Seasonal Climate Forecast Dec. 2021 –Feb. 2022

[Pages:22]Seasonal Climate Forecast Dec. 2021 ? Feb. 2022

Issued: November 18, 2021

Contact: ODF Lead Meteorologist Pete Parsons 503-945-7448 or peter.gj.parsons@odf.

Oregon Department of Agriculture (ODA) - Oregon Department of Forestry (ODF) Production support: Diana Walker; Jacob Cruser; Andy Zimmerman; Julie Waters

El Ni?o Southern Oscillation (ENSO) Current Status and Forecast

n The August ? October 2021 Oceanic Ni?o Index (ONI) dropped to -0.7?C, reflecting strengthening La Ni?a conditions. n The ONI is a 3-month running mean and lags real-time SSTS. It continues to show La Ni?a conditions. n NOAA's Climate Prediction Center (CPC) has issued a La Ni?a Advisory and expects La Ni?a to continue through this coming winter. n Computer models favor a moderate-strength La Ni?a this winter.

IMPORTANT NOTE: Beginning with the October 2017 update, ONI values use ERSSTv5 data (Huang et al. 2017, J. Climate, vol. 30, 8179-8205).



Forecast Highlights

n The analog years (1971-72, 1996-97, & 2008-09) have been performing well and remained unchanged from last month. 1971-72 & 2008-09 were La Ni?a winters, and 1996-97 bordered on La Ni?a.

n La Ni?a winters typically exhibit a wide variety of weather conditions, with large swings between relatively cold and mild periods. The analog years above were no exception. 1971-72 & 2008-09 also produced significant valley snow events.

n Above-average precipitation and mountain snowfall is strongly indicated, which should begin to bring drought relief (see next slide). The chance of significant valley snowfall is highly elevated this winter.

Disclaimer: This forecast is based on past and current weather data and is not associated with CPC predictions (see "Forecasting Methods..." at: ) nor the official CPC "Three-Month Outlooks," which are available here:

U.S. Drought Monitor

National Drought Mitigation Center (NDMC)



Pacific Ocean

Animated (PowerPoint only) SSTs (top) / Anomalies (bottom)

Real-time tropical Pacific SSTs show La Ni?a conditions

Courtesy:

Tropical Pacific Ocean

SSTs indicate La Ni?a conditions

La Ni?a has returned

Courtesy:

Tropical Pacific Ocean

(1970-71; 1995-96; 2007-08) Strong El Ni?o

Moderate Weak

ENSO-Neutral

Weak Moderate

Strong La Ni?a

Aug. ? Oct. analogs

ranged from ENSO-Neutral to weak La Ni?a

Aug. ? Oct. ONI (-0.7?C) cooled to weak

La Ni?a

Tropical Pacific Ocean

(1970-71; 1995-96; 2007-08) La Ni?a

ENSO-Neutral

El Ni?o

Oct. analogs ranged from ENSO-neutral to La Ni?a

Oct. SOI (+0.7)

bordered on La Ni?a

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