Medium Range Discussion Summer 2012

[HM]

Don great posts and forecast for August! Just as the McCabe et al. paper (2004) suggested and many others, the current regime we are in will favor expansive drought conditions (-pdo/+amo long term cycle).

[Isotherm]

Don great posts and forecast for August! Just as the McCabe et al. paper (2004) suggested and many others, the current regime we are in will favor expansive drought conditions (-pdo/+amo long term cycle).

Yeah we're back in the 1950s in terms of long term cycles: +AMO/-PDO produced widespread droughty summers in the 50s

[HM]

Yeah we're back in the 1950s in terms of long term cycles: +AMO/-PDO produced widespread droughty summers in the 50s

Agreed. The question ahead is: are we headed for a 1957-58 type of cold season or a 1953-54 type of cold season?

[usedtobe]

Don, nice forecast, certainly seems reasonable.

[Ginx snewx]

Agreed. The question ahead is: are we headed for a 1957-58 type of cold season or a 1953-54 type of cold season?

How about a 54-55 type hurricane season?

[bluewave]

The 2011-2012 drought progression from south to north looks faster than what we saw during the 1950's.

The 51-53 drought conditions were mainly focused south before lifting north during 54-56. We saw this

current northward expansion in one year.

[donsutherland1]

Thanks all for the very kind words. It will be interesting to see how the drought continues to evolve, especially if the U.S. has few or no tropical cyclone impacts.

[donsutherland1]

Some highs from today (through 2 pm):

Baltimore: 102° (tied record set in 1887)

Hartford: 100° (broke record of 99° set in 1982)

Newark: 104° (broke record of 100° set in 1982)

New York City: 100° (2012 is the 3rd consecutive year with a 100° reading at NYC and only second such streth; the last time was a 4-year strech from 1952 through 1955)

Philadelphia: 100° (broke record of 99° set in 1953)

Washington, DC:

...DCA: 101° (7th 100° or higher reading this year)

...IAD: 101° (broke record of 100° set in 1986)

Wilimington, DE: 100° (tied record set in 1953)

[usedtobe]

Agreed. The question ahead is: are we headed for a 1957-58 type of cold season or a 1953-54 type of cold season?

Of the 4 nino's during the 1950's, 1958-1959 was the worst

Here's a list of the snowfall by city

dca nyc bos

1951-1952 10.2 19.7 39.6

1953-1954 18 15.8 23.8

1957-1958 40.4 44.7 44.7

1958-1959 4.9 13 34

I've typed in bold the snowfall years that were 5 inches or more below normal and used italics for the totals more than 5 inches above normal. Overall not great years except for 1957-1958 for the Mid ATl. 1953-1954 had the worst AO and NAO look with the AO being positive each of the 4 months Dec-Mar.

[WxMidwest]

Don great posts and forecast for August! Just as the McCabe et al. paper (2004) suggested and many others, the current regime we are in will favor expansive drought conditions (-pdo/+amo long term cycle).

HM, That paper has become really popular as of late. I Used it for ILL drought anomaly reasearch in early june. Looking at the AMO/PDO cycle (about out of phase 90 degrees http://oceanworld.ta...ges/pmo-amo.gif ), the AMO switch to negative would be great if it could occur soon..

Don, Forecast looks pretty much spot on with drought feedback and the current atmospheric pattern. Not much hope here in the next few months. Maybe some come fall, if your typical probablistic temperature pattern for CONUS shows up for the input of +ENSO anomalies. Unfortunately, we haven't been "typical" pattern wise in quite awhile.

[carley5]

if dons hot august transpires i think roger smith will have done a great job.

[uncle W]

Of the 4 nino's during the 1950's, 1958-1959 was the worst

Here's a list of the snowfall by city

dca nyc bos

1951-1952 10.2 19.7 39.6

1953-1954 18 15.8 23.8

1957-1958 40.4 44.7 44.7

1958-1959 4.9 13 34

I've typed in bold the snowfall years that were 5 inches or more below normal and used italics for the totals more than 5 inches above normal. Overall not great years except for 1957-1958 for the Mid ATl. 1953-1954 had the worst AO and NAO look with the AO being positive each of the 4 months Dec-Mar.

for those analogs 1958-59 was the coldest in NYC...

12/1-2/29 ave temp. for NYC...

1951-52...37.0

1953-54...37.4

1957-58...33.2

1958-59...30.9

[icebreaker5221]

HM, That paper has become really popular as of late. I Used it for ILL drought anomaly reasearch in early june. Looking at the AMO/PDO cycle (about out of phase 90 degrees http://oceanworld.ta...ges/pmo-amo.gif ), the AMO switch to negative would be great if it could occur soon..

