Just released today. Not much different than my previous posting, other than the predictions are getting more locked down. OND = October, November, December; JFM = January, February, March, etc. First, here are the graphics for the US, both temperature and precip:

OND:

Temp:

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Precip:

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JFM:

Temp:

Precip:

Narrative (due to this board, I can't use the special character 'ny', so below La Nina is really La Ninya):

Summary:

The seasonal outlook for OND 2011 shows enhanced chances for above normal seasonal mean temperature for areas stretching from the southwest, across the central portion of the CONUS to parts of the great lakes as well as the north slope of Alaska. Below-normal temperatures are favored for parts of the Florida peninsula and much of southern Alaska. Below-median seasonal total precipitation is forecast for much of the southern portion of the country with enhanced chances for above-median precipitation indicated across parts of the Pacific Northwest. In locations where the likelihoods of seasonal mean temperature and seasonal total precipitation are similar to the climatological probabilities, equal chances (ec) of below, near, and above are indicated.


As we shift into and through the winter, enhanced odds for below normal seasonal mean temperature appear for southern Alaska, the west coast and much of the northern tier of the U.S.. Above normal temperatures are expected across much of the south. For precipitation, above median seasonal total precipitation is indicated for portions of the Pacific Northwest and northern Rockies and areas of the Ohio valley and great lakes during this same period. Enhanced odds for below-median precipitation are indicated for much of the southern tier of the U.S..

Detailed Discussion for all of winter:

PROGNOSTIC DISCUSSION OF OUTLOOKS - OND 2011 TO OND 2012

TEMPERATURE.

For OND 2011, enhanced probabilities for above normal seasonal mean temperature are indicated from the southwest U.S. Across the central portion of the country to near the great lakes. There is good support for this from a number of forecast tools including La Nina composites. The area across the northern plains is kept ec due to the tendency for colder air to begin to impact the northern plains during La Nina as we move towards the month of December. This is supported by the map for NDJ 2011-2012. Below normal temperatures are favored across the southern half of the Florida peninsula for both OND 2011 and NDJ 2011-2012 based on the con and La Nina composites. Along the north slope of Alaska, long-term trends for above normal temperatures, primarily a result of much below normal sea ice extent during the autumn months supports enhanced chances of above normal temperatures in this area. La Nina composites and the cfsv2 support enhanced odds for below normal temperatures across southern Alaska from OND 2011 through mam 2012. La Nina composites during NDJ indicate weaker signals and so coverage is somewhat lower during this season.

As we move into the winter period, the primary drivers for the forecast are La Nina composites and dynamical model forecasts. For DJF 2011-2012, below normal temperatures are favored for the west coast to the northwest and then much of the northern tier of the U.S. With the highest probabilities and largest coverage shown for JFM 2012, where La Nina impacts in the U.S. are typically the strongest. The FMA 2012 forecast coverage can be adjusted as we move closer to this period if La Nina continues to evolve as forecast. In DJF 2011-2012, although sample size is low, consideration was given to second year La Nina composites which tend to indicate below normal temperatures further to the east in the great lakes region. Probabilities are kept low and included only in this season due to this uncertainty.

Precipitation.

During OND 2011, enhanced probabilities for below median total seasonal precipitation is indicated for much of the southern half of the country supported by La Nina composites and several dynamical and statistical forecast tools. Above-median precipitation is also favored for the Pacific Northwest as La Nina composites indicate wet conditions begin during the autumn months. As we move through the winter seasons into spring, below median precipitation is favored for much of the southern tier of the CONUS and also for portions of east-central Alaska. In addition to La Nina composites, the con and several dynamical model forecasts also support drier-than-average conditions in many of these areas. During the OND 2011, NDJ 2011-2012, FMA 2012 and mam 2012 seasons, there is also a tendency for below-median precipitation to extend across portions of the central CONUS. Above-median precipitation increases in coverage across the northwest and northern Rockies during the winter seasons and is depicted across areas of the Ohio valley, great lakes and northeast as we move through FMA 2012. The primary drivers for the forecast in many of these areas are La Nina composites and the cfsv2. Long term positive precipitation trends also contribute to the expectation of above median precipitation across portions of the northern Rockies.

Little confident climate signals exist during AMJ 2012 to JJA 2012 and so only areas of ec are indicated during these seasons. A few small areas are forecast for the remaining seasons associated with long term trends.