PATTERN CHANGE BY THE NUMBERS ????
2300 EDT SATURDAY NOV 5
CLICK ON THE IMAGES TO SEE FULL SIZE !!!
There has been a lot of talk recently from a lot of meteorologists and weather hobbyists about the potential for a pattern change coming up sometime in the middle of November. This idea has been “fed” by the last several runs of the operational GFS which has from time to time over the past 5 to 6 days which gone absolutely bat shit crazy – like Michelle Bachman bat shit crazy– in developing a rapid transition to a winter like pattern over the central and eastern portions of the CONUS by the time November 15 rolls around. The operational GFS and GFS ensemble have… several times in the past 6 days… developed significant blocking at the high latitudes over Greenland and developed a significant trough over the central / eastern Conus AND ridging in the Jet stream over the West coast.
However it’s not just the operational GFS or the GFS ensemble. Over the past several days there had been some impressive runs of the European model in detecting some important shifts in some of the high latitude weather patterns. However the European model because of its overall superiority has NOT been developing the extreme cold pattern that the GFS has. The European model has not developed significant RIDGE over the West coast of North America nor has it developed a deep trough over the eastern third of the CONUS.
The European model / european ensembles the shift towards a colder overall pattern has been much more gradual and realistic.
One of the reasons why energy and grain meteorologists are able to see significant pattern changes coming somewhat sooner than a regular or operational meteorologist can… is because we have look at all portions of the world. This is especially true for GRAIN meteorologist like yours truly. Every single day (except for the weekend) I spend a lot of time focusing on South America weather… Australian weather… the current dry conditions in the wheat areas of the Ukraine and Western Russia… the harvest in Eastern China and conditions in India. Most meteorologists whether its TV or NWS do not and this is critical IF you are trying to see what is going to happen day 10… day 15…. or day 20. That is why most forecasters don’t try and make a forecast past Day 7.
Some people were born to play baseball. Some people were born to complain. I was born to forecast.
Let’s take a look at the Maps!
This first image shows the current overall pattern across the entire northern hemisphere at 500 MB. And there are several important features we can talk about
I have highlighted the important features by NUMBERS in order for you to be able to follow which particular features I am focusing on …and also so that you can begin to see how weather patterns are all interconnected and related. By getting a better handle about how things are developing hemispherically a good forecast has a better idea of what if a model solutuon at day 8 or day 12 is reasonable or well… bullshit.
The MOST important feature here is the PV — POLAR VORTEX which is centered the ASIAN side of the arctic circle. This Position ois the KISS OF DEATH for anyone wanting cold weather in the eastern or central Conus. ANY Model solution that shows a cold pattern developing over the central and eastern CONUS cannot possibily be “valid” as long as the main PV is over on the Siberian side of the Arctic circle. Keep that in Mind.
…and Yes this is WHY the AO — the Arctic Osciallation has been so strongly positive.
FEATURE #1 Over the past week has been a deep and persistent trough in the jet stream over the northeast Atlantic Ocean which has been battering Western Europe with a series of powerful Lows. Some of the deep Low pressures between Iceland and Ireland have reached as low as 950 MB. The trough has become massive over the past week and has extended as far south as northeastern Spain and Portugal.
This is major trough is part of the VERY strong +NAO
FEATURE #2… Remembering your basic physics… for every action there is as an equal and opposite reaction… the atmosphere responses to this deep trough over the northeastern Atlantic… by countering it with an equally strong and large Ridge which has covered much of Eastern Europe the Ukraine Belarus and Western Russia. Last week it was reported that over 20% of the winter wheat crop in the Ukraine has to be implanted the cause of excess of the dry conditions– which is due to the persistent Ridge in the Jet stream.
In addition to take a look at the strong TROUGH over the central Russia… extending from the Urals into the Caspian Sea. This trough is the opposite of the ” cahirs connection” … a feature which JB has mentioned many times. Briefly if you are not familiar with this particular feature the argument goes that when there is a Ridge developing over Central Russia from the Caspian Sea north towards the Urals it leads to a +PNA pattern over the N. America 7-10 day later.
