June Outlook

Forecast for the next little while...

We will be receiving some relief from the current heat across eastern Canada with the cool front moving through tonight into tomorrow morning. A refreshing airmass will be welcomed... High's will not be that much lower for the beginning of this week although they will be ranging in the low to mid twenties for most of us.

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Departures from normal Tomorrow to Thursday from left to right:

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Towards the end of the week and continuing into the beginning of the forth week of june is a very strong ridge over the eastern part of the country. This ridge will be followed by a breif cool down and then another ridge continuing into the beginning of July. Ridge still easily maintained at 192 hours...

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As we get further out to tuesday the 26th a trough gets established in the eastern part of the country causing a cool down for the last part of june. GFS ensembles at 360.

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Canadian has the same idea going out to 360 hours with a trough in the east and the west and a ridge in the central u.s.

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We are going into an increasingly dry pattern as the El Nino is coming on and pushing the storm track further south.As far as the tropics go there will be an area of low pressure forming off the north Carolina coast that will then retrograde south west and try to hit South Carolina or Georgia.

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This combined with the recent slug of moisture that worked its way into the Southeast is showing us that an El Nino like pattern is setting up with more dryness up to the North (Ontario) and wetness across the Southeast. The recent rainfall from Beryl and the latest low pressure system have helped to relieve the drought down in southern areas of florida which is much needed although the north stays dry.

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The GFS is hinting at more tropical development for texas and the gulf coast at hour 300 due to lower shear shaping up in the western gulf along with a trough forming in that area under the big ridge building over the east. But you have to remember that this is just one off run of the operational 06z GFS which isn't even shown on the latest 12z GFS. I would say its nothing to worry about yet unless we see more consistency on the modelling. It is definitely something to watch out for in the el nino pattern that we are in which favours troughs in the east or gulf/caribbean which helps to produce homegrown development frequently near the U.S coastline. 

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We can see the cool in the East for the start of June and the wetness in the Southeast. Warmer in the central part of the continent.

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I am expecting severe weather to continue to level off after having the fastest start to the tornado season ever we are now down to about the normal point. This makes sense because 400mb temperatures have been warmer lately limiting the cold punch troughs can pack. This causes less of a clash between cold and warm and less severe weather overall.

Tornadoes:

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400mb temperatures compared to last year:

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My Analogs For Next Winter

 Starting to think about possible/ best analogs for next winter. Here is a chart I created which shows the correlation between this year and possible analogs I looked at. I gave every year a rank for each category (ENSO,PDO,AMO,PNA,SOI,EPO,QBO,NAO/AO). I gave a rank out of 2 for the PDO and AMO. The ENSO was out of three given 1 point for each of the following 1) West/central based nino 2) Year coming off of a double nina 3) A Weak to Moderate Nino from +.5 to +1.5. I gave a score out of 1 point for the rest of the categories and added up the totals on the right. I left a space in the chart between the SST related indices and indices not related to SST's. Hope you enjoy it!

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My Analogs:

The analogs I chose were based on ENSO,PDO,AMO,QBO,PNA,NAO,EPO,PNA and SOI. 2009-10 had the closest correlation, matching almost perfectly with PDO,AMO, ENSO and SOI. I double weighted it. 2002-03 was close with regards to the AMO,PDO and ENSO although not perfect. I also looked at 1976-77 which was the closest with the PDO but had a cold AMO. It came off of a triple nina (not double) but was west/central based and moderate strength. SOI was close and so was the QBO. 1972-3 was close with regards to enso position and it did follow a double la nina. The problem was that it was too strong compared to most forecasts (peaked at 2.1). SOI was very close and the QBO shared similarities as well as the MEI. If the PDO stays negative i will double weight it but for now i will leave it out. I looked at 1957-8 as well which was the second closest analog following 2009-10. PDO and AMO close, ENSO not as close but similar (more east based). SOI and NAO similar as well. I looked at 1951-52 which was similar to 1972-73 which both had a cold PDO and no warm spike for the winter like the other analogs had. If the PDO does indeed stay negative then 1972 should be counted twice but for now I am assuming it will spike positive based on current SST patterns so I am leaving it out. I will include 1951 due to its similarities. If the PDO stays cold I will double weight 1952 as well. I chose to look at 1965-66 but realized that it didn't share many similarities unless the AMO goes negative which is unlikely. I left 1966 out but will be watching the AMO. If it does go negative I will double weight 1976. 

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If PDO remains negative my analogs will look like this:

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For now we just have to wait and see what plays out as we get closer to winter.

