A Halo of Storms and Heatwaves — New Study Confirms that Global Warming is Wrecking the Northern Hemisphere Jet Stream

“We came as close as one can to demonstrating a direct link between climate change and a large family of extreme recent weather events.”Michael Mann

*****

The Earth is warming, the weather is growing more extreme, and from the observational perspective, it appears that the Northern Hemisphere Jet Stream has undergone some seriously disturbing changes. Over the past five years, this subject has been one that’s spurred heated debate among scientists, meteorologists, and global climate and weather watchers. Now, a new model study finds that it’s likely that the Jet Stream is being significantly altered by human-forced climate change and that this alteration is helping to drive extreme weather events like the 2003 European heat wave, the 2010 Pakistan flood and Russian heat wave, the 2011 Texas heat wave and recent floods in Europe.

(More extreme variation in upper level wind speeds is an upshot of polar warming during boreal summer. The result is that risks of severe heatwaves, droughts, wildfires and floods increases as the Earth warms. Image source: Michael Mann, Penn State.)

From the study:

… our analysis of both historical model simulations and observational surface temperature data, strongly suggests that anthropogenic warming is impacting the zonal mean temperature profile in a manner conducive to wave resonance and a consequent increase in persistent weather extremes in the boreal summer.

What this means is that the new study provides still more evidence that the Jet Stream’s north to south variance is increasing during summer. As a result, it is enabling powerful heat domes to form in regions where winds run from south to north. In regions where the upper level winds run from north to south, it creates cooler zones in which powerful storms can flood large swaths of countryside. In other words, increasingly juxtapposed zones of extreme temperature anomalies and higher atmospheric instability and moisture loading tend to form more and more often. And this results in weather patterns that we have never really seen before.

(An Inconvenient Sequel is a call for action on climate change like we’ve never seen before. And the imperative to act on climate is now stronger than it ever was.)

The fact that the Mann study uses observational and model assessments to find that such changes are likely to very likely now being caused by human-forced warming and related polar amplification is a highly significant scientific finding. It adds one more attribution tie to the extreme weather events that we’ve been seeing with increasing frequency. A tie directly to global warming. And it does so through model studies that identify the underlying physical mechanisms at work. It’s a pivotal moment in the atmospheric sciences. And everyone needs to sit up and pay attention.

Credits: 

Hat tip to Colorado Bob

Hat tip to Cate

Scientific hat tip to Dr Michael Mann

(Please support publicly-funded, non-special interest based science that is now under assault by the climate change denying Trump Administration)

Monsoon At Dead Halt: Chances For Summer El Nino Jump to 70% as India Swelters

mon-prog

Current advance of the Indian Monsoon indicated by the green line vs typical historic advance indicated by the dashed red line. Image source: India Meteorological Department.

The Indian Monsoon arrived in Sri Lanka on June 2nd, 8 days late, with extreme force. Dumping excessive rainfall even for a typically powerful event, it forced 2,500 to flee and resulted in the loss of 22 souls. There it stalled, battening into a Bay of Bengal moisture flow that hasn’t budged since May 23rd.

*   *   *   *

By today, June 5th, powerful storms should be dumping rain over a wide swath including the entire southern tip of India, almost all of the waters between Myanmar and the Tamil Nadu and Andhra Pradesh coasts, and over most of Bangladesh. But in the satellite shot only scattered storms are visible where powerful, wall-to-wall squalls should now cover an impressive swath.

By this time last year, more than a third of India was obscured by cloud. Today, the skies of this nation of 1.25 billion people are ominously clear. The steely-gray aerial tint of coal ash smog is the most impressive feature in an otherwise open expanse from the northwest deserts to the southeast coast. A massive zone showing only sparse hint or hope of rain.

Even Sri Lanka seems mostly cloud-free. The monsoon and, more importantly, the crop-essential rains it brings are walled out, pushed into the margins by El Nino and some of the hottest global temperatures on record.

India monsoon stalled

Blazingly clear skies laced with ominous coal ash over India during a time when monsoonal storms usually advance. Image source: LANCE-MODIS.