Don, Forecast looks pretty much spot on with drought feedback and the current atmospheric pattern. Not much hope here in the next few months. Maybe some come fall, if your typical probablistic temperature pattern for CONUS shows up for the input of +ENSO anomalies. Unfortunately, we haven't been "typical" pattern wise in quite awhile.

The AMO and PDO index run in fairly predictable 30-year cycles. Unfortunately, we just entered a +AMO in 1995 and a -PDO in 2008, so we will likely remain in a +AMO/-PDO until about 2025. While a dry pattern alone can be devastating, the recent record-breaking heat really adds insult to injury with those higher evaporation rates.

You can see the 30-year cycles quite nicely in the blue and orange figures on wikipedia:

AMO

http://en.wikipedia.org/wiki/Atlantic_multidecadal_oscillation

PDO

http://en.wikipedia.org/wiki/Pacific_decadal_oscillation

[WxMidwest]

Icebreeaker, I agree on the 30 year cycles, where there is divergence when it comes to the begining of the PDO cycle. some say around 1999/2000 some say like yourself 2008...

1998 0.83 1.56 2.01 1.27 0.70 0.40 -0.04 -0.22 -1.21 -1.39 -0.52 -0.44

1999 -0.32 -0.66 -0.33 -0.41 -0.68 -1.30 -0.66 -0.96 -1.53 -2.23 -2.05 -1.63

2000 -2.00 -0.83 0.29 0.35 -0.05 -0.44 -0.66 -1.19 -1.24 -1.30 -0.53 0.52

2001 .60 .29 0.45 -0.31 -0.30 -0.47 -1.31 -0.77 -1.37 -1.37 -1.26 -0.93

2002** 0.27 -0.64 -0.43 -0.32 -0.63 -0.35 -0.31 0.60 0.43 0.42 1.51 2.10

2003** 2.09 1.75 1.51 1.18 0.89 0.68 0.96 0.88 0.01 0.83 0.52 0.33

2004** 0.43 0.48 0.61 0.57 0.88 0.04 0.44 0.85 0.75 -0.11 -0.63 -0.17

2005** 0.44 0.81 1.36 1.03 1.86 1.17 0.66 0.25 -0.46 -1.32 -1.50 0.20

2006** 1.03 0.66 0.05 0.40 0.48 1.04 0.35 -0.65 -0.94 -0.05 -0.22 0.14

2007** 0.01 0.04 -0.36 0.16 -0.10 0.09 0.78 0.50 -0.36 -1.45 -1.08 -0.58

2008** -1.00 -0.77 -0.71 -1.52 -1.37 -1.34 -1.67 -1.70 -1.55 -1.76 -1.25 -0.87

2009** -1.40 -1.55 -1.59 -1.65 -0.88 -0.31 -0.53 0.09 0.52 0.27 -0.40 0.08

2010** 0.83 0.82 0.44 0.78 0.62 -0.22 -1.05 -1.27 -1.61 -1.06 -0.82 -1.21

2011** -0.92 -0.83 -0.69 -0.42 -0.37 -0.69 -1.86 -1.74 -1.79 -1.34 -2.33 -1.79

2012** -1.38 -0.85 -1.05 -0.27 -1.26

[icebreaker5221]

Icebreeaker, I agree on the 30 year cycles, where there is divergence when it comes to the begining of the PDO cycle. some say around 1999/2000 some say like yourself 2008...

