Pacific Northwest DEWS Drought & Climate Outlook Webinar: December 16, 2024

Webinar Introduction

Speaker: Jason Gerlich | Cooperative Institute for Research in Environmental ScNOAA's National Integrated Drought Information System (NIDIS)

• This bi-monthly webinar is co-hosted by NIDIS, the USDA Northwest Climate Hub, and the Oregon Climate Change Research Institute (OCCRI).
• Read the most recent Snow Drought Status Update.
• Stay up to date with the Pacific Northwest DEWS activities next year by joining our email list.

Climate Recap and Current Conditions

Speaker: Zachary Hoylman | Montana Climate Office at the University of Montana

• Temperatures have been much hotter than normal across Montana and Idaho, with more normal conditions in Oregon and Washington over the last 30 to 90 days. 
• In the near term, conditions have been more variable across the region. 
• Precipitation shows a west to east gradient with higher precipitation totals in Oregon and Washington, and drier conditions in Montana and Idaho. 
• Soil moisture remains variable across the region. 
• Snowpack accumulations have been encouraging across the Cascades, but the snow season is off to a slower start across the Rockies.  

Seasonal Conditions & Climate Outlook

Speaker: Andrea Bair | National Weather Service Western Region

• La Niña has been slow to develop, and if it does develop, it will be weak. 
• Sea surface temperatures are still only slightly cooler than normal. 
• The tropical atmosphere has begun to exhibit more La Niña–type behavior. 
• The NOAA Climate Prediction Center’s outlooks reflect conditions that are typical of a La Niña.
• The most recent updates are now available on the Climate Prediction Center website. 

Impacts of El Niño and La Niña Conditions on Reservoir Storage 

Speaker: Larry O’Neill | Oregon Climate Service at Oregon State University

• On average, La Niña years are wetter in the Pacific Northwest than El Niño years, contributing to increased water storage, except for northwest Oregon and northern Idaho. 
• The exception to this rule is that, during the strongest El Niño events, conditions rival the strongest La Niña events, characterized by elevated precipitation, snowpack, and reservoir storage. 
• The significant variation in hydrologic outcomes between strong and very strong El Niño events poses a challenge for forecasting water supply during the spring/summer.  

Seasonal Peak Snow Predictability Derived from Early-Season Snow in North America 

Speaker: Jessica Lundquist | University of Washington

• Predicting peak snow from fall snow has high skill by January for northern and colder locations due to a high fraction of the season's snow having fallen and persisted. 
• This prediction of peak snow from fall snow also has high skill across some upper Colorado locations where fall and winter precipitation are correlated. 
• Across the Pacific Northwest, early season snow can generally retain later rain on snow as part of the snowpack, which will increase peak snow water equivalent (SWE).

Q&A and Conclusion 

Speaker: Erica Fleishman | Oregon Climate Change Research Institute