Statewide conditions

As the state's lead agency for water supplies, we pay close attention to multiple data sources and monitor them closely. Here you can find:

A graphic of Earth with a thermometer beside it

Current climate conditions & previous month's data
Expert knowledge, chaired by Dept. of Ecology
Predicted forecasts (based on accumluated data)
Data round-up of latest information from multiple agencies!

What is WSAC?

The Water Supply Availability Committee (WSAC) is a group of experts from state and federal agencies who evaluate statewide water supply conditions. Ecology chairs this group that provides an important consultative role to Ecology. WSAC advises Ecology on current and forecasted water supply conditions and whether the hydrologic drought threshold has been met or is likely to be met: seventy-five percent of normal water supply within a geographic area (RCW 43.83B.405 and WAC 173-166-050).

If you would like to receive notices about WSAC meetings after they are posted to this page, subscribe to the Washington Water Supply Email list.

Tacoma Old Town Dock. Photo by Wayne Hsieh, https://flic.kr/p/2pBqtCX

The Office of the Washington State Climatologist (OWSC) serves as one credible and expert source of climate and weather information for the state. Their monthly newsletter reviews the previous month’s data and details, as well as an introduction to the Natural Resources Conservation Service’s Snow and Water Interactive Map (iMAP), climate summary and outlook, and a link to reporting your observed drought impacts. Check out our Water Supply Monitoring page for additional sources.

Summary of recent conditions

Although some areas of Washington had above normal temperatures in October, averages were near normal overall. Averaged statewide, October was the 28^th warmest in the 130-year record.

Rainfall was normal to above normal in western Washington, but below normal east of the mountains. An atmospheric river brought heavy rain in mid-month brought heavy rain to the area, particularly the western Olympic Peninsula and the northern Cascades. A deep cyclone over the Gulf of Alaska landed October 26^th, causing a record 2.12 inches of rain in Bellingham on the 27^th. Averaged statewide, October was the 58^th wettest in the 130-year record.

Drought conditions have almost completely cleared from western Washington in the U.S. Drought Monitor. Little change occurred east of the Cascades. The Washington Drought Emergency declared in mid-April for most of the state remains in effect.

Find details in the November issue of the State Climatologist’s Newsletter, as well as a Water Year in Review, Climate Summary, and climate Outlook.

Now that the 2024 Water Year has ended, you are encouraged to fill out the Water Year Impacts Survey. The information gathered is vital to completing the PNW Water Year Impacts Assessment. The survey will stay open until November 27.
You may also be interested in leading your community to develop and implement a heat monitoring campaign. NOAA is offering funding and technical support. An expression of interest form is due by November 15, followed by a full application by January 17, 2025.

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Climate Outlook, OWSC forecast:

El Niño-Southern Oscillation (ENSO): Neutral ENSO conditions, La Niña likely by late summer

According to the Climate Prediction Center (CPC), ENSO-neutral conditions are present in the tropical Pacific Ocean. Sea-surface temperature anomalies have remained below normal in the eastern tropical Pacific, neutral in the central tropical Pacific, and remained above normal in the western tropical Pacific Ocean. The latest ENSO models have delayed the onset of La Niña slightly, and models are now predicting development by the August-September-October period. The chances of La Niña during August-September-October are 70% compared to neutral conditions (29%). The developing La Niña is unlikely to have much of an effect on our summer weather, but will likely impact our weather by early fall.

What does this mean for Washington in the coming months?

The CPC one month temperature outlook for August indicates higher chances of above normal temperatures for a majority of the state. The odds are higher (between 40 and 50% on the three-tier scale) in eastern Washington. The Olympic Peninsula and southwest Washington have equal chances (~33% chance each) of below, equal to, or above normal August temperatures. The August precipitation outlook indicates higher chances of below normal precipitation across eastern Washington. Western Washington has equal chances of below, equal to, or above normal August precipitation.

The August-September-October (ASO) is also calling for equal chances of below, equal to, or above normal temperatures for a majority of the state. Southeastern Washington has a higher probability of above normal temperatures, with the odds between 33 and 40% on the three-tiered scale. For precipitation, there are higher chances of above normal precipitation for the Olympic Peninsula, southwestern Washington, and the northern Puget Sound region. The rest of the state is uncertain: there are equal chances of below, equal to, or above normal ASO precipitation.

Last Updated: 7/18/2024

Data round-up: drought conditions summary

Highlight from the new State Climatologist newsletter: At this point in the season, snow is fully melted out at all SNOTEL sites. Paradise in Central Puget Sound was the last site to melt out.

Below is a snapshot of wide variety of data sources that helps Ecology to understand evolving drought conditions. This will be updated weekly.

After recent hot weekends, with temperatures 15-19 degrees higher than normal in some areas, led to continued rapid snowmelt and increased impacts on the April-September forecasted water supply, with some streamflows now significantly below normal.
- Snowpack is now fully melted off from all SNOTEL sites.
- Due to existing deficits, June precipitation did not have a major impact on the streamflow, outside of a few sites in SW WA.
We are in ENSLO neutral conditions and out of El Nino, but the potential switch to La Nina in the Fall is not expected to have an impact on summer precipitation or temperature.
July, August and September now are now anticipated to have equal changes or hotter than normal or “normal” temperatures for 2/3 of the state, except for the Eastside, but this is not anticipated to impact drought conditions with existing deficits in many areas of the state.
While our Water Year to Date numbers may look promising, when water is available is still impacted by the snowpack drought, along with other water supply factors.

