ARCTIC SEA ICE –The Surge Snipped–

The Pole continues to make for interesting theater, though the drama has died down from what it was a week ago, when temperatures were soaring to 35 degrees above normal and the ice at the north edge of Barents Sea was retreating. Fueling this weather was a strong south wind from the Atlantic that at times pushed right past the Pole towards the Pacific, thus confusing everybody, because a south wind became a north wind without changing direction.  This flow achieved its peak around November 14:

By November 16 the flow was pushing an Atlantic low and its secondary up through Fram Strait, whereupon, due to the strict laws of this website, they are automatically dubbed “Ralph”. The southerly flow, while remaining southerly, had swung east, and was now coming less off the Atlantic and more off shore from Europe, but it nearly was able to push above-freezing temperatures to the Pole.

So strong was this flow that the sea-ice, which usually is expanding south as a thin sheet of ice, was pushed north by strong wind until it was briefly well north of Franz Josef Land, and unable to refreeze because temperatures were above freezing in that area. This produced a brief and unusual dip in the ice “extent”graph, which usually is rocketing upwards at this time of year. However the ice swiftly grew back down to Franz Josef Lands’s north coast as conditions began to change, and the graph resumed its upward climb.

dmi4-1123-osisaf_nh_iceextent_daily_5years_en

The surge from the south had raised eyebrows by raising temperatures to unprecedented levels (in a history that goes back 58 years).

dmi4-1116-meant_2016

However my eyebrows were raised by the steep decline that followed.

dmi4-1126-meant_2016

This interested me because, whereas other places can get colder air from lands further north, there is no place north of the North Pole. Therefore it must get cold air imported from colder tundra to the south, but I didn’t see any strong flow from such tundras. This meant the cold must instead be home grown. Or, to put it more scientifically, the heat was lost locally, radiated upwards into the unending winter night.

Still, it seemed odd to me that the warm southerly flow should just turn off like a spigot. My curiosity sought reasons, for the cessation was obvious as early as November 17, because the first and second lows, following a storm track straight north to the Pole, (incarnations of “Ralph”), weakened with surprising speed. It was as if they were cut off from their warm inflow of mild, moist air, while the third storm in the sequence came to a dead halt and refused to head north, and just sat off the coast of Norway and twiddled its thumbs, remaining fairly strong.

I wondered if the stalled low off Norway might be consuming all the available energy, but this didn’t satisfy me, for the isobars in the above map still indicate a strong flow from the south. Why wasn’t the warmth heading out over arctic waters? The temperature anomaly map still showed the above-normal temperatures moving north in central Europe, but then being bent east at the top. What was stopping the import of heat north to the Pole?

surge-7-gfs_t2m_anom_eur_21

I’d likely still be mystified, but dawn broke on Marblehead when I visited Joseph D’Aleo’s blog over at the Weatherbell Site, and during the course of one of his elegant descriptions of complex situations he turned on the light-bulb in my noggin.

Just as a meandering stream straightens its course from time to time, cutting across the neck of a loop and leaving an oxbow lake behind

snip-1-a8dcd06cd8cd3559b399ecc64af3a2032812ccf0

So too can a loopy jet stream decide to straighten up its act, and the “surge” was part of a loopy jet:

snip-2-screen_shot_2016_11_23_at_5_15_03_am

When a jet straightens up it act, the cut off part of the stream is not called an “oxbow”, but rather a “cut off”, (which shows that meteorologists are occasionally more sensible than geologists).  By November 23 the upper air maps showed the “cut off low” was sitting down over Spain. Over Spain a large part of the surge was no longer heading north, but caught up and going around and around and around, like a taxpayer caught up in a bureaucracy.

snip-3-ecmwf_uvz500_eur_5

You will notice that at the top of the above map the jet is basically zooming west to east. The surge from the south has vanished, making a mess of all my forecasts that calculated the surge would move east this far one day, and this far further east the next. The surge simply disappeared, or at the very least fell over and surged west to east. It was confusing. (Actually the same thing happens when I straighten up my own act. It confuses people who depend on me to be loopy.)  In any case, this morning’s surface map had a reflection of the cut-off-low stalled over Spain, but what about the North Atlantic low? It will plow west-to-east across Scandinavia in the jet, nothing like the lows that headed straight north, last week.uk-met-20161126-42268142

