Summer analogs 2011

[skierinvermont]

It seems to me that the summer following strong dying Ninas tend to be cooler than average for most of the U.S. including the east. There is a notable lack of a SE ridge during most of these summers. I'd probably use that as my starting point for a forecast. If the Nina starts intensifying by summer that may make a difference and could be one reason 1999 was hot.

[nzucker]

It seems to me that the summer following strong dying Ninas tend to be cooler than average for most of the U.S. including the east. There is a notable lack of a SE ridge during most of these summers. I'd probably use that as my starting point for a forecast. If the Nina starts intensifying by summer that may make a difference and could be one reason 1999 was hot.

Yes, second/third year Niña summers tend to be chilly, with the exception of 1999....good examples of this cold pattern are 1974 and 2000.

However, I'd be cautious about going below normal given the dry soil in the Southern Plains/Southeast...that aridity suggests to me we may have ridging in these areas since the drought will surely not be alleviated by that point. If we stay in Niña with the dominant -EPO/Aleutian ridge, I'd expect some cold shots to hit the Northern Tier, possibly making PHL/NYC/BOS the battleground between the heat over the Southern Plains/Southeast and the colder air over Canada. If the Niña redevelops, then we can see a warmer summer for everyone.

[Ellinwood]

Ellinwood, is there any reason you have 2008 excluded? Maybe I'm missing something, I'm obviously no Met, but 2008 seems like a strong contender to me, has the -PDO/+AMO/low solar/Matching Global Temps/ENSO, etc. Colder anomalies over the Great Lakes/interior NE/Apps, and Warmth in the SW US/interior West and Immediate East Coast seem very plausible?

Taking a better look at it, I would say that 2008 is a good analog, minus the higher + anoms in the west, where in 2008 it was quite dry vs. now where there is no drought.

[Ellinwood]

Why is the Southeast Ridge "rebuilding?" The ridge has been predominately over the Southwest and southern Plains. Yes, there will be times of a 2-day warm shot to the East, but I wouldn't call this a rebuilding SE ridge. Heck the term "rebuilding" doesn't seem to fit with what has been occurring.

I agree with Brian. 2010 is a terrible analog.

No SE ridge? While the biggest ridging has been over the S+SW, there is still a good amount of ridging in the SE since Feb:

Add the drought conditions on top of that:

and the +AMO trending towards more positive... you can end up with some pretty warm conditions.

EDIT: I'll also add that anyone that gets the Euro weeklies can compare the Week One forecast to the previous week's Week Two forecast (especially over the last few weeks) and watch the Week Two belows turn into Week One aboves across the Southeast, most of the Midwest and the Mid-Atlantic. I won't say that this helps my forecast, but I will say that it hurts the monthly/seasonal outlooks that are getting put out by the models given how poorly they've been performing in that region.

[VAwxman]

No SE ridge? While the biggest ridging has been over the S+SW, there is still a good amount of ridging in the SE since Feb:

Add the drought conditions on top of that:

and the +AMO trending towards more positive... you can end up with some pretty warm conditions.

EDIT: I'll also add that anyone that gets the Euro weeklies can compare the Week One forecast to the previous week's Week Two forecast (especially over the last few weeks) and watch the Week Two belows turn into Week One aboves across the Southeast, most of the Midwest and the Mid-Atlantic. I won't say that this helps my forecast, but I will say that it hurts the monthly/seasonal outlooks that are getting put out by the models given how poorly they've been performing in that region.

Two things...

Why would you expect the pattern now to last another 5 months? That rarely happens.

And the AMO is not trending more +, but has actually been trending less so. Still positive mind you, but you have the trend wrong as of now at least.

[Ellinwood]

Two things...

Why would you expect the pattern now to last another 5 months? That rarely happens.

And the AMO is not trending more +, but has actually been trending less so. Still positive mind you, but you have the trend wrong as of now at least.

Oops @ the AMO... it has indeed been trending less in the winter months. However, while eye-balling the the SST anomaly maps from the past month it looks like a change towards the more positive (especially in the southern areas).

I'm not expecting the pattern to last a full 5 months more so than it be the dominant pattern. Looking back at 2010's anomalies, the hot pattern was pretty apparent from April - November, of which April, May, June, kind of July, August, kind of September and finally November all had a negative anomaly pattern in the West.

[VAwxman]

Oops @ the AMO... it has indeed been trending less in the winter months. However, while eye-balling the the SST anomaly maps from the past month it looks like a change towards the more positive (especially in the southern areas).

