Much Different March. Same Reason?

March 20, 2013


Dittohead reasoning: “So when it’s warm, you blame it climate change. When its cold, you blame it on climate change. It can’t be both.”

Well, yeah, it can, kinda.

Meteo people weigh in.

7Weather Blog WHDH-TV:

I think we’ve passed the point of tolerance with these ceaseless storms. Gone are the days when viewers would flood our inboxes with pretty pictures of their pets and kids frolicing in the snow. Constant cleanup has made us snippy and short – even a few plow guys have hoisted the white flag. The holidays are long past, the winter is stale, and the people just want spring…

…and accountability.  Instead of pictures, I get questions in my inbox. “Why are we getting so much snow? Why did it turn on a dime? And when will it stop?”

Those are fair questions. But with the limits of the long range (10-14 day) forecasts, I’m not ready to answer the last question. We may sail out of this in April, but so far the first week of the month isn’t looking much different from the first week in March. The ultimate question is why.

The jetstream has taken on an odd path.

The black lines represent the jetstream (wind moving from west to east). The colored areas represent the departure from the normal position of the jetstream. The bullseye is apparent: right over Nunavut (Northern Canada). High pressure has dominated this area since early February, diverting the cold and the jetstream over the Lower 48.

So there you have it. The culprit, the scapegoat, the reason for over 100″ of snow in Worcester, and the reason I can’t talk about 70s and 80s like last March. But the bigger question is, why does it last so long.

Ocean/atmosphere interaction is still a young branch of the science of meteorology. There are many reasons for stalled weather patterns, but I believe the biggest is the lack of sea ice from climate change. An open ocean leaves a lot of heat in the poles. This fosters high pressure (or blocks in the jetstream), and with very little movement to weather patterns at the top and bottom of the globe, we get pinned down in these long periods of heavy precipitation/drought and hot or cold.

An undeniable link in the cog has been established. And we’re left to wait it out.

Let’s compare the Jet stream behavior from a year ago.

Path of the jet stream on March 21, 2012.

Andrew Freedman in Climate Watch, from a year ago:

The jet stream, the study says, (Francis and Vavrus here Peter) is becoming “wavier,” with steeper troughs and higher ridges. Weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods, and heat waves.

“[The] tendency for weather to hang around longer is going to favor extreme weather conditions that are related to persistent weather patterns,” said Francis, the study’s lead author.

One does not have to look hard to find an example of an extreme event that resulted from a huge, slow-moving swing in the jet stream. It was a stuck or “blocking weather pattern” – with a massive dome of high pressure parked across the eastern U.S. for more than a week – that led to the remarkable March heat wave that sent temperatures in the Midwest and Northeast soaring into the 80s. In some locations, temperatures spiked to more than 40 degrees above average for that time of year.

The strong area of high pressure shunted the jet stream far north into Canada. At one point during the heat wave, a jetliner flying at 30,000 feet could’ve hitched a ride on the jet stream from Texas straight north to Hudson Bay, Canada. In the U.S., more than 14,000 warm-weather records (record-warm daytime highs and record-warm overnight lows) were set or tied during the month of March, compared to about 700 cold records.

According to the study, Arctic climate change may increase the odds that such high-impact, blocking weather patterns will occur. The study cites examples of other patterns that led to extreme events that also may bear Arctic fingerprints, including the 2011 Texas drought and heat wave, which cost the state’s agricultural sector a staggering $7.62 billion – making it the most expensive one-year drought in that state’s history.

Surface temperature departures from average during the March 2012 heat wave.

19 Responses to “Much Different March. Same Reason?”

  1. ahaveland Says:

    I believe it used to be that what happened in the Arctic, largely stayed in the Arctic because of jetstream ringfencing.

    As the latitudinal amplitude of the jetstream increases, it reaches further into the Arctic cold reservoir, and brings more cold air down with it.

    Of course, that cold air has to be replaced with warmer air from the south, and this increases the melt rate, increasing jetstream ‘waviness’, increasing heat exchange etc – probably yet another positive feedback.

    Let’s hope that cloud cover will change to compensate.

  2. daveburton Says:

    That’s pretty silly. Here’s the current jet stream map:

    It wanders around. If you cherry-pick, you can find some odd-looking jet stream maps, of course, but that doesn’t portend a trend.

    Some things oscillate, and many things fluctuate, but, overall, there’s been no increase in extreme weather coincident with the last ~ 3/4 century of steadily increasing CO2 levels.

    A lot of smart people (like meteorologist Richard Keen) have noticed this fact. Why haven’t you?

  3. You are too nice Peter. I love it when you call horse pucky what it is. We are dealing with a “legal ban on ocean rising” troll and NC-20 member. Get to know your trolls. Bjorn Lomborg just did a hit piece disguised as journalism on WSJ. The folks on some of the green auto blog sites did not recognize him.ørn_Lomborg
    Dave is a regular at WUWT and more of a Monty Python black knight of denialism.

  4. For denialists climate change is like a mirror. What they see as the stupidity of climate change is little other than a mirror reflection of their own inability to deal with the issue.

  5. […] my interview from last fall,  – check those for background if you haven’t yet, – and yesterday I made the point about the forces responsible for the difference between last march, and this march in North […]

  6. – about the drought in Texas:

    “In the case of Texas and adjoining states, the linear trend is generally flat or negative across the past 50-100 years.”
    “So it appears that global warming, if it has affected mean precipitation, has had a minor impact compared to other influences, and even the sign of its effect on precipitation is unknown. Until we learn more, it is appropriate to assume that the direct impact of global warming on Texas precipitation has been negligible, and that the future precipitation trend with or without global warming is unknown.”
    “There is conflicting evidence regarding whether global warming will produce an increase or a decrease of annual precipitation, an increase or a decrease of the variability of annual precipitation, or an increase or a decrease in the frequency or intensity of the primary cause of interannual precipitation variability.”

    [see also: – increasing trend of precipitation in the twentieth century]

    „Also note that the increase in greenhouse gases will cause the additional warming in future droughts to become larger and larger with time.”

    … however: North America – the last ice age – a period of 21-17 thousand. years ago: “At the most extreme stage of the last glaciation … Colder and often drier than present conditions predominated across most of the USA.”

    12 thousand years ago (warmer – then present -period):
    “Through much of the southern and central Cordilleran area of the USA, conditions may have been slightly moister than at present (although generally semi-arid), with greater woodland and scrub cover than at present. The same appears to have been the case for the lowland American and Mexican deserts to the south (Thompson et al. 1993, Benson et al. 1997).”

    Conclusions: “Subsequent cooling and drying of the climate led to a cold, arid maximum about 70,000 years ago, followed by a slight moderation of climate with a second aridity maximum around 22,000-13,000 14C years ago. Conditions then quickly became warmer and moister, though with an interruption by cold and aridity in many areas around 11,000 14C years ago.” :
    “Knowing that the odds of a certain type of event have increased anthropogenically is an abstract sort of knowledge.”

  7. […] a recent item on Climate Crocks examining the changes in March’s weather, 2013 vs 2012.  From which I […]

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