The tipped over surge can be seen giving some relief to central Asia in the temperature maps.

snip-4-gfs_t2m_asia_2

In the anomaly map the west-to-east surge looks like an arrow, making a layer cake out of the map (to mix my metaphors). The old cold is to the south, still capable of generating a few headlines, but likely to be slowly moderated out of existence. The new cold is along the top, and likely needs to be watched, for it seems likely to be a lasting feature. The “surge” itself seems likely to linger but weaken, but will remain interesting to watch.  At the very least it will give some Asians a break, after they have been through an autumn colder than some winters.

snip-5-gfs_t2m_anom_asia_2

But this is all off the point, which was (in case you can’t remember), that the mild air is not surging up to the Pole any more, and that the vast pool of mild air that was transported up there is slowly cooling, day by day.

I should note that Joseph D’Aleo mentioned that when a jet really gets roaring west to east it can act downright human. (After humans have straightened out their act, what tends to happen next? Answer: Their resolve buckles.) In like manner, we should be on our toes, watching for where the jet will next buckle, and get all loopy, (like a human falling off the wagon after keeping a New Year’s resolution as long as they can bear it).   However, for the time being, up at the Pole, “Ralph” has little hope of reinforcements from the Atlantic.

Not that “Ralph” has vanished completely. Largely he has retreated to the Canadian Archipelago, as high pressure dominates the Arctic. At the end of my last post there actually was a small ghost of Ralph by the Pole, and hint of Ralph’s “signature” in the temperature map, hooking mildness towards the Pole, despite the power of the expanding high pressure. (See the tiny low by the Pole?)

The next day Ralph’s ghost was just a dent in the high pressure’s isobars. Freezing temperatures had snuck down to the northeast coast of Svalabard.

 

The next dawn Ralph, like all good ghosts, was vanishing, because that is what ghosts do at dawn. (If you you squint you can still see a microscopic low under the Pole.) The only real import of air towards the Pole was from central Siberia.

The following dawn saw an odd dimple in the high pressure’s isobars, on the Canadian side. It looked like (if you use your imagination) a face, that the ghost of Ralph had punched. Freezing temperatures were engulfing Svalbard. By evening the ghost of Ralph reappeared, (as good ghosts do at dark), just north of the Canadian Archipelago.

Today saw the freezing isotherm slump well south of Svalbard, and Ralph retreat and regroup north of Canada. Models are suggesting Ralph will soon start attacking the Pole from the Canadian side, though with colder air than before. The North Atlantic flow is totally from the north, and Scandinavia looks likely to get a dose of north winds.

The north winds are allowing the sea-ice to build south again where the “surge” had forced it to retreat, in the north part of Barents Sea, and sea-ice is again touching the north coast of Franz Josef Land. There was also a slight reduction on the Pacific side, due to strong south winds and a brief mild inflow a week ago, but that has been more than made up for by regrowth, which has now engulfed Wrangle Island.

concentration-20161125-attachment-1

A major difference from last year is that Hudson Bay was half skimmed-over last year, and the refreeze hasn’t even started this year. I think this will soon change. The Bay’s waters are shallow, and it tends to freeze over with remarkable speed, which contributes to the speed of the growth of the “extent” graph.  I’ll bet a nickle the Bay is entirely frozen by Christmas.

Even though the flow from central Siberia has been weak, it appears to have nudged the thicker ice just off shore, in the Laptev Sea. Watch for the formation of polynyas along the shore there, for that is indicative of the export of ice into the Central Arctic Basin.

Baffin Bay is swiftly icing over, but remains behind last year’s rate of growth..

The Kara Sea’s sea-ice shrank back before the “surge”, but that sea has since swiftly grown sea-ice on its eastern side.