Forecasts indicate that some of the long-delayed rain could arrive to the coast by tomorrow through Sunday. Sparse comfort to sweltering interior sections that may not now see the cooling monsoon until after July 1st.

Unrelenting Heat Risks Late Switch to Violent Storms

In the north, the heat and drought just builds and builds. Jaipur recorded its highest temperature in 33 years on Thursday at a scorching 46.3 degrees Celsius (115.3 F). Meanwhile, New Delhi hit a new record high for the day of 45 C (113 F). Forecasts for New Delhi on Saturday and Sunday show the potential for even more extreme heat with temperatures projected to climb to 116 F. Over the coming ten days, the coolest is expected to be Friday of next week at 109 F.

The continued delay of monsoonal rain combines with record heat throughout northern and western sections of India to enhance risks of drought and loss to crops. Heatwave conditions have already reduced Lychee fruit crop yields by 40%. But an extended stalling of the monsoon and ongoing heat could result in increased damage.

Atmospheric thickening that comes with such extreme heat can also spur intense rain and hail events causing another kind of damage to crops. So a flash switch from heat to heavy storms like those seen earlier this week in Sri Lanka may not be so much of a boon as a terrible jolt to affected lands.

Moderate to Strong El Nino Ever More Likely

This year’s monsoonal delay and related extreme weather were likely amplified by a combination of record atmospheric heat due to human-caused greenhouse gas forcing and a growing and strengthening El Nino. In April, global atmospheric temperatures hit new record highs of +.91 C above 1880s values even as El Nino rapidly gained ground in the Pacific through May.

Multivariate ESNO Index values catapulted to +0.93 in May hitting the seventh highest values on record for the month and pushing the current El Nino into Moderate-Strong range for this time of year. During previous years, similar high values resulted in strong El Ninos on 3 of 5 occasions in the climate record. So historical indicators point toward a 60% chance of a strong event emerging by later this year.

From to NOAA’s El Nino Discussion Page:

The long anticipated breakthrough to El Niño conditions in 2014 is clearly under way, leading to the next question of how big it will get. Of the 10 nearest-ranked April-May values, five had clearly come up to this level over the previous three months. Among those five, four continued at El Niño levels through the rest of the year, while one (1993) dropped back to borderline neutral conditions by the end of the year. One (2002) ended up as a weak-to-moderate event, while the other three (1957, 1987, and 1997) are classified as strong El Niño events in the MEI sense. In other words, the simple-minded odds for El Niño remain at or above 80% through the remainder of 2014, and are consistent with previous discussions on this website. The odds for a strong El Niño are perhaps slightly higher than before, somewhere around 60%.

Meanwhile, the official NOAA forecast is more cautious, with model interpretations pointing to a higher likelihood for a moderate El Nino during 2014.

Consensus El Nino Forecast

El Nino probability graph. Image source: CPC.

Overall, chances for evolution to full-blown El Nino rose significantly with today’s forecast now showing a 70% chance for El Nino development by this summer and nearly an 85% chance for El Nino development by Fall-Winter.

Regardless of El Nino strength, such an event is likely to have broad-ranging global impacts in the context of human-caused warming.

India’s Heightening El Nino + Climate Change Threat to Crops

For India, history shows numerous cases of severe monsoonal disruption during strong, moderate, and, recently, even weak El Nino events. In addition, record high atmospheric temperatures enhance extreme drought and flood potentials by amping up the hydrological cycle and thus increasing the rate of both evaporation and precipitation. Storms, where they do occur tend to be both tall and abnormally powerful under current human-warming related stresses even as droughts tend to develop with higher velocity and to persist for longer periods.

