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!

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

May was cooler (1.5 degrees below average) and dryer (86% of average) than normal statewide. A drought emergency declaration is now in effect for nearly all of Washington State. Despite the cooler temperatures, much of the state’s snowpack has already melted, and streamflows have been dropping in snowmelt-dominated rivers as well as others in response to the low rainfall. Proratable water users in the Yakima basin are expected to receive only 47% of their April-September water allotments this year according to the Bureau of Reclamation.

Find details, in the June issue of the State Climatologist’s Newsletter, as well as a climate summary and outlook, and an announcement of the newly appointed State Climatologist. If you are experiencing drought impacts, please share your observations at CMOR-drought.

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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), the El Niño in the tropical equatorial Pacific Ocean has ended and ENSO-neutral conditions are now present. Sea-surface temperature anomalies have become below normal in the eastern tropical Pacific and remained above normal in the western tropical Pacific Ocean. The latest ENSO models show higher chances of a transition to La Niña conditions during the July-August-September period (65% chance) compared to neutral conditions remaining (34%). A “La Niña Watch” has been issued and the likelihood of La Niña increases into next fall and winter. The chances of La Niña during November-December-January are at 85%. The developing La Niña is unlikely to have much of an effect on our summer weather.

What does this mean for Washington in the coming months?

The CPC one month temperature outlook for July indicates higher chances of above normal temperatures for just the far eastern portion of the state. This represents a change from previous outlooks, and now the remainder of the state has equal chances of below, equal to, or above normal July temperatures. The July precipitation outlook indicates higher chances of below normal precipitation statewide.

The late summer outlook (July-August-September; JAS) is also calling for equal chances of below, equal to, or above normal temperatures for a majority of the state. The eastern quarter of the state bordering Idaho 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 below normal precipitation for only the eastern quarter of the state. Late summer precipitation for the rest of the state is uncertain: there are equal chances of below, equal to, or above normal precipitation.

Last Updated: 6/20/2024

Data round-up: drought conditions summary

Highlight from the new State Climatologist newsletter: At this point in the season, most of our snowpack has melted out. Some of the higher elevation sites have SWE left; Paradise, for example, had 51.2” of water left in the snow on June 1. Aside from the high elevation sites, the west slopes of the northern Cascades and the west slopes of the southern Cascades have SWE remaining. With much of the state’s snowpack already gone, streamflows started to drop in the snowmelt dominated rivers in May. Low May streamflows in Pierce and southern King County are likely a response to the lack of May precipitation.

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

Recent precipitation in early June improved the magnitude of conditions in some areas, but did not make up for existing deficits. Coupled with forecasts for a warmer and somewhat drier than normal summer, drought conditions are expected to continue into summer.
The switch from El Nino to La Nina is currently expected in the early fall, but with no anticipated impact on summer precipitation or temperature.
The rest of June, July, and August are expected to be hotter and somewhat drier than usual for Washington. This will impact the ability of recent precipitation to make up for existing deficits.
We continue to encourage water users to plan for a drier than normal year. The magnitude of impacts is different for different areas of the state.
While our Water Year to Date numbers may look promising, the available water 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:

Summer Outlook: The transition to La Niña is not expected to play a large role in our summer weather in Washington. The summer (June-July-August; JJA) temperature outlook has higher odds of above normal temperatures statewide. The odds are highest (between 50 and 60%) in eastern Washington. Summer precipitation is more likely to be below normal statewide. The odds are between 40 and 50% on the three-tiered scale for a majority of the state.
May summary: Mean May temperatures were below normal across Washington State. May precipitation was on the dry side, tying as the 68th driest in 130 years with 86% of normal precipitation.
Last updated: June 10, 2024; Next update (monthly): Mid-July

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

55% 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
9% = Water YTD precipitation (Down 1% from last week).
On this date in 2015, Statewide SWE was 0% and Water YTD precipitation was 89%.
Reminder for Basin numbers: The Lower Snake-Walla Walla, Lower Pend Oreille and Spokane SWE Basin numbers include stations in Oregon and Idaho.
Why does “SWE” matter – USDA Factsheet
Last updated: June 16; Next update (daily): June 17.

Bureau of Reclamation data and information updates:

Yakima River system (Keechelus, Kachess, Cle Elum, Bumping, Rimrock) is at 68% of capacity and storage is at 74.9% of average, but with a range of levels at the different reservoirs (e.g. 54% at Keechelus vs 88% at Rimrock(.
Last updated: June 24, 2024; Next update: June 25 (daily).
June 6 BOR forecast: The U.S. Bureau of Reclamation (BOR) projected that Yakima River basin irrigators with junior water rights will receive 47% of their full allotments between April and September. Allotments could drop to as little as 39% if the weather is dry and warm.

Northwest River Forecast Center data and informaiton updates:

10 Day Meteorological Forests – Minor Westside precipitation in the middle of the next 10 days, then likely no precipitation the following week. Temperatures to increase in Central.
Forecast report and Forecast map – There are areas projected to receive below 75% of normal streamflow in all regions of the state, with the majority of areas in Central and Eastern projected at below 75% normal streamflow for April – September. (screenshot of natural forecast as compared to Normals and to the historical record)
Streamflow forecasts: Chelan River is forecasted at 59%; Stehekin at 64%; Methow at 69%, Okanagan at 51% 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: June 24; Next update(daily): June 25

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

8-14 day Outlook:
Leaning toward probability of below normal temperature and above normal precipitation.
- Valid: July 1=7, 2024, Issued: June 23, 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 June 20, 2024; Next update (monthly) July 18, 2024.

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

New narrative for PNW: Drought Early Warning Update for the Pacific Northwest | June 6, 2024 | Drought.gov
National Drought Monitor – Moderate drought in the Olympics, most of the Cascades, including Central and South of Olympia, and NE areas of the State (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
- Changes in ocean temperature led to a cooler than Normal June for parts of the PNW.

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

National Water Dashboard – Continued areas with below normal streamflow, with the majority of Central below or significantly below normal, with some red (significantly below normal) streamflow in NE Olympic Peninsula
Last updated: June 16; Next update: June 17 (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