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srainhoutx
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Advancing Kelvin Wave has stirred that Pacific. We'll see what next month brings. My hunch is above average 'precip' and below to 'slightly below normal' temps for the upcoming winter season.. December is always a 'tricky' month in SE and Central TX... ;)
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Portastorm
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srainhoutx wrote:Advancing Kelvin Wave has stirred that Pacific. We'll see what next month brings. My hunch is above average 'precip' and below to 'slightly below normal' temps for the upcoming winter season.. December is always a 'tricky' month in SE and Central TX... ;)
I would agree. I think the first half of the 2012-13 winter season for us will bring some "wintry" excitement!
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Ptarmigan
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This Week's ENSO
Niño 4 0.4ºC
Niño 3.4 0.3ºC
Niño 3 0.3ºC
Niño 1+2 0.5ºC

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf

Region 3.4 has cooled, while 1+2 has warmed. Despite the cooling, I think we could see El Nino this winter. This pattern has happened before in 1991 and 1994.

ENSO Forecast Model
Image

Most are calling for a weak to moderate El Nino.

Image
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JackCruz
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What would a weak to moderate El nino mean for Houston?
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Ptarmigan
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JackCruz wrote:What would a weak to moderate El nino mean for Houston?
For Upper Texas Coast (1895-2012)

Weak El Nino
Rainfall
Mean = 11.22
Median = 10.77
Standard Deviation = 2.45
Driest = 7.56 (1987-1988)
Wettest = 18.31 (1923-1924)

Temperature
Mean = 53.73°F
Median = 54.09°F
Standard Deviation = 2.90
Coolest = 48.90°F (1977-1978)
Warmest = 60.13°F (1951-1952)


Moderate El Nino
Rainfall
Mean = 13.35
Median = 13.17
Standard Deviation = 2.60
Driest = 8.22 (1941-1942)
Wettest = 16.48 (1965-1966)

Temperature
Mean = 53.32°F
Median = 53.70°F
Standard Deviation = 1.63
Coolest = 49.63°F (2009-2010)
Warmest = 55.77°F (1940-1941)


Overall
Rainfall
Mean = 10.72
Median = 10.19
Standard Deviation = 3.47
Driest = 2.84 (2008-2009)
Wettest = 23.72 (1991-1992)

Temperature
Mean = 55.10°F
Median = 55.19°F
Standard Deviation = 2.63
Coolest = 48.90°F (1977-1978)
Warmest = 60.93°F (1949-1950)

Overall, a weak and moderate El Nino is going to be cooler and wetter than normal. There are some dry and/or warm winters in El Ninos, but those are an exception.
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Thanks Ptarmigan! :D
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John Nielsen-Gammon's Climate Abyss blog in the Chron today has an interesting take on the projected El Nino

http://blog.chron.com/climateabyss/2012 ... e-fingers/

a few exerpts:

The Pacific Decadal Oscillation (PDO) is still strongly negative, meaning that temperatures are tending to run cool in the tropics and warmer at higher latitudes. The Atlantic Multidecadal Oscillation (AMO) is still strongly positive, meaning that temperatures are tending to run warm in the North Atlantic. The last time large-scale conditions were like this was during the 1950s.

3. This El Niño appears to be setting up to have its warmest temperature anomalies in the central tropical Pacific rather than the eastern tropical Pacific. In recent years, it has been recognized that there are two types of El Niño events, and the central Pacific type has been given the name “El Niño Modoki” (modoki means “similar, but different” in Japanese). The El Niño Modokis do not tend to produce as much rainfall across the southern United States as the regular El Niños do.

4. We may not get an El Niño after all. The latest forecast from the Climate Prediction Center has the odds of an El Niño event begin only slightly better than 50/50, and it’s forecasted to probably be gone by the beginning of the new year. If we have neutral conditions rather than an El Niño, there’s not much reason to favor above-normal rainfall over below-normal rainfall.
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http://www.cpc.ncep.noaa.gov/products/p ... enso.shtml

Image


from Jeff Masters: http://www.wunderground.com/blog/JeffMa ... rynum=2250

The progression of oceanic conditions in the Equatorial Eastern Pacific towards El Niño has been interrupted by a marked cooling over the past two weeks, and the onset of a full-fledged El Niño event this fall and winter is now in considerable doubt. Sea surface temperatures in the Equatorial Eastern Pacific were approximately 0.5°C above average--the threshold for a weak El Niño event--from the beginning of July through mid-September. However, for the past two weeks, these temperatures have fallen to just 0.2°C above average--solidly in the neutral category. In addition, over the past three months, winds, pressures, and cloud cover over the Pacific have not responded in the fashion typically associated with an El Niño (one exception: some stronger westerly surface winds than usual have developed near New Guinea and Indonesia, which could act to push warm water eastwards towards South America in coming months and tip the ocean more towards El Niño.) NOAA's Climate Prediction Center (CPC) classified conditions as being neutral in their monthly El Niño discussion, issued October 4, but continued their El Niño watch, giving a 55% chance that an El Niño event will be in place for the October-November-December period. This is a big reduction from 69% odds given in their September forecast. NOAA's final take on the matter:

Due to the recent slowdown in the development of El Niño, it is not clear whether a fully coupled El Niño will emerge. The majority of models indicate that borderline ENSO-neutral/ weak El Niño conditions will continue, and about half suggest that El Niño could develop, but remain weak. The official forecast therefore favors the continuation of borderline ENSO-neutral/ weak El Niño conditions into Northern Hemisphere winter 2012-13, with the possibility of strengthening during the next few months.

