Saturday, May 25, 2013

2013 Summer Outlook

BLOG SONG: "Obsession" by Sky Ferreira 

Good Evening,

Has anyone waken up in the morning and questioned themselves which season we are in? If so, you are not alone. It has been a cool and wet spring, one we have not seen for quite some time. There has been a delayed start to both the gardening and beach season. Hell, there has even been a delayed start to the 17-year cicada invasion. Fortunately, warmer weather is on the way and we can begin to enjoy the outdoors once again. Including the cicada sounds...

I wanted to take this time to talk a bit about the upcoming summer season and what I am seeing in the form of an outlook.

The above image are temperature departures between June and August of 2012. It was HOT for pretty much the majority of the country, besides the northwest and southeast corners of the U.S. Since the Midwest was experiencing a drought at the time, much of that heat was able to expand eastward and bring warmer than normal temps into the northeast. 

This is the amount of moisture in the soil throughout the U.S. as of the 23rd of May. 

And this graphic is the amount of moisture in the U.S. through all of April. 

Moral of the story here is: the end of March, into April, and most of May has been very wet in the east-central Midwest, Pacific Northwest, Ohio Valley, Southeast, Mid-Atlantic and the Northeast. Lets take a quick look at the U.S. Drought Map

Besides portions of New England, the largest and most significant drought is found in the southwest and west-central Midwest. This map nicely coincides with the soil moisture maps I posted above. What this tells me is the western U.S. is going to be under the heat dome for the majority of the summer. They have already been battling forest fires and it will only continue to get worse as we head into the heart of the summer. 

The above 3 graphics prove that the upcoming summer will feature an ENSO-neutral, in other words, no La Nina or El Nino. The dynamical models are in consensus on this, and the SST's in the east-central Pacific would also verify the neutral ENSO conditions. I want to note that the ENSO related to creating summer outlooks does not have the strongest influence on the overall climate. An ENSO-neutral summer does not mean this summer will be hotter or colder than usual. I do like to mention it though because I think it is important to check on the ENSO, specifically for the hurricane season. 

A check on the PDO still shows below normal SST's in the Gulf of Alaska. However, there has been strides in the PDO getting to neutral and potentially positive. I can not confidently say the PDO will be positive by the time this summer is over, but I do have a feeling it will NOT be. 

These sets of values are the PDO Index. As you can see, the PDO was on a positive trend December-January of this past year, but it has gone back negative February-March. As of April, it took a rather large positive trend and currently sits at -.16. May will be over in about 1 week, and we will see where the PDO will stand. I think it will take another trend in the positive direction given the warmer SST's in the eastern GOA. 

The CFS forecast as shown above (June, July, August respectively), is in general consensus the above normal temperature departures will persist in the western/southwestern U.S. This is where the drought currently is and where the forests fires have imploded. 

So, what am I thinking for the eastern U.S.? Specifically the Northeast...

I think for the most part, the northeastern U.S. is going to experience mainly average temperature departures with periods of extreme heat waves that could take us to an above average summer. I do not feel this will be an all out and widespread above average summer, but I can see isolated areas in the eastern U.S. end the summer with above average temp. anomalies. 

Given the current wet soils across much of the eastern U.S. thanks to the above normal precipitation through the spring, I feel that the heat dome that will persist in the western U.S. will have a difficult time translating eastward. 

As the ridge moves east, temperatures will moderate. The -PDO in the Pac. Northwest will help keep them at the least around average, and with that I feel the overall Jet Stream will take more of a double-dip in the U.S. One dip in the northwest and another in the northeast. I can also see how we go through periods of wet stretches. More-so than last year. The Gulf of Mexico is beginning to warm up and that will help feed moisture into low pressure systems that move into the eastern U.S. Between the GOM and the Bermuda High, we could also see a lot of tropical moisture enter the northeast U.S. this year, specifically not until August and into September. 

We will see how things transpire. These are just some of my thoughts. 

Have a GREAT and safe Memorial Day and make the best out of Sunday and Monday! 

-Francesco Paparatto 

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