It is possible, due to both changes to the hydrological cycle and to atmospheric circulation, that the Indian monsoon has become even more sensitive to the El Nino pattern under current human-caused warming. This year’s monsoonal delay with El Nino just emerging shows an almost instant response to the forcing coming from increased temperatures in the Equatorial Pacific. As such, conditions of heightening threat for crop damage throughout a land where 1.25 billion people rely on the annual rains is a critical issue.

nepac_anomaly_ophi0

(Extraordinary sea surface temperature anomalies in the Northeast Pacific including numerous pools of +2.25 to +4 C or higher departures are indicative of both a strengthening El Nino pattern and a general warming of Ocean surface waters through human greenhouse gas heat forcing. Image source: NOAA Environmental Modeling.)

Overall, the forecast remains for continued monsoonal delay and disruption, continued heatwaves and a likelihood for extreme rainfall and storms in the regions where the monsoon finally arrives. With El Nino conditions in place over the Pacific now, with atmospheric temperatures rising into record range, and with an official El Nino status likely to be declared by summer, this forecast is lent yet more certainty and urgency.

Links:

India Meteorological Department

LANCE-MODIS

NOAA’s El Nino Discussion Page

CPC

North India Reels Under Heatwave

Monsoon Delayed Across India, Deadly Flooding in Sri Lanka

Weather Underground Ten Day Forecast for New Delhi

(Hat Tip to Timothy Chase)

 

May Likely to Break Global High Temperature Record as El Nino Conditions Strengthen in Pacific

The human warming-riled monster weather event that is El Nino continued to advance over the Equatorial Pacific this week. Ocean surface temperatures throughout the basin from north and east of New Guinea and along a broad stretch of thousands of miles of ocean climbed. Sporadic west winds and an overall weakness in the trades extended the expansion of warm surface waters along the serpentine back of the El Nino pattern from west-to-east even as a high heat content Kelvin Wave kept conditions below surface much warmer than normal.

sstaanim

(Pacific Ocean sea surface temperature anomalies from 2 April to 28 May. Animation source: NOAA)

Large and growing regions of 1 to 2 C warmer than normal surface temperatures expanded in broad, 1,000 + mile stretches near the date line and ranged out from the west coast of South America. An impressive region of, very hot, 2-3 C positive anomalies grew through an ever-larger span from Santa Cruz Island to coastal Ecuador and Peru. Though the above graphic is not granular enough to catch it, daily anomalies in this hot pool exceeded extremely intense +3.5 to +4 C readings.

Readings in the range of +0.5 to +1 C invaded regions north to south, east to west, joining in an extraordinary zone stretching from the Philippines to South America, and from Baja to Hawaii to the Solomon Islands. A separate pool of very hot water north of New Guinea and near the Philippines is likely to play a further role in El Nino development throughout this year should weak trades and anomalous west winds persist. Then, a second and reinforcing pulse of warm water is predicted to push the entire Equatorial Pacific Basin well above a +1 C positive anomaly by late Summer through Fall.

Weekly Anomalies

(Sea surface temperature anomalies in the four key Nino regions all show continued warming through the end of May. Image source: NOAA.)

The tightening grip of El Nino is plainly visible with each of the four key Nino zones showing ongoing temperature increases in what is now a 3-4 month long event. Meanwhile, the key Nino 3.4 zone closed its 4th straight period above the +0.5 C Nino threshold even as it jumped to +0.6 C above average this week. Notably, the Nino 1+2 zone off South America hit a very warm +1.6 C average positive anomaly this week, showing additional warming from strong late April values.

Together, these values all show very solid continued progress toward El Nino.

image

(Map of geographical Niño zones provided by NOAA.)

Conditions in Context: May 2014 Likely Hottest on Record Amidst Ongoing Extreme Weather

Overall, Equatorial Pacific ocean surface temperatures continued their advancement from May 27 to June 2, rising from +0.59 to +0.68 C above the 1979 to 2000 average throughout the week. Global sea surface temperatures have remained in an exceptionally hot and likely global record range between +1 and +1.25 C above 1979 to 2000 averages throughout the month of May and into early June. These extraordinary readings likely combined with very high atmospheric values to put May of 2014 in the range of hottest on record. It is worth noting that, according to NOAA, April of 2014 was also the hottest in the 134 years since global temperature measurements began.

