Hi all, and its been a while since I have posted, but I will help you catch up to speed on what’s occurring in the tropics and how my summer & hurricane forecasts are panning out in comparison to some of the model guidance & other factors offering support for it.
First of all, remember my hurricane outlook, with this picture from my last post on April 21st, with ideas from this that were derived from my post back in March, ahead of all the other forecasts shown below, thus I can say I was the first to put my hurricane season ideas out there.
My hurricane season forecast
Looks a lot like the forecast from Joe Bastardi and weatherbell that was released several days later
Here’s a few other forecasts just for entertainment purposes.
Hurricane forecast from an Accuweather forum
Matthew’s hurricane season forecast
Weathertrends360.com’s hurricane forecast
Occupyweather’s landfall risk forecast
Weatherworks east coast hurricane risk forecast compared to climatology (a forecast I strongly agree with here)
Now, here is the UKMet office hurricane model forecast for the month of July
The CFSv2 forecast for the same exact time period showing a very similar solution
Now look at my analog years that I complied back on March 24th with 1960, 1969, 1979, 2004, and 2010, pretty close eh?
Interesting in how these model solutions appear somewhat similar to the 500 millibar pattern in the 1938 Long Island Express, a year that was mentioned in my last post with some similarities in the summer outlook and of course late season snows over the midwest, particularly Chicago in the month of April. Notice in the picture below, like in the model forecasts, the notable ridge over southern Canada, a reoccurring theme that seems to be present during significant hurricane landfalls as the ridge helps to “block” the forward progression of tropical cyclones in the SW Atlantic, forcing them into the US coast
500 mb 1938 long Island Express September 19-22 1938
Of course my solution is nowhere near as bad as what the climate models are predicting, a ridge sitting in the position being predicted by the CFS & the UKMET is a signature for hurricane landfalls on the US coast because that region of high pressure located directly to the north of the east coast, southwest Atlantic and Gulf of Mexico helps to focus lower than normal pressures and convergence over this area, which helps to fuel tropical cyclone development. Also consider that as tropical cyclones exit from the tropical easterlies and enter the mid-latitude westerlies they have a tendency to recurve northwest, north, and eventually northeast, however when you have a ridge of high pressure to the north or to the northeast of a storm’s position, this “blocks” (a good reason why these areas of high pressure are also referred to as “blocks” not just high pressure, they are generally interchangeable terms.) the natural progression of these storms into the mid-latitudes and eventually towards the poles, where hurricanes have a tendency to move towards as they are essentially created to balance the difference in temperatures from the tropics to the poles (they’re also referred to as “earth’s air conditioning systems”), thus they have a prolonged movement in the tropical easterlies, which means if you have a storm in the SW Atlantic, as opposed to just going out to sea, the storm will have a tendency to come towards the coast.
Look at the highest hurricane landfalling years since 1948 on the US coast, and look how close this pattern being predicted by the climate models is to the highest hurricane landfalling years on record, not good news for the US.
Also remember the western Pacific typhoon connection, the same pattern over the western Pacific (ridging directly north of the deep tropics focusing lower pressures, convergence and forcing storms closer to land), where there is anomalously large amount of typhoons over the west Pacific hitting the east coast of Asia, specifically Japan and Korea, this teleconnects to increased hurricanes especially on the US east coast.
You can also see the models are also finally beginning to pick up on the increased tropical activity in the Atlantic, indicated by the shades of blue (lower than normal pressures) near the southeastern US coast in the CFSv2 MJJ pressure forecast, a signature that there is increased tropical activity in this area, offering yet more support for hurricane landfalls.
The global water temperature anomalies reveal that at this time, 2004 is very similar to what’s being observed now, with an Atlantic Tripole Signature, (warmer than normal in the tropics, cool in the mid-latitudes, warm again towards the Arctic) typical in warm AMOs, and also the warmer than normal waters over the Indian Ocean (reason why the MJO will be diving so deep into octants 2 & 3, as this area is warmest relative to normal over the global tropics, and thus promotes rising motion, in which the upward MJO is a measure of) Cooler than normal water situated west of the South American coast is also very interesting to note as well as generally warm conditions over the Southern Hemisphere offer further a further similarity with this year and 2004.
May 1, 2004
May 1 this year
The following 2004 hurricane season, which is one of my top 5 analogs for this year featured a barrage of hurricane landfalls on the US coast, particularly in Florida and the Gulf of Mexico.
