32 monthly high temperature records were set or tied along with 12 monthly records for highest overnight low temperature. That compares to 24 monthly records for coldest high temperature, and zero monthly records for the lowest overnight low temperature. There were, however, eight records set or tied for the coldest daytime high temperature.

This data suggests that the extreme cold in the Midwest and East, while noteworthy, may not be as unusual from a historical standpoint as the warmth in the West and Alaska.

Of course, for those in the path of this current Arctic outbreak, that’s of little consolation.

“More Like The Whole Enchilada”: Arctic Stratospheric Warming Event Pushes Entire Polar Vortex Down To Middle/Lower U.S.

In Uncategorized on January 7, 2014 at 8:17 pm

Oldspeak: “At the peak of the Arctic outbreak, temperatures may be between 20°F and 40°F below average in large parts of the continental U.S., with dangerous wind chills affecting cities like Minneapolis, Chicago, Cleveland, St. Louis, Washington, D.C., New York, and Boston. The U.S. will have the dubious distinction of experiencing the largest cold temperature anomalies of any land area in the Northern Hemisphere during the height of the biting cold… The cause of the Arctic outbreak can be traced to northeastern Canada and Greenland, where an area of high pressure and relatively mild temperatures is set to block the eastward progression of weather systems, like an offensive lineman protecting the quarterback from the other team…  The atmospheric blocking is forcing a section of the polar vortex to break off and move south, into the U.S. The polar vortex is an area of cold low pressure that typically circulates around the Arctic during the winter, spreading tentacles of cold southward into Europe, Asia, and North America at times. Except this time, it’s not a small section of the vortex, but what one forecaster, Ryan Maue of WeatherBELL Analytics, called “more like the whole enchiladaAndrew Freeman

More than half the US population is under a wind chill warning as a blast of freezing Arctic air sweeps south and east across the country, bringing the coldest temperatures for decadesThe US saw colder temperatures than Almaty, Kazakhstan, where it was -22C (8F), Mongolia at -23C (-8F) and Irkutsk, in Siberia, at -33C (-27F)… The National Weather Service has issued life-threatening wind chill warnings for temperatures as low as -51C (-60F) in western and central Dakota and officials in Indiana – hit by high winds and more than a foot (30cm) of snow – urged residents to stay indoors. –Duncan Barkes

“When America is colder than fucking Siberia, something is terribly, terribly wrong.  Entire weather patterns are being drastically altered on a regular basis. The temperature dropped 50 degrees in 3 HOURS yesterday in New York.  Last year the polar vortex, that’s always supposed to stay in or near the arctic, was cleaved in two and moved south as a result of arctic warming via loss of sea ice. This year, the whole fucking thing moved south in one direction at once. As the climate warms the irreversible feedback loops currently in progress will accelerate. Weather will become less and less predictable and more and more extreme. Meanwhile, at the same time record cold grips North America, record heat is wilting Australia. This is the new normal. The era of stable climate has passed.” -OSJ

Related Story

Polar Vortex: 187 Million Hit By Big Freeze

By James S @ Daily Kos:

If the planet is warming — how can it be so damn cold out there, in the winter?

Well the connections are complex, but they are not unfathomable (to science and physics literates.)
‘Polar vortex’ to blast frigid air over much of US

by Carson Walker, Associated Press; boston.com — Jan 3, 2014

SIOUX FALLS, S.D. (AP) — The weather warnings are dire: Life threatening wind chills. Historic cold outbreak.Winter is normally cold, but starting Sunday tundra-like temperatures are poised to deliver a rare and potentially dangerous sledgehammer blow to much of the Midwest, driving temperatures so far below zero that records will shatter.

One reason?  A “polar vortex,” as one meteorologist calls it, which will send cold air piled up at the North Pole down to the U.S., funneling it as far south as the Gulf Coast.
[…]

Here’s what our current mid-latitude Jet Stream looks likes:

Weather ModelGlobal Jet Stream Wind and 250 mb Pressure (animated loop)


larger

Notice how it has those big ‘loopy waves’  (aka high-amplitude Rossby Waves).  It is the big swoop southward that is ushering in the current frigid polar air.
Arctic Outbreak:  When the North Pole Came to Ohio

by Andrew Freedman, climatecentral.org — Jan 2, 2014

[…]
At the peak of the Arctic outbreak, temperatures may be between 20°F and 40°F below average in large parts of the continental U.S., with dangerous wind chills affecting cities like Minneapolis, Chicago, Cleveland, St. Louis, Washington, D.C., New York, and Boston. The U.S. will have the dubious distinction of experiencing the largest cold temperature anomalies of any land area in the Northern Hemisphere during the height of the biting cold.
[…]The cause of the Arctic outbreak can be traced to northeastern Canada and Greenland, where an area of high pressure and relatively mild temperatures is set to block the eastward progression of weather systems, like an offensive lineman protecting the quarterback from the other team.

The atmospheric blocking is forcing a section of the polar vortex to break off and move south, into the U.S. The polar vortex is an area of cold low pressure that typically circulates around the Arctic during the winter, spreading tentacles of cold southward into Europe, Asia, and North America at times. Except this time, it’s not a small section of the vortex, but what one forecaster, Ryan Maue of WeatherBELL Analytics, called “more like the whole enchilada” in a Twitter conversation on Thursday.
[…]

Computer model projection showing the location of the polar vortex (outlined in orange) and areas of below average temperatures (green and blue) and above average temperatures (orange and red), as indicated by the height of atmospheric pressure levels. The annotations show the cold temperature anomaly in the U.S. and mild anomalies across the Arctic. Credit: WeatherBELL Analytics.

