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Another Global Warming Enhanced Heatwave is on the Way — 111 Degree (F) Temperatures Predicted For Central US

It was in the 80s along Alaska’s Arctic Ocean shores yesterday. Record hot temperatures for a far northern region facilitated by factors related to human caused climate change such as warming ocean surfaces, sea ice melt, and an increasingly wavy Jet Stream.

North Slope Temperatures

(Record hot temperatures in the lower to middle 80s F [26 to 28 C] spread into the North Slope region of Alaska along the shores of the Arctic Ocean yesterday. And according to Dr. Jeff Masters, the 66 F [19 C] reading at Barrow tied its all time record high. Image source: Brett Brettschneider.)

But extreme heat along the northern reaches of Alaska appears now to be ready to morph into another record heatwave for the lower 48. For the past two weeks, weather models have been consistently predicting severe heat for the Central US. And with each passing day, as the forecasts grow evermore certain, the development of yet one more period of record hot temperatures becomes more and more likely.

An extremely tall dome of hot and heavy air is expected to build up over Colorado, Oklahoma and Nebraska. Heat beneath the dome and near the surface is expected to intensify. By the middle of next week, temperatures over a continuous large swath from Northern Texas to Montana and the Dakotas is predicted to experience near or above 100 degree F (38 C) temperatures. By late week, some of these readings could peak at around 111 degrees Fahrenheit (44 C) for parts of Central Nebraska.

111 degree temperatures Central US

(Saturday, July 24 GFS model forecast shows severe heat settling over the Central US. It’s the kind of heatwave that is now more and more likely to occur due to human-forced climate change. Image source: Pivotal Weather.)

These temperatures are expected to range 18-25 F (10-14 C) or more above typical July averages. And if temperatures do hit so high, they will likely make a number of new record highs for this region of the US.

By Sunday, the heat is expected to sprawl both east and west. And high temperatures near or above the Century mark could ultimately stretch in a great triangle from Alabama west to the Central Valley of California and north to Montana’s Canadian Border.

Conditions in Context — Human-Caused Global Warming, Hot Ocean Surfaces

This extreme heat comes in the context of record hot global temperatures. During 2016, global surface temperatures are likely to range near 1.2 degrees Celsius above the late 19th Century average. These record temperatures have been spurred by greenhouse gasses spiking to levels not seen in millions of years. CO2 concentrations this year hit near 408 parts per million at the Mauna Loa Observatory — a level high enough to significantly further increase global temperatures, melt large glaciers, substantially raise sea levels, and prevent another ice age for thousands or tens of thousands of years. And continued burning of fossil fuels by human beings will likely push that number near or above 410 parts per million by May of 2017.

image

(A North America surrounded by sea surface temperatures in the range of 1-5 C above average is one that is more susceptible to extreme heat, heavy downpours, and drought. Image source: Earth Nullschool.)

Closer to home, very warm sea surface temperatures surrounding the US are likely also aiding in the formation of the predicted heatwave. Hotter oceans surrounding continents can increase the prevalence of heat waves and droughts. And, in this case, 1-5 C above average sea surface temperatures encompass most of North America. In fact, the extent and extreme range of sea surface temperatures — which in the past have rarely exceeded 2 C above average — is notably pretty extraordinary.

These conditions, overall, are less and less impacted by El Nino which has now mostly faded in the Eastern Pacific. As ENSO neutral status now prevails, most temperature extremes are far more related to human-forced warming than El Nino. And, in any case, there’s practically zero chance than any given El Nino year would have resulted in global average temperatures hitting 1.2 C above 19th Century averages without the added heat forcing provided by human greenhouse gas emissions. So the truth of the matter is that the record heat we’re seeing is in greatest part the result of human-forced climate change.

Links:

Two Flavors of Record Heat: Dead Horse and Houston

Pivotal Weather

Earth Nullschool

NOAA El Nino

Brett Brettschneider

NASA GISS

Hat tip to Colorado Bob

Hat tip to DT Lange

Hat tip to Cate

Hat tip to Greg

 

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Arctic ‘Heat Wave’ to Rip Polar Vortex in Half, Shatter Alaska’s All-Time Record High for January?

62 Degrees Fahrenheit. That’s the all time record high for anywhere in the state of Alaska for the month of January. 57 Degrees Fahrenheit. That’s the temperature measured earlier this week in southern Alaska.

And forecasts call for warmer weather from Friday through Monday…

Across Alaska, temperatures are as much a 30 degrees above average for this time of year. This record winter warmth has pushed Alaska’s average temperature, according to reports from Anchorage, to 24 degrees Fahrenheit. By comparison, the lower 48, hundreds of miles to the south, is experiencing average temperatures of 22 degrees Fahrenheit. Though 24 degrees is not typically seen as a heat wave, readings in the upper 50s and lower 60s for Alaska in January may as well be. If these same temperature extremes were occurring during summer, some parts of Alaska would be experiencing a 90+ degree scorcher.

Mangled Jet Stream, Anomalous 10 Month Blocking Pattern to Blame

What we are witnessing is what amounts to a ten month long warm air invasion of the Arctic, with Alaska at ground zero. Human-caused global warming has resulted in an amplification of polar temperatures well above the typical average. Now the region is experiencing readings that range of 15-30 degrees warmer than normal.