This video below brings back some personal memories as it was Hurricane Charley in 2004 that I can recall one of my first experiences with the weather (really grabbed my interest from that point on), although it wouldn’t be at least for me, until hurricane Bill in 2009 that I would finally begin to strive to become a weather forecaster.
However, the major difference between this year and 2004 is the cold PDO signal over the north Pacific, indicated by the anomalously warm water north of Hawaii, with a tongue of colder than normal water down the west coast of North America, indicated in the right side of the picture below labeled as the “Negative Phase” of the PDO, which was in place from the 1950s to the late 1970s.
Now, look at just how similar the tracks of the storms in the 2004 & 2005 seasons are to the last time the PDO began to turn cold (although not completely warm), and the Atlantic was in the height of its warm phase, the 1940s.
2000s major hurricane landfalls (all in 2004 & 2005), notice the congregation of storms near Florida & the Gulf of Mexico.
Interestingly, a similar landfall pattern seems to present itself in the 1940s
However, look what happened after the 1940s, once the PDO turned cold, the tracks of major hurricane landfalls shifted to the east coast, as a major trough buckling began to force itself towards eastern North America.
Thus, with such a shift in storm tracks towards the east coast from the Gulf of Mexico and Florida where they have been for the past decade is certainly very concerning for the east coast, especially as although Irene & Sandy have been significant storms in their own respect, the major hurricane drought continues for the US east coast and the US coast in general, as each passing day sets a new record for longest streak in US history since somewhat viable hurricane tracking began around the Civil War.
This shift in storm tracks is becoming evident, however, the US should consider itself lucky the past several years, as many storms have avoided the US coast due to a persistent trough feature near the US east coast.
However, you should take note of the relative region of abnormally higher than normal pressures near the Davis Straits, and although there is a considerable block in this region, which would suggest using the knowledge that regions of high pressure help to block the natural progression of tropical cyclones into the mid-latitude westerlies, that this type of pattern would help to yield a large amount of landfalls, however, this was not the case, except for Irene & Sandy.
2011 hurricane season
2012 hurricane season
Hurricanes Irene & Sandy from last year and 2011 at their peak intensities, almost scary how closely both storms resemble one another.
Hurricane Irene (2011)
Hurricane Sandy (2012)
Now, why would a pattern with blocking directly to the north of the deep tropics over Greenland & the Davis Straits be a hinderance to major hurricane landfalls on the US coast? The answer seems to lie within the blocking itself, as although the block of high pressure does help to block some storms, at least ones in the mid-latitudes, there is an issue with blocking the progression of storms in the tropics. It would seem that the block of high pressure is too far to the north of the deep tropics, and thus the subsequent region of low pressure forcing underneath the block of high pressure, instead of being near the SW Atlantic or southern US coast, is much farther to the north towards the Great Lakes & northeastern US. Considering that storms in the tropics have a stronger tendency to go from the tropics to the poles as they increase intensity, as they are naturally created to act as earth’s air conditioning systems, helping to regulate the temperature gradient between the poles & the tropics, a ridge over the arctic towards Greenland & north of Atlantic Canada helping to force a trough higher up in the mid-latitudes would actually have the opposite effect compared to a similar ridge north of the tropics, like what is observed in major hurricane landfalling seasons. What makes the difference in this case is the fact that a ridge farther to the north towards the arctic like what was observed in the past few years is so far to the north that as tropical systems begin to close in on the US coast, this ridge is far enough to the north to allow a trough in the mid-latitudes to have the ability to force storms out to sea as it is just far enough to the north to allow the effects of the mid-latitude westerlies under the “Ferrel Cell” to kick storms out to sea.
Compare this pattern to high hurricane landfalling years, and the difference is not essentially in whether or not a region of anomalous blocking is to the north of the tropics, rather it is a matter of where the block is in relation to the tropics that makes all of the difference in whether the US is relatively spared from tropical cyclones or hit very hard in a particular season.
500 mb pattern greatest hurricane landfalling years since 1947.
Despite the fact that this pattern with the blocking well into the arctic for most of the year, still resulted in the landfalls of hurricanes Sandy & Irene, and upon looking at those storms, it’s interesting to note in how the block of high pressure that was present near the Canadian arctic & Greenland moves significantly farther to the south, resulting in these storms making landfall on the US coast.