1998 0.83 1.56 2.01 1.27 0.70 0.40 -0.04 -0.22 -1.21 -1.39 -0.52 -0.44

1999 -0.32 -0.66 -0.33 -0.41 -0.68 -1.30 -0.66 -0.96 -1.53 -2.23 -2.05 -1.63

2000 -2.00 -0.83 0.29 0.35 -0.05 -0.44 -0.66 -1.19 -1.24 -1.30 -0.53 0.52

2001 .60 .29 0.45 -0.31 -0.30 -0.47 -1.31 -0.77 -1.37 -1.37 -1.26 -0.93

2002** 0.27 -0.64 -0.43 -0.32 -0.63 -0.35 -0.31 0.60 0.43 0.42 1.51 2.10

2003** 2.09 1.75 1.51 1.18 0.89 0.68 0.96 0.88 0.01 0.83 0.52 0.33

2004** 0.43 0.48 0.61 0.57 0.88 0.04 0.44 0.85 0.75 -0.11 -0.63 -0.17

2005** 0.44 0.81 1.36 1.03 1.86 1.17 0.66 0.25 -0.46 -1.32 -1.50 0.20

2006** 1.03 0.66 0.05 0.40 0.48 1.04 0.35 -0.65 -0.94 -0.05 -0.22 0.14

2007** 0.01 0.04 -0.36 0.16 -0.10 0.09 0.78 0.50 -0.36 -1.45 -1.08 -0.58

2008** -1.00 -0.77 -0.71 -1.52 -1.37 -1.34 -1.67 -1.70 -1.55 -1.76 -1.25 -0.87

2009** -1.40 -1.55 -1.59 -1.65 -0.88 -0.31 -0.53 0.09 0.52 0.27 -0.40 0.08

2010** 0.83 0.82 0.44 0.78 0.62 -0.22 -1.05 -1.27 -1.61 -1.06 -0.82 -1.21

2011** -0.92 -0.83 -0.69 -0.42 -0.37 -0.69 -1.86 -1.74 -1.79 -1.34 -2.33 -1.79

2012** -1.38 -0.85 -1.05 -0.27 -1.26

Yeah, there is always some ambiguity. The start of the last -PDO was pretty well defined and occurred in the mid-40s. Then the next cycle began in the mid 70s and was also pretty well defined. So the recent -PDO should have began in the mid 2000s (2005ish) when PDO was actually quite positive (as your data demonstrates). So was the current -PDO early or late? Hard to say for sure.

However, even if it began in 1999, that would still mean we should expect generally +AMO and -PDO until 2025!

[easternsnowman]

if dons hot august transpires i think roger smith will have done a great job.

It does'nt take a rocket scientist to figure that august will be above normal. In fact as I stated previously if you forecast above norm (based on recent trends) you will be right over 80% of the time.

June was around normal for many places in the east and I believe Roger Smith said that was supposed to be well above normal.

[Brian5671]

It does'nt take a rocket scientist to figure that august will be above normal. In fact as I stated previously if you forecast above norm (based on recent trends) you will be right over 80% of the time.

June was around normal for many places in the east and I believe Roger Smith said that was supposed to be well above normal.

June was above for a good part of the USA. July will be very warm. Saw very few forecasts for a hot summer, so Roger is definitely the best to date...

[easternsnowman]

June was above for a good part of the USA. July will be very warm. Saw very few forecasts for a hot summer, so Roger is definitely the best to date...

I guess if you look at the USA is a whole...you're probably right. I was just thinking about our region.

[donsutherland1]

I guess if you look at the USA is a whole...you're probably right. I was just thinking about our region.

Region made a big difference. The Southeast had its 20th coolest June on record. The Pacific Northwest had its 29th coolest June on record. The Southwest had its 3rd warmest June on record. Nationwide, June 2012 was the 14th warmest on record.

[NJwinter23]

Nice August forecast Don. With the continued painfully slow progression of ENSO into the + territory, combined with the slow break down of the North Pacific -PDO sst state, persistence seems like the way to go (especially with it being the summer)...

A nice picture representation of what HM is talking about with the -pdo/+amo drought correlation in the McCabe paper

[Isotherm]

To further illustrate the decadal PDO/AMO cycling -->

1950s - similar to today --> -PDO/+AMO

Very dry look

1965-1975 --> -PDO and -AMO

Dryness centered further northeast. Very droughty decade in Northeastern US

1980s --> +PDO and -AMO

Dry from the Plains east, wet in the West

1995-2005 --> +PDO and +AMO

Warmth in both oceans yields wetness for most. Hence the past 15 years are probably the wettest we'll see for awhile in the CONUS

Moving back toward drier times in the Plains/Central US. The 50s weren't bad on the East Coast, but the dryness spread eastward with time (by the 60s). We'll probably see a similar situation evolve. Obviously doesn't mean every year will follow the decadal trend, but in the overall sense, yes, it should progress drier.

[donsutherland1]

Thanks for posting the maps, NJWinter23 and Isotherm. They do a great job portraying the cyclical pattern of precipitation for the U.S.

[Hoosier]

Next week looks really hot in the Corn Belt. Probably going to be the death blow for a lot of crops.

[NJwinter23]

Next week looks really hot in the Corn Belt. Probably going to be the death blow for a lot of crops.

Iowa/Nebraska corn, especially, looks done-zo

[Ed Lizard]

Iowa/Nebraska corn, especially, looks done-zo

0Z Euro 6 hour max temps off AccuWx PPV site show decent sized areas in NE/IA exceeding 105ºF for daytime highs several days next week, and new 12Z Euro shows aoa 28º 850 mb temps at 7 am CDT Tuesday and Wednesday.

[donsutherland1]

For those who are interested in reading it, the McCabe paper on the Pacific and Atlantic influences on U.S. drought frequency can be found at: http://wwwpaztcn.wr.usgs.gov/julio_pdf/McCabe_ea.pdf

[Hoosier]

0Z Euro 6 hour max temps off AccuWx PPV site show decent sized areas in NE/IA exceeding 105ºF for daytime highs several days next week, and new 12Z Euro shows aoa 28º 850 mb temps at 7 am CDT Tuesday and Wednesday.

Probably gonna have highs AOA 100F extending eastward into IL/IN too.

