Experts Agree on Rain Forecast: It’ll Be Dry. Or Not.

If you talk to the National Weather Service, they will tell you (link) that we're in an "ENSO-neutral" condition, and for that reason they're unwilling to predict the upcoming rain season in our region.

But according to this typically excellent story from Rob Krier at the San Diego Union-Tribune, many forecasters who spoke at a winter forecasting seminar last weekend suspect that despite normal sea surface temperatures in the Pacific today, we will have a dry winter in our region. Krier explains:

One of the key factors that long-range forecasters watch, sea-surface temperatures in the central Pacific Ocean, is not providing much of a clue this year. When those waters are abnormally warm, a condition known as El Niño, Southern California tends to get a very wet winter. When the waters are much cooler than normal, a La Niña occurs, and the region is generally dry.

This fall, the water temperatures in the Pacific have been very close to normal. Under such "neutral" conditions, the forecasters look at other factors but usually have a more difficult time predicting precipitation patterns. The Climate Prediction Center in Maryland has basically punted, forecasting an equal chance of a wet, dry or normal winter in Southern California.

The Climate Prediction Center explains their logic, or tries to, in their inimitably eye-glazing way:

majority of the SST forecasts indicate a continuation of ENSO-neutral
conditions (-0.5°C to 0.5°C in the Niño-3.4 region) into the first half
of 2009 (Fig. 5).
Several dynamical models suggest the development of a La Niña during
Northern Hemisphere Winter 2008-09. This outcome becomes more likely if
the current Madden-Julian Oscillation were to stall in a location that favors enhanced
low-level easterlies and increased upwelling in the east-central and
eastern Pacific. However, it is rare for La Niña to develop late in the
year. Therefore, based on current atmospheric and oceanic conditions
and recent trends, ENSO-neutral conditions are expected to continue
into early 2009.

Huh? They write that badly and still couldn't even reference the models?

This is why we need reporters. Krier reports that Klaus Wolter, a climate research at NOAA, predicted "a more bleak picture for Southern California. He believes that the atmosphere is dialing up a weak La Niña and that other forces will contribute to a drier-than-normal winter."

Meanwhile a little rain is expected this evening, and more tomorrow. The call is for "a slug of moisture" that will move "directly over L.A. and Ventura County." Yay!

Below see an infrared image of the incoming clouds and moisture from the NWS:


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