Hurricane Sandy 500 mb pattern
Hurricane Irene 500 mb pattern, interestingly enough has very little in the way of blocking to the north of the storm, other than some high pressure (indicated by the shades of yellow & orange) displaced slightly to the south towards southern Greenland & near Atlantic Canada, merely it would appear that hurricane Irene timed the trough just right to allow it to come towards the east coast.
Another aspect about the pattern that seems to grab my attention is the distribution of the water temperatures over the north Pacific in association with the cold PDO. Compare this year’s water temperatures to the past several years and one can easily see there is a notable difference in the placement of the warmer than normal waters north of Hawaii, associated with the cold PDO.
What really seems to grab my attention in this instance is the fact that compared to the last few years, the PDO, although still considerably cold, the signature of warmer than normal waters naturally found north of Hawaii is located much farther west. What this would imply for is that when you have the cold PDO, the natural trough that is near or just offshore the western US is forced to move westward in response to the westward displacement of the of the water associated with the cold PDO, this in turn, forces a reaction in the pattern downstream over the US & North America, in that the ridge forced over the Great Plains from the western US trough & deep la nina is now forced to migrate farther east as the trough off the west coast moves east, this also means the eastern US trough that has been helping to protect the US coast the last few years will be non-existent, and instead will likely be replaced by ridging, which would imply for a pattern more supportive of high latitude blocking that favors US hurricane landfalls.
This picture below helps to illustrate this concept
Looking at some of the forecasts for this upcoming summer and using the conditions at hand, once can get an idea as to where exactly the pattern will be going this summer over the arctic, perhaps giving an indication as to where precisely the blocking will be north of the tropics. First of all, consider the fact that the Nov-Apr period has been the snowiest on record in the northern hemisphere since accurate record keeping began in the 1960s.
All time top 25 Northern hemisphere snowfall rankings for the Nov-Apr period, notice how this year is first place, and also look at how 4 out of of my top 5 hurricane analog years of 1960, 1969, 1979, 2004, and 2010 are among the years listed below as being very snowy in the Nov-Apr time period. You can also see there are a few other interesting years to note including 1985 (#3) (holds the record for most hurricane landfalls on the US coast in a single hurricane season, 2003, 1996 that has been mentioned several times in many of my previous posts as being somewhat reminiscent of the current pattern, (a year that later featured hurricanes Bertha & Fran), 2004, & 2005 towards the bottom of the list.
Consider the fact that snow, in comparison to an environment with a lack of snow reflects 85-90% of incoming solar radiation, thus cooling the atmosphere, and in the fall & winter, even into the spring to some extent, colder air, taking up less space with the same amount of air molecules (making it denser than warm air), helps to force a contraction of the layer of atmosphere in the lower troposphere, which gives an opportunity for the upper troposphere and the stratosphere to expand, which is characteristic of warmer air that is more freely to move about, and such a condition helps to lead to stratospheric warming events, which are known to be associated with abnormally cool spells of air originating from the arctic, which under the right conditions, can be forced into North America and the US. In the summer, the conditions in place are different as the wavelengths of energy are much stronger, and force the natural jet stream to become much weaker and retreat in the summertime, forcing the natural weather patterns as well to shift northward in response to this. Thus, with a stronger than normal snowpack going into the summer, the effects are the opposite compared to the winter as the polar jet stream is much weaker and confined to the pole, which means that only regions of the arctic in the summer have significant snow cover. Thus, when snowpack in the spring is above normal in the northern hemisphere, (like what is being observed this year), this means only regions of the arctic experience the effects of increased snowfall, and due to the strong temperature gradient near the southern extent of the snowpack, this forces a bundling of cold air in the arctic, thus, cyclonic energy is induced, which is indicative of lower than normal pressures. Thus, when you have lower than normal pressures in the arctic compared to normal against the mid-latitudes, this helps to tighten the pressure gradient between the mid-latitudes and the arctic, thus inducing a +NAO.
Here is the correlation of summer NAO to 500 mb heights over the Atlantic, and to no surprise, if you have lower than normal pressures towards the Greenland & Canadian Arctic, this helps to strengthen the Azores-Bermuda high, which is the main steering mechanism for tropical cyclones in the Atlantic, thus with a stronger than normal Azores-Bermuda high thanks to a +NAO in the summer, this naturally forces storms farther west, closer to the US coast, and with this region of high pressure in the mid-latitudes, this also helps to promote lower than normal pressures towards the tropical Atlantic, helping to enhance hurricane activity (in a general sense).