This massive temperature increase (also associated with a reduction of land and sea ice) is causing a weakening in the polar Jet Stream which is allowing more warm air to invade the Arctic from the south. Early last spring, a weakness in the Jet resulted in a powerful and extraordinarily persistent blocking pattern forming over Alaska. Warm air flooded continuously up and over Alaska, occasionally penetrating deep into the Arctic Ocean region. Heat wave after heat wave impacted Alaska, which set numerous all-time record high temperatures during the summer of 2013.

This anomalous heat flooded in and spilled out around the Arctic Circle, disgorging so much hot air that the term ‘Arctic Heat Wave’ became common parlance. Now, this historic and extraordinary pattern has continued for 1o months running. A kind of persistence that may well give new meaning to the term blocking pattern.

south to north weather pattern Alaska

(Image source: NASA)

The wave pattern stretches so high into the upper latitudes that what we are seeing is weather systems more often rise up from the south and travel northward over Alaska and into the Arctic, than proceed in their typical east-west progression.
The west-east weather train is broken. And a strange south-north train from equator to Arctic is instead set in place.

In the above image sequence, provided by NASA, the heat and associated moisture flow all the way from the equatorial region near Hawaii, up over thousands of miles of Pacific Ocean waters before flooding on through Alaska and into the high Arctic. The extraordinarily powerful and persistent blocking pattern has linked the deep tropics to the high Arctic in unprecedented and anomalous fashion. Especially when one considers that the current pattern has lasted for almost an entire year.

This it the kind of extreme weather pattern that Dr. Jennifer Francis warned about. The kind of pattern Dr. Jeff Masters continues to point out in his cutting edge blog — Weather Underground. In my view, we ignore Dr. Francis and Dr. Masters at our risk. Their observations hold true to what is happening now and they are very useful tools for predicting the weather of a world in which human global warming has now become the primary driver of the world’s climate. Without the actual and ongoing context that is human warming, the few meteorologists still associated with climate change deniers scramble to find the increasingly rare analogs in past climate that match today’s extreme weather. But there is no analog to warmest ever temperatures in Alaska and polar temperatures that are now hotter than they were at any time over at least the past 44,000 years. And there is certainly no analog to CO2 levels higher than they’ve been at any time during the past 4.5 million years.

For this is the disrupted Jet Stream pattern not only directly responsible for the anomalous Arctic heat Alaska is now experiencing. It is also the cause of colder air being driven out of the Arctic and southward over the US, causing multiple cold snaps and extreme winter weather events in the lower 48. For the warm air influx, both at the surface and at the upper levels of the atmosphere, result in multiple polar vortex collapse events.

Polar Vortex to be Ripped in Half

And we are in the midst of just such a polar vortex collapse now. Over the past week, warmer air has flooded the high Arctic, weakening the polar vortex as the center of cold air began to split and streamed down over the continents. By Monday, these warm wedges of air, driving up over both Svalbard in the east and Alaska in the west, will have completely separated the polar vortex into two disassociated cold centers.

In essence, the polar vortex will have been ripped in half by a pincer style warm air invasion from the south. Who knew that atmospheric warming would come to mimic the battlefield tactics of Germans rumbling over the fields of France during World War II? But here we are:

Polar Vortex Ripped in Half

(Image source: University of Washington)

In the above image, we can plainly see the much warmer than normal air wedge driving up from the south and over Alaska in association with the now, ten month old, blocking pattern and related Rossby wave feature over the Pacific and North America. A second, albeit weaker, wedge drives in over Europe and across Svalbard. The net result is a ‘pincer’ of warm air invading the Arctic and cutting the polar vortex in half.

Note that one cold air vortex is predicted to be centered over Eastern Canada near Hudson Bay (Monday). The other is shown to be driven south to Russian Kamchatka near the Sea of Okhotsk. Perhaps coincidentally, this cold air core is very close to the Amur region of Russia and China that experienced a 150 year flood event just this summer. A flood event also associated with anomalous Jet Stream patterns linking polar, temperate, ocean and monsoonal storm patterns (see Song of Flood and Fire and Requiem for Flooded Cities).

Under this pattern the Arctic and especially Alaska will continue to experience record or near-record warmth, while the lower 48 continues to suffer the repeated blows of extreme winter weather as the conditions that are supposed to be affecting the Polar region are instead mercilessly driven southward by a human caused warming and polar vortex collapse event.

Links:

Jet Stream Flip Flop: Alaska is Warmer than Lower 48 Again

Sea Ice Loss Locks Jet Stream into Severe Winter Storm Pattern for Much of US

The Arctic Heatwave: Greenland, Siberia, Alaska Heat Domes and a Mangled Jet Stream

From Archangel to Alaska, Heat Waves Now Flank the Central Arctic

NASA

Dr. Jennifer Francis, Top Climatologists, Explain how Global Warming Wrecks the Jet Stream and Amps up the Hydrological Cycle to Produce Extreme Weather

Weather Underground

Arctic Temperatures Now Hottest Seen in at Least 44,000 Years

Cold Snap for the US? It’s the Collapsing Polar Vortex, Stupid.

University of Washington

A Song of Flood and Fire

A Requiem for Flooded Cities

Hat tip to Colorado Bob

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