Climate Letter #2162

I found another article about the Antarctic warming event that you may find interesting because of all the quotes from scientific experts:  “https://www.theenergymix.com/2022/03/20/scientists-shocked-as-impossible-antarctic-heat-wave-sends-temperatures-40c-above-normal/.  One paragraph is especially interesting:  “The warm conditions were caused by an extreme atmospheric river of water vapour in the sky. When the river landed on the east coast it brought rain and moisture that spread over the continent, but a strong high-pressure system prevented the moisture from escaping. While it was trapped in place, the excessive moisture retained more heat than it would have under normal air conditions, while liquid-rich clouds radiated heat towards the surface.”  This last sentence basically describes the workings of the greenhouse energy effect in any atmosphere.  The effect is generated whenever outgoing longwave radiation from the surface, originally headed toward space, is instead trapped by substances suspended in the atmosphere and re-radiated in a normal way.  About half of the re-radiated energy returns to the surface and is captured and added  to the prevailing energy mix, where it soon becomes engaged in further processing.  Air close to the surface is very much involved in this heat transfer activity and is warmed as a result.  The warming happens bit by bit, at the speed of light.

There are several things these scientists do not seem to understand about greenhouse energy.  One is that it can be generated by particles other than gas molecules, as long as the particles are plentiful, suspended in the atmosphere, and have the ability to capture energy.  Are there any liquid or solid objects that do not have that last-mentioned ability? Why not little drops and droplets of water, which happen to be very plentiful when partly condensed atmospheric rivers (ARs) are moving over?  An AR can hold a concentration of greenhouse energy power in the form of PW, some of which is pure vapor, that is many times greater than the cumulative powers of all the ambient gases in the atmosphere directly below the river. 

Another thing poorly understood is the concept that the greenhouse effect of all individual generators is delivered logarithmically. Whenever the amount of units of a generator in the atmosphere increases there is a corresponding decline in the power per unit. The logarithmic effect is such that each double in amount reduces the energy per unit by one-half. This is a well-known and publicized fact with respect to CO2 molecules but not established as such for other greenhouse gases or unrecognized generators like PW. By studying the weather maps I have had no trouble forming the consistent revelation that each double in the total weight of PW has a full 10C of warming power on surface air. Antarctica provides a unique venue where multiple doubles of PW can occur quickly and easily, and then vanish. This latest was an extreme example. The real question is what caused it to happen? I will stick with the answer provided here a few days ago, up to a point. We can see how the deep cavity in the high-altitude air pressure configuration was involved, admitting a powerful jet stream that was visibly transporting the AR, but what caused the cavity to form? The article mentions a “strong high pressure system” as a factor, which I think is likely but in need of a better proof and explanation.

The Arctic today shows an almost flat anomaly-(from a baseline of 1979-2000) for the third time this month—about in line with the day’s global number.  Map study suggests that ARs with plenty of PW are currently knocking at the Arctic door but having trouble being admitted, more so than we’ve come to expect.  Jetstream winds are encircling the Arctic in positions that apparently do not favor advances in poleward movement by the ARs. The map of air pressure configuration is noteworthy because of the many appendages in the green zone that protrude from three of its sides, adding extra length to the totality of jetstream pathways.

I’m adding one more image today, showing the pattern of sea-level air pressure. I notice that large blobs of low pressure are commonly associated in size, shape and positioning with the various appendages on the high-altitude air pressure map. This linkage could indeed have an effect on jetstream occurrence, positioning, and probable intermittent strength.

Carl

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Climate Letter #2161

Warm anomalies in both polar regions have dropped a degree or more today. Each change is associated with the reduced influx of a key atmospheric river (AR) and its overhead precipitable water (PW) content. I will be showing four images from each region with limited commentary. I have no plans to continue following Antarctica on a regular basis after this incredible episode, partly for lack of time and also because of several difficulties that I have no way to deal with, which will be explained in a moment. First, today’s anomaly, still large in size but now having no readings over +32 that go off the scale:

On the PW map I especially want to point out a confusing complication that is difficult to explain. On the above map you can observe a large cool anomaly—about the same size as the warm one and just off to its right. On the PW map you will see that there is not much difference in the pattern of absolute kg values over areas of land in each of these diverse anomalies. How can this be? I believe an explanation could be made by showing stark differences in elevation, but have no means of illustrating either the elevation comparisons or differences in the actual amount of ambient water vapor that is multiplied when an overhead AR arrives:

The looping jet stream over the continent has clearly lost strength since yesterday, reducing its ability to transport as much PW as it did before:

On the air pressure map a bright blue spot is all that remains of the large cavity that formed earlier in the week.  The jet stream must be finding a pathway that enables it to stay in place and circle around this spot.  I think the spot probably exists—temporarily—as a positive feedback from relatively warm air temperature at the surface below, but must leave that as a speculation:

Now for the Arctic anomaly map, which is in a cooling trend made up of mostly small changes:

The one AR that is supplying most of the PW entering the sky over this region has lost some of its strength, as measured in kg value, at the point of entry and is also following a less direct course of approach:

A growing bulge in the upper right part of the blue zone on this day has expanded the zone toward the east:

As a result we can see a distinct bend in the pathway taken by the strong jet that is involved here each day.  This would be a good reason behind the change of course taken by the principal AR we are watching, causing it to diffuse its contents and lose intensity when it stops.  (You may want to directly compare these images with the ones in yesterday’s letter in order to get the clearest picture.)

Carl

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Climate Letter #2160

The Washington Post published another interesting article about the Antarctic anomaly yesterday, which has again been reposted by Peter Sinclair:  https://climatecrocks.com/2022/03/18/antarctica-90-degrees-above-normal-nothing-to-see-here/.  Scientists who were interviewed have more to say about the explanation, which they can see is related to the massive incoming atmospheric river, but no mention is made of any greenhouse energy effect.  There is one bit of extraordinary information in the article that I missed because the scale on the anomaly map stops giving readings of more than +32C: “Some computer model simulations and observations suggest temperatures may have even climbed up to 90 degrees (50 Celsius) above normal in a few areas.”  Today the anomaly for the entire region has dropped back to +3.7C.  The images are similar to yesterday except that the locations of maximum gain in warmth, including the area above 32C, are somewhat smaller than before.  I still need to show the two maps that illustrate the mechanism that made this anomaly possible in the first place.  You will see that the large cavity in the high-altitude air pressure configuration is now being squeezed shut, and by tomorrow will probably be gone.  The strong jet stream that has followed a looping passage over the continent as a consequence of the cavity having opened will no longer have a pathway for continuation, and it should move off to the side as suddenly as it made an entry.  As it fades away so also will the extended AR and its PW, and thus the huge anomaly they caused to exist.

The Arctic also cooled off by a full degree today. No new AR is entering the zone and the one large one coming off the Atlantic is gradually losing some of its power. The overall anomaly numbers for this past week have been above the trendline of +2.2C, which is four times that of the global average. Here are the four key maps, being kept as a collective record of daily transitioning:

Carl

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Climate Letter #2159

Antarctica captured my attention again today with an anomaly of +4.8C. The average for the whole continent is now up a total of 5.6 degrees in just four days. The bulk of the gain is happening in just one quarter of the entire zone, and in particular on a fairly large area (whitish patch) which has an astounding reading greater than 32C—which is no less than +58F.and maybe 60 or more:

Here is how it looks when magnified by 400%. This makes it easier to distinguish the obscure difference between two shades of deep red on the map when you get your face up close to the screen:

Like yesterday, a relatively massive influx of precipitable water (PW), formed as the body of an incoming atmospheric river (AR) in the overhead atmosphere, created overwhelming multiples of ambient quantities of ground level PW.  On a normal day Antarctica is notorious for its regular ability to resist any AR penetration of this type.  Today is a truly major exception:

How the region looks when PW differences are well-magnified. Inside the zone of darkest gray shading you can get actual kg values well below 500 grams, but there is no way to read them on these maps:

I also want to give you a magnified view of actual temperatures in this same area today. The area of coldest anomaly has readings that mostly range between -10 and -20C. Magenta is -30, and below that you’ll find readings near the pole that drop below -50C and are fairly close to normal. In all of these places “normal” depends on how high the mountains are in each locality. The highest are away from the pole.