North America summer temperature composite of the top 20 northern hemisphere snowpack years (excluding this year due to the fact that data has yet to be attained) for the Nov-Apr period reveals this increased snowpack in the spring having lingering effects into the summer pattern over the northern hemisphere, with colder than normal temperatures (shown in blues and purples) noted in the Canadian & Greenland Arctic.
At 500 millibars, the pattern reveals that due to the abnormally high spring snowpack, the resulting pattern in the summer during the hurricane season features a gyre of low pressure centered near the Hudson Bay and north-central Canada, with a resulting ridge towards Atlantic Canada, extending its influence into the northeastern US.
Look at just how close this is to my hurricane analog package 500 mb pattern released way back in March, with features like the “Hudson Bay Gyre” and the block of high pressure near Atlantic Canada notable features.
It makes sense for a large region of low pressure to situate itself over the Hudson Bay given the conditions at hand, especially in considering the above normal snowpack over the northern hemisphere, which was still above normal even into spring, somewhat different than the past several years.
April northern hemisphere snowfall anomaly
Those following summers with higher than normal snowpack in the northern hemisphere looked like this, (a lot like my summer forecast back in April), with below normal temperatures over the southeastern US, warmer than normal towards the northeast & New England, and warmer from the Rockies and points westward, with the plains, although possibly warm because of the cold PDO, it’s not as bad as last year.
The precipitation in those summers (blue above normal, purple well above normal, yellows and oranges below normal precipitation) seems to reflect some of the main ideas in my summer precipitation forecast that I released back in April, with wetter than normal towards the southeast, potentially drier towards the plains (although not as bad as the last few years), with hints towards drier than normal conditions and at least comparatively drier conditions to the surrounding environment in areas of the northeast and from the Rockies and areas westward.
Of course, if conditions are wetter than normal in the southeast, this is an indication of a few things. First of all, those of you living in the southeast, you often experience drought, however, in the summer comes the threat of tropical cyclones, and during those summers that you experience tropical cyclones, there are usually significant flooding problems. Yet, over a 10 year period for instance, 2 or 3 summers may have tropical cyclones, while all the others have none, well, the “normal” over this period of 10 years favoring or not favoring a tropical cyclone, favors a pattern without a tropical cyclone as 7 or 8 years (hypothetically speaking) do not have a tropical cyclone. Yet, in those 7 or 8 years without a tropical cyclone, drought is observed, but why? Well, “average” in of itself is just an average between two extremes drought and flooding rain, and when you have just a few tropical cyclones over a decade or so, the rainfall produced by those storms is so significant that it drives up the average several inches against the years, thus these tropical cyclones jack up the precipitation average well above the point where it would be in a “normal” pattern, thus in the southeastern US, it’s usually a feast or famine scenario when it comes to precipitation over the summer, rather than being in between. Thus, when I see in the analog patterns given the conditions at hand and other forecasts hinting at wetter than normal conditions over the southeast, there’s plenty of reason to be concerned.
Let’s take for example some years that featured an influx of tropical cyclones over the southeast US and look at those summer patterns.
1960 (one of my hurricane analogs)
Summer precipitation anomaly, overall near to slightly above normal in the southeast, note the above normal anomalies up the east coast, thus you can probably associate these precipitation anomalies with Hurricane Donna.
1960 hurricane season
1964 precipitation anomaly, notably wet towards Georgia, South Carolina, and north Florida.
To no surprise, those areas that were wetter than normal in the southeast were the same regions that experienced major tropical activity.
1964 hurricane season, note the congregation of storms in areas where it was wettest.
1979, another one of my hurricane season analogs, look at its precipitation anomaly, wetter than normal over the southeast
1979 storm tracks
1985 precipitation anomaly, once again showing, although not nearly as conclusive as the other years shown, wetter than normal conditions over the southeast, with regions of focus towards the immediate east coast and the northern Gulf coast.
The 1985 hurricane season, showing a collection of tropical cyclones towards the Gulf Coast and Hurricane Gloria up the US east coast, thus I think you can see a reoccurring theme here, where it is wettest over the US coast, (especially the southeast) is where tropical cyclones tend to be, and this essentially is common sense given that tropical systems are notorious for dumping large amounts of rainfall over areas affected by the storm.
Considering the cold AMO, a blend of the 1989 & 1991 summers gives you this precipitation wise over the US, notably wetter than normal over the southern US.