The reversing winds have seen multi-year ice start down through Fram Strait, along the east coast of Greenland, but the ice down towards the coast opposite Iceland in Denmark Strait is largely home grown.

thickness-20161125-attachment-1

I’m not sure how it is possible, but some models see a colder version of Ralph moving up from Canada to regain complete control of the Pole in a week to ten days. Stay tuned.

CROSS POLAR FLOW —OR, HOW TO MESS UP COMPUTER MODELS—

I am very ignorant concerning computers, and I only mention this as a ignorant soul telling a Rembrandt his shoelace is untied.

The models amaze me with their accuracy five days into the future, most of the time. I have a hard time forecasting tomorrow. Therefore I rely on models, and notice when they are not amazing, five days into the future. Recently they have been spectacularly wrong, especially as you get up into northern latitudes.

I’ve been wondering if they think in a circular manner. They might see weather patterns going around and around the earth.  It might throw a wrench in the works, and be over-the-top, so to speak, when rather than around and around, cross-polar-flow brings things over the top.

The recent cold that clobbered Europe was unseen by models, even three days ahead of time. I think it may be because the models are based on a nice, “zonal” flow, and have trouble when the Pole is afflicted by what some (me) call a “loopy” flow, and others call “meridianal.”

The best model at handling such cross-polar-flow seems to be the Canadian “JEM” model, likely because Canada gets clobbered by cross-polar-flow more than most other nations. Perhaps the JEM model does not do as well with round-and-round the earth patterns, for it is not the best model overall, however when it does score a “coup” it seems it is because it added over-the-top cold to the mix. (Of course, the JEM model has a habit of creating over-the-normal super-storms, but no one is perfect.)

I thought it might be interesting to see what the JEM model produced, and what follows gives you an idea of the wrenches the Pole can throw into the works of any model that accepts a zonal flow as a basic premise.

(These maps are produced by a Rembrandt of the weather-map-world called Dr. Ryan Maue, of the Weatherbell site, however these maps are blemished by a bit of digital graffiti down the left sides. Likely Dr. Maue was operating on two hours of sleep when he wrote the code for this map, or perhaps the Canadian computers produced the glitch and the graffiti  is beyond Dr. Maue’s control. In any case, it is an untied shoelace, and I hope you will ignore it and enjoy the great art.)

All these maps can be clicked, or opened to a new tab, to enlarge them. Then they can be clicked a second time to enlarge them further.

The first, “initial” map shows a Pacific invasion has nearly reached the Pole, but a tremendously cold airmass in Siberia, (the hottest pink is -70°), is rushing north behind the invasion, cutting it off. (The clash between the the milder and frigid air is creating a decent polar storm.) This northward rush of Siberian air is what I called “the snout of Igor” last year, and makes me worry, though I am off the map and on the far side of the planet.

CPF1 cmc_t2m_arctic_1

The next map shows that a day later the Siberian air has charged right across the Pole. The Pacific invasion is cut off, but an Atlantic invasion is starting north west of Norway. (Notice the cold air has been driven from northern Scandinavia.) Things look bad for Canada, with that thrust of Siberian air charging their way.

CPF2 cmc_t2m_arctic_5

The next map, 48 hours later, makes one say, “But what is this?” A new invasion of Pacific air is attacking the cross-polar-flow from one side, as the Atlantic invasion proceeds from the other. Will the flow be strangled?

CPF3 cmc_t2m_arctic_9

After 72 hours the Pacific invasion seems to be overpowering the Atlantic invasion, and rather than the cross-polar-flow being nipped in the bud, it is developing a curve, or a sort of saddle. Warmth has pushed east of Finland into Russia.

CPF4 cmc_t2m_arctic_13

After 96 hours the curve in the cross-polar flow has become such an oxbow that the air is starting to aim not towards Canada initially, but west towards Scandinavia. Notice that west of Finland, the cold is no longer retreating east in Russia, but starting to advance west.

(I think this is where some models start to lose it.)

CPF5 cmc_t2m_arctic_17

After 120 hours the original cross-polar-flow has collapsed into a surge of cold back towards Scandinavia. However a new cross-polar-flow is starting, and the most-recent Pacific invasion is again being cut off. Northern Scandinavia is much colder.