The lack of a progression towards El Niño so far this October means that the Atlantic hurricane season is likely to extend into November, as has been the norm over the past decade. El Niño events tend to increase wind shear over the tropical Atlantic, suppressing hurricane activity. However, the latest 2-week wind shear forecast from the GFS model shows continued near-average wind shear levels over the Caribbean and tropical Atlantic through mid-October. Given the recent faltering of El Niño, I expect that near-average wind shear levels will continue over the tropical Atlantic into November, and that we will see one or two more tropical storms in the Atlantic this
hurricane season.

Image

Figure 1. Departure of sea surface temperature (SST) from average between October 2011 and October 2012 in the Equatorial Eastern Pacific between 5°S - 5°N, 170°W - 120°W (the Niño 3.4 region.) A La Niña episode occurs when SSTs in the Niño 3.4 region are 0.5°C cooler than average for an extended period (below the thick blue line.) La Niña conditions were in place between October 2011 - March 2012. El Niño conditions occur when SSTs in the El Niño 3.4 region are more than 0.5°C warmer than average (above the thick red line.) El Niño conditions developed in early July, but have fallen below the threshold for a weak El Niño event over the past two weeks. Image credit: NOAA's Climate Prediction Center (CPC).
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wxman57
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Looks like this winter will be neutral, not El Nino.
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Ptarmigan
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This Week's ENSO
Niño 4 0.4ºC
Niño 3.4 0.2ºC
Niño 3 0.2ºC
Niño 1+2 0.5ºC

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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Last Week
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This Week
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The subsurface is quite warm.

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srainhoutx
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We'll likely see an up tick in tropical activity as we head beyond mid October into mid November time frame in the Atlantic Basin. The long range GFS has been suggesting for several days increased tropical mischief in the Caribbean. We will see.
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Ptarmigan
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This Week's ENSO
Niño 4 0.3ºC
Niño 3.4 0.1ºC
Niño 3 -0.1ºC
Niño 1+2 -0.1ºC

Looks like no El Nino at this point, but do not rule it out yet.

Interesting to note in 1991, ENSO Region 3.4 went up and down. It peaked at +0.9 on July 31, 1991 and went down to +0.1 on September 11, 1991. It started to go up rapidly from there and hits +1.1 on October 16, 1991. By December 18, 1991, it reaches +2.0. 1991-1992 was a Modoki El Nino.

It also happened in 1994. Started as neutral and than peaked at +0.7 on August 10, 1994. It bottoms out at +0.1 on September 14, 1994. From there it warms up to +1.4 by November 30, 1994. Like 1991-1992, 1994-1995 was a Modoki El Nino.
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wxman57
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That was during a warm PDO (early 90s). PDO is cool now, and that makes it more difficult to get a strong or long-lasting El Nino.
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Ptarmigan
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wxman57 wrote:That was during a warm PDO (early 90s). PDO is cool now, and that makes it more difficult to get a strong or long-lasting El Nino.
I noticed there was a period of warm PDO from 2002-2007. Than it cools down in 2008, which has been there since. 2009 to 2010 had a briefly warm PDO due to El Nino.

1925-1947 Warm
1947-1976 Cool
1976-1998 Warm
1998-2002 Cool
2002-2007 Warm
2008-? Cool

http://www.nwfsc.noaa.gov/research/divi ... ca-pdo.cfm
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Ptarmigan
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El Nino and Pacific Decadal Oscillation (PDO) are correlated with each other.
r = 0.47
p > 0.01

That is no surprise. A warm PDO is more favorable for El Nino, while cool PDO is more favorable for La Nina. Let's look at what PDO has an impact on other oscillations.

PDO is highly correlated with Pacific North America (PNA).
r = 0.73
p > 0.01

A warm PDO is more favorable for positive PNA, while cool PDO is more favorable for negative PNA. A positive PNA is more favorable for cooler winters in Houston area and Texas.

PDO is correlated with Eastern Pacific Oscillation (EPO) or North Pacific Index (NPI).
r = 0.25
p = 0.05

A warm PDO favors a more positive EPO/NPI, while cool PDO favors a more negative EPO/NPI. A more negative EPO/NPI favors cooler winters in Houston area and Texas.

PDO is also correlated with Arctic Oscillation (AO), but not North Atlantic Oscillation (NAO)
AO
r = -0.30
p = 0.02

NAO
r = -0.09
p = 0.34

A cool PDO favors a more positive AO, while warm PDO favors a more negative AO. A negative AO and NAO favors cooler winters in Houston area and Texas.
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Ptarmigan
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This Week's ENSO
Niño 4 0.4ºC
Niño 3.4 0.1ºC
Niño 3 -0.2ºC
Niño 1+2 -0.6ºC

Region 1+2 are now in La Nina territory. If we have El Nino, it could be a Modoki El Nino like in 2009-2010.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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Ptarmigan
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Forecast model shows no El Nino for Region 3.4. We shall see.

Image
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Ptarmigan
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This Week's ENSO
Niño 4 0.7ºC
Niño 3.4 0.5ºC
Niño 3 0.1ºC
Niño 1+2 0.0ºC

Thins are warming up again, especially around Region 3.4 and 4. Probably a Modoki El Nino is likely.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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