Those following hurricane seasons, to no one’s surprise were active on the US coast with hurricanes Hugo and Bob on the east coast.
Hurricane Hugo (1989)
Hurricane Bob (1991)
Also, let’s not forget the sunspot cycle to US hurricane landfall connection that I made in of my earlier posts, as it should come to no surprise, despite the cold AMO that these major storms struck when they did, at the peak of the solar cycle.
The picture below showing solar cycle 22, with the corresponding numbers at the bottom of the image indicating the date (yr then month from bottom to top), showing the solar cycle, a “double-peak” with one peak in 1989, the other in 1991, both years which featured a major tropical system on the US coast. (despite the cold AMO which usually does not favor US hurricane landfalls)
1995 summer precipitation anomalies, although near normal mostly everywhere due in part to the warm AMO flip, a few hints at slightly above normal precipitation over the southeast are shown with some regions of blue showing up.
1995 hurricane season
1996 summer precipitation anomalies, two distinct regions of heavy precipitation noted, one band towards the Carolinas & Mid-Atlantic, the other towards the western Gulf of Mexico & southern Plains
1996 hurricane season, with notable storms like Bertha & Fran hitting the Carolinas, although in this instance, the wetter than normal conditions over the western Gulf and the southern plains are not associated with tropical activity.
2002 summer precip, notice the shift farther to the south towards the Gulf of Mexico, with drier conditions towards the Carolinas
2002 hurricane season showing how the congregation of storms towards the Gulf of Mexico help to lead to the anomalously wetter than normal conditions over that area.
2004, a hurricane season analog, showing a large region of considerably wetter than normal conditions, the core of wet towards Florida, exactly where the barrage of hurricnes struck, and the wet conditions were not just over the southeast, but extending well northward into much of the eastern US.
To no surprise, with wetter than normal conditions in the summer, the culprit, a large number of tropical cyclones.
2008 summer precipitation, although not wet everywhere, it is wet towards the western Gulf areas that were affected by Ike & Gustav and its not quite as dry towards the Carolinas where tropical storm Hanna hit, but in between towards South Carolina, Georgia, and much of Tennessee, its drier than normal.
The 2008 hurricane season tracks help to reflect the summer precipitation pattern over the south
The composite of all of these active hurricane years on the US coast strongly supports the idea that increased tropical cyclone activity leads to above normal precipitation over the south.
Look at how close this is to my analog hurricane years of 1960, 1969, 1979, 2004, and 2010
Those summers with higher tropical activity that led to above normal precipitation overwhelmingly had cooler than normal summers, especially over the southern US.
In this type of pattern in the summer it will usually be colder than normal, (unlike the past several years), due to the fact that the increased amounts of water with its heat content being one of the highest of any substances known to man, helps to regulate temperatures in the surrounding environment, thus in the summer, as the sun angle becomes anomalously high and more radiation is received to earth’s surface, the water having a higher heat capacity has the ability to absorb similar amounts of energy without changing temperatures drastically, thus, significant heat waves are reduced dramatically under such a pattern (which in this case includes the southeastern US), and this is exactly why I have the southeastern US colder than normal this summer.
As mentioned earlier in this post, this increased snowpack in the summer has the opposite effect as opposed to the summer, in that it helps to enhance the natural temperature gradient between the mid-latitudes and the polar regions, and considering that colder air, due to the limited movement of the air particles in comparison to warmer air induces a sinking motion in the atmosphere, thus enhancing regions of high pressure. Also, knowing that air naturally flows from regions of higher to lower pressure, much like the biological process of osmosis, this time involving the movement of air particles from a higher to a lower concentration, this means air will naturally spiral inwards (due to Coriolis Effect) towards the region of low pressure directly to the south of the region of higher snowpack, this usually is an indication for low pressure just south of the Arctic, exactly where my hurricane analog package and the high northern hemisphere snowfall years have been putting an area of low pressure.
Now, when you look at the CFSv2 forecast for the summer, you can see it is beginning to pick up on a region of colder than normal temperatures (in blue), (implying for below normal pressures as well, which means a +NAO) over Greenland and the Canadian Arctic.
Another depiction of this cold over Greenland & northern Canada, this time from a global perspective.
Already since April, due to the abnormally high snowpack in the northern hemisphere, temperatures and pressures have fallen to below normal levels over the arctic, potentially offering as a precursor to what the summer may hold.