CPF6 cmc_t2m_arctic_21

Lastly at 144 hours, (which is starting to enter la-la land, for models), we see some bizarre feature north of Greenland throwing mild air up towards the Pole.  (“I’ll believe it when I see it.”)  However what seems a little more reliable is, first of all,  that the new cross-polar-flow has hooked up with Canada, and the air in northern Canada is nearly as cold as Siberia’s.  Secondly, the old cross-polar-flow has sent really cold air crashing into Scandinavia.

(It is sort of like the cross-polar-flow was a meandering river, and cut off an oxbow, but in the atmosphere an oxbow does not just sit stagnant, as an oxbow lake, but is a mobile thing, as Scandinavia may see first hand, 144 hours from the time of the first map.)

CPF7 cmc_t2m_arctic_25

Please remember all of the above is occurring in the virtual world of computer models. It is theory, not reality.  However what is so fascinating to me is how different weather patterns look, when you view the globe from the top, rather than always from one side or another.

ARCTIC SEA-ICE RECOVERY –Sneak Attack onto Europe–

The last two weeks has been interesting to watch, though the growth and extent of the ice is fairly normal. Here are the extent maps from December 12 (to the left) and December 27 (to the right).

DMI2 1212 arcticicennowcastDMI2 1227B arcticicennowcast

As Hudson Bay and the Bering Strait have frozen up, most of the growth in ice from now on has little to do with the Arctic. You could almost call it cosmetic. It will be occurring in the Pacific, or the mouth of the Saint Lawrence River, or the Baltic Sea, and therefore will be fleeting, and have little to do with the Arctic Sea itself, which is what all the fuss is about in the summer.

I tend to watch the arctic ice-thickness maps, which can give you an idea where the ice is moving. It moves far more than many imagine. For example, hundreds of square miles of thicker ice that had been lodged north of Franz Josef Land was shifted west by storms and crashed into the north coast of Svalbard, over the past month. This created a sort of polynya of open water where the ice had been by Franz Josef Land, which swiftly froze over and became thin ice.

DMI2 1227B arcticictnowcast

If this large body of ice continued to move west it might be flushed south through Fram Strait, which could create a situation much like occurred in 2007, when the thick ice was flushed south of the Pole, leaving the Pole with a thin skim of ice as summer approached, and, because the thin ice melted easily, the people who assume the icecap is in a “Death Spiral” had something to hype. (The main difference between now and 2007 is that there is much more thick ice north of Canada now.)

Watching the thickness maps allows you to see where the ice is piling up and where it is thinning, and gives you a rough idea on the total volume of ice up there.  There are many interesting processes occurring that you seldom read about.  For example, the same strong winds that blew the ice away from Franz Josef Land also blew the ice away from the south coast of the Kara Sea, and you can see that ice as thin blue lines of thicker ice now out in the middle of the Kara Sea.

Ice really piles up on the west coast of Baffin Bay, and grinds southeast along that coast and then along the coast of Labrador towards the North Atlantic. Ice also can pile up on the south and east coast of Hudson Bay, while the north coast can see polnyas form, so that even though the north was the first to freeze and the south was the last to freeze, by spring the south has thicker ice than the north. Lastly, ice can be seen piling up just west of the Bering Strait on the north coast of Russia; last year this ice was piled up 20 feet thick there by spring.

Watching the thickness maps brings many surprises, especially when storms wrack the ice. In the dead of winter, with temperatures at -40°, I have seen leads of open water form that are scores of miles across and hundreds of miles across. The open water freezes to thin ice almost immediately, but sometimes you can still see signs of that thinner ice months later. In a similar manner storms had a lot to do with the build up of thicker ice north of Canada.

At times the thick ice can crumble and be spread out into open waters, and mess up all sorts of neat calculations in the process. Where a cold current often sinks when it meets a warmer current, and more saline waters want to sink beneath more brackish waters, it is physically impossible for the ice to sink, and it bobs merrily onwards on top, often significantly chilling both the temperatures of the surface waters and the air, until it melts away. Therefore a strong wind transporting ice south can alter temperature maps with startling speed.

