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:
- 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.
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
July had above normal temperatures statewide, ranking the second warmest July in the 130-year record. Northeastern areas averaged as much as 8 degrees above the 1991-2020 normal, with the Spokane area having the warmest July on record.
Despite the month ending with a short-lived cool and wet period, July precipitation was minimal, and most of the state received less than 30% of normal. Drought conditions were unchanged in western Washington, but worsened in some areas east of the Cascades in the U.S. Drought Monitor.
Details are available in the August issue of the State Climatologist’s newsletter, as well as an article on adapting to heat waves, and a climate summary and outlook. If you are experiencing a drought impact, please share your on-the-ground observations with the National Drought Mitigation Center by responding to a short survey.
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.
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.
Related links
Contact information
Caroline Mellor
Statewide Drought Lead
caroline.mellor@ecy.wa.gov
360-628-4666