El Nino

Not Much Winter Weather Until Now. What’s Going On?

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You might remember that I wrote past column articles about what causes winter weather patterns over the Pacific Northwest. In 2013 the article was titled ” Whose Fault Is It? El Nino, La Nina, Or Even La Nada?” Those three terms give meteorologists the tools to determine what kind of winter we will have and whether the current winter weather pattern will continue as is or change to another one.

El Nino
El Nino Jet Stream Pattern | Image by www.washingtonpost.com

Let’s review the three terms and what they mean. El Nino is defined as a warm water current (shown in red/orange) that appears annually, around Christmastime, along the coasts of Ecuador and Peru. The name El Nino means the boy child and refers to the “Christ Child” who’s birthday is celebrated in December when the warm water pool extends itself closer to the South American coast. It was first discovered or noted by the fisherman who found warmer water where they usually would catch fish.  El Nino’s warm water pool actually deflects the Jet Stream in the Winter in such a way as to set up a high pressure ridge over the Pacific Northwest.  That ridge keeps the cold air and the Winter storm track to our North or South and tends keep us warmer and drier. During an El Nino year there is less tropical storm activity in the tropical Atlantic due to increased vertical wind shear over the area.

La Nina
La Nina | Image by pmel.noaa.gov

La Nina is defined as a cold water current (shown in blue) that appears annually, around Christmastime along the coasts of Ecuador and Peru. The name La Nina means the girl child and is the opposite of El Nino and is the cool water pool that extends itself closer to the South America in December.

Vertical Wind Shear
Vertical Wind Shear Diagram | Image AMOL/NOAA

Vertical wind shear is the change of wind direction with height. In order to build the storm clouds it takes to produce a hurricane there must be steadily rising columns of air and the change of wind direction as the air is rising tends to stop the development of the storm clouds. La Nina’s cold water pool has the opposite effect and deflects the Jet Stream so as to send the Winter storms right at us.

La Nada
La Nada | Image by weather.gov

It seems obvious that El Nino and La Nina can’t occupy exactly the same area along the South American coast at the same time. That is where another term comes into play. The ENSO or El Nino-Southern Oscillation. El Nino is often called the warm phase of ENSO while La Nina can be called the cold phase of ENSO. Often the sea surface temperatures waver between the two in the same season. When neither El Nino nor La Nina come to visit the West Coast of South America it is called La Nada which in Spanish translates as nothing. That means the current is stable, neither warm or cold.

What these currents do is deflect the Jet Stream in such a way to either bring the colder air and the Winter storms our way or to act as a barrier to protect us from the stronger Winter storms and keep us warmer. So what’s been going on these last few months? A USA Today article posted February 9, 2018 and written by Doyle Rice touts that the LaNina has ended and now we are being controlled by La Nada. That’s according to climate scientists interviewed for the story. The short-lived La Nina did bring unusually cold air in December and January to Alaska, western Canada, and the Northern plains. La Nina usually brings more precipitation to the Pacific Northwest and Northern California, but that did not happen.

Sea Surface Temperatures
Eastern Pacific Ocean Sea Suyrface Temperature Amomaly | Imagr ospo.noaa.gov

Historically we have had La Nina winters in the Pacific Northwest which were more on the dry side and even warmer than expected. Instead the rain hit Central and Southern California ending in a declaration by Southern California that the drought was officially over.

The ski areas in the central part of Oregon have been suffering from a serious lack of snow cover while the Sierra in California have been experiencing one of their snowiest winters ever recorded. That shows that the deflection of the jet stream is such that the areas receiving significant snowfall were to the south and north of the southern Willamette Valley. That suggests that the Jet Stream was deflected, but the Pacific Northwest was protected from the storms by having a high pressure ridge over the Eastern Pacific and a parade of upper level Low Pressure Troughs which brought us some rain, but also kept temperatures above normal for quite some time. For some reason the Jet Stream set up to being the cold Arctic air down through Canada into the Midwest and as far south as the Gulf Coast states. Snow and record temperatures punched well into the Deep South, but nothing for us.