El Nino tends to spike atmospheric heat and, when combined with a brutal human greenhouse gas forcing, greatly increases the likelihood that a given year will reach new global heat extremes.

For 2014, El Nino and global warming related weather disruptions already appear to be taking hold with the Indian Monsoon appearing weak and delayed, a summer heat dome building over Europe and Western Russia, with Southeast China experiencing record floods even as northern and western China and Japan experience record heat. Ongoing droughts and crop disruptions in Brazil, building heat and drought in Indonesia, and Australia experiencing two back to back hottest years on record is also indicative of the screaming global heating that typically comes when El Nino gives human-caused warming an explosive boost.

Links:

NOAA

Indian Monsoon Disrupted

Monsoon Misses Date With India, Onset Delayed

Monster El Nino Emerging From the Depths

 

Drought, Burning Rings of Fire out West, Severe Flooding in the East: How Climate Change and a Mangled Jet Stream Wrecked US Weather

Earlier this summer, I had a weather conversation with my mother. She was excited about a new business venture my sister had undertaken (Adventure Kayaks) and for an upcoming trip to Yosemite in August to celebrate her and my father’s 45th wedding anniversary. She wondered about the weather, hoping it would be a good summer for both the new business and the trip. Without thinking too much, I said:

‘Rain, cooler weather, and storms in the east, drought, heat and fires in the west.’

Immediately after saying this, I felt reticent. Perhaps I shouldn’t have spoken? Maybe I would scare my mom. What good would it do to ruin her enjoyment or her looking forward to both the trip and to my sister’s potential success?

It’s worth noting that, thankfully, the storms and cooler weather that did emerge with fury and flood in the east did not ruin my sister’s kayaking venture (although it did result in numerous interruptions both during spring and throughout summer). Should a tropical storm or hurricane make landfall on the US east coast this August, September or October, however, the devastation could be vast, perhaps exceeding a 1 billion dollar disaster event (more on this below).

But as my mother boarded her plane to California and a potential date with Yosemite yesterday morning, these were the satellite images I was looking at:

Yosemite Fire NASA Earth Observatory

Yosemite Fire NASA Earth Observatory

Image source: Earth Observatory

The vast Rim fire that had grown to consume over 192,000 acres as of today was steadily devouring the western border of Yosemite. You can see it on the above infrared satellite picture provided by NASA as a ring of bright white steadily inching into the indicated yellow border of Yosemite.

Jennifer Francis, Stu Ostro and How I Knew

Earlier this summer, my mother chided me on my ‘attempts to predict the weather.’ In a phone conversation last night, she asked ‘how did you know?’

It’s fair to say that in the overall prediction of more storms and rains in the US east, with more risk of flooding, and more heat and dryness out west, with more risks of fire, that I wasn’t entirely certain. However, I’d recently read the work of climatologist Jennifer Francis and had been listening to and following the statements of Stu Ostro. During early spring and summer, I observed a Jet Stream pattern setting up over the US that appeared to be settling into a ‘stuck position’ that would result in the high likelihood of the conditions I communicated with my mother. It’s worth noting that in looking at these Jet Stream patterns it’s not difficult to make such predictions because the patterns change slowly, they lumber and tend to remain stuck for long periods. Once a pattern settles into place, it’s a good bet that it will stick around for at least a few months these days, a fact that the models nail but which meteorologists, in general, have failed to communicate. In short, this is a climate change driven change in the weather.

In fact, some meteorologists and climatologists seem entirely reticent to accept this new weather pattern, despite the fact that it is a powerful tool for weather prediction and will tend to result in less surprises. The big troughs equal record floods sticking around for a long time and the big ridges equal record heat, drought, and probably fires sticking around for long periods of time.

In an example of this reticence, a recent paper by a University of Colorado researcher concluded that Jennifer Francis did not have enough evidence to support her claims of an observed slowing in the Jet Stream. Unfortunately, the paper included, as a part of its findings, a cross section of the atmosphere in which the Jet Stream does not typically reside even while the paper included a sample during which changes were already occurring, which would have likely biased its results. Despite these biases and errors, where the paper actually did measure Jet Stream flows, it corroborated Francis, showing Jet Stream slowing during the periods measured. This is odd considering the fact that the concluding statement contradicts the papers own findings, a point which Dr. Francis, herself, provides.