[donsutherland1]

August 1-7, 2012 Thoughts:

The story of this period will likely continue to be a persistence of high heat and lack of rainfall in the drought-stricken Central Plains. Although the East Coast and Great Lakes regions are likely to be warmer than normal, excessive heat does not appear likely to predominate during the opening week of August.

The charts shown below are as follows:

Top Left: Composite temperature anomalies for ENSO Region 3.4 anomalies of +0.20°C to +0.80°C, a PNA of -1.00 to 0.00, and an AO of +0.25 to +1.00 for North America.

Top Right: NAEFS forecast for the July 30-August 5, 2012 timeframe

Bottom Left: 7/22/0z GFS ensemble mean 850 mb anomalies at 312 hours (August 4, 2012)

Bottom Right: Observed decadal temperature trend for August

For the August 1-7 timeframe, there appears to be little prospect of significant rains over most or all of the drought-affected portion of the CONUS.

Taking into consideration all of the date, my thoughts are as follows:

- Warmer than normal across most or all of Canada

- Near normal to somewhat above normal in the Great Lakes Region and the Mid-Atlantic/Northeast regions.

- Much warmer than normal in the Central Plains

- Warmer than normal across the rest of the U.S.

[donsutherland1]

August 8-15, 2012 Thoughts:

The story of this period yet again will likely continue to be a persistence of high heat and lack of rainfall in the drought-stricken Central Plains. The potential will exist for heat to surge into the Middle Atlantic region and possibly New England later in the period.

The charts shown below are as follows:

Left: Composite temperature anomalies for ENSO Region 3.4 anomalies of +0.30°C to +1.00°C, a PNA of -0.50 to +0.50, and an AO of -0.25 to +0.50 for North America.

Top Right: NAEFS forecast for the August 5-11, 2012 timeframe

In terms of rainfall prospects, the East Coast (particularly the Southeast) and the Northern Plains have prospects for above normal rainfall. The Central Plains and possibly Gulf States could be drier than normal.

Taking into consideration all of the date, my thoughts are as follows:

- Near normal in an area running from central Canada into the Northern Plains

- Near normal in California.

- Much warmer than normal in the Central Plains

- Warmer than normal across the rest of the U.S. and Canada

Finally, in terms of the analogs appearing, 70% saw less blocking than normal during the winter, while 30% saw more blocking than normal. The greatest tendency for blocking among those with less than normal blocking occurred in February. For now, much can change and nothing is cast in stone, but the state of blocking will likely be key as to whether Winter 2012-13 delivers in terms of cold and snow to portions of North America. A blocky winter (but not extreme blocky outcome like 2009-10) could see the eastern quarter to third of North America wind up colder and possibly snowier than normal, but the evolution of the drought could have an impact on snowfall possibilities. An absence of blocking could lead to widespread warm anomalies, especially if a basin-wide El Niño unfolds.

Although it is too soon for me to be sure how Winter 2012-13 will turn out, what does appear unlikely is a coast-to-coast cold outcome ala Winter 1978-79. During Summer 1978, much of the Northern Hemisphere's land areas saw colder than normal readings (anomaly on the NCDC dataset was -0.320°C). During Fall 1978, the Arctic was covered by anomalously cold readings while the Northern Hemisphere's land areas were somewhat warmer than normal (+0.107°C anomaly) courtesy of a very warm November. During that month, the AO averaged +2.470 as the Arctic grew especially cold. Once strong blocking developed in late December and predominated into mid-February, the bitter cold that had accumulated in the Arctic flooded into North America and Eurasia.

The opposite has been the case this summer. Much of the Northern Hemisphere has been very warm, with the Northern Hemisphere land areas seeing their warmest June on record. It remains to be seen how things will unfold during the fall.

[donsutherland1]

A thought concerning the prospects for winter blocking...

The June 2012 AO averaged -0.672 and the July AO has averaged +0.09 through July 30. Assuming the AO averages < 0 for the summer (June-August) timeframe, odds would favor the AO's averaging < 0 for the upcoming winter (December-February).

Since 1950, there were 38 cases during which the summer AO averaged < 0. 26/38 (68.4%) saw the winter AO also average < 0.

In cases when the summer AO averaged < 0, a winter AO < 0 was 1.4 times more likely than an AO > 0 during El Niño events. Winter 2009-10 was the most recent El Niño case that saw a negative winter AO.

In contrast, during those 38 cases, a winter AO > 0 was 2.9 times more likely than an AO < 0 during a La Niña. Winter 2011-12 was the most recent La Niña case that saw a positive winter AO.

In sum, if the summer 2012 AO averages < 0 and the upcoming winter experiences an El Niño (or even neutral ENSO conditions), there should be more blocking than last winter. Moreover, a blocky winter would appear more likely than not. Nevertheless, things are not yet cast in stone. Such developments as early-season Siberian snow cover expansion could provide a hint as to how things will turn out during Winter 2012-13.