I'm not expecting the pattern to last a full 5 months more so than be the dominant pattern. Looking back at 2010's anomalies, the hot pattern was pretty apparent from April - November, of which April, May, June, kind of July, August, kind of September and finally November all had a negative anomaly pattern in the West.

A pattern trending hard from solid nino to solid nina is supposed to have the kind of anomaly 2010 had. Obviously 2010 went to the extreme, but the general pattern was no surprise. It's a different feedback when in a decaying nina state, which is what we have for this upcoming season. I just cannot figure out how 2010 gets in the mix still. There are some analogs that were on the hotter side that could be used (1999 for example), but for very different reasons than 2010. Since the block died, almost everything has been different from 2010 to this point.

[weatherwiz]

I don't care how this summer is as long as there is lots of severe wx in the Northeast.

[HM]

No SE ridge? While the biggest ridging has been over the S+SW, there is still a good amount of ridging in the SE since Feb:

Add the drought conditions on top of that:

I'm not going to comment on the Euro weeklies because I think that's irrelevant. I didn't say "no SE ridge" and agree that it shows up in the anomalies, especially when you include February. However, continue to move your start time forward and you'll watch it disappear and shrink toward the West. I'm not saying that the SE ridge is not going to be a feature...it always pops up...heck it is guarenteed to pop up every year. My point is that it is not rebuilding like you claim and relatively speaking, the southern Plain's ridge is the main focus here. Even the drought conditions as you show are much more expansive here. And the AMO/PDO phases that you speak of are correlated nicely with this feature and the drought conditions (see McCabe et al. 2004).

The pattern has been in a state of retrogression. What I can't get over is the how long the models are making the waves in the extended period. If I didn't know any better, I would say that trough showing up around the 16th was a winter height map.

[BethesdaWX]

I'm not going to comment on the Euro weeklies because I think that's irrelevant. I didn't say "no SE ridge" and agree that it shows up in the anomalies, especially when you include February. However, continue to move your start time forward and you'll watch it disappear and shrink toward the West. I'm not saying that the SE ridge is not going to be a feature...it always pops up...heck it is guarenteed to pop up every year. My point is that it is not rebuilding like you claim and relatively speaking, the southern Plain's ridge is the main focus here. Even the drought conditions as you show are much more expansive here. And the AMO/PDO phases that you speak of are correlated nicely with this feature and the drought conditions (see McCabe et al. 2004).

The pattern has been in a state of retrogression. What I can't get over is the how long the models are making the waves in the extended period. If I didn't know any better, I would say that trough showing up around the 16th was a winter height map.

The SE ridge this winter was squashed by the -NAO right? With a +QBO at this point in time, wouldn't you say the chance for a +NAO is growing? And I'd think that would coincide with warmer anoms in the East...

If the La Nina Holds this Summer, and we see the Multi-year event as usual, would that really coincide with a Ridge/+PNA in the west/-NAO during a +QBO phase?

Again, I'm no meteorologist, and am not as knowledgable as you, but Powerful Nino's sich as 1999 followed by Hot La Nina years during a +NAO, during the +QBO, seems to reflect warmth in the East, more specifically towards the Coast?

[uncle W]

second year official la nina's

[nzucker]

The SE ridge this winter was squashed by the -NAO right? With a +QBO at this point in time, wouldn't you say the chance for a +NAO is growing? And I'd think that would coincide with warmer anoms in the East...

If the La Nina Holds this Summer, and we see the Multi-year event as usual, would that really coincide with a Ridge/+PNA in the west/-NAO during a +QBO phase?

Again, I'm no meteorologist, and am not as knowledgable as you, but Powerful Nino's sich as 1999 followed by Hot La Nina years during a +NAO, during the +QBO, seems to reflect warmth in the East, more specifically towards the Coast?

A -NAO in summer causes the Mid-Atlantic/SE to be warmer than normal....not what you'd expect from how this index behaves in summer. Due to the shorter wavelengths, the SE ridge hooks up with the Greenland block so you see above normal anomalies.

[nzucker]

I'm not going to comment on the Euro weeklies because I think that's irrelevant. I didn't say "no SE ridge" and agree that it shows up in the anomalies, especially when you include February. However, continue to move your start time forward and you'll watch it disappear and shrink toward the West. I'm not saying that the SE ridge is not going to be a feature...it always pops up...heck it is guarenteed to pop up every year. My point is that it is not rebuilding like you claim and relatively speaking, the southern Plain's ridge is the main focus here. Even the drought conditions as you show are much more expansive here. And the AMO/PDO phases that you speak of are correlated nicely with this feature and the drought conditions (see McCabe et al. 2004).