It’s easy to understand why reticence still lives in the science. As I noted above, it’s understandable to feel reticent when being the bearer of bad news. No one wants to be the messenger that gets metaphorically ‘killed.’ But without making use of the clear understanding provided by Francis and Ostro, we will continue to be surprised by extreme floods, storms, fires, heatwaves and droughts that can be easily predicted by simply looking at how the Jet Stream sets up and where it gets stuck. Instead, ‘surprise’ after ‘surprise’ just keeps coming our way.

When Rossby Waves Get Stuck: Changing to a More Radical Jet Stream

Dr. Jennifer Francis has observed that loss of sea ice and snow cover in the Northern Hemisphere has resulted in a slowing of the Jet Stream in recent years. Sea ice volume, the measure of total ice in the Arctic Ocean, since 1979 had declined by as much as 80% when measured at its low during 2012 (this measure may rally back to around 75 to 78 percent lower than 1979 this year, but the overall trend remains a death spiral). Greenland melt is unprecedented at 500 gigatons per year and with Arctic heatwaves blasting the tundra both permafrost and snow cover are at record and near record lows. 80 to 90 degree temperatures now often advance to the shores of the Arctic Ocean, with the coldest air pushed back above the 80 degree north latitude line, confining it to a shrinking region that, increasingly, huddles closer to the remaining large ice sheets in Greenland. Overall rates of warming for much of the Arctic are about .5 degrees C temperature increase each decade, more than twice the global average.

A more quickly warming Arctic results in changes to the atmosphere’s heat balance. According to Francis, the height of the atmosphere over the Arctic is rising relative to atmospheric heights in the lower lattitudes, this loss of slope results in lower gradients from north to south and since temperature, atmospheric height and pressure gradient drive Jet Stream speed, the Jet Stream slows down. And as the Jet Stream slows, it tends to seek out the highest gradients it can find. The result is more northward invasions of the polar region of the Jet Stream ridges and more southward invasion of the Jet Stream troughs. This amplification creates a rather large and elongated sine wave called a Rossby wave pattern.

Jet Stream Pattern Change. Image source: NOAA.

Jet Stream Pattern Change. Image source: NOAA.

In the sequence above, we see the progression of a flat Jet Stream to a Rossby wave ridge/trough configuration to, eventually, cut off lows and highs. In the past, such waves tended to set up for briefer periods, extending for days or weeks before returning to the usual, more flattened motion of the Jet. In more recent years, large Rossby type waves have been the typical pattern, one that transitions to cut off lows before it returns to a configuration more similar to (b) in the diagram, before setting up as a Rossby-type wave again.

Perhaps more importantly, this b, c, d progression has tended to occur again and again and again over the same geographical region for months and months on end. And, looking back at Jet Stream maps over the past months, this is exactly what we find.

Below is a progression of images I’m providing from this blog’s archive. It includes either direct temperature measures that indicate Jet Stream patterns or a mapping of air flow speed indicating the Jet Stream’s path.

Clover leaf Jet Stream Pattern April, 2013.

Clover leaf Jet Stream Pattern April, 2013.

(Image source: ECMWF)

In ‘For Central US, Climate Change and a Mangled Jet Stream Means Drought Follows Flood Follows Drought’ I described how the Jet Stream pattern had consistently switched from large trough to large ridge configurations over the past few years bringing either heatwaves and droughts or storms and floods. But the left hand portion of the image provides a good record of the Jet Stream configuration as of mid April this year. Following the temperatures, on the west coast we see a large, hot ridge and in the central and eastern US we see a deep, cool and stormy trough.

Wednesday July 3, Rossby wave still in effect over US.

Wednesday July 3, Rossby wave still in effect over US.