The Arctic Vortex is supposed to stay in the Arctic.  It is supposed to form a tight circle, racing around the pole. It is not supposed to branch out and send frigid polar air to the temperate mid-latitudes.  At least not on a ‘regular basis’.

But then again, unusual stratospheric warming in the Arctic, is not supposed to be breaking that Polar Vortex up into smaller pieces, either.

Just because it’s out of sight, doesn’t mean it should be out of mind.

 

[Note:  most of what follows is analysis of last winter’s arctic events — which are looking remarkably similar to this winter’s arctic events.]


Who says all that record-breaking Arctic Ice Melt really doesn’t matter?

Certainly not well informed meteorologists, because they say it kind of does
Stratospheric Phenomenon Is Bringing Frigid Cold to U.S

by Andrew Freedman, climatecentral.org — Jan 21, 2013

[…]
Sudden stratospheric warming events take place in about half of all Northern Hemisphere winters, and they have been occurring with increasing frequency during the past decade, possibly related to the loss of Arctic sea ice due to global warming. Arctic sea ice declined to its smallest extent on record in September 2012.
[…]Sudden stratospheric warming events occur when large atmospheric waves, known as Rossby waves, extend beyond the troposphere where most weather occurs, and into the stratosphere. This vertical transport of energy can set a complex process into motion that leads to the breakdown of the high altitude cold low pressure area that typically spins above the North Pole during the winter, which is known as the polar vortex.

The polar vortex plays a major role in determining how much Arctic air spills southward toward the mid-latitudes. When there is a strong polar vortex, cold air tends to stay bottled up in the Arctic. However, when the vortex weakens or is disrupted, like a spinning top that suddenly starts wobbling, it can cause polar air masses to surge south, while the Arctic experiences milder-than-average temperatures.
[…]

Ok, what’s a Rossby Wave and how does global warming effect them?  (If you have a low threshold for watching videos, this is the best one of the bunch, imo.)
Jennifer Francis – Understanding the Jetstream (and Rossby Waves)

link to clip

Published on Feb 26, 2013 — by rustneversleeps3

A short review of how the jetstream and Rossby waves work, and some emerging indications that the dynamics may be changing in a warming world.

So, what’s a Polar Vortex, and what happens when it get displaced, by one of those unusually TALL bubbles of relatively warm atmosphere, surging northward?
Polar Vortex

link to clip

Published on Jan 18, 2013 — WTHI-TV
Here’s an meteorological map analysis of various Arctic Vortex splits, what causes them, and what they lead to (… record cold in the Mid-Latitudes).
Stratospheric Warming by The SI Weather

link to clip

Uploaded on Dec 16, 2011 — TheSIWeather
Here’s one meteorological speaker, who’s a bit eccentric, but does seem to have a good grasp on Stratospheric Warming events — going Polar, anyways.
Extreme Event  (Vortex Formation and Displacement)

link to clip

Published on Jan 18, 2013 — TurtleIslandNewsDaily.info

Sudden Stratospheric Warming Split the Polar Vortex in Two.the polar vortex was intact at 50 millibars(height in m) on January 1 to 3.

the polar vortex had broken in two (50millibar heights in m) on January 10 to 13

Finally, here’s a good old-fashioned science satellite composite (it’s a very short clip), that shows what happens when the Polar Vortex, gets nudged into going for ‘a power walk’.
GMAOGEOS-5 Stratospheric Sudden warming Event

link to clip

Published on Mar 4, 2013 —  Harold Saive

http://gmao.gsfc.nasa.gov/…http://gmao.gsfc.nasa.gov/…

And finally here’s an updated 2014 Winter forecast, once again ‘blaming that Polar Vortex’ for ‘deciding’ to go meandering somewhere — that we’d rather not see it go.
WRGX; wtvy.com — January 4, 2014

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Valid 12Z Sat Jan 04 2014 – 12Z Mon Jan 06 2014[…]
Forecast models remain consistent in carrying the polar vortex into the northern tier of the U.S. while carrying it eastward in time.

Many locations may see their temperature readings drop to near record values.
[…]

Incredibly, it may feel as cold as -50 to -60 on Sunday night over sections of the north-central states with the frigid air remaining in place into early next week.

As the vortex shifts eastward, the polar air will begin to affect the Great Lakes and Ohio Valley with temperatures plummeting rapidly.

While the air mass will modify, temperatures will remain downright cold with the forecast high in Chicago, IL being only -11 on Monday.

A strong frontal boundary surging eastward ahead of the polar air mass will become rather active as it intercepts increasing amounts of low-level moisture.
[…]

If only those record-melting Arctic ice packs would stay in place and not keep warming up their supposed-to-be Arctic neighborhoods by exposing all that open sea water — then maybe that Arctic Vortex might not have to ‘go wobbling around like a wildly spinning top — losing its fast-track momentum‘ … at such an ever increasing rate.

But then again, Who needs stable Jet Streams anyways?

Certainly not farmers, not foresters, not ranchers;  Certainly not suburban folks who hate all these crazy arctic deep freezes …  the ones who ask, “Why in the world, is it so damn cold, anyways?”

Now hopefully, you can tell them.