An El Nino, a spell of warmer than average sea surface temperatures in the Pacific, is significant for the Winter 2018-2019 weather forecast. The opposite of “La Nina”, an El Nino event is typically associated with a strong polar jet affecting the north eastern states of the United States from Quebec, Nova Scotia and into Maine to the Great Lakes, bringing colder than average weather and more persistent snowfalls, whilst the Pacific North West favors dry and temperatures slightly milder than average. After a UK Winter Forecast instead? Click here to get more information.
Explanation of the Winter Forecast: 1. United States.
As you can see a significant three way split is evident for the winter period. The southern states, from Tx to Fl experience a rather wet and cool winter with temperatures slightly colder than average and “high” precipitation. Temperature wise the north west is warmer thanks to a strong ridge or area of high pressure producing a fair deal of settled weather, and temperatures will be higher than average, but of course this is the upper North West and North West Canada we are talking about so it will still be freezing, but perhaps not as snowy here in November to December as it was during last winter. And the upper north west: an active polar jet increasing the snow totals prediction for winter 2018-2019 to higher than average, slightly.
Factors influencing this year’s winter outlook for the US
1. El Nino outlook for Winter 2018-2019 We are speaking relative, so when the map suggests “less cold” over the Pacific Northwest for states like Oregon, Montana etc, it will still be cold there of course, however forecast “less cold” compared to the average. We are also suggesting slightly drier than average conditions for the north west of the U.S, mostly due to El Nino. This would result in slightly less snow than average. You can see more on how El Nino impacts the pattern here. There is a difference with El Nino this year, however. We are expecting a more “Central” based El Nino with the bulk of the warm Pacific sea surface temperatures centered over the central Pacific region as opposed to spread out equally thought the Pacific region. This could have the impact of weakening the El Nino signal slightly and “relax” the pattern we would see during a “uniform” El Nino event.
2. Low Solar Activity (Solar Minimum) forecast. In the recent long range weather information posted by us, we have mentioned this idea of solar minimum often. The current phase of solar cycle means there are barely any sunspots and, this has impacts on the outer magnetosphere, the layer that is between the atmosphere and space, as the sun is a significant driver of our climate. For Winter 2018-2019, a reduced or “minimal” level of solar activity could introduce more in the way of Northern Blocking, which strengthens the polar jet stream and amount of cold air that “falls” or empties out of the polar regions. This increases the cold signal for the United States. However El Nino usually restricts the cold to the North East of the country, so we can be fairly confident that the North East will see it’s fair share of cold plunges, noreasters and snow for winter forecast 2018-2019.