Response to Question regarding Fall 2012

I wanted to respond to R.J's question about my fall outlook. He said "Will this El Nino turn out to be Trtaditional(East-Based) or Modiki(Central/West-Based)? And if Modiki, is there a posibility that Florida will again see an anomalous October heatwave like in 1986 and 2009?"


My Response:


I believe that this El Nino will turn out to be a west/ central based nina due to the modelling showing the warmth migrating westwards into nino 3.4 and cooling nino 1 and 2. This usually gives much colder conditions to North America in winter and fall as opposed to an east based Nina. These are my analogs for this october. I give 1 spot on the list for each of he following 1) Warm AMO 2) Cold PDO decadaly (overall) 3) PDO flipping to warm during the fall/winter. All my years are el nino's coming off of 1 or more la nina's.

The core of the cold is across the Northern Plains but florida stays about normal to slightly below normal. I don't see any heat waves for october or even any of the fall for florida although it may certainly be above normal at times.Taking a look at the SST's off the Florida coast and up the majority of the eastern seaboard we see colder anomalies which would signal more cooling and troughiness in the southeast. 

The JMA model has florida cold for the fall as well in terms of temps. CPC analogs show this from there super ensembles:

These years look cool in the southeast for october with warmth across the north but should be taken lightly because this models analogs change daily:

The IRI has a lot of wetness in florida  for the late summer/ early fall meaning that it will be generally cooler. This is probably signally possible tropical threats.

On the topic of precipitation I believe that there will be a lot of in close development with hurricanes and many tropical moisture threats for florida resulting in a wetter then normal summer and a cooler fall with very little chance of a big heatwave. I hope I answered your question, thanks for commenting!

The importance of the PDO flip in winter 2012-13

I think we all understand that next winter has the potential to produce weather that will make up for last winter. What I want to break down for you is what factors are involved and which ones are most important in the development of next winter. Firstly I am using two sets of analog years showing the two  most possible outcomes for next winter. You will notice these sets have huge differences in temperatures based on a few key factors. In the first set I am using el nino years coming off of a la nina or multiple ninas, with a cold PDO and a warm AMO in one  year, negative AMO in the other. I am using 1921-52 and 1972-73 for this analog set which looks like this:

You notice warm anomalies in the east while the west stays cool. This would not be the winter that we are looking for in terms of cold and snow.

 My second analog set would be el nino years following a double or triple la nina, with a positive PDO in the winter months although still negative in a decadal sense. Every year except for 2002-03 is in a cold PDO phase overall but the coming El Nino causes the PDO to flip to positive for the winter and spring months. I also chose years with a warm AMO, expect for 1976-77. My years are 1957-58, 1976-77, 2009-10 and 2002-03. Now I know that some people do not want to include years following a triple nina but I believe that those years should be included in the analog set and share many similarities to double nina's anyways. Here is what these years looked like.

So there we have it, its the PDO thats driving the winter pattern! The PDO flipping to warm is one of if not the number one driver in producing a cold winter in my opinion. Notice cold in the east and warmth in the west. Also notice the very warm anomalies across greenland showing a lot of blocking in these years. In my other set there is little to no blocking across the north due to very warm anomalies there. This year is favoured for blocking because of the negative AAO values showing up now, as well as the NAO and also the warm, cold then warm AMO trifecta which favour blocking. Solar activity has been running pretty low lately as well.  Now here are the keys we should be watching very closely for next winter with the knowledge that we are heading into a weak to moderate el nino after a double la nina (shown strongly by the modelling and SST's) . 1) The warmest water must be found in nino 3.4 detached from the coast. 2) The PDO has to flip to positive in time for next winter as a result of the coming el nino 3) Blocking should be found across North America due to the PDO spike which I will show later in the post

 So in order to produce an analog set you want to include all the possible variables, so it is important as I had shown before with my MEI analogs that all the players are on the table here. As we can see most of the time when the AMO is positive, and an el nino is coming off a la nina or two la nines/ three la nines you get a positive PDO as well even though its overall negative. For example 57-58, 09-10, 76-77. 51-52 went the other way with the same positive AMO, cold PDO overall and nino off of la nina. Notice 1951-52 is the only year that is following just a single la nina. This is good news for us because this may be showing that if you are coming off of a multiple nina in a warm AMO your chances of a warm PDO spike is better.

Now what if the AMO stays colder then what will happen. There is a cold signal here as well with three years that I found were 1965-66, 1976-77 and 1972-73. This scenario probably would be cold as well.  72-73  ended up with a cold PDO winter and a warm winter overall and 1965-66 and 1976-77 had cold winters across the east. This cold AMO scenario seems unfavourable at the moment so until we see signs this may occur it probably won't and all modelling I've seen is hinting the other way.