The pattern has been in a state of retrogression. What I can't get over is the how long the models are making the waves in the extended period. If I didn't know any better, I would say that trough showing up around the 16th was a winter height map.

It seems like we all agree on the S Plains being above average, but you have the ridge centered further west than what Ellinwood and I imagined...I also factored in the last couple of summers which have tended to be cooler across the N Plains/Upper Midwest, this goes against the climo for summers after a moderate/strong Niña which suggests above normal for these areas.

[BethesdaWX]

A -NAO in summer causes the Mid-Atlantic/SE to be warmer than normal....not what you'd expect from how this index behaves in summer. Due to the shorter wavelengths, the SE ridge hooks up with the Greenland block so you see above normal anomalies.

Was last summer a +NAO?

The One issue I have is Comparing Nino To Nina Summers (Like Last Summer) to this summer... I don't think we're going Nina to Nino Like we were in 2009, where we saw a very cold summer for the East Coast...that was Nina to Nino.

but this Yr May very well be no real ENSO change, or less dramatic. So if the Atmosphere remains "Nina-ish", why would the Signal be dampened?

[nzucker]

Was last summer a +NAO?

The One issue I have is Comparing Nino To Nina Summers (Like Last Summer) to this summer... I don't think we're going Nina to Nino Like we were in 2009, where we saw a very cold summer for the East Coast...that was Nina to Nino.

but this Yr May very well be no real ENSO change, or less dramatic. So if the Atmosphere remains "Nina-ish", why would the Signal be dampened?

No, it was a -NAO summer clearly in 2010:

One thing you see though is the warming effect of the strong El Niño in which almost no one in the Hemisphere has below normal heights for the summer.

What "signal" are you referring to? Having a Niña-like MJO/convection pattern isn't going to produce the same conditions in the U.S. summer pattern as the U.S winter pattern...

[skierinvermont]

[nzucker]

Skier, you're missing 1955, which was a summer after a moderate Niña year:

One of the hottest summers in the Northeast and with a record-breaking heat wave at NYC.

[skierinvermont]

I skipped it because the Nina never subsided and actually strengthened which I think is pretty unlike this year. I didn't even know it was a hot year but that strengthens the idea that it was different than the majority of the rest.

[gil888]

I'm not going to comment on the Euro weeklies because I think that's irrelevant. I didn't say "no SE ridge" and agree that it shows up in the anomalies, especially when you include February. However, continue to move your start time forward and you'll watch it disappear and shrink toward the West. I'm not saying that the SE ridge is not going to be a feature...it always pops up...heck it is guarenteed to pop up every year. My point is that it is not rebuilding like you claim and relatively speaking, the southern Plain's ridge is the main focus here. Even the drought conditions as you show are much more expansive here. And the AMO/PDO phases that you speak of are correlated nicely with this feature and the drought conditions (see McCabe et al. 2004).

The pattern has been in a state of retrogression. What I can't get over is the how long the models are making the waves in the extended period. If I didn't know any better, I would say that trough showing up around the 16th was a winter height map.

stratospheric warming influences for the long waves???

[nzucker]

I skipped it because the Nina never subsided and actually strengthened which I think is pretty unlike this year. I didn't even know it was a hot year but that strengthens the idea that it was different than the majority of the rest.

The 1955 La Niña actually did subside a little bit in the spring, reaching a minimum of -0.9C for the February/March/April trimonthly reading. It started to rebound in the summer as we worked towards a record strong event for Winter 55-56, but I don't see how it was that different from this year considering we're now around -0.8C on the weeklies. I wouldn't be shocked if this La Niña had a similar restrengthening later in the summer since the easterly trade winds seem to keep coming back regardless of whatever MJO and solar impetus you throw at this thing:

In any case, I don't think we'll see the extreme temperature pattern of Summer 1955...I expect the placement of the anomalies to be much different considering that Eastern Texas is now in "exceptional" drought status with much of the Southern Plains/Southeast being in a moderate drought that has carried over from the hot summer last season. I think most forecasts are agreeing on above normal temps in the Southern Plains, but the disagreement comes in whether you extend that ridge further west towards the Desert SW or further east into the Mid-Atlantic region. Also, we'll have to see if the -EPO pattern that's popped up a lot this winter/early spring continues, as that could argue for cooler than normal temperatures over the Northern Plains/Upper Midwest given that those places are largely influenced by cold airmasses coming from Canada, even during mid-summer. June and July in Montana were marked last year by several unusual Canadian cold fronts that brought very chilly temperatures to the state, mostly a result of the blocking over AK.

