by Matthew Holliday
An El Niño continues to develop across the central and eastern Pacific and is expected to strengthen through the fall and remain in place through the winter months. An El Niño can have major effects on the overall pattern during the United States winter and often brings cooler and wetter conditions from California to Texas into the Southeast/along parts of the East Coast, while the northern half of the country gets warmer conditions with less precipitation and snow. However, I strongly feel that despite the strength of this El Nino that is already breaking modern records, the future state of the warm pool in the northeast Pacific over the Gulf of Alaska is going to have to be taken into consideration, unless it weakens significantly between now and this winter.
Our previous two winters have been driven by the anomalously warmer waters over the northeast Pacific, which caused ridging to strengthen over the western U.S., bringing with it record warmth and dry weather. In response, this forced a trough to dig into the eastern half of the U.S, bringing with it record cold and snow/ice. If you look at the past two winters, the 2014-15 winter was a near repeat of the 2013-14, except the ridge was farther east last winter, which in return shifted the trough farther east.
Despite the strength of this El Niño, it will likely begin to weaken some through the winter, especially since it began to develop/strengthen much earlier than most other El Niños typically do.
Local Region Predictions for most of Montana, Wyoming, and the Dakotas:
Region 4) This zone should end up with well-above temperatures and less snow overall. Let me remind you that this forecast covers a 3-month period, so that does not mean that there won’t be any Arctic intrusions at all in this region. During many El Niño years, the northern jet stream usually stays north of this region, keeping most of the truly Arctic air farther north. Even though I do expect the overall pattern not be nearly as zonal (a west to east flow) as some of the stronger El Niño years in the past, it seems that most of the Arctic intrusions will occur east of this zone.
Some bigger Arctic intrusions could occur later in the winter, especially closer to Great Lakes region. The bigger cities such as Chicago and the Twin Cities should end up with lower than average snowfall.
CLICK HERE to see a full regional breakdown of the 2015-16 Winter Forecast
Source; First hand Weather