Flood Potential Outlook
Issued by NWS Portland, OR

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Water Supply Outlook
National Weather Service Portland OR
1015 AM PST Tuesday Feb 11 2025

...OREGON WATER SUPPLY SUMMARY AS OF FEBRUARY 11TH 2025...

The water supply forecast for the spring and summer of 2025 is near
to slightly below average for western and far-northeast Oregon
watersheds and above average for far-southwest, central and
southeast Oregon watersheds. Note that conditions and water supply
forecasts may evolve significantly through the rest of winter and
spring.

Precipitation so far this water year (Oct 2024 - Jan 2025) is near
to above average for most of the state, except below average for
northwest and far-northeast Oregon. Temperatures for the water year
thus far are generally near average for lower elevations, including
most populated areas, and above average for the Coast Range,
Cascades, Blues, and other mountain ranges of central and eastern
Oregon.

Refer to the sections below and links provided for additional
details and updates through the summer regarding precipitation,
seasonal climate outlooks, reservoirs, streamflow, and water supply
forecasts.

The next update to this outlook will be issued in early March 2025.

PRECIPITATION AND TEMPERATURES ACROSS OREGON

Precipitation for the 2025 water year thus far (Oct 2024 - Jan 2025)
ranges from about 90 to 110 percent of average in Oregon. The lowest
values relative to normal are in northwest and far-northeast Oregon.
The highest are in southeast and portions of southwest Oregon.
January precipitation was below average statewide, ranging from 45
to 75 percent of average.

Temperatures for the 2025 water year thus far (Oct 2024 - Jan 2025)
were near average for lower elevations throughout the state.
Temperatures were 1 to 3 degrees above average for higher
elevations, including the Cascades, Blue Mountains, other mountain
ranges in central and eastern Oregon, and portions of the Coast
Range. January temperatures were 1 to 2 degrees below average for
most of the state but 1 to 3 degrees above average for the Cascades.

Details on precipitation and temperatures:

NOAA National Weather Service - Northwest River Forecast Center
www.nwrfc.noaa.gov/water_supply/wy_summary/wy_summary.php

NOAA NWS - California-Nevada River Forecast Center (Klamath basin)
www.cnrfc.noaa.gov/water_resources_update.php

Westwide Drought Tracker Precipitation & Temperature graphics
wrcc.dri.edu/wwdt/index.php?region=or


SNOWPACK ACROSS OREGON

As of February 10, 2025, mountain snowpack is above average
statewide, in terms of the water content of the snowpack. In terms
of percent of median, values range from 105% to 180% and across the
southern part of Oregon. Significant snow accumulation is possible
through March for southern Oregon and through April for northern
Oregon.

Additional snowpack information:

NOAA National Weather Service - Northwest River Forecast Center
www.nwrfc.noaa.gov/snow/

USDA Natural Resources Conservation Service
nwcc-apps.sc.egov.usda.gov/imap/


PRECIPITATION AND TEMPERATURE OUTLOOK

The Climate Prediction Center produces monthly and seasonal
outlooks, in which there is a weighing of the odds of near normal,
above normal, or below normal temperatures and precipitation. ENSO
conditions are weak La Nina as of late January and are projected to
transition to neutral conditions spring 2025.

The outlook for February through April is for an enhanced likelihood
of below-average temperatures and above-average precipitation
statewide. Conditions trend toward average later in the spring, with
an enhanced likelihood of above-average temperatures and below-
average precipitation this summer.

Visit www.cpc.ncep.noaa.gov for more about seasonal outlooks.


RESERVOIRS

Reservoir storage for irrigation reservoirs across the state is
generally above average. The main exceptions are reservoirs in
southwest Oregon, where reservoir storage ranges from 45 to 65
percent of capacity and generally below average. Flood control
reservoirs in western Oregon will gradually refill through the late
winter and spring.

Owyhee, located in southeast Oregon, is the largest irrigation
reservoir in the state. It has observed storage of about 539,000
acre-feet, which is 75 percent of capacity and 170 percent of
average for this time of year.

Reservoir data is provided by the Natural Resources Conservation
Service, the Bureau of Reclamation, and the US Army Corps of
Engineers.

Additional reservoir information:

www.nwd-wc.usace.army.mil/nwp/teacup/willamette/
www.usbr.gov/pn/hydromet/select.html
www.wcc.nrcs.usda.gov/basin.html


OBSERVED STREAMFLOW

Observed runoff so far this water year has been above average for
most watersheds statewide, particularly so for watersheds in central
and southweast Oregon. The only areas with below-average runoff are
northwest and far-northeast Oregon.

Visit waterwatch.usgs.gov for details on observed streamflow. Runoff
data is available at www.nwrfc.noaa.gov/natural/index.html at water
year and monthly time scales for several locations in Oregon.


WATER SUPPLY SEASONAL FORECASTS

Water supply forecasts for April-September runoff volume are near to
slightly below average for western and far-northeast Oregon
watersheds, ranging from 70 to 100 percent. Forecasts are above
average for far-southwest, central and southeast Oregon
watersheds, ranging from 105 to 200 percent.

The forecast for the Columbia River at The Dalles, which is a good
index of conditions across the Columbia Basin, is 86 percent of
average for April-September.

Details on basin-scale water supply forecasts:

NOAA NWS - Northwest River Forecast Center
www.nwrfc.noaa.gov