[OKpowdah]

Easterly shear zone is descending pretty steadily now

[skierinvermont]

The 1955 La Niña actually did subside a little bit in the spring, reaching a minimum of -0.9C for the February/March/April trimonthly reading. It started to rebound in the summer as we worked towards a record strong event for Winter 55-56, but I don't see how it was that different from this year considering we're now around -0.8C on the weeklies.

I'm looking right at the same numbers you are. I don't think the slight fluctuation from -1.1 NDJ to -.9 in spring and then back up to -1 in summer is at all similar to this year which will likely decline from -1.4 to between 0 and -.5. The years I picked are all declining Ninas which tend to be colder in the northern and central plains as well as the ohio valley.

[bluewave]

my top three Summer 2011 analogs are 1956, 1967 and 1996 as of today...If the Summer is like these it will be cooler than normal especially in the SE and warmer in the west......The hottest temperatures will come in May or June...Precipitation will be above normal along the mid Atlantic coast as far north as Long Island...Dry in Florida...1996 had a great hurricane season while 1956 and 1967 did not...Other analogs show a wetter than normal summer around NYC...

Similar pattern of drought over the past six months to those analog years.

[nzucker]

I'm looking right at the same numbers you are. I don't think the slight fluctuation from -1.1 NDJ to -.9 in spring and then back up to -1 in summer is at all similar to this year which will likely decline from -1.4 to between 0 and -.5. The years I picked are all declining Ninas which tend to be colder in the northern and central plains as well as the ohio valley.

I hear you..the analogs strongly argue for a cooler than normal summer in most of the CONUS. Of course, the analogs this winter would have suggested a SE ridge, so go figure.

I'm still betting on warmer than normal for the SE and Southern Plains, which goes against dying Niña climo. I think the dry soil is going to make for quite a ridge there, and we've already seen a bit of this pattern in March and April with the cut-off for warmer than normal temperatures being around RIC/RDU. I think the -EPO/Aleutian ridge argues for cooler Canadian air to make inroads in the Northern Plains and Upper Midwest, sort of like 2008 and 2009 when those areas had some shots of cold weather.

[uncle W]

Similar pattern of drought over the past six months to those analog years.

temperature maps for Oct-Mar...55-66-95 and 2010-11

[VAwxman]

I hear you..the analogs strongly argue for a cooler than normal summer in most of the CONUS. Of course, the analogs this winter would have suggested a SE ridge, so go figure.

I'm still betting on warmer than normal for the SE and Southern Plains, which goes against dying Niña climo. I think the dry soil is going to make for quite a ridge there, and we've already seen a bit of this pattern in March and April with the cut-off for warmer than normal temperatures being around RIC/RDU. I think the -EPO/Aleutian ridge argues for cooler Canadian air to make inroads in the Northern Plains and Upper Midwest, sort of like 2008 and 2009 when those areas had some shots of cold weather.

The dry soil isn't going to force a ridge, but yes will enhance heat when a ridge is present.

[OKpowdah]

The dry soil isn't going to force a ridge, but yes will enhance heat when a ridge is present.

Thank you!

Soil moisture doesn't change upper level patterns. It can have an influence on lapse rates in perhaps the lowest few hundred meters of the atmosphere. Nothing more

[nzucker]

Thank you!

Soil moisture doesn't change upper level patterns. It can have an influence on lapse rates in perhaps the lowest few hundred meters of the atmosphere. Nothing more

DT doesn't agree....you were also the one that thought snow cover couldn't influence the upper pattern, and you had to eat crow on that one:

"Large areas of very dry soil moisture regions and Droughts.... as well as large areas of very wet soil moisture conditions and Flooded areas ....can and DO produce what is known as a "positive feedback loop ". This positive feedback loop can be major reason why a particular weather pattern is going to continue. When the soils dry out... there is less moisture for fronts and other trigger mechanism to lift and therefore there is a continuation of less rainfall. Excessively dry grounds can help feed more energy in the atmosphere. This additional heat can help keep a warm dry pattern / ridge in the Jet stream in place. In a similar manner when grounds are excessively wet or super saturation over a PROLONGED period of time the supply of evaporating moisture to the atmosphere is continuous. This only helps provide a new moisture source but it lowers the atmosphere temperatures which in turn can help keep a trough staying in the same general locations for weeks at a time."

http://1664596.sites.myregisteredsite.com/seasonalforcst/winter1011/prelimwinterPUBLIC.htm

[BethesdaWX]

DT doesn't agree....you were also the one that thought snow cover couldn't influence the upper pattern, and you had to eat crow on that one:

"Large areas of very dry soil moisture regions and Droughts.... as well as large areas of very wet soil moisture conditions and Flooded areas ....can and DO produce what is known as a "positive feedback loop ". This positive feedback loop can be major reason why a particular weather pattern is going to continue. When the soils dry out... there is less moisture for fronts and other trigger mechanism to lift and therefore there is a continuation of less rainfall. Excessively dry grounds can help feed more energy in the atmosphere. This additional heat can help keep a warm dry pattern / ridge in the Jet stream in place. In a similar manner when grounds are excessively wet or super saturation over a PROLONGED period of time the supply of evaporating moisture to the atmosphere is continuous. This only helps provide a new moisture source but it lowers the atmosphere temperatures which in turn can help keep a trough staying in the same general locations for weeks at a time."

http://1664596.sites...interPUBLIC.htm

I'm skeptical in the Significance of the + feedback loop, it has to be very Minor IMFO.

I'm not so sure the effect of "snowcover" is what has been causing the -NAO/-AO in recent years, IMO its the other way around, because the high snowcover was still present even with the +AO/+NAO since Mid JAN... although not ruling out smaller feedbacks, (as formentioned).

Ocean SST's obviously are another story......But when we have a winter with a +QBO, La Nina, & +IO, an uber -NAO in DEC seems almost impossible, and "snowcover" won't change that big an opposition from the atmosphere. The Sun has to play a Role, and it correlates well to Geomagnetic Activity, I think.

Just my Worthless 2 cents

[nzucker]

I'm skeptical in the Significance of the + feedback loop, it has to be very Minor IMFO.

I'm not so sure the effect of "snowcover" is what has been causing the -NAO/-AO in recent years, IMO its the other way around, because the high snowcover was still present even with the +AO/+NAO since Mid JAN... although not ruling out smaller feedbacks, (as formentioned).

Ocean SST's obviously are another story......But when we have a winter with a +QBO, La Nina, & +IO, an uber -NAO in DEC seems almost impossible, and "snowcover" won't change that big an opposition from the atmosphere. The Sun has to play a Role, and it correlates well to Geomagnetic Activity, I think.

Just my Worthless 2 cents

The high-latitude autumn snow cover is theorized to affect Rossby waves and thus the amplitude of the jet stream in the arctic, hence the -AO/-NAO. As you say, the correlation is small and certainly does not explain this year's extreme -NAO block in December when a colder than normal stratosphere due to the +QBO/Niña should have produced lower heights over the high latitudes. I think a lot of this year's blocking pattern was due to the Atlantic SST and geomagnetic activity associated with the solar minimum. Although the solar minimum in theory should further cool the stratosphere and compound the QBO/Niña, long periods of solar minimum in the past have locked in a -NAO pattern, such as during the Maunder Minimum in the 17th century...it may have to do with the fact that the natural downward variation in the NAO ascribed to the decadal cycle becomes "stuck" in a jet stream that is slower and less prone to fluctuation when we have a solar minimum. We're certainly in the negative NAO decadal cycle, and I think the tri-pole pattern in the Atlantic is exacerbating this...the Newfoundland cold pool (50/50 LOW) is well connected to the Greenland block, especially during the winter. We still see the warm-cold-warm pattern dominating in the Atlantic, despite that the NAO has recovered.

So what does this all mean for the summer? Well, unlike last year, I'm expecting a more +NAO summer...the vortex over Baffin Island has become dominant, probably enhanced by the strong Aleutian ridge which extends all the way back into Siberia, a result of the Niña-like tropical convection patterns. This amplified Aleutian ridge really seems to be cementing the Northern Canada vortex into place, limiting the amount of blocking we're seeing on the Atlantic side. With the Niña holding its ground, I expect this pattern to continue...the combination of the -EPO and this cold pool over Arctic Canada should give the northern tier some cold shots during the summertime, meaning that I'm preliminarily forecasting a below-normal summer for the High Plains/Upper Midwest, and potentially into Northern New England. Given that I see the La Niña potentially restrengthening later on, especially given the inability of the MJO to move into the Niño like Phase 7/8, I expect the Bermuda ridge to be prominent, with the strongest warm anomalies over the drought-stricken areas of the Southern Plains. Although the analogs show the S Plains being hot during April with a fading La Niña, and then cooling off during the summer into below normal values, I'm not sure this is going to happen this year. With the dearth of moisture in the far South and very wet/stormy conditions in the Ohio Valley and Northern Plains, I'm thinking this could augment the amplified ridge/trough configuration we're seeing this April. I expect a hotter and drier summer than normal for the Southwest, Southern Plains, and far Southeast with more normal temperatures as you venture further north, and an active severe weather season continuing unless El Niño somehow gets a foothold.