Feb-April Temperatures
February Through April Temperature Probability| Image by weather.gov
Feb-April Precip
Precipitation Probability February Through April 2018 | Image by weather.gov

The National Weather Service Temperature and Precipitation outlooks for February through April give us a look into our possible weather future. The temperature graphic shows about a 40% chance of below average temperatures and the precipitation graphic shows about a 40% chance of above normal precipitation. Does this give us a handle on what the rest of our winter will be like? Not really. The potential is still there for the intrusion of much colder air moving down through Canada (this past weekend) and if there is sufficient moisture available from the South and West at the same time we could still see significant snowfall in the mountains and possible valley snow if the conditions are right.

At this point in time I’d say a flip of a coin could predict the snow chances for the rest of our winter about as accurately as the combination of the sea surface temperatures and the exact position of the jet stream over the Eastern Pacific Ocean and the Pacific Northwest. Hang on it will still be an interesting ride.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

Will This Winter Be Like Last Winter?

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Recently I have had people asking me what is in store for us this winter. Will it be like last winter with the great mountain snow cover? So far, I don’t have a definitive answer, but there has been some chatter in the professional journals  about the potential of another El Nino winter just like the one we had last winter.

It’s been quite a while since I discussed the mechanism that determines what kind of winter we experience here in the Pacific Northwest. We should start with the terminology used in meteorology to describe the variables that control our fate in winter.

El Nino
El Nino | Image by pmel.noaa.gov

The first term, which I’m sure you remember is El Nino. El Nino is defined as a warm water current (shown in red/orange) that appears annually, around Christmastime, along the coasts of Ecuador and Peru. The name El Nino means the boy child and refers to the “Christ Child” who’s birthday is celebrated in December when the warm water pool extends itself closer to the South American coast. It was first discovered or noted by the fisherman who found warmer water where they usually would catch fish.

La Nina
La Nina | Image by pmel.noaa.gov

The second term is La Nina which is defined as a cold water current (shown in blue) that appears annually, around Christmastime along the coasts of Ecuador and Peru. The name La Nina means the girl child and is the opposite of El Nino and is the cool water pool that extends itself closer to the South America in December.

It seems obvious that El Nino and La Nina can’t occupy the same area along the South American coast at the same time. They tend to alternate which is dominant. That is where the third term comes into play. The ENSO or El Nino-Southern Oscillation. El Nino is often called the warm phase of ENSO while La Nina can be called the cold phase of ENSO. Often the sea surface temperatures waver between the two in the same season.

La Nada
La Nada | Image by weather.gov

I have one more definition that is almost never mentioned. What would you call it when neither El Nino nor La Nina come to visit the West Coast of South America? I guess you could call it the “nothing” and that is just what they decided to call it. In Spanish it is La Nada.

Now that you have the key definitions we need to find out how they can make our lives more pleasant or more difficult in winter. What these currents do is deflect the Jet Stream in such a way to either bring the colder air and the Winter storms our way or to act as a barrier to protect us from the stronger wInter storms and keep us warmer.

El Nino’s warm water pool actually deflects the Jet Stream in the Winter in such a way as to set up a high pressure ridge over the Pacific Northwest. That ridge keeps the cold air and the Winter storm track to our North or South and tends keep us warmer and drier. During an El Nino year there is less tropical storm activity in the tropical Atlantic due to increased vertical wind shear over the area.

La Nina’s cold water pool has the opposite effect and deflects the Jet Stream so as to send the Winter storms right at us. Which one is controlling our weather now and what kind of Winter can we expect?