(Image source: ECMWF)

Throughout May and into June, this ridge over west, trough over east, pattern continued. By late June, a massive, record-shattering heatwave had set up over the US southwest. I described this highly anomalous event in ‘Mangled Jet Stream and Global Warming to Shatter Earth’s Highest Recorded Temperature This Week?’

Looking at the ECMWF image above we again see the highly exaggerated ridge/trough dichotomy setting up over the US with very hot, dry conditions out west and cooler, wet and stormy conditions in the east.

At this point, I want to tap Stu Ostro’s own observations to add to the Jennifer Francis mix. What Stu has found is that large, powerful high pressure systems have tended to develop more and more often. These extraordinarily dense systems seem to be exploding to new heights in a thickening atmosphere. Primarily, these monsters are driven by heat and so they tend to live in the massive ridges provided by our new, exaggerated and slowed, Jet Stream pattern. That said, these beasts can spring up almost anywhere there is a massive abundance of heat to tap, as one did over a super-heated region of ocean near Shanghai this summer sparking its own monstrous heat wave.

These large heat domes have major and far reaching effects. To understand them, we must first step back to think about the broader effects of human caused warming before looking at how heat domes manifest in the atmosphere. Based on models of the Earth’s atmosphere, we know that for each 1 degree Celsius of Earth temperature increase we get a corresponding 8% amplification of the hydrological cycle. What this means is that evaporation happens 8% faster and condensation happens 8% faster — OVERALL.

Since 1998, we have observed temperatures that are, on average, .8 degrees Celsius above those seen during the 1880s. What this means is that the hydrological cycle has amplified by 6% over this same time period. Because of this dynamic, droughts are more intense, but rainfall events are also more intense. Yet since the atmosphere is uneven we can expect this 6% amplification to manifest in somewhat more extreme fashion at the locations where more extreme Jet Stream patterns set up.

Mangled Jet Stream Dumps Deluge on US Midwest

Mangled Jet Stream Dumps Deluge on US Midwest

(Image source: California Regional Weather Server)

What goes up must come down. And that massive heat dome over the western US and Canada had been baking moisture out of the soil at unprecedented rates over an extended period from April to August. The moisture injected into the heat dome rose and rose, The high pressure system suppressed cloud formation so the moisture had no where to go but up and out. Eventually, this moisture found the edge of the massive high and spilled over into the storms riding along the Jet Stream trough rushing down from the Arctic Ocean and into eastern Canada and the US (hat tip to Colorado Bob).

The result was multiple flood events starting with the Midwest floods of April, then the massive Canadian floods (Calgary) of June, then the Toronto floods, then the Midwest floods of early August, and lastly the east coast floods of mid to late August. The Calgary floods were the worst ever recorded in Canada, the Toronto floods were the worst recorded for that region, and in the Midwest floods of early August, four months worth of rain fell in just one week.

Monthly rainfall estimates August 2013.

Monthly rainfall estimates August 2013.

(Image source: The Weather Channel)

On 8 August, the time of the second barrage of major Midwest floods this year, we find the Jet Stream in the same elongated configuration with a large northward ridge extending all the way from the southwestern US to the Arctic Ocean and with a deep trough diving back down into the central and eastern United States. As noted above, the mangled Jet Stream delivered its overburden of moisture directly to the US Midwest, dumping four months worth of rain in just one week.

A second pulse of moisture rode far south along this Jet Stream flow to dump massive amounts of rain over the southeastern US about a week after pummeling Missouri. This flow combined with a compromised tropical system to saturate the southeast, with some regions receiving as much as 300 percent their annual rainfall totals by late August.

One of the hardest hit areas is Lake Okeechobee. Water levels there as of mid August hit 16 feet at the Hoover Dike, a level that requires weekly monitoring for cracks or ruptures. The dike stretches over 140 miles along the perimeter of lake Okeechobee and was intended to keep the lake in check during major storms and hurricanes after large outburst events in the early 20th Century resulted in thousands of lives lost. The dike is 25 to 30 feet high and is as wide as a football field. The US Army Corps of Engineers has been working feverishly to shore up the dike in a project that will take years to complete.

