Focus your attention on the 0-degree latitude line (Equator) when you are looking at the SST Anomaly map. Got that? Good. Now I want you to look at the next image:
The ENSO regions are broken into 4 parts and sit along the "Equatorial Pacific." So if you compare, for instance, ENSO region 1+2 with the SST Anomaly map I posted, you will notice there is quite a bit of warming taking place off the northwestern coast of South America. In fact, there appears to be normal to above normal anomalies in all the ENSO regions. Of course, in case you did not know, when the Equatorial Pacific is experiencing SST's running consistently above normal, that is an indication that an El Nino could be forming. Specifically, most Climatologist go by Nino region 3.4 to determine La Nina or El Nino by looking at the ONI (Oceanic Nino Index). If the ONI in Nino region 3.4 exceeds +0.5 degree C for 5 straight overlapping seasons, an El Nino will be officially declared.
The CFS certainly insists that Nino-regions 3 and 3.4 will reach El Nino criteria, not just for this summer, but into winter of 2014-2015. But that outlook will not be out until around Thanksgiving. Lets not get ahead of ourselves.
Just in case you do not buy into the good ol' CFS model, here is the EURO for ya:
Some of those members are getting the ONI as high as +3-degree C (anomaly). The mean, however, looks to be around +1-degree C (for the summer).
To what extent has the Equatorial Pacific been warming? It has been warming quite a bit since January 2014. Take a look for yourself.
January 2014 SST's:
May 2014 SST's:
Look off the west coast of Latin America, wow at the difference!!
So...with all that being said, I think it is safe to assume we are looking at conditions in the Pacific progressing toward an El Nino. And by the looks of it, it has the potential to last through next winter. Whether it reaches "super" status remains to be seen.
The ENSO is not the only thing we should look at when we are making a seasonal outlook. One important driver in our weather pattern this past winter was the EPO. It has been consistently negative (positive height anomalies in Alaska and northwest Canada) dating back to this past winter. I think it is a good idea to look into how that is progressing, as well as the PDO, which has been in a "cold" phase for what seems like an eternity (since 2010 to be exact).
The PDO is no longer in a cold phase (hallelujah?) Over the last couple of months, it has made strides to staying in a warm phase, which means SST's off the Pacific coast are running above normal and cooler than normal in the interior North Pacific.
Like I stated before, the EPO has been running consistently in a negative phase for quite some time, going all the way back into Fall of 2013. For the time being, I am going to go off the assumption that the EPO remains primarily negative during the summer months, especially for June.
So when we look at past years, we should be looking for summers that dealt with a...
-EPO, +PDO, and a developing El Nino (+ENSO).
After doing some research of the ESRL database, here is a list of years I came out with:
1951, 1953, 1957, 1965, 1972, 1982, 1986, 1997, 2004, 2009
Most of these years featured a -EPO, +PDO, +ENSO summer but some of them are extreme relative to others in terms of the intensity of all three teleconnections. What I did next was look at the SST anomaly maps of those years and see which ones I felt matched up closely to our current SST anomalies over the Pacific Ocean.
Here is an example of why 1982 is a BAD analog year, in my opinion.
While there is warming taking place over the Equatorial Pacific, the northern Pacific and northeast Pacific is experiencing below normal temp anomalies, which goes against our current observations of which we concluded is a -EPO and +PDO. Discard 1982!
I am obviously not going to go through all the years with you, so here are my top 3:
1957, 1997, 2004
1997 was a pretty extreme year with a raging +PDO and +ENSO. Take a look at its SST anomaly map from May 1997:
It matches closely with our current SST anomaly map (refer back to first image of this blog) when it comes to the areas of above normal and below normal SST's. It does not match intensity wise.
Aggregating my top 3 years together, this is the temperature departure from normal map I come out with:
Looks a little...cool. I went to go check out the NAO for each of those years out of curiosity and some of those summer months in each of those years did feature a -NAO, a pretty strong one at times. The NAO is a wildcard as always since it could inhibit ridges from progressing too far eastward if there is blocking overhead of our area.
Meteorological spring months temp. departures from normal indicate that the above map may not be THAT far off.
March-April 2014
May 2014 (so far)
Is it just me, or do those two maps have similarities to the analogs map I created? The below normal regimes exist in the center of the country and above normal regimes in the west side. The east side is mainly around average with below normal intrusions at times.
With all that said, here is my official outlook:
Temperatures
The persistence of the -EPO along with the developing +PDO will keep the western U.S. toasty this summer. Unfortunately there are droughts and wild fires damaging property and just making peoples lives miserable out there, so hopefully the pattern undergoes a change by mid-summer. Since I am expecting the western U.S. to be under the influence of ridging, I can see how an area of below normal temps. develop over the Great Lakes into the mid-section of the country. The northeast will see some temperature swings, but should stay around normal with less 90-degree days this year compared to last.
Precipitation
A lot of northern stream energy is going to find its way into our area this summer which will promote wetter than normal conditions, especially if blocking takes shape. We have seem some training storms already this spring with a couple of cut-off low's and trough's. There is a good chance this persists through the rest of this month and into June. By the time we get to July / August, we will have to monitor the tropics very closely. I can see a scenario where we are dealing with numerous extra-topical type of storms or developing low pressure systems off the east coast. The west-central U.S. and parts of the western U.S. will continue to bake and stay mainly dry.
Please keep in mind seasonal outlooks carry a great deal of risk and are hardly 100% accurate. I focus more on trying to get the general "gist" of how things may play out. It has worked out well for me for the most part, so we will see how this one plays out.
Have a safe and happy summer!
Thanks for reading,
Francesco Paparatto
*Please visit the NJ Strong Wx forum at www.njstrongweatherforum.com*