FEATURE #3 is enhanced Pacific Jet stream that is caused by a ridge over the north Pacific ocean. This ridge is pressing up against the large Polar Vortex that is Just North of Siberia. This is causing the Pacific Jet to get ” squeezed” or compressed so its velocities are enhanced. This give the Pac jet a lot more power… which leads to
FEATURE #4… the deep persistent trough over the West coast. This trough combined with the very strongly +NAO means a ridge over the eastern US and eastern Canada and NO “significant” injections of cold air (just the occasional cold air blast for a day or so).
By day 10 there are significant changes developing over all of the northern hemisphere.
This IMAGE compares the day 9 European ( LEFT side) and the day 9 GFS ( RIGHT side). To begin with the deep persistent trough in the northeast Atlantic extending from Iceland and down towards Portugal has weakened significantly. Both models move is trough back out further from Western Europe into the eastern / central N. Atlantic.
In response (#2 ) the persistent large ridge over the Ukraine and Western Russia is able to slide west into Central Western Europe. This in turn causes the ridge to build towards Iceland & eastern Greenland.
However as you can clearly see both models continue the strong positive height anomaly – RIDGE -over the central portions of the northern Pacific (#3).
As a result this strong Pacific jet stream continues to really fire across the northern Pacific through the gulf Alaska and down into the west coast of North America and especially of the CONUS. (#4) .
This is telling me that the persistent trough over the Western North America is NOT about to shift or change in any significant way through the middle of the month. In order to get deeper western trough to go away… and to get a Ridge over western North America… the Pacific jet stream has got to relax… and that in turn means the N Pacific Ridge has got to breakdown OR the polar vortex over the Siberian side of the arctic circle has got to change.
#5… Both models show t the PV is going to be moving or shifting position by day 9… from the n. Siberian coasts along the Arctic circle… then moving towards far northwest portions of North America. In fact some of the model show the PV splitting into two features with one remaining over central Siberia and the other one moving towards the north slopes of Alaska.
We can clearly see this on the enlarged European map at DAY 10.
Not surprisingly if we look at the TRENDS with the AO and the NAO we see that most of the data showing an increasingly negative values into both of these features.
The 12z operational GFS showed the AO staying quite positive right through the next two weeks but the GFS ensemble and the European and European ensembles showed increasingly negative trend. This should be a warning sign that along as the pattern is in transition … whatever the GFS happens to be showing past day 7… it should be regarded as essentially worthless until the new pattern finally reveals itself.
The NAO TRENDS… are even better. All four plots show that the NAO is going to turn negative and the European models are specially bullish on this. In fact I have seen the individual European ensemble maps in the 11-15 day . I cannot post them but I can tell you that they are quite impressive with the developing Heights and ridging over Greenland building towards eastern Canada.
Now that being said… this is where weather hobbyists and weenies often miss the boat. Right now we are in a very bad pattern for any sort of winter weather. I think I had made very clear about all the things which are hostile with regard to getting any sort of sustained cold pattern over any portion of North America Eastern Rockies.
- The PV is on the wrong side of the world.
- The Pacific jet is howling and we have a deep persistent trough on the West Coast.
- The NAO is extremely positive.
- The lack of any sustained large cold air masses over the entire southern half of Canada!!!
- There is no way of getting any sort of this severe cold which is developing in Siberia over into North America in any way shape or form.
Just because the AO and NAO are both going to turn negative NEXT WEEK…. it does not mean that it is going to be snowing at your house by November 15. All it means is that the OVERALL pattern is going to turn somewhat more favorable by the Middle of the month. In other words IF you like cold and wintry weather … the pattern shifts from unbelievably crappie to a pattern which does not totally suck moose.
We still have a long way to go and we still have to get that the persistent trough along the West Coast to change . The AO and NAO can be negative for a long while before the pattern begins to shift in the northern Pacific. EVENTUALLY …If we do get the PV towards north central Canada or Hudson’s Bay that would be an impact the pattern over the north Pacific area and allow the Pacific jet to relax and the deep trough over the West Coast to go away.
But we are still talking a few weeks here folks. He ware headed in the right direction but there are a LOT of things to FIX here … and its going to take a while.