I imagine there are times when such alterations make a difference in the forecasts generated by computer models. They may even explain why the models utterly failed to foresee the cold that slumped south onto Europe recently. Just as it only takes a single pebble to start an avalanche, a single miscalculation can mess up a computer model.

Although the models did not see the cold coming, Joseph D’Aleo and Joe Bastardi on their blogs at the Weatherbell site did say we should be on guard for cold waves to hit Europe, as the autumnal patterns were similar to years in the past that saw cold waves hit Europe. They didn’t explain how it was going to happen in a step-by-step way, so I watched very carefully to see if I could see the steps as they occurred.

Back on December 12 we were seeing south winds bring warm air flooding north over Scandinavia, as the Atlantic storms veered north towards the Pole. A lot of Barents Sea was above freezing. Cold air was exiting the Arctic down the east coast of Greenland.

DMI2 1212 mslp_latest.big DMI2 1212 temp_latest.big

 

This pattern continued on December 14

DMI2 1214 mslp_latest.big DMI2 1214 temp_latest.big

 

And peaked around December 17

DMI2 1217 mslp_latest.big DMI2 1217 temp_latest.big

By December 19 the storms were no longer heading up to the Pole, but were moving east along the north coast of Russia. Barents Sea was cooling down, and to the east of the storm cold Siberian air was drawn up over the Arctic Sea and then dragged back west, and the milder Atlantic air lost its influence over the Pole.

DMI2 1219 mslp_latest.big DMI2 1219B temp_latest.big

 

By December 21 the new storm track had the east winds to its north starting to drag cold air back towards Scandinavia. The following Atlantic Gale didn’t bring such a flood of warmth north.

DMI2 1221B mslp_latest.big DMI2 1221B temp_latest.big

 

By December 24 the new storm track had penetrated weakly to the Pacific side of the Pole, and chilled Pacific air was being drawn over the Pole, but was too cold to warm the Pole much, and the cold air over the Pole was heading south to Scandinavia, and below freezing temperatures seeped down the coast of Norway.

DMI2 1224B mslp_latest.big DMI2 1224B temp_latest.big

 

By the 26th of December the cold was building over the Pole, and the strongest low pressure was east of Scandinavia, transporting Siberian air back west over its top towards a Barents Sea that was now far colder, especially to its north. The Pole was as cold as it ever gets, except on rare occasions, and the weight of that dense air was spreading out, including down towards Europe.

DMI2 1226B mslp_latest.big DMI2 1226B temp_latest.big

 

Today we see the following North Atlantic low is weak, without a surge of southerly winds, and the isobars hint of a discharge straight from the Pole to Scandinavia and areas further south.

DMI2 1227 mslp_latest.big DMI2 1227 temp_latest.big

This afternoon’s map shows the weak low bringing snow to Britain and the cold continuing to press south over Europe.

DMI2 1227B mslp_latest.big DMI2 1227B temp_latest.big

The computer models didn’t see this cold coming, even a few days ago, but now much of western Europe is below normal. As this cold continues to press south it is likely create elongated high pressure west to east. There may be a warm-up over Scandinavia as winds turn west to the north of the high pressure, but east winds to the south of the cold high pressure will bring very cold Siberian air further and further towards the Mediterranean, and a southern storm track will bring snows to Italy and perhaps even the north coast of Africa, before the cold is moderated.

DMI2 1227B gfs_t2m_anom_eur_1

 

 

However I have no business talking about Africa in a post about the Arctic, so I’ll just show the graph of temperatures north of 80 degrees latitude, which informs us the arctic is loaded with midwinter cold, and has plenty to spare.

DMI2 1227B meanT_2014

Besides dumping cold down on Europe, some is being dumped south into Canada and the western USA.  The thing to remember is that not only the Pole creates cold, but all areas of Tundra and Taiga generate cold as well, during these shortest of days. Better look for where you left your mittens.

DMI2 1227B gfs_t2m_noram_1

(These maps are created by Dr. Ryan Maue at the Weatherbell site.)