At 16.5 feet water level, the dike will require daily monitoring. For each inch of increase above that level, the pressure put on the dike would greatly increase risks of catastrophic failure. The causes of such high water, this year, were neither tropical storms nor hurricanes. Florida has been, thus far, spared the wrath of these strong storms. Deep Jet Stream troughs and a constant Atlantic moisture flow have, instead, resulted in day after day rain events for much of southern Florida, pushing August totals near Lake Okeechobee above 16 inches, filling the massive lake and putting the dikes at risk. Should a hurricane or tropical storm strike Florida during late August, September, or October, the dike could overtop or rupture, unleashing the massive lake on communities sitting beneath it. (Hat tip to Colorado Bob).

As the threat of massive floods continued to increase in the east, the west was erupting with wildfires. Fire containment efforts went into high gear both exhausting the Forest Service Fire budget and briefly pushing the national fire alert level to 5. The Rim Fire, so close to my parents’ vacation site, expanded to 192,723 acres today making it the 6th worst in California history.

Rim Fire on August 28th, 2013

s Rim Fire on August 28th, 2013

(Image source: Lance-Modis)

You can see this massive fire, now 23% contained, burning to the west of Yosemite in the Modis shot below. A more detailed report of this major wildfire is provided by WeatherUnderground here and here.

Mangled Jet Stream Temporarily Edges Eastward

My parents wanted to see Yosemite’s amazing waterfalls. A major source of my reticence in telling them the likely pattern for this summer was that the heat and drought out west would probably dry out many of those magnificent falls. And, sadly, this has happened. So even if they brave the smoke and fires to reach Yosemite, the one attraction my mom had been most excited to see will likely be somewhat less magnificent.

But a cloud has suddenly appeared in this wrinkle. For the Jet Stream had edged slightly east.

As of the middle of last week, reports of heatwave conditions had emerged throughout the US Midwest with North Dakota, South Dakota, Nebraska, Illinois, Wisconsin, Iowa, Minnesota and Missouri experiencing temperatures in the range of 20 degrees (Fahrenheit) above average. With heat index values hitting as high as 110 degrees, communities sweltered and school systems declared closings. In California, where temperatures had remained in the upper 90s to lower 100s for much of summer, the trough advanced, pushing temperatures back down to the 70s. An upper level low flirting with the west coast may even toss a few fog clouds and rain showers toward California. Such an event would be a welcome change for both my parents and for beleaguered fire fighters in the region.

In any case, the shift is expected to be short lived with ECMWF models showing the Jet Stream again backing up and reforming a hot and dry ridge pattern over the US west. So the Midwest can expect cooling and a return to more stormy, rainy conditions while the US west, after only a brief respite, continues to bake:

Mangled Jet Stream Early September

(Image source: ECMWF)

The September 7 ECMWF forecast again shows a large and powerful Rossby-type wave pattern with a very large and hot ridge setting up over the US and Canadian West with a deep trough digging down toward the US East Coast. It is the same pattern we’ve seen since at least April, a pattern that has delivered numerous rounds of heat and drought to the US west and an equally vicious and persistent pattern of storms and flooding from the central US to the east coast. The Jet Stream has, essentially, been stuck these past 5 months and there is no end in sight. For even if this configuration of the Jet were to move, it would likely simply re-distribute the locations of heatwaves and droughts and storms and floods.

If anything, this past summer has been yet one more validation in evidence of the work of Dr. Francis. And it is because of her work that I, a relatively untrained observer, can make the accurate prediction that a large region from the Mississippi west to California will continue to stay hot and dry and will continue to see risk for large fires, while the region to the east will remain cooler and stormier so long as the current Jet Stream configuration continues to persist. The western region will risk periods of record heat, continued drying of lands, rivers and aquifers, and fires of record size. The eastern region will continue to risk record floods and storm events. As summer proceeds to fall, shifts in these weather patterns have the potential to grow violent with the possibility of powerful nor-easters or hybrid storms developing near the US East Coast. Both the southeast and Florida remain very vulnerable to continued large rain events or tropical storms and hurricanes as time moves forward and in the event of pattern persistence. Meanwhile, long range model forecasts show this general pattern continuing to persist until at least early to mid September.