500 mb heights for over the last month, and you can see how the cold over northern Canada & Greenland correlates to the increased snowpack, and you can also begin to see the pattern seems to be revealing itself for what the summer may hold with a ridge over the north Pacific, (classic under cold PDOs) a trough over the central US (a good reason why I am forecasting a much wetter & cooler summer than last year there) and a ridge beginning to balloon over Atlantic Canada and in the northeastern US, which of course are also features evident in my hurricane analog forecast that was issued way back in March (even ahead of weatherbell).
North American temperature anomalies over the last month
Of course, a +NAO usually results in more sea ice as cold air is bundled up over the arctic, helping to slow the rate of melting, leading to generally more arctic sea ice (although there are always exceptions from time to time), thus when I see sea ice forecasts from the CFSv2 indicating the next minimum to be between 5-6 million square kilometers, closer to the mid 2000s average, (much higher than last year’s minimum that fell below 4 million square kilometers.), this is giving me an indication that the NAO will be weighted towards its positive state this summer, which of course, given the information above, spells big trouble in accordance to US hurricane landfalls.
CFSv2 summer minimum sea ice extent forecast
JAXA sea ice & 1980s, 1990s, and 2000s, mean sea ice.
Upon looking at arctic sea ice and comparing it to oceanic heat content temperature anomalies for the top 700 meters of the ocean surface, I discover something that furthers my thinking that looking and focusing on the ocean rather than the atmosphere is a much better way to go when trying to look at arctic sea ice.
Let’s just remember, the energy budget of the oceans in comparison to the atmosphere is at a magnitude of 1100x, in favor of the oceans.
One should not be too terribly surprised with the recent arctic sea ice declines as the AMO entered its warm phase in 1995, and has been on an overall upward trend in oceanic heat content over the north Atlantic since that time, although it has appeared to have peaked in 2007, and the AMO may be on its way towards its cold phase.
Of course, the AMO beginning to head towards its cold phase has major implications on the overall pattern in the next several years, many implications which I have mentioned in my previous post from April 21st, one of the most significant being the major shift in hurricane tracks from the east coast to the Gulf of Mexico as the pattern at 500 millibars shifts in a general west-southwestard motion in response to the cooling Atlantic. With the colder than normal Atlantic and Pacific under a cold PDO, cold AMO pattern like what was observed in the 1960s & 70s, this argues for more activity towards the Gulf of Mexico because with both oceans being colder than normal in the deep tropics, this helps to enforce higher than normal pressures, and is a contributing factor to colder than normal temperatures at the 400 millibar level in the tropics, which is not favorable for tropical activity. The reason is due to the fact that tropical systems rely on the release of latent heat energy, which involves condensation, or the process of water vapor turning into liquid water, an exothermic reaction, which releases heat in order to compensate for the change in the overall movement of air molecules that is slowed under this process. The release of heat allows for further evaporation from the ocean surface, thus the process of latent heat energy release is enhanced, and along with the Coriolis Effect as well as the differences in the coefficient between the ocean surface and the higher levels of the atmosphere, helps to force air to spiral inward around a common center, forcing surface pressures to fall and more latent heat to be released in the process.
Speaking of 400 millibar temperatures, look at what has been observed thus far, clearly a favorable pattern for tropical cyclones with cold in the mid-latitudes, enhancing higher than normal pressures there, which help to focus convergence over the tropics underneath the already warmer than normal temperatures at 400 millibars.
Observed 400 millibar temperatures Jan-Apr 2013
Look at just how close this is to my analog hurricane season package of 1960, 1969, 1979, 2004, and 2010 for the exact same time period.
Certainly is not last year when it was colder than normal at 400 millibars in the deep tropics, a very good reason why despite the active African Wave train, there was a lack of activity in the deep tropics.
Last year’s 400 millibar temps
2012 hurricane season
Also remember that as temperature increases, the amount of energy difference between each degree increment is also greater, thus a larger energy exchange is observed in the tropics as opposed to regions of the poles, and combine this with the fact that the oceans have 1100x the energy capacity of the atmosphere, this effect of greater energy differential in the tropics is only enhanced by the oceans, this has effects on the 1950s-1960s observed pattern change between states of the AMO and its relation to the cold PDO, a relationship that is already beginning to show itself once again.
