Wednesday, September 24, 2014

Updated JAMSTEC Model Supports Cold, Snowy Winter

The latest run of the JAMSTEC long range model came in last night, and it's still calling for a heavy-duty winter for millions across the country.

The graphic above shows the temperature anomaly forecast for the December-January-February period of 2014-2015. In this image, focusing on North America, we see an outlook very similar to what I had been pondering a handful of weeks ago. In this outlook, much of the south half of Canada is inundated with below-normal temperatures, which then intensifies and extends into the Northern US.

Interestingly enough, these below normal anomalies only hit the Plains, Great Lakes, Midwest, and eastern Rockies. For all other areas, save for the Southeast, temperature anomalies are actually above normal. The projection for the Eastern Seaboard includes a warmer than normal winter, though not a "blowtorch" winter, per se. The Western US also looks to see a warm winter, according to this outlook.

For precipitation, zooming in on North America, we do see a well-above normal precipitation trend over the Ohio Valley. This trend continues into the Northeast and Mid-Atlantic, even backtracking through the Great Lakes and Midwest. Such a wet forecast is also observed in the Southwest, where rain would certainly be welcome. The Pacific Northwest may then see slightly below normal conditions.

The piece that puzzles me (pun intended) in this forecast is the swath of above-normal precipitation anomalies across the Ohio Valley. The West US is exhibiting typical El Nino characteristics, with dry conditions in the Pacific Northwest and wet conditions in the Southwest. However, more La Nina-like conditions are observed in the East, with the above-average precipitation forecast over the Ohio Valley. It remains to be seen how reliable this outlook is, since this is the minority opinion out of the global forecast models right now.

To summarize, the new JAMSTEC is supporting a cold and snowy winter for much of the Central and East US, possibly spoiled by a warm winter in the Eastern Seaboard.



Anonymous said...

"possibly spoiled" because we are warm in the East? Andrew, I thought this was a neutral forecasting blog and not Joe Bastardi's? I was wrong I guess. It is obvious you are a cold lover also.

From my perspective, I love the Jamstec right now cause it give Philadelphia an above normal winter.

Frank-o said...

Andrew: I said several days ago that all of a sudden we are seeing a La-Nina set-up in "some" of these long-range forecast.
Whats more..... What I see in the first image of temps for the east, is classic La-Nina with a off coast North Carolina Block or Wedge if you will.
Two other things..Would not...The NAO have to be in a positive and the Southern Jet will have to be wedged up the Ohio valley.... With lows just riding the west facing spine of the mighty Appalachian Mountain Range. The image reminds me of the jet in the classic "S" on its side position.
Last but not least....El-Nino is continuing to build.
.....Looks like what I call "Pocket" it looks like just "pockets" of winter here and there...Did I say that this winter will drive Weather folks mad and to drink.....(;-)

Andrew said...

Anonymous at 1:04: If it bothers you that much, I'm sure there are other blogs that are discussing the warm weather. The majority of viewers here want to know more about cold weather risks than warm weather, so that's what I produce.