At this point, the current US Jet Stream pattern will have been in place for at least 6 months.

 

 

 

It’s Hotter Up North than Down South: Tundra Fires Erupt Over Canada as Heatwave Pushes to Arctic Ocean Shores

Tundra Fires Near Lake MacKenzie

Tundra Fires between 62 and 66 degrees North

(Image source: NASA/Lance-Modis)

Over the past week, large tundra fires have been erupting over a section of extreme northern Canada between the Great Slave Lake and the shores of the Canadian Arctic Archipelago. With a major Arctic heatwave predicted as various extreme weather conditions arise, this region will be worth very close monitoring over the next few days.

The fires are emerging in a region of the Arctic between 62 and 66 degrees north latitude, near the Arctic Circle. In the image above, we see the Great Slave Lake in the lower left hand corner, the Great Bear Lake in the upper center, and Coronation Gulf and Amundsen Bay bordering the map’s right hand side. The fires are visible, along with their tell-tale smoke plumes and underlying scorch marks, in a region between the Great Slave Lake and Great Bear Lake. Terrain type in the regions burned include boreal forest and tundra.

Weather conditions over the past two weeks have been both warm and dry for this Arctic region. But over the past few days, temperatures have been heating up. As temperatures rose, wildfires sparked and grew. Forecasts now call for a region of very hot Arctic weather to stretch all the way to the shores of the Beaufort Sea by Friday with temperatures likely to exceed 30 degrees C (86 degrees F) over the broad stretch of land surrounding the Mackenzie Delta.

This high Arctic heat pulse is being driven north by a powerful high amplitude wave in the Jet Stream which is setting up very extreme temperature differentials between the Beaufort Sea and North Canadian land masses. Temps over the Beaufort are now in the range of -5 degrees C in some areas (about 22 F), with temperatures over land hovering, at this time, in between 15 and 23 C (60s and 70s) and predicted to surge as high as 30 C + (86 F+). This amazing temperature differential is likely also providing fuel to a powerful 978 mb (Smokey) Arctic Cyclone now traversing from the Laptev and into the Central Arctic. It will also intensify winds and drive greater heating over Arctic land masses over the next few days.

Heatwave Hits Arctic Ocean Shores

(Image source: Arctic Weather Maps)

The map indicates forecast daytime temperatures for the Northern Hemisphere land masses bordering the Arctic on Friday, August 9, 2013. Note the highly anomalous condition in which temperatures are predicted to be hotter further north, over regions near the Mackenzie Delta, than they are further south. This is an extraordinary inversion and one certainly worth putting into the context of the extreme weather conditions that are now ongoing. (Areas of red on the map indicate average temperatures in the range of 77-86 degrees (F). Maximum daily values are likely to exceed this average predicted range.)

Though not as massive or extensive as the fires raging across the Arctic Ocean in Russia, these fires are still quite large — with burn marks stretching 6 or more miles at their widest point in many cases. Another region just west of the fires shown in the image above is also experiencing a very large blaze. This complex of fires is raging along the banks of the Mackenzie River and is shown to have a fire line more than ten miles across at its widest point.

Mackenzie River Fire

Mackenzie River Fire

(Image source: NASA/Lance-Modis)

Note the extremely large scorch mark to the lower center portion of the map, with a large, energetic fire blazing in the upper right portion of the map and a smaller, though still substantial, blaze erupting to the upper left.

As noted above, fire-conducive conditions for this region are forecast to intensify well before they moderate. So this particular spate of fires may well be just starting to ramp up.

For a final note, I’d like to add the observation that this event represents a bit of rather harsh irony. These fires now rage in a region dominated by Canada’s Tar Sands Industry. Carbon is being baked and burned out of the land and soil by anomalous heat caused by human warming and not just by the immense grind and crush of fossil fuel industry. The steps of carbon extraction, in this case, have been shortened and are now out of our control.

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