Sea Surface Temperatures
Sea Surface Temperatures Image by ospo.noaa.gov
Note blue color off Pacific Coast of South America (cooler pool that stretches westward)

According to an ElDoradoCounty.com report issued September 14, 2017 “A majority of the models in the IrI/CPC suite of Nino-3.4 predictions favor ENSO-neutral through the Northern Hemisphere 2017-18 winter. However, the most recent predictions from the NCEP Climate Forecast System (CFSV2) and the North American Multi-Model Ensemble (NMME) indicate the formation of La Nina as soon as the Northern Hemisphere Fall 2017. Forecasters favor these predictions in part because of the recent cooling of the surface and sub-surface temperature anomalies, and also because of the higher degree of forecast skill at this time of year. In summary, there is an increasing chance (55-60%) of La Nina during the Northern Hemisphere Fall and winter 2017-18.”

90-Day Temperature Outlook
90-Day Temperture Outlook | Image by ccp.ncep.noaa.gov
90-Day Precipitation
90-Day Precipitation Outlook | Image by ccp.ncep.noaa.gov

It is a bit early in the season to make a solid prediction for Winter. The best time is mid-November (that is more than a month away) when the sea surface temperatures are set up for the Winter months. That prediction would be for the actual Winter months of December, January, and February. So for the predictions seem to be for a small chance of above normal temperatures and precipitation. Now we just have to believe that this winter should be a lot like last winter, until proven otherwise, with plenty of snow in the Cascades producing a bountiful snow pack for the spring thaw producing plenty of water for the reservoirs and area rivers.

Let me know what you would like me to talk about or explain. You can email me at: [email protected].

Did It Seem That Hot To You?

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The National Weather Forecast Office in Portland revealed that this was the warmest meteorological summer in our recorded history. What is meteorological summer? That is the time period of the months of June, July and August. It has also been reported that worldwide the average temperature this summer was 61.86 degrees which is also the hottest ever recorded.

Meteorological Summer | Image by bbc.com through www.scoopnest.com
Meteorological Summer | Image by bbc.com through www.scoopnest.com

As opposed to astronomical summer which is measured from the summer solstice on or about June 21st through Autumnal equinox on or about September 21st.

Astronomical Seasons | Image by www.ncdc.noaa.gov
Astronomical Seasons | Image by www.ncdc.noaa.gov

The actual numbers for this meteorological summer for Portland, Salem and Eugene are as follows: (They show the average temperatures for the hottest 5 summers in descending order top to bottom)

Portland                               Salem                                   Eugene

Avg. Temp.(Degrees F)          Avg. Temp.(Degrees F)      Avg. Temp.(Degrees F)

2015               72.2               2015               71.3                 2015               69.5

2009               69.8               2014               69.4                 1967               68.5

2014               69.6               1958               68.8                 1958               68.1

2004               69.5               1926               68.4                 2014               67.9

1967               69.4               2013               68.4                 1970               67.6

75 years of data                    120 years of data                    120 years of data

Let’s take a look at June, July and August listing the number of days that warmed to 90 degrees or more. June: 7th-90, 8th-93, 9th-91, 25th-94, 26th-98, 27th-98, 29th-91,and 30th-95. The month of July started right off hot: 1st-99, 2nd-101, 3rd-100, 4th-91, 5th-93, 7th-92, 8th-93, 18th-100, 19th-94, 20th-92, 29th-100, 30th-105, 31st-103. Then the month of August also started off hot: 1st-100, 12th-92, 17th-91, 18th-96, 19th-99, and on the 27th-92. Sum up those numbers we have a total of 27 days with temperatures of 90 degrees and above and 7 days with 100 degrees or higher. That’s a lot of hot days for Eugene, but what made it worse was low temperatures that were often well above normal also.