The following two maps are similar to those shown in yesterday’s letter, with the principal features appearing a bit larger and equally intensified:

Now we can proceed with our regular overview of daily changes in the Arctic warming pattern. The warm anomaly area is again very broad, and still very high at +3.3C, but not nearly as intense as the one we’ve been studying above. Observe how about 80% of the broad warm anomaly is surrounded by an unbroken string of cool anomalies. The energy doing the warming of the interior is all being introduced through a window that stretches from Greenland across Scandinavia into northern Russia:

This energy supply is being fed by a massive AR that originated in the central Atlantic. Unlike the river we just saw in Antarctica, which was carried in by a strong jet stream that made a wide circular loop and then pulled out, this AR simply came to a stop, spilling out most of its contents in the act of stopping. These contents have then become dispersed, along with considerable freedom to roam for long distances over a broad landscape:

There is a present and quite normal dearth of significant jetstream wind activity in the center of the Arctic region:

The deep blue zone on the high-altitude air pressure is relatively large and compact at this time. It could temporarily squeeze off some of the large amount of PW coming in at the one wide entry point, but as summer approaches the current size and shape of the blue zone will be prone toward withering away.

Carl

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Climate Letter #2158

The Arctic is just as warm today as it was yesterday, +3.5C above the 1990-2000 baseline average.  (Add about one degree for a late 19th century baseline.)  I’ll be showing the relevant maps below, with a few comments, but first, I’d like you to compare my analysis of the warming to that of the scientific community, as reported in the Washington Post via Peter Sinclair’s website:  https://climatecrocks.com/2022/03/16/temperature-spikes-in-arctic/.  The story is introduced with a sentence that immediately stimulated my interest—“Possible new mechanism for warming acceleration in Arctic, – Atmospheric River injecting large volumes of warmth and moisture.”  A “new” mechanism means new to science, in terms of placing a significant amount of the burden on atmospheric rivers (ARs) for the first time, at least at this wintry time of year.  You can read the whole story to learn how ARs accomplish this feat under this new way of thinking.  There is no mention at all about precipitable water (PW), which the incoming ARs are made from, having a greenhouse effect capable of doing the warming.  Oh, well.

The Arctic anomaly is actually not the biggest story today.  For the biggest we have to go down to the other pole, where Antarctica is now beating the Arctic with an anomaly of +3.6C.  That’s up from 2.0 yesterday and minus-0.8 just three days ago!  Things can indeed change in a hurry in the polar regions.  The Antarctic maps will tell you why today is so special, and I will produce them below, but the Arctic must come first.  The reasons behind the anomaly are basically the same as yesterday, except that all the forces have shifted positions in the usual counter-clockwise direction.  Please notice how the shoreline parts of northern Siberia plus Europe have a warm anomaly on the western half and a cold one on the east, plus Alaska:

The PW map tells you with a quick glance why these two temperature sequences are divided as noted. The story is basically a sample of what happens everywhere else:

On the air pressure map observe the way the blue-zone border stays offshore with respect to western Siberia while overlapping over land in the east, extending over much of Alaska as well:

The jetstream winds that come and go on the long and winding pathway that tracks the border of the blue zone are positioned in ways that may be favorable to the movement of incoming ARs in some places, like on the Atlantic side, but have the ability to act only as buffers in other places, as we can see at this time on the Pacific side.  Places where they die down the most is where incoming PW may have the best opportunity to find a way into the interior of the blue zone.

Now we want to see what’s going in in Antarctica, starting with its anomaly map. It’s clear that one large section is singularly responsible for the big number. There is actually one very small spot—that must be magnified to see, which has an anomaly in the very top bracket of the scale, meaning a bit greater than +32C. I have never seen that happen before. It is still very cold in that part of the continent—most likely around -45C for normal, and currently -15:

By my way of reckoning, an event like this could not happen without an extraordinary influx of PW, just as we see on the next map.  The main area of warmest air (+30 anomaly) has a reading of around 4kg on the scale.  Normally, any PW value associated with -45C can be estimated at no more than 400-500 grams—which means one is 8 times greater than the other.  As understood in my theory, three doubles of PW weight will ordinarily make a difference of 30 degrees. Note the unusually heavy PW content of the AR as it approaches and successfully penetrates the continental interior:

That kind of penetration by an AR can only succeed with the help of a strong jet stream that has an unusual ability of its own to deeply penetrate the skies over the continent:

The next image accounts for the unusual shape of the pathway the jet stream is following. The border of the air pressure blue zone in the Antarctic region is normally quite regular. You seldom see a deep cavity like this one:

