Forecast: Lake Tahoe may not benefit from strong El Niño

A strong El Niño is predicted to help ease drought conditions in some, but not all of California. The National Weather Service's Climate Prediction Center released their latest seasonal weather assessment on Thursday, and the news isn't very good for the Lake Tahoe Basin.

By the end of January, the strong El Niño is forecast to bring a wetter-than-normal winter to much of California so southern California cities and counties are preparing for heavy rainfall, mudslides and flooding. The Sierra may see some needed precipitation, but with above average temperatures forecast, the much needed heavy snowpack is not expected.

The drought is forecast to persist or intensify across northern California, northern Nevada and all of Oregon and Washington, according to the weather service.

Strong El Niño conditions are ongoing across the equatorial Pacific, with robust atmospheric coupling," according to the Climate Prediction Center. "The latest CPC ENSO advisory indicates a 95 percent chance that El Niño conditions will persist through the winter months. Therefore, climate anomalies associated with El Niño events, which become increasingly prominent over the U.S. during the Fall and Winter months, played a significant role in this outlook."

The good and bad news drawn from this latest forecast:
Good News: The central valley and southern California should see an early wet season thanks to El Niño and drought improvement is expected. The CPC has a greater confidence for improvement across the coastal regions and valley.

Bad News: The Sierra needs substantial snowfall to show significant improvement in the drought, and that isn't in the forecast.

Bad News: The warm and dry weather of the past four weeks was contributed to an expansion and degradation of drought across the southern Plains and lower Mississippi Valley away from the immediate Gulf Coast, with many stations across the region recording top-5 driest Septembers on record. Short term abnormal dryness and areas of moderate drought also developed over parts of the middle Mississippi Valley.

Good News: In contrast, excessive rainfall associated with an upper level low and a stalled frontal boundary inundated parts of the East. In particular, rainfall in excess of 20 inches across central and eastern South Carolina generated widespread catastrophic flooding. Rainfall also eased drought conditions across the Northeast.
Bad News: Pockets of moderate drought remain in southeastern New England and the Tri-State region. Abnormal heat dominated the western half of the continental US.

Good News: Areas of above average precipitation brought relief to parts of southern Arizona and New Mexico, southern Idaho, and Montana.

Good News: Through the end of January, widespread drought relief is anticipated across the central and southern Plains, lower Mississippi Valley, and the eastern U.S.

Bad News: In contrast, a drier ENSO climate signal over the middle Mississippi and Ohio Valleys makes substantial relief of the short term drought conditions less likely, although there is too much uncertainty to warrant additional drought expansion in this outlook. Based on the CPC seasonal forecasts, the greatest potential for drought development is across the northern tier of states, including the Great Lakes region and northern Plains. Drought persistence or intensification is forecast across the Northwest.

Good News: Further east, drought removal or improvement is forecast across the southern Great Basin and interior deserts.

Bad News: A pronounced dry signal during El Niño years favors drought development across Hawaii. Drought persistence with no further expansion is forecast across Puerto Rico, where the start of the dry season may be offset by a wet climate signal during El Niño years.

Good News: Drought development is not anticipated across Alaska during the first part of the winter season.
The next seasonal outlook will be issued November 19.