Saturday, July 25, 2015

Preliminary 2015-2016 Winter Forecast

Hello everyone, and welcome to The Weather Centre's Preliminary 2015-2016 Winter Forecast. As always, the standard caveats of very-long range forecasts apply here; in other words, do not take this at face value. Rather, this should be interpreted as an introduction to the conditions that are probable in the coming winter, which will be built on in coming months.
As a note, this outlook will be far shorter than previous seasonal outlooks. This comes from a combination of items, which have significantly restrained my time available to work on this. However, I'm committed to putting out this product, as I have been advertising.

We will begin with a look at the sea surface temperature picture across the world.

Glancing around the globe, we see a few points of interest.

1) We do have a Moderate to Strong El Nino coming on, continuing to manifest itself in well-above-normal SST anomalies off the western coast of Ecuador, well into the central Pacific. These El Nino's tend to result in warmer than normal temperatures in the North US, cooler than normal temperatures in the South US, as well as stormy conditions in the South and East US.

2) The warm pool continues to persist in the Gulf of Alaska and entire Northeast Pacific region. This is the same warm pool that brought us severe cold in the last two winters, through the abundance of ridging along the West Coast. If this warm pool is to persist into the coming fall and winter, the threat of a third consecutive cold winter skyrockets, especially given the warm pool's geographic location immediately upstream of North America, maximizing its effects.

3) There are below-normal SST anomalies around the island nation of Japan. The Typhoon Rule states that storms and high pressure systems that occur over Japan are 'replicated' in the US about 6-10 days later. The Sea of Japan experiencing below-normal SST anomalies could hint at a stormier than normal weather pattern for that area, which could spell a stormy winter if it continues into the fall and winter.

I will not be discussing the QBO or sunspot factors in this outlook. If this were a normal outlook, I certainly would, but there are things out of my control that have simply made the prospect of such an extensive outlook unattainable. I apologize for the inconvenience, and hope you can understand.
In spite of these time constraints, I have been glancing at long range models and some other seasonal factors, so I could come up with my preliminary thoughts on the coming winter.


Pacific Northwest: Very much a toss-up. Warm pool in Gulf of Alaska could spell a hot and dry summer, while the El Nino could bring about more wet conditions. I'll lean towards a warmer and slightly drier than normal Pacific Northwest this winter, with low confidence.

Southwest: Expecting a cooler than normal and slightly wetter than normal winter, as a result of the expected strong El Nino. Have to keep an eye out for interference from that warm pool in the Gulf of Alaska, which could dry things out yet again. Once again, a low confidence forecast.

North Plains and Midwest: A Strong El Nino predicts a warm winter ahead, but I'm not completely convinced so long as the body of warm water exists in the Northeast Pacific. Still, a slightly dry, slightly warm winter is my best projection for now.

South Plains and Gulf Coast: Decent probability of cooler than normal to average temperature pattern for the winter, along with some stormier than normal activity.

Southeast: Difficult forecast for this region, as the El Nino could result in a very wet and cool winter. However, there are other variables which significantly complicate this region's forecast, namely the Atlantic Multidecadal Oscillation, which I'm not prepared to discuss due to very low confidence. I'll side with a wet and cool winter for now.

Ohio Valley: Early projections do favor a slightly warm, slightly dry winter, and for now I agree. This is one of the less complicated forecasts (for now).

Northeast and Mid-Atlantic: This certainly has the potential to be a 'feast or famine' winter for the Northeast, in terms of snow. I do think we see around average temperatures for the winter, but I'll go ahead and favor a snowier than normal winter.