What does this mean? Well in my own humble opinion there isn’t yet enough definitive evidence that next summer will be even hotter. It does suggest a trend since in all three cities the average summer temperature has increased for at least the last two years in a row. In my column published Monday August 24th,  “El Nino Is Growing Stronger. What Does It Mean To Us”?, I explained that all indications are that this winter will be an “El Nino” winter which means we’ll be milder and drier than normal for another winter. It is also expected to last well into the spring season. Often an El Nino winter is followed by a hot and dry summer. Whether you use a super computer or a crystal ball predicting next summer’s temperatures is at best an educated guess. We’ll just have to wait and see how it turns out.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

El Nino is Growing Stronger. What Does It Mean For Us?

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There has been some talk lately about the phenomenon called El Nino. All indications point to it getting stronger and stronger (possibly the strongest ever) so as to control what our winter of 2015-2016 will look like. Let’s start with a good definition of El Nino. Wait a minute! I explained that in my column published September 16, 2013. It was titled “Whose Fault Is It? Could It Be El Nino, La Nina, Or Even La Nada”?

Sea Surface Temperatures As Of 8/18/15 | Image by NOAA
Sea Surface Temperatures As Of 8/18/15 | Image by NOAA

Here is the definition that I used in that column: El Nino is defined as a warm water current (shown in red/orange) that appears annually, around Christmastime, along the coasts of Ecuador and Peru. The name El Nino means the boy child and refers to the “Christ Child” who’s birthday is celebrated in December when the warm water pool extends itself closer to the South American coast. It was first discovered or noted by the fisherman who found warmer water where they usually would catch fish. The above chart shows the sea surface temperatures in degrees Celsius and you can easily see that the area in red is quite widespread. That indicates a very large area of ocean water that is getting even warmer and spreading out.

Jet Stream Position El Nino Or La Nina | Image by NOAA via slideplayer.com
Jet Stream Position El Nino Or La Nina | Image by NOAA via slideplayer.com

You might ask: How does El Nino actually control the winter weather pattern? The answer is quite simple. The warm water pool in the Pacific Ocean deflects the Jet Stream so as to keep us in the warm sector and in most cases the dry sector also.

The Climate Prediction Center, the National Centers for Environmental Prediction (NCEP),the National Oceanic and Atmospheric Administration (NOAA)- the National Weather Service (NWS) and the International Research Institute for Climate and Study collectively studied the various computer models and the latest available hard data and issued a formal “El Nino/Southern Oscillation (ENSO) Diagnostic Discussion.” The synopsis of their results is much easier to understand than the detailed version. They stated “There is a greater than 90% chance that El Nino will continue through Northern Hemisphere winter 2015-2016, and around an 85% chance it will last into early spring 2016.

90-Day Temperature Outlook | Image by NOAA
90-Day Temperature Outlook | Image by NOAA

Let’s take a look at the NOAA 90-day Extended forecasts. The Temperature outlook for October, November and December 2015 shows the temperatures for the Pacific Northwest from extreme Northern California through Oregon and Washington are expected to be above normal values.

90-Day Precipitation Outlook | Image by NOAA
90-Day Precipitation Outlook | Image by NOAA

The Precipitation outlook for the period October, November and December 2015 shows the precipitation, including rain and melted snow, will be below normal. So if we put the data from the two outlooks together it can be said that that 90-day period will be warmer and drier than normal. More to the point, it is a strong indication that the drought will continue due to warmer than normal temperatures which would mean another winter with below normal snowpack and not enough water in the spring for the reservoirs.

An article in the June 2015 issue of the Bulletin of the American Meteorological Society titled “Understanding ENSO Diversity” reveals that there are different types of of El Nino and that they have identified. ” To better understand ENSO diversity, several indices have been introduced to identify different event types, with emphasis on the warm (El Nino) ENSO phase. Indices have been constructed from (sea surface temperature) SST (indices a-d), subsurface ocean temperature (index e), sea surface salinity (index f), or outgoing longwave radiation anomaly information index (index g).” The best way to understand that is to know there are 7 indices which use various methods to determine the type of El Nino and what kind of weather pattern it will produce. The more we learn about how El Nino, La Nina and even La Nada work the better we can forecast them in advance and know what kind of weather to be prepared to experience.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

Whose Fault Is It? Could It Be El Nino, La Nina, or even La Nada?

