Strong El Niño likely to peak late fall-early winter, NOAA forecasters say

Aug 14th 2015 5:47AM811264155

 

Forecaster consensus unanimously favors a strong El Niño at its peak in the late fall and early winter, according to an updated forecast released Thursday by the National Oceanic Atmospheric Administration (NOAA).

 

The prediction for a strong El Nino at its peak is based on the latest guidance from computer models, which all forecast a strong El Nino during that period of time. NOAA also said that all signs in the atmosphere and the Pacific Ocean point to a significant and strengthening El Niño.


El Niño now has an 85 percent chance of lasting into early spring 2016. This is an increase of five percent over NOAA's last El Niño update in July. NOAA also continues to say that there is a greater than 90 percent chance of El Niño lasting through the upcoming winter.

El Niño is an anomalous, yet periodic, warming of the central and eastern equatorial Pacific Ocean. For reasons still not well understood, every 2-7 years, this patch of ocean warms for six to 18 months.

The fact that El Niño is likely to last into spring is important for the United States since precipitation and temperature impacts from a moderate-to-strong El Niño are typically most noticeable during the colder months. We have more on what those impacts are later in this article.

NOAA reports that sea-surface temperature anomalies increased in July in the Niño 3.4 region. This is the middle portion of the equatorial Pacific Ocean that is most commonly used to measure the intensity of an El Niño event.

As mentioned above, NOAA's forecaster consensus is for a strong El Niño at its peak, perhaps the strongest since the 1997-1998 episode and, thus, may play a stronger role in your weather.

What does warm water have to do with the weather?

A 'Sea Change' in Atmospheric Circulation

Typically, easterly trade winds near the equator pile warm water into the western Pacific Ocean. Conversely, the resultant upwelling, or upward movement of deep, cold ocean water keeps the eastern and central Pacific Ocean cooler.

Thunderstorms require at least some degree of warm, humid air near the surface, so they're more numerous and persistent over the western Pacific warm pool, and much less so in the eastern equatorial Pacific.

During an El Niño, these trade winds weaken, and may at times reverse from west to east. Warmer western Pacific water then slowly sloshes back toward the central, even eastern Pacific Ocean in what's known as an equatorial-trapped Kelvin wave.

Therefore, the most persistent thunderstorms will shift from the western to the eastern and central Pacific Ocean in an El Niño.

This trade wind reversal and the resulting reorientation of thunderstorms changes the atmospheric circulation not just over this swath of the equatorial Pacific Ocean, but can also have far-reaching impacts on the atmospheric circulation.

Weather Impacts

First, keep two things in mind throughout this discussion of potential impacts:

1) El Niño is not the sole driver of the atmosphere at any time. Day-to-day variability in the weather pattern, including blocking patterns, forcing from climate change and other factors all work together with El Niño to determine the overall weather experienced over the timeframe of a few months.

2) No two El Niños are exactly alike. The intensity matters for impacts.

El Niño's clearest impact on northern hemisphere weather patterns occurs from late fall through winter.

Looking at past moderate-strong El Ninos, here are the upshots for temperatures and precipitation from late fall through winter in the U.S.:

- Wetter: Southern U.S. from California to the Carolinas then up parts of the East Coast

- Drier: Parts of the Ohio Valley, Great Lakes, Northwest and Northern Rockies

- Cooler: Desert Southwest, Southern Plains, northern Gulf Coast

- Warmer: Northern tier of states from the Pacific Northwest to the Northern Plains, Great Lakes, and Northeast

Note these are impacts that are typically expected, but they aren't always the rule.

Residents of the western states may remember the flooding that struck California during the strong 1997-98 El Nino. In February 1998, a series of storms caused an estimated $550 million in damage and killed 17 people in California. A total of 35 counties were declared federal disaster areas. This fits into the bucket of the wetter-than-average winter you would typically expect in a moderate or strong El Niño.

Interestingly, during the previous winter there was also major flooding in California and it was even more costly with a total price tag of $1.8 billion, according to Jan Null, a consulting meteorologist in California. However, El Niño was not present that winter and rainfall for the season was near average. The flooding was the result of excessive rainfall that fell in a short time period combined with snowmelt from late December to early January.

The weak El Niño in the winter of 2006-07 provided a totally different story than what we saw in the very strong 1997-98 El Niño winter.

California had its 23rd driest winter season on record when looking at the three-month period from December 2006 to February 2007. In Los Angeles, the entire water year from July 2006 to June 2007 was the driest on record with just 3.21 inches of rainfall.

So, those hoping for drought relief next winter in the Golden State shouldn't immediately draw a conclusion that significant rains are ahead in any El Niño year. The strength of the El Niño can play a role in the outcome. In addition, heavy rainfall can occur with or without El Niño present and that was the case in the winter preceding the strong 1997-1998 El Niño.