I must show one more map, where we see a zone of high sea-level pressure in exactly the right spot for enabling a strong influence on the high-altitude configuration of air pressure gradients.  In effect, it “raises the canopy” of 500hPa readings at that location, putting this reading beyond the zone that normally maintains blue shading:

Carl

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Climate Letter #2157

Another big day for Arctic warming—up 3.5C in just over three decades—and more than six times the global trendline increase for the same period (0.55C). The map shows us one spot quite close to the North Pole that has an anomaly in the +24-28 bracket when you apply full magnification. That is a huge number, equal to around +45F:

Here is how the situation looks from a temperature standpoint. There is obviously something unusual going on in the far north of the Atlantic that makes a considerable contribution to the warmth:

One likely contributor is easily spotted on the sea ice map.  I can’t offer immediate evidence, but I’m quite sure the area of open water has expanded over the three decades, adding several degrees of local warmth for that reason alone. Open water would also add some extra moisture to the air via evaporation, creating a potential for more far-reaching greenhouse energy effects:

The precipitable water (PW) map is very much in step with this last thought, when you see how values have picked up over two areas of open water. Oncoming atmospheric rivers have thereby been fortified while continuing their journey deeper into the polar zone. Considerable spreading of PW content is pictured, heading out in two directions, especially so on the North American side of the zone. You will find plenty of local warming effects from these inputs on both the anomaly chart and the temperature chart.

Today I want to pay more attention to another kind of coincidence, this time on a broader scale, that involves a number of other weather maps. Go back to the temperature map and observe the compact, well-rounded shape of the cold air mass that lies within the dark blue area that extends toward the southeast for several thousand miles from the global top. On the above sea ice map you can also see how snow cover corresponds quite well with that same shape, which is not surprising. There are still more things that have corresponding imagery, starting with the configuration of high-altitude air pressure gradients. The blue zone on this map features a large, compact bulb-like shape that closely overlaps with the ones already pictured. We normally look for an association like this between the blue zone and sub-freezing surface temperatures, so once again there is no surprise:

The border of the blue zone, in combination with the outer border of the green zone, regularly have full control over the positioning of two major jetstream pathways. We can see how true this is again today. The streams that appear on these two pathways typically have a significant influence on the prospects for atmospheric rivers to keep advancing on their courses of migration toward the poles:

I’m not yet done showing maps that have this same, large coincidental image shape. The nest one shows the configuration of air pressure gradients as established at sea level. The large zone of low pressure that you see, plus the smaller zone of low pressure that branches off to the left, both have close correspondence today with the blue zone on the high-altitude air pressure map. Things are not always lined up this way, but when they do get lined up the low-level pressure, as I have noted before in several letters, seems to have an effect on the structure of the blue-zone pressure higher up. It does so in a way that appears supplementary to the contraction effect of cold air on the surface. The reasons are elusive, but should be worth investigating.

And finally, there is one more map to throw in because of the common fact that ground level wind pathways are typically controlled by the configuration of sea level air pressure gradients—which automatically makes them part of today’s mix. We also know these winds have the power to deliver PW over considerable distances as contents of a separate, low-level array of atmospheric rivers. Are Arctic temperatures being affected today by this sort of activity? Perhaps. On the other hand, a ring of strong winds appears to be imparting a cooling effect on Greenland today, as compared with the warmth that was there yesterday.

Carl

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Climate Letter #2156

When we open the anomaly map today we see the Arctic up 3.1C from the baseline average—over five times greater than the global trendline number of 0.55C. One quick glance tells us that areas of warm anomaly inside the Arctic Circle far outweigh those that are cold. Anyone who is scientifically inclined, other than a climate scientist, should want to know the reason why. Well, the answer is right under your nose. All you have to do is to open this and a few other maps and learn how to read them. It’s an easy thing to do, and practically effortless if one is willing to dive in and spend a few minutes of time. So here is today’s map. All of Greenland’s surface is warming with big numbers and so is a large share of the Arctic Ocean surface, where some of the numbers are really big:

We want to know where all the heat is coming from, and we are going to do so by putting a test to my oft-stated claim that a daily influx of irregular amounts of precipitable water (PW), introduced into the atmosphere high overhead by late-stage atmospheric rivers, is responsible for practically every outcome.  When a total PW measure over any location is above average for the day we get a warm anomaly, if below average, a cool one, all because PW has its own powerful greenhouse energy effect—similar in strength, by molecular weight, to that of the water vapor it is derived from.  And furthermore, it’s strength, in terms of greenhouse energy effect, is multiplied logarithmically, such that each and every double in the value of its vertical columnar measure, starting at a rock-bottom level of around fifteen grams (for temperatures of -90C), is a large enough amount to add an extra 10C to surface temperatures directly below.  We have an abundance of opportunities every day to test these ideas, so let’s get started. Our first example is a modest one. In the map above, focus your attention on a small warm anomaly area with an oblong shape like a football at the top of the ocean image.  We will look for a localized counterpart on today’s PW map:

You must use your magnifying zoom button to do this effectively, up to no less than 200%. You will see an area of PW in that locality with a value measured in a range of 2 to 3kg on the shade scale. The surrounding area—just on the oceanic side—has a reading mostly in the 1 to 2kg range, with some internal bits below 1kg as seen in the darkest of all grays. The football shape has revealed a warm anomaly in a range close to +6C, while the surrounding area reads -1 to -2C, for a total difference of about 6-7C. The corresponding PW values, based on best estimates, show the the warm zone being a little more than 50% greater than the colder zone, perhaps 2.5 v. 1.5kg, which is a little more than half of a double. No problem.

Now we’ll go after some bigger game. Using the same two maps, and the same magnification, drop your gaze down a short way to the much stronger warm anomaly to the left of the North Pole, and do the same thing on the PW map. There is a lot going on. As we drop down, anomalies start at zero and go all the way up to a range of +16 to 18C in one spot, with a multiple set of thin layers and different anomalies in between. The PW map is layered in the same way, in the very same places. Every layer has its own reading of kg range, all the way up to 6-7 kg in the warmest place. You can find places going from around 1.5kg up to 6, for a full two doubles, reporting temperatures differing by a full 20C. The best way to check out such temperatures with the most accuracy is by going straight to the temperature map, still magnifying:

In making these comparisons, we can be pretty sure that “all else is equal” at this time of year if we stay within the confines of the flat, ice-covered ocean surface, which is topped with a foot or more of snow. There is not much going on, other than irregularities of PW abundance, that can account for all the temperature irregularities that occur on any given day in this area, or from one day to the next. The maps make it easy to establish close relationships between PW abundance and temperatures by anyone who goes to the bother of taking a close look. There are two more maps to show, without comment, which help to illustrate the way AR movement each day is influenced by the closely combined strength and positioning of high-altitude air pressure gradients and jetstream winds:

Carl

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Climate Letter #2155

A new way of measuring the thickness of Arctic sea ice enhances predictions of further rapid decline.  This was the conclusion reported in a study released on March 10 and reviewed by Phys.org::  https://phys.org/news/2022-03-icesat-remarkable-arctic-sea-ice.html.  The thickest ice, which is the most difficult to clear away by melting, was reduced in volume by 16.3% in just the last three years.  “Current models predict that by the mid-century we can expect ice-free summers in the Arctic, when the older ice, thick enough to survive the melt season is gone,” says the lead author.  By implication, that timetable may need to be shortened by at least a decade.  At the newly discovered rate of melting the thick, multi-year ice would most likely all be gone at the end of summer in another 15 years or so.  The full study outlines the advanced method of measurement used for the research. Open access is found at https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097448

Any absence of sea ice on a given day produces warmer air air above the surface, a transition from solar energy reflection to absorption of energy in the waters below, and a new source of evaporation. All of these consequences have been happening for the last several decades and will remain in effect, especially during the late summer season. At this time of year none of them are operative, and the ice itself is quite well insulated by the snow that covers it. The amplified warming that we see almost every day must therefore have one or more other sources. These sources, moreover, are known to come and go with a great deal of irregularity from one day to the next. I have begun showing the same set of maps every day in order to build my case that the greenhouse energy effect of precipitable water (PW) introduced each day at high altitude by inflows from atmospheric rivers (ARs) is capable of performing as the agency. Here is today’s anomaly map, revealing a gain of 2.4C in the Arctic, an increase unmatched anywhere else by a wide margin:

The most interesting feature is the exceptionally warm zone of anomaly at the very edge of the North Pole, which has a reading of around +22C—or 40F. Yesterday we saw a similar anomaly, moving northward around Greenland at the tail end of a long AR. The river is still there, somewhat stretched out, while continuing to make forward progress:

Overall, when you look at all the anomaly zones in the Arctic region, you can see a wide range of warm ones that measure +10C and up. The cold zones are smaller in size and lower in amplitude, which accounts for the final balance being above 2C. Our ability to make connections between PW inputs and all the different anomalies is limited by the fact that practically all of the PW values, apart from those coming directly off the one sizable AR, are sustained within a few brackets at the very bottom of the kg scale. Since every double in PW value, from any level, produces 10C of warming, we’d be much better off with readouts measured in tenths of kg at these low levels or even in grams. It does help to magnify the gray shadings to pick out their distinctive positions.

The high-altitude air pressure map again shows highly irregular boundaries around the blue zone, mainly because of the two dog ears at the top, as seen here:

The ear to the right reflects the contracted density of a patch of extremely cold surface temperatures, which is perfectly normal:

The one to the left is positioned over relatively warm surface temperatures, which requires an explanation. All I can come up with is illustrated by a very close spatial association on the sea level pressure map, a phenomenon that has also been noticed on previous occasion:

Both of these dog ear shapes have the same kind of effect on isobar placement, causing similar jetstream pathway formations that track the outer border of the blue zone. Every enactment of this kind affects the movement of PW concentrations that go on to have an effect on surface temperatures, and for that reason become worthy of study:

Carl

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Climate Letter #2154

Weekend letters are being issued mainly for the purpose of daily archiving of images. Comments are added when something of keen interest appears—like we will be seeing today.

Look closely at the bright red area of anomaly extending from northeast Greenland toward the pole. The inner part of it has a section with a reading in the +21-24C bracket on the scale—around +40F. The actual average temperature in that spot has extraordinary readings as high as +1C, or 34F:

Nothing can explain such an extreme anomaly better than a strong influx of precipitable water (PW) at that location.  This one has kg values in the 11-12 bracket on the scale.  My estimate for the average kg value in that spot three decades ago is in the 2-3 bracket, let’s say 2.5.  (It would be nice to have access to an exact number.)  Today we are getting more than two doubles of that number, just as expected when searching for the most likely cause of an anomaly greater than 20C.

The jetstream map reveals the pattern of winds that trace out the same course as the complex of atmospheric rivers, as seen on the above map, that were responsible for transporting such a high concentration of PW to such a remote location. Some of the river vapor, under the influence of the way these jet streams are positioned, takes a detour all the way to the Strait of Gibraltar before heading north.

Jet stream positioning is always governed by the pattern of air pressure gradients that prevail at that altitude. This next map, despite its lack of isobars, accurately portrays the overall pattern. The jetstream map does a suitable job of revealing the isobars.

Carl

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Climate Letter #2153

Today’s anomaly map.  During the past week the world, tropics and NH have all experienced short-term  cooling trends, the SH has been flat, and both polar regions have been warming.  The Arctic today is very close to being on the long-term trendline as set up over the past three decades, which currently has a reading of +2.2C .  The world’s trendline for the three decades is much lower, at just +0.55C.  Each of the six designated regions on the map has its own peculiar set of factors that cause the region to be either above or below its long-term trendline on a given day.  These factors can only be fully appreciated after doing an analysis of all the warm and cold anomalies over the entire region for the day, a daunting task.  In the two polar regions this task is quite a bit easier than anywhere else, because these regions are relatively small compared to the others, their anomalies in most cases are relatively large in size, and the factors of causation for each anomaly are usually heavily weighted by how much precipitable water (PW) is in the atmosphere above each one of them on that day.  These factors can be measured in a straightforward way and their effects can be calculated quite accurately.if one has the best available tools—estimates made with limited tools, like the ones I use, can still have value.

Now for today’s PW map. For a perfect example of how low-value PW, in terms of kg weight, causes cooling of surface temperatures, look for the slender T-bone shape in dark gray that crosses the center of the Arctic Ocean on this map, then match its shape with the position of the cool anomaly in the same area on the top map. The same principle applies to the interpretation of every anomaly:

The next two maps are saved today as archives, without comment.  They provide illustrations of processes that occur high in the atmosphere.  These processes have a powerful influence over the final destiny of the PW content of the atmospheric rivers that are seen approaching the polar region in the above map, following journeys that originate in warm tropical waters.

Carl

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