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Is it El Nino, La Nina, or maybe even La Nada? You have heard those terms bandied about by meteorologists and news anchors alike, but what do they really mean and why should you care. The three terms describe the sea surface temperatures in the Pacific Ocean which have a significant effect on the weather patterns around the world and particularly over the Pacific Northwest.

I’ll start off with the definitions of the terms so we can then use them to explain how they specifically control our weather patterns, particularly during Winter.

Latest Sea Surface Temperatures Pacific Ocean | Image NOAA
Latest Sea Surface Temperatures Pacific Ocean | Image NOAA

El Nino is defined as a warm water current (shown in red/orange) that appears annually, around Christmastime, along the coasts of Ecuador and Peru. The name El Nino means the boy child and refers to the “Christ Child” who’s birthday is celebrated in December when the warm water pool extends itself closer to the South American coast. It was first discovered or noted by the fisherman who found warmer water where they usually would catch fish.

La Nina is defined as a cold water current (shown in blue) that appears annually, around Christmastime along the coasts of Ecuador and Peru. The name La Nina means the girl child and is the opposite of El Nino and is the cool water pool that extends itself closer to the South America in December.

It seems obvious that El Nino and La Nina can’t occupy the same area along the South American coast at the same time. That is where another term comes into play. The ENSO or El Nino-Southern Oscillation. El Nino is often called the warm phase of ENSO while La Nina can be called the cold phase of ENSO. Often the sea surface temperatures waver between the two in the same season.

Just when you thought I was finished giving you definitions I have one more. What would you call it when neither El Nino nor La Nina come to visit the West Coast of South America? I guess you could call it the “nothing” and that is just what they decided to call it. In Spanish it is La Nada.

The Jet Stream | Image ww2010atmos.uiuc.edu
The Jet Stream | Image ww2010atmos.uiuc.edu

Now that you have the key definitions we need to find out how they can make our lives more pleasant or more difficult. What these currents do is deflect the Jet Stream in such a way to either bring the colder air and the Winter storms our way or to act as a barrier to protect us from the stronger WInter storms and keep us warmer.

El Nino’s warm water pool actually deflects the Jet Stream in the Winter in such a way as to set up a high pressure ridge over the Pacific Northwest. (See Picture to left)  That ridge keeps the cold air and the Winter storm track to our North or South and tends keep us warmer and drier. During an El Nino year there is less tropical storm activity in the tropical Atlantic due to increased vertical wind shear over the area.

Vertical Wind Shear Diagram | Image AMOL/NOAA
Vertical Wind Shear Diagram | Image AMOL/NOAA

Vertical wind shear is the change of wind direction with height. In order to build the storm clouds it takes to produce a hurricane there must be steadily rising columns of air and the change of wind direction as the air is rising tends to stop the development of the storm clouds.

La Nina’s cold water pool has the opposite effect and deflects the Jet Stream so as to send the Winter storms right at us. I know what you are expecting me to say next. Which one is controlling our weather now and what kind of Winter can we expect? The experts say we are in the La Nada now. It is a bit early in the season to make a solid prediction for Winter. The best time is mid-November when the sea surface temperatures are set up for the Winter months. That prediction would be for the actual Winter months of December, January, and February. As of now the sea surface temperatures indicate neither El Nino or La Nina so that leaves us with La Nada continuing and neither the cold water nor the warm water dominating. That makes for a difficult forecast. My best guess is that this Winter will be very similar to last winter. That means no major snowfall down on the Valley floor. Remember that this is only an educated guess at best and should be updated when the new winter prediction computer model from the National Weather Service produces the national forecast for October, November, and December. That should be ready soon. It takes a very small change in data for an unexpected storm to appear. That is what makes weather forecasting such a challenge.

Let me know what you would like me to talk about or explain. You can email me at: [email protected].