What About Hurricane Season?

There is a body of scientific evidence linking the occurrence of El Niño with increased wind shear in the tropical Atlantic Basin, which is one factor - along with dry air - that limits the development and strengthening of tropical cyclones.

As of this writing, we are seeing those hostile conditions in parts of the Atlantic Basin.

Dry air has dominated from the southern Gulf of Mexico to east of the Lesser Antillesduring the first two months of the hurricane season. Wind shear has been and remains strong from the Caribbean Sea and parts of the Gulf of Mexico to the far western and eastern Atlantic.

(MORE: Hostile Conditions in the Atlantic)

During the 2013 hurricane season, 14 storms formed, but only two reached hurricane strength. Neither of these hurricanes reached major hurricane status, which is defined as Category 3 or stronger on the Saffir-Simpson Hurricane Wind Scale.

When considering overall season activity via the ACE index, 2013 was the least active Atlantic hurricane season since 1994. There was no El Niño in place in 2013.

Now, consider the 2004 Atlantic hurricane season. Four hurricanes - Charley, Frances, Ivan and Jeanne - hammered Florida in less than six weeks. There were 15 storms and nine hurricanes that season, which is an active one by any measure, and it developed despite a weak El Niño.

Taken together, the five El Niño hurricane seasons since 1995 averaged about 11 storms, 5 hurricanes, and 2-3 major hurricanes, a reduction of four storms, 3 hurricanes, and 1-2 major hurricanes from the average since 1995.

Prior to the current active phase of Atlantic hurricane activity (pre-1995), there were several other relatively slow hurricane seasons: 1982, 1986, 1987, 1991 and 1994. The 1982 season was particularly inactive, with only six tropical storms and two hurricanes. The next year, despite one of the strongest El Niños on record finally fading by early summer, only four storms formed the entire season.

Exactly where the equatorial Pacific Ocean warms in an El Niño matters, as well.

Warming in the eastern equatorial Pacific: lower numbers of Atlantic tropical cyclones
Warming in the central equatorial Pacific: higher numbers of Atlantic tropical cyclones

As we've stated, El Niño is only one driver of the atmospheric circulation. Wind shear over the Atlantic Basin may be less on some days, despite being higher when averaged over an entire season.

While we have focused on numbers of storms and hurricanes, it's ultimately a storm's path that matters for impact.

"Even if we get a strong El Niño, that doesn't mean no U.S impacts (from hurricanes or tropical storms)," says Dr. Phil Klotzbach, a tropical meteorologist and researcher at Colorado State University.

Klotzbach notes that Hurricane Betsy hit both Louisiana and Florida in 1965 and Agnes flooded out the eastern U.S. in 1972, both during strong El Niños. All it takes is one intense, landfalling hurricane to make many forget an El Niño was even there.

Meanwhile, the eastern, central and western Pacific Basins remain very active. At one point in mid-July we had six active tropical cyclones across the Pacific Ocean at the same time.

In early August, Typhoon Soudelor hammered Saipan, Taiwan and eastern China. As of this writing, computer model forecast guidance indicates that two more typhoons are possible in the next few days.

Colorado State University tropical scientist Phil Klotzbach found tropical cyclones are about three times more likely to impact Hawaii in El Niño years vs. La Nina years.

So far this season, three named storms have formed in the central Pacific Basin. In addition, two named storms have crossed into the central Pacific from the eastern Pacific.

Those two systems that originated in the eastern Pacific have brought some impacts to Hawaii. Guillermo brought high surf, but otherwise passed well enough north to minimize rain and wind impacts. Hilda was forecast to bring enhanced rainfall chances to the Big Island in the next few days.

Ultimately, this El Niño will exert some influence on the numbers. However, all it takes is one tropical cyclone making landfall in a populated area to change perceptions of an active season.

It has come to our attention that a few Landscapers that are UN-licensed or unskilled at Draiange & erosion control have popped up in the Phoenix area recently advertising that they do Drainage work. Funny thing is these companies are trying to imitate us. Since we started the category with the Arizona Registrar of contractors 13 years ago back in 2003, we have the experience & know how having completed hundreds of successful drainage projects in Arizona. We still enjoy a perfect record of no complaints with the Arizona Registrar of Contractors! Don't take a chance with your home by using UN-licensed  or UN-skilled companies. Landscape Drainage Solutions is the Real Deal in Arizona for all of your Landscape Drainage & Erosion control Solutions! 

I have been on hundreds of Drainage consultations over the years here in Arizona & I always hear the same thing, But it only rains a couple of times a year! Not true! And when it does rain here it is usually quite an event. So why is rain a problem here in the desert? Well one answer is our clay soil.