Going back to the difference between the 1950s and the 1960s in terms of the pattern of storm tracks in the Atlantic, (which is an indication of where our current pattern will be headed as the AMO begins to cool over the next several years) clearly shows that there is a major shift in the zone of focused low pressures from the African Coast and the deep tropical Atlantic towards the Caribbean. Such a shift in the focusing of tropical energy has major implications on where storms are likely to go as evidence strongly supports in a general sense that storms in the Caribbean are more likely to impact the Gulf of Mexico and the classic “Cape Verde” storms more likely to strike the east coast.
This picture below helps to illustrate this concept, described above where storms in the Caribbean are more likely to affect the Gulf of Mexico (indicated by positive values and contours), whereas storms near the African coast and the eastern Atlantic, the east coast (indicated by negative values & contours).
More reason to be concerned about this year for the east coast is that the predictions for neutral ENSO based on the fact that another year of la nina will be difficult to come by given the multiple years of la nina already observed, and an el nino given the cold PDO signature in the North Pacific helping to force cooler waters into the equatorial Pacific, reducing the chances for el nino. When you compare east coast & Florida hurricane tracks from la nina years (like what’s been observed the last several years) and compare them to neutral ENSO years like what’s being forecasted, the one notable difference is the fact that the storms in a neutral ENSO pattern tend to come farther inland as opposed to la nina years. This is exactly why I am concerned about this hurricane season, in the fact that it being a neutral ENSO year and with the pattern of warm AMO, cold PDO like what was observed in the 1950s & 1890s, means that whatever storm systems attempt to hit the US east coast this year, unlike the last several years with Sandy, Irene, and Earl in 2010, will more than likely affect areas much farther inland as opposed to primarily coastal areas, thus, putting not just the coast, but much of the eastern US under the threat of significant tropical cyclones this season.
La nina east coast hurricane tracks
Neutral ENSO US east coast hurricane tracks
La nina Florida hurricane tracks
Neutral ENSO Florida hurricane tracks
You can see the shift westward evident in overall storm tracks not just for individual seasons, but between the 1950s & 60s, as the PDO, although still cold, has a much better opportunity to result in el ninos, because during the 1950s, with the Atlantic Ocean warmer in relation to the Pacific, this forces that ocean to remain its cold state, (la ninas), however, when the Atlantic cools down, this helps to “even the playing field” between the two oceans, inducing more neutral & warm ENSO years, which as was shown in the comparison of the two pictures above showing major storm tracks between la nina & ENSO neutral years, in which, ENSO neutral conditions usually result in storms moving farther west, which is exactly what happened in the 1960s after the east coast barrage in the 1950s.
1950s US Major hurricane hits
1960s US Major hurricane hits
Also, another consequence of a cool AMO is the drought in the plains diminishes, while the winters in the US generally get much colder & snowier.
You can even see some resemblance beginning to show up in the European winter pattern, very comparable to the early 1960s, before the flip to cold AMO
Europe winter temperatures last 5 winters
Europe winter temperatures winters 1960-1963
Look at this from a previous post, showing the relationship between the AMO & sunspot cycles, with lower sunspot cycles over the last several years beginning to coincide with an cooling (but still quite warm) AMO like what was observed in the early 1960s before the AMO crashed into its cold phase in 1965.
Oceanic heat content top 700 meters of the north Atlantic since the beginning of the reliable satellite record, revealing the substantial increase in ocean temperatures from 1995-2007, coinciding with a major fallout in arctic sea ice.
Northern hemisphere sea ice since 1979, notably dropped from 1995-2007, but since the time when the top 700 meters of ocean in the north Atlantic peaked in temperature, arctic sea ice has declined not quite at the rate observed in the early 2000s under a warming AMO, and a relatively warm (but cooling) PDO.
A map of arctic sea ice at the current time reveals the oceanic relationship to the cycles of AMO & PDO, with of course the Pacific side of the arctic towards Alaska, under a relatively cooler oceanic cycle of a -PDO, is observing near to above normal sea ice. However, since the fact that a much larger region of the arctic is open to the north Atlantic, this means the AMO has a greater effect on sea ice, especially towards the North American & European sides of the arctic, where the greatest region of sea ice loss compared to normal is currently being observed, as it would make sense given the AMO is in its warm mode.
