Random Thoughts As Summer Dwindles Down

This is the time of year when we try to make the best of these last few weeks of summer before the leaves begin changing colors, daylight gets shorter and shorter, and the cool weather is back to remind us the holidays are not too far away. Speaking with many different people this summer, everyone seemed to agree it has been fantastic weather-wise. Not too hot, not too cold. Rain seems to come during the week and the weekends have been gorgeous. Here are just a few random thoughts I have on the weather going forward:

1. Yesterday into this morning was pretty unbelievable for coastal NJ into central and eastern Long Island. An upper level low located north of the Great Lakes was acting as a pivot for a secondary coastal storm that developed on top of NJ. With that secondary low came a tremendous amount of convective rain that dumped nearly a foot of water in some locations in a short period of time. The two low pressure systems were essentially feeding off each other, but the western side of the secondary low was moisture starved so the east side of the secondary low is where the heaviest rain fell. Below you can see the estimated rainfall map.

2. The hurricane season...or lack of I should say. Hopefully none of you are surprised because it was well-documented in the spring that this will be a quiet season due to the emergence of El Nino and relatively cool sea surface temperatures in the eastern Atlantic. The Atlantic Basin is as inactive as the Yankee offense, with only a couple of storms developing close to land. Hurricane Arthur bringing some problems to Hatteras of NC, but for the most part, boring. I do think we will see the Atlantic heat up in September, with possibly 2-4 named storms in the month, but how strong they get and where they travel as a big fat unknown. 

3. A lot of chatter about the 2014-2015 winter season already. From what I have read, most are predicting a "brutally cold" winter with "above normal snowfall" for our area. Oh great! Just what we want to hear, right? Right. The problem is that forecast has a better chance of failing than it does verifying. Predicting both below normal temperatures and above normal snowfall for the NYC Metro area in August is not the wisest thing to do when there are so many unknown variables vital to long range forecasting. Lets take a look at the graphic below. 

The above image shows the sea surface temp. anomalies from January. The bottom one shows the same thing, except for July of this year. Flashback to January and you will remember the negative EPO is pretty much what drove our winter pattern, with ridging over the Aleutians and Alaska into western Canada leading to deep troughs over the eastern U.S. There was little if any blocking in the Atlantic, meaning the NAO was in a mainly positive state so most of the storms were fairly quick movers. 

Comparing the two images, we see that the Pacific about 6 months later is much warmer. We are transitioning from a -PDO to a +PDO, the ENSO is going from neutral to positive (or at least trying to), and the warm SST's in the northern Pacific are STILL there. If the Pacific continues this trend and it holds for the winter, we are likely to see plenty of storminess in the eastern U.S. as the STJ (sub-tropical jet stream) becomes active. An active STJ combined with an active PJ (polar jet stream) is likely to lead to an above normal precipitation season. (Note: precipitation is not the same as saying snow!) 

 However, Nino region 1+2 is where the warming is occurring. In order for us to see a true El Nino event come to fruition this winter we need to see region 3.4 warm and that has not happened yet. Will it happen? This is the million-dollar question and one that I think no one truly has an answer to. The CFS model still insists on a weak-El Nino event this winter, as does the NMME model. Here is the CFS.

The SOI (southern oscillation index) forecasts the intensity of El Nino or La Nina events. Sustained SOI values below -8 indicate a healthy El Nino. When you reach -11 or even lower is when the Nino is in "strong" territory. The SOI for July came in at -4.0. In May, it was at +4.0 so it is steadily declining. Problem so far is we are not seeing those warm SST's in Nino-region 3.4 respond just yet. When we do, I think that is when we can strongly consider this upcoming winter of being El Nino. Until then, much of what you are reading on the web is speculation at this point. 

4. I will have much more about the winter obviously in my 2014-2015 Winter Outlook set to be released November 17th. There will be MUCH more to talk about then. Until then, has anyone else noticed how much media attention winter has been getting over the last few years? It has gone from The Weather Channel naming winter storms to media outlets abusing fancy phrases such as "Polar Vortex." Anything to draw in people, I guess. 

Ciao for now. 

Francesco Paparatto

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