First of all clay soil does not percolate well like sand does for instance. So once the clay soil becomes saturated, it no longer seeps into the soil & finds it's way under your homes foundation or inside your house, patios, garage or basement. 

Besides Arizona's clay soil, Poorly planned & executed  Landscaping, Pools, Patios & other structres can block stormwater from flowing off your property.

Also, many homes are built on flat lots making it difficult to drain stormwater from the back yard to the front street.

Summer monsoons pack a lot of stormwater in very little time quickly saturating the clay soil & running off.

 Winter storms although lighter, tend to last longer than summer monsoons often lasting up to three days! 

 So as the saying goes here in Arizona, When it rains, it pours! 

 Tom Rubino, President, Landscape Drainage Solutions 

The rain & hail came down in torrents on October 5th 2010 & covered the entire valley from Queen creek to Glendale. This storm dropped more water than I have ever witnessed in my 33 years in Arizona. The hail started out as golf ball size then morphed into basemall size pounding on my windows & dropping into the pool like meteroites.

After very little rain this past summer it looks as though we are going to get it all back at once!
The rain started coming down on Tuesday, 1/19/2010 in the afternoon & continued throughout the evening.

Today we are drying out a bit but the next storm is lining up in California & is expected to produce heavy rain in Arizona on Thursday & Friday.

It doesn't rain a lot here but as they say..."when it rains it pours".

October is the month to convert your lawn to rye grass here in the valley. Once night temperatures hit 65 degrees at night, Bermuda & Hybrid Bermuda (Tiff) grass begin to slow down. There is a small window of opportunity to get your winter lawn established. Once it gets to cold, Rye-grass seed is slow to germinate if at all. The seed doe's germinate quickly when temperatures are in the 80's. So once October is gone so is your opportunity to establish a winter lawn. I like to over-seed within the first two weeks of October,
 

This is when you want to scalp & verticut your lawn.
Verticutting removes the built up thatch that accumlates through out the summer. You can rent a verticutter or you can buy a
de-thatching blade that attaches to your lawnmower.
Once you have detached your lawn you can then sow your winter grass seed.  For perennial Rye grass spread rates vary so read the label on the bag. It is important to make sure that your grass seed makes good soil contact so that it can germinate. Germination usually takes 5 to 10 days.
Water your new seed up to 5 times per day. You want to keep your soil moist at all times, you do not want it to dry out in between waterings. Your new lawn should be pretty well established in 10 to 14 days. Cut the water back & begin mowing weekly.

Grass seed comes in annual & perennial varieties. Annual is cheaper but steer clear of this nasty grass. it grows to much & stains everything green! Perennial grass is much more like golf course grass. So in this case it is best to spend the extra money for perennial grass seed. Expect to pay about $85.00 for 50 lbs or about 5,000 sq.ft.


Good luck & enjoy your winter lawn!

What happened to this years Monsoon season? I posted an article in a previous blog that quoted experts predicting an active monsoon season. Though we did have a couple of storms, so far the 2009 monsoon season has been relatively mild.

Some people are breathing a sigh of relief, although we really could use some more rain in the valley. It makes it very hard on trees, shrubs & summer lawns when they are only receiving irrigation water.
Some of the larger landscape trees & shrubs rely on the supplemental rainfall they receive to help keep them lush. Particularly the non native species.

So from a Landscapers perspective, I am doing the Rain dance!

Lets hope for a wet fall & winter ****Only six more weeks of summer! This summer seems to be flying by!



  

So the monsoon season has gotten off to a little bit later start this year. Only a couple of days after the start of last years monsoon season on July 10th, 2008 we received our first batch of storms on July 12th & 13, 2009. Another big storm brought high winds, lightning & rain to most of the phoenix metro area the week of July 20th, 2009

August is usually a big month for some furious monsoon activity. August is also one of the wettest months of the year in Arizona along with December.
I think the worst is yet to come in August so batten down the hatches & make sure your storm drainage issues are taken care of.

As they say it doesn't rain much in arizona but when it doe's it can reek havoc!

Here is the definition of Monsoon from Wikipedia:

The English monsoon came from Portuguese monção, ultimately from Arabic mawsim (موسم "season"), "perhaps partly via early modern Dutch monsun". The Arabic-origin word mausam (मौसम, موسم) is also the word for "weather" in Hindi, Urdu, and several other North Indian languages. The definition includes major wind systems that change direction seasonally.

"Most summer monsoons have a dominant westerly component and a strong tendency to ascend and produce copious amounts of rain (because of the condensation of water vapor in the rising air). The intensity and duration, however, are not uniform from year to year. Winter monsoons, by contrast, have a dominant easterly component and a strong tendency to diverge, subside, and cause drought.