As I mentioned before there was a lot of blocking found in the winters of 1957-58, 1976-77 and 2009-10. 1951-52 and 1972-73 on the other hand had a positive NAO throughout most of  the winter. I will compare 1957-58, 2009-10 and 1951-52 separate from 1976-77 and 1972-73 because of the AMO which was warm in the first set. You can see that the correlation is found in the PDO which went warm for the winters even thought the PDO phase was cold overall. Its not the AMO because blocking is still shown in 76-77 with a cold AMO! Also you can't say the double nina before is the driver because 1972-73 had that and look what happened.

NAO values for dec-feb:

1951   12   1.13
1952    1   0.57
1952    2  -1.38

Compared Too:

1957   12   0.02

1958    1  -1.14

1958    2  -1.64





2009   12  -1.88

2010    1  -1.80

2010    2  -2.69




Cold AMO years:




1972   12   0.09
1973    1  -0.46
1973    2   0.52



Compared Too:


1976   12  -1.57

1977    1  -1.72

1977    2  -1.00



Somebody could argue that the QBO would be the cause of blocking or no blocking in these winters (similar to the upcoming one). The winter of 1972-73 had a negative QBO but could still not develop a block due to the PDO which remained negative. QBO values from dec-feb 1972-73.




-16.78  -4.40    0.08 



Same case in 1951-52:

-3.98   -6.80   -7.71 

You could argue the warm water detached from the south american coast is the driver but all these years have this and we still see the differences in blocking and cold.

Now the only difference between these years is the PDO which spiked in all the years except for 1951-52 and 1972-73. I think we are seeing a strong correlation between the NAO going negative and the PDO flipping to warm giving just another reason why the flip of the PDO is the most important driver with regards to next winter. This will occur by the warmth shifting into nino 3.4 which its forecasted to do.

Taking a look at the current AAO which is already strongly negative and is forecast to dip below -3. A negative AAO in the summer is usually an indication that we will see blocking during our winter. We are already seeing a pattern that is capable of producing strong blocking(shown this week) and we are seeing a much different pattern then last winter where no blocking was found.

I hope you appreciate the important links I showed you and the work it took to dig this up. I am trying to show you why the NAO was so negative in these years and how they match up to our current pattern. I'm not just saying 1951-52 and 1972-73 were warm winters because the NAO was positive, it is why the NAO was positive which controlled  the pattern in these winters. Please feel free to leave comments!

June Thoughts

Thoughts for the rest of June

Taking a look at what to except in june, i will first go to the modelling. CFS has cool pool in the Great Lakes region with ridging in the southwest and along the west coast. Normal south and east.


GFS ensembles are showing a big trough in the east until about hours 204 when the ridge starts to move eastwards into the east. It is not showing a strong ridge at the moment but since the PNA is expected to go negative at that point I expect the trough to dig deeper in the west and the ridge to be stronger in the east. How long this sticks around is still to be determined but it looks like the week from june 11th to the end of june look warmer if not really warm in the east.

GFS upper height anomalies:

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Larger ridge being backed up by negative PNA during the period:

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Brett Anderson's interpretation of the Euro weeklies is showing this too:

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Euro ensembles has the ridge:

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Canadian has trough in the west but will probably amplify the ridge more in the East over time:

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NAEFS departures 10th-17th:

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It appears as though ridging will be returning with above normal departures in the east for the second half of june after the much below normal departures experiencing now. Now I will take a look at some of the closest years chosen by the CPC:

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2001 and 2006 are two years that I like the best and think that they are most similar to our current pattern.

2001 shows ridging in the southwest and a trough in the middle of the nation with a very cold BC. The deserts are very hot this year, B.C looks to end up very cold and the east slightly warm. There are clearly some similarities here.

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2006 has ridge in the west and warm anomalies across the north with a weakness off the east coast. Possibly could end up close to 06 in the East if departures get low enough in the next week as the trough continues to dig off the coast. I have used 06 as an analog several times this year, showing many similarities. I believe that the trough will hang on until about the 13th due to a typhoon making its way near Japan 6-10 days earlier and promoting more of a trough in east asia, off the west coast and into the east. This will occur before letting a big ridge build back into the great lakes for the end of the month. This is in line with my summer forecast which I am expecting more frequent cold shots as we progress later into the summer and the El Nino comes on. I still expect June to be slightly above normal for the east.

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