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:

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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!
Check out the Water Year 2024 Report by Washington State Climate Office, with support from Ecology

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.

The Water Supply Availability Committee (WSAC) met last on March 13. Presentation materials and recording is now available: Water Supply Availability Committee website.

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

Forecasts continue to predict additional precipitation and colder temperatures for the northern quarter of the state for next few weeks, and then switch to hotter and drier in May.
While La Niña usually means wetter and colder, weak and late means less of an impact on our temperature and precipitation (CPC: ENSO Diagnostic).
- This pattern is expected to depart in coming weeks.
The Yakima Basin, North and Central Cascades are an area of particular concern for drought recovery and compounding deficits after back-to-back droughts in 2023 and 2024. While the statewide SWE (snowpack measurement) map shows some better overall averages, there are individual SNOTEL (snow measuring) sites that are at less than 50% of average snowpack for this time in March. BOR reservoirs continue to be at 60% of average storage level, for this day in March (compared to 30-year normals). This is a concerning storage level in order to fill the gap in storage from back to back droughts in 2023 & 2024 and compounding deficits in precipitation for the area since October 2023.
BOR announced at an April 3 briefing that the March estimate for Total Water Supply Available) is 58% (up 10% from March).

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Climate Outlook from the state climatologist:

El Niño-Southern Oscillation (ENSO): Weak La Niña conditions are expected to transition to neutral conditions in the next month.

La Niña conditions continue to weaken driven in large part by warming sea surface temperatures in the central and eastern Tropical Pacific. Winds and precipitation patterns in this region also demonstrate a trend toward neutral ENSO conditions. Although our region tends to continue to experience slight influence from La Niña conditions as we transition out of La Niña into neutral conditions, we are likely to see waining influence from ENSO on local conditions over the next few months. As we look toward the July-September 2025 period, ENSO models still show a slight favorability for either neutral or weak La Niña conditions, but no single ENSO phase has greater than 50% likelihood, indicating high uncertainty for the summer months and beyond.

What does this mean for Washington in the coming months?

Latest guidance from the CPC indicates slightly higher than normal precipitation and near-normal temperatures for the state for the month of April. Slightly better chances (40-50%) of wetter than normal conditions exist for the northwestern half of the state, while the southeastern half of the state has a 33-40% chance of above average precipitation. As for temperature, equal chances of above, near, and below normal conditions exist across the entire state. This is an indication of higher uncertainty in temperature anomalies as we transition out of La Niña.

The CPC’s 3-month outlook for April-May-June shows uncertainty in both precipitation and temperature. This is an indication of little agreement among climate models and no clear climate signals for the upcoming season. Therefore, there are equal chances of above, near, and below normal temperatures and precipitation across the state for April through June at this time.

Last Updated: 4/8/2025

Data round-up: drought conditions summary

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

Bureau of Reclamation (BOR) announced on May 5 a new May-Sept of 51% water supply for pro-rated irrigation districts.
- Yakima system storage is now 8^th lowest since 1971. April precipitation for the Yakima basin was 51% of average.
We continue to be "neutral" conditions (as of last Thursday, 4/10) regarding the La Niña vs El Niño global patterns. TBD on long-range predictions with any level of confidence.
- The Climate Prediction Center's outlook for May shows equal chances of below or above normal conditions, for much of the state, with slight likelihood of warmer than normal in the eastside and slight lean to wetter than normal for parts of the westside.
- There is consensus among seasonal climate models for drier and hotter than normal conditions for early summer statewide, but this is not a statement of magnitude.
Ecology continues to monitor concerning snowpack levels in the advisory areas. As conditions indicate, Ecology may go through the drought declaration process to bring some or all of these areas into the drought declaration.
- Snowpack levels continue to decline below normal in additional areas in the North and Central Cascades, after this dry April and somewhat warmer than normal April.
- Melt off is occurring two weeks earlier than normal in some areas.

The Washington State Climate Office - Climate Outlook

NEW: Late April Climate Outlook: Neutral ENSO conditions are likely to continue through summer. Beyond this summer, there is currently around an 80% chance of either La Niña or ENSO-neutral conditions as we head into late autumn and early winter.
Last updated: May 5, 2025; Next update (monthly): Early June

69% Statewide snowpack (Down 5% from last week, down 11% in the last two weeks), compared to normal (the 30-year average for today; info: Climate Normals | NOAA or Climatic Normals | NRCS.
87% Statewide water year to date precipitation (Down 1% from last week).
SWE Interactive Map - NWCC iMap or SWE by Basin - PDF
Last updated: May 5; Next update (daily): May 6. (Why does “SWE” matter – USDA Factsheet).

Bureau of Reclamation (BOR)

Yakima River system (Keechelus, Kachess, Cle Elum, Bumping, Rimrock) is at 57% of capacity and storage is at 74.5% of average (for this time of year).
BOR announced on May 5 a new forecast for the May-Sept period of 51% water supply for pro-rated irrigation districts.
Last updated: May 5, 2025; Next update (daily): May 6, 2025. Next BOR forecast will be mid-May, tentative May 16, with the next briefing and a forecast June 5.

Northwest River Forecast Center data and informaiton updates:

10 Day Meteorological Forecasts – Minimal precipitation in the middle of the next 10 days, monthly on the Westside; with temperatures hitting above 80 degrees on the Eastside in the middle period.
Forecast report and Forecast map – Areas in North Cascades, Chelan, Okanogan/ Methow, Wenatchee, Colville, and increasing sites in the Puget Sound, have May-Sept forecast below 75%.
For April-September the period, the Okanagan River is forecasted at 48% of normal, Methow at 69%, Stehekin at 67%, and Chelan at 60%.
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: May 5; Next update(daily): May 6, 2025.

8-14 day Outlook: Slightest likelihood of above normal precipitation statewide, with slight lean towards below normal temperature statewide.
- Valid: May 13-19, 2025, Issued: May 5, 2025
Three-month: Temperature and precipitation outlook (May-June-July) - Leaning below normal precipitation statewide and leaning above normal temperature statewide.
- Last updated: Issued April 17, 2025; Next update (monthly) May 15.

National Integrated Drought Information System (NIDIS) Drought monitor

National Drought Monitor – Central and North Cascades, including the now Western and Eastside flanks continue to be in "D1" status. Full Westside, except for the very southern Cascades and far NE are in "abnormally dry" status.
Reminder: Tool does not account for anticipated impacts on water supply from snowpack or BOR storage.
Updated: May 1, 2025 (U.S. Drought Monitor map is released every Thursday morning, with data valid through Tuesday at 10am PT).

United States Geological Survey (USGS) - WA Water Science Center:

National Water Dashboard – A range of significantly low and normal flows in the Westside, with mostly normal among some lower than normal flows in the Eastside.
Last updated: May 5, 2025; Next update (daily): May 6, 2025

Other data tools used and updated:

Odds of 2024 Water Year Precipitation Reaching 100% - As of April 1, For NW and far SE closer to 100% odds, while Central and North Cascades show odds between 25-50% for reaching 100% of normal precipitation for water year 2025.
Climate Mapper – Mean Temperature & Precipitation Anomaly- Last 30 days - Higher than normal temperatures statewide; lower than normal precipitation in Central and above normal precipitation in surrounding areas of the state.
PRISM Palmer Drought Severity Index – Continued drought concerns for central areas of the state.

Contact information

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