The Office of Washington State Climatologist's summarized data. Forecast can be found here as well: Climate Outlook & July Newsletter

Summer Outlook: The August-September-October (ASO) is also calling for equal chances of below, equal to, or above normal temperatures for a majority of the state. Southeastern Washington has a higher probability of above normal temperatures, with the odds between 33 and 40% on the three-tiered scale. For precipitation, there are higher chances of above normal precipitation for the Olympic Peninsula, southwestern Washington, and the northern Puget Sound region. The rest of the state is uncertain: there are equal chances of below, equal to, or above normal ASO precipitation.
June Summary: Average June streamflow was bolstered by the early June precipitation, particularly in western Washington. Stream gauges along the coast, southwestern Washington, and parts of the southern and central Puget Sound regions averaged normal to above normal for June. Below normal June streamflow was common elsewhere in the state, including the region in the Olympic Mountain rain shadow, and watersheds in eastern Washington where both the mountain snowpack had melted out and June precipitation was below normal.
Drought conditions have worsened in parts of eastern WA. In addition to the drier than usual June, a majority of eastern WA has had below normal precipitation since April and some areas even below normal precipitation since January. As a result, the U.S. Drought Monitor has designated an area of “severe drought” (D2) in Washington.
As a reminder, the categories of the U.S. Drought Monitor are based on percentiles so for D2 to be depicted in Washington, a majority of the drought indicators should be between the 5th and 10th percentile in the historical record.
Last updated: July 18, 2024; Next update (monthly): Mid-August
Last updated: July 22, 2024; Next update (monthly): Mid-July

According to National Resources Conservation Science & U.S. Department of Agriculture

0% Statewide, compared to Normal (Up 1% from last week) Snow Water Equivalent (SWE); By Basin: WA Report or by maps: SWE by Basin – PDF (attached) or Interactive map
86% = Water YTD precipitation (Same as last week).
On this date in 2015, Statewide SWE was 0% and Water YTD precipitation was 88%.
Why does “SWE” matter – USDA Factsheet
Last updated: July 22; Next update (daily): July 23.

Bureau of Reclamation data and information updates:

Yakima River system (Keechelus, Kachess, Cle Elum, Bumping, Rimrock) is at 53% of capacity and storage is at 67.8% of average, but with a range of levels at the different reservoirs (e.g. 29% at Keechelus vs 87% at Rimrock).
Last updated: July 22, 2024; Next update: July 23 (daily).
July 1 BOR forecast: The U.S. Bureau of Reclamation (BOR) projected that Yakima River basin irrigators with junior water rights will receive 51% of their full allotments between April and September. This is up 4% from the June forecast, which is very rare this time of year. Allotments could drop to as little as 43% if the weather is dry and warm.

Northwest River Forecast Center data and informaiton updates:

10 Day Meteorological Forests – No precipitation statewide; summer temperatures to continue but not projected to be above 100 degrees F.
Forecast report and Forecast map – There are areas projected to receive below 75% of normal streamflow in all regions for some or all of the April – September period, with areas now forecasted to receive less than 50% of normal in the Eastern region (screenshot of natural forecast as compared to Normals and to the historical record).
Streamflow forecasts: Chelan River is forecasted at 65%; Stehekin at 66%; Methow at 71%, Okanagan at 55% and Skagit at 69% for April to September.
NOTE: April – Sept forecasts are based on the next 10 days of forecast data, then based on climate Normals from 1991-2020 average.
Lasted updated: July 22; Next update(daily): July 23.

National Oceanic and Atmospheric Administration (NOAA), National Weather Service (NWS) and Climate Prediction Center (CPC) data update:

8-14 day Outlook: Likelihood of higher than normal temps across the state, with increased probabilities in Central and Eastside; leaning towards above normal temperatures Westside and Central.
- Valid: July 29-Aug 4, 2024, Issued: July 21, 2024
Three-month Temperature and precipitation outlook (July-August-September):
- Temperature: Now equal changes of above or Normal temperatures in the Western and Central parts of the State, with leaning toward above normal temperature in the Eastside (change in probability).
- Precipitation: Now equal changes of above or Normal precipitation in the Western and Central parts of the State, with leaning toward below normal precipitation in the Eastside (change in probability).
Last updated: Issued July 18, 2024; Next update (monthly) August 15, 2024.

National Integrated Drought Information System (NIDIS) latest collected data and outlooks:

For PNW: Washington | Drought.gov
National Drought Monitor – Moderate drought in the Olympics, most of the Cascades, including Central and South of Olympia, and additional areas Eastside, now with "severe drought" in part of the Central (Reminder: this tool does not account for snowpack or anticipated impacts on water supply).
Updated: The U.S. Drought Monitor map is released every Thursday morning, with data valid through Tuesday at 7 am Eastern.
PNW June Drought and climate outlook webinar on 6/24: Recording

United States Geological Survey (USGS) data collected by WA Water Science Center:

National Water Dashboard – Continued areas with below normal streamflow, including in North and Central Puget Sound and multiple in Central and Eastern regions, as well as the Olympic basin. This now includes streamflows that are significantly below normal.
Updated daily

Other data tools utilized, updated:

Odds of 2024 Water Year Precipitation Reaching 100% - Below 30-40% for different parts of the state.
Climate Mapper – Mean Temperature & Precipitation Anomaly- Last 30 days – A mix of above and below normal for temperature and for precipitation in different parts of the state.
PRISM Palmer Drought Severity Index – “4” or “5” out of 6 negative scale on drought severity for parts of the Olympics, part of Kitsap peninsula, North. Central Cascades and South Cascades, and NE and SE WA (“based on a simplified water budget that considers water supply (precipitation), demand (evapotranspiration) and loss (runoff)”). Updated monthly, January most recent.

Contact information

Caroline Mellor
Statewide Drought Lead
caroline.mellor@ecy.wa.gov
360-628-4666