I don’t usually like to focus on computer models, as it is not what I believe makes a great forecaster, rather looking at the conditions at hand and then making a forecast, using the models only as a guide or a tool to help give minor forecast adjustments here or there. That being said, I have begun to fall in love with the CFSv2, as it has proven to be unusually accurate of late in “sniffing-out” patterns before most other climate models. Take for example last December when everyone was concerned that this winter would be just like last year, and many thought I was completely nuts for claiming that winter would make a comeback later in the month, and not only that, but in my post on December 3rd I made a very bold and specific prediction on my white Christmas ideas for one to occur in areas east of the Rockies and south of the I-40 corridor. Here’s a quote from that post “Given all of this information, I’m going to go out on a limb and say that a majority of the US experiences a white christmas this year, (average is 33%), with someone east of the Rockies,(excluding the appalachians of NC & TN) and along and south of the I-40 corridor seeing a white christmas.”
This idea was heavily supported by the CFSv2, which seemed to pick up on this very early, despite some thinking that this winter was already over before it even started (lol).
Also, back in early January, after the brief period of cold in the US in late December, the CFSv2 for the Jan-Mar period, was predicting colder than normal conditions over the US, with the core of the cold towards the plains and southern Canada, and this certainly was a huge forecast win for the model. Meanwhile, other climate models like the ECMWF and the UKMET had absolutely no idea this was coming.
Actual temperatures, for the same time period, not bad eh?
Or even the late season cold, which lingered well into spring, the CFSv2 was “sniffing it out” well in advance, here is its forecast all the way back in December for the Feb-Apr period for North American temperatures.
Actual temperatures in North America for the same time period
In fact, look at the newly released NCDC temperature map, coldest April on record in the state of North Dakota, with it being top 5 and top 10 coldest throughout much of the midwest.
Meanwhile, other climate models like the ECMWF and the UKMET did not see this cold coming at all, and their forecasts busted big time in areas like Europe, and it would seem to me that models like the ECMWF and the UKMET have a significant amount of difficulty picking up on upcoming cold, while the CFSv2 appears to do fine. The issue may not be the climate model itself, but the parameters built into the model, like if it was to assume that constantly rising CO2 would equate to warming, and it is not occurring, then there’s a huge problem there, and the ECMWF does seem to be struggling immensely with the upcoming hurricane season, although that may be a combination of this and the oncoming neutral ENSO.
The ECMWF’s forecast for MSLP or atmospheric pressures, with shades of blue indicative of lower than normal pressures (rising motion), which is favorable for tropical cyclones, while areas of red are indicative of higher than normal pressures, which of course is not favorable for tropical cyclones.
Now look at the forecasted ACE index of the CFS, in its latest 20 runs, and take note of the bright colors showing up in a band extending from the west coast of Africa to near the US east coast, this is indicative of the model keying on on this area as a region for abnormally high tropical activity. Also, when you have higher than normal tropical activity over a particular region, the release of latent heat and increased thunderstorm activity from the tropical cyclones would mean that the overall surface pressures, in a general sense should be lower than normal in this area as well. However, this forecast should be taken with some grain of salt as the CFSv2 forecast is based off of the GFS a few years ago, (which even to some extent today) has a very definitive poleward bias for storms, meaning that it has a tendency to force storms too quickly into the mid-latitude westerlies, thus its storm track predictions were often too far north & east, and if this is taken into account, this would give us the impression that the actual main storm track should be farther to the south & west of where the CFSv2 currently has it.
Compare this to the 500 millibar heights in my hurricane season analog package of 1969, 1979, 2004, 1960, and 2010 released all the way back in March (even before weatherbell), and look at just how closely (almost scary) in how this resembles the CFSv2 forecast above, as it seems some of the models are finally beginning to catch onto my ideas.
Others seem to be finally catching onto my summer temperature & precipitation forecast, shown below, which was released back on April 21st, looks very close to the forecast released later by Accuweather.
Accuweather summer precip forecast
My summer precipitation forecast from April 21
Accuweather summer temperature forecast
My summer temperature forecast from April 21st
Also, with an active US hurricane landfalling season, as was shown in my previous post, those years tend to be followed by cold starts to the following winter, particularly December. Here is the composite of the most active US landfalling hurricane seasons and the resulting temperatures in those following Decembers, which indicated by the shades of blue, is colder than normal over the eastern US.
This temperature composite image above based off of the active hurricane landfalling seasons being followed by colder than normal Decembers in the eastern US, and warmer towards the west was the premise for my forecast for the “start” of next winter, not the winter in its entirety.
The CFSv2, which has proven itself of late in being a reliable climate model is sniffing out this cold start to next winter, as I’ve been talking about for quite some time now, with a cold signature developing over North America, seems as if the start to next winter may finish off where this winter left off.