Miguel Pierre

Long Range Outlook: Active Pattern in December. But Will it Snow?

/by

Meteorological winter is just one day away, and while snow lovers are beginning to get excited, much of the meteorological community is aware that the coming weeks are not likely to offer many wintry precipitation prospects. Our long range outlook will discuss the meteorological pattern for the upcoming 30 to 45 days. With an in depth look into meteorological patterns and the developing global circulations, we’ll explain the processes occuring that will drive our weather pattern through the month of December.

Read more

Miguel Pierre

Long-Range Outlook: Late November and December; December 1 Storm Threat

/1 Comment/by

Welcome to our long-range outlook for the next 30-45 days. We hope to provide these outlooks with more in-depth analysis and discussion about every Monday and Thursday. The discussion is divided into several topics to cover all aspects of the model guidance and climate indicators.

For today, we discuss the overall pattern and what to expect going into late November and through much of December.

1. Model Guidance Discussion

The 500mb pattern this week will feature a North Atlantic ridge being suppressed by a deep polar vortex developing over Greenland and Iceland. This is a classic +AO/NAO pattern that typically supports a strong ridge for the East Coast. A -EPO ridge forming over the the Northeast Pacific and Alaska will cause a trough to dig into the Western US. In response, a ridge will build over the Central and Eastern US.

Read more

Miguel Pierre

The PDO, MJO and Their Potential Influence In This Upcoming El Nino Winter

/1 Comment/by

When a forecaster makes a seasonal outlook or forecast, he/she must consider all possible climate drivers and variables with teleconnections. Previous articles such as Monitoring the Stratosphere and The Importance of High Latitude Blocking in Upcoming Winter discussed the variables that were considered for our winter forecast, and how much weight was put into each. Now it’s time to look at some other climate patterns in Pacific.  For example, this year’s strong El Nino is something you probably have heard the most about.

There is little doubt that a strong El Nino has a large influence over the atmospheric pattern in the Pacific Basin. Some have used the term “Godzilla El Nino” to describe this year’s phenomenon; which, while catchy, could perhaps be unneeded sensationalism. Another common thought is that after 1997-98 — the last “Super” El Nino, which was an extremely warm and snowless winter — that this winter will also be very warm and snowless in the Northeast. However, there are other climate patterns in the Pacific that can still have influence, even in the midst of such a strong El Nino, which makes such strongly-worded conclusions about this winter not justified.

Read more

Miguel Pierre

An Early Look at the Pattern for Thanksgiving Week

/1 Comment/by

The days before Thanksgiving are some of the busiest travel days of the year, meaning that the weather has an even larger impact than usual. Accordingly, we have already been keeping an eye on model guidance for this period. While it’s still too far out to forecast with confidence, our November outlook did show some cooling to near average later this month, with an overall warm month in the means. Not coincidentally, there does appear to be some kind of pattern change on the model guidance that has piqued our interest.

Forecast models and their ensembles have consistently showed above normal 500mb heights developing early next week over the Northeast Pacific. These heights extend up to Alaska, which causes the Eastern Pacific Oscillation (EPO) to go into its negative phase. Another ridge initially over the eastern US this will be forced to build into the Davis Strait and Greenland — temporarily bringing the North Atlantic Oscillation (NAO) down into its negative phase as well. This pattern will bring one or two cold shots into the Western and Central US on Thanksgiving week. The main questions are: a) will this airmass make it into the Eastern US, b) if so, how much (if any) modification will there be, and c) how long will this colder regime last?

Read more