Posted by: pyeager | October 21, 2010

NOAA 2010-2011 Winter Forecast

By Paul Yeager, author of Weather Whys: Facts, Myths, and Oddities

NOAA issued its official 2010-2011 winter outlook today, and not surprisingly, it reads like a lot like a standard La Nina tutorial.

They chose to highlight the potential for extremes, which most notably would be heavier rain and mountain snow (along with the potential for flooding and mudslides) in the Pacific Northwest and the lack of rain in the South. This is of particular note since the Deep South is already in a drought, and the Southwest can get into one with one dry “wet season.”

Other possible dramatic events associated with a “typical” La Nina winter  include (although not necessarily highlighted by the NOAA outlook):

  • potental for more precipitation than normal in the Plains and Midwest (could be snow if it matches up with the occasional cold blasts associated with La Nina)
  • exceptional warmth in the South
  • blasts of warmth into the East and Mid-Atlantic regions

The Mid-Atlantic and Northeast are generally given “equal chances” of having warmer, colder, wetter, and drier weather from the outlook since La Nina doesn’t correlate well with specific weather in these regions.

Let’s look at the pictures; precip, then temps:

2010-2011 NOAA winter outlook--precipitation

2010-2011 NOAA winter outlook--precipitation

2010-2011 NOAA winter outlook--temperatures

2010-2011 NOAA winter outlook--temperatures


Responses

  1. Hi Paul. Is NOAA’s thinking generally that this will be a typical La Nina cycle (with historical precedents to go by in forecasting) or is this shaping up to be something of an unorthodox or hybrid La Nina winter, making forecasting even more of a challenge? To put it another way, what’s the confidence level of the forecast guidance?

    • It seems as if they’re expecting it to be a fairly typical La Nina; however, last winter was certainly not a typical El Nino winter…so…perhaps there will be a few surprises!


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