Day: October 7, 2011

The October 6 El Niño/Southern Oscillation (ENSO) Diagnostic Discussion says this year’s La Niña event is not as strong as last season, so far

surfaceseatemperatures09282011.jpg

Here’s the current report from NOAA’s Climate Prediction Center. From the report:

La Niña conditions are expected to gradually strengthen and continue through the Northern Hemisphere winter 2011-12.

During September 2011, La Niña conditions strengthened as indicated by increasingly negative sea surface temperature (SST) anomalies across the eastern half of the equatorial Pacific Ocean. The weekly Nino indices continued their cooling trend and all are currently at or below –0.5°C. Consistent with this cooling, oceanic heat content (average temperature anomalies in the upper 300m of the ocean) remained below-average in response to a shallower thermocline across the eastern Pacific Ocean. Also, convection continued to be suppressed near the Date Line, and became more enhanced near Papua New Guinea. In addition, anomalous low-level easterly and upper-level westerly winds persisted over the central tropical Pacific. Collectively, these oceanic and atmospheric patterns reflect the continuation of La Niña conditions.

Currently, La Niña is not as strong as it was in September 2010…

Across the contiguous United States, temperature and precipitation impacts associated with La Niña are expected to remain relatively weak during the remainder of the Northern Hemisphere early fall, and to strengthen during the late fall and winter. It is important to note that the strength of U.S. impacts is not necessarily related to the strength of La Niña across the equatorial Pacific. During October-December 2011, there is an increased chance of above-average temperatures across the mid-section of the country. Also, above-average precipitation is favored across the Pacific Northwest, along with a higher probability for drier-than-average conditions across much of the southern tier of the country (see 3-month seasonal outlook released on 15 September 2011).

Bob Berwyn (Summit County Citizen’s Voice) takes a look at the availability of forecasting tools. From the article:

While last winter’s snowfall broke records in some mountain areas, parts of Colorado where also very dry, notably the southeastern corner of the state, which was under the influence of the same pattern that brought devastating drought conditions to Texas and parts of Oklahoma. The sheer variety of satellite images, radar screens and other online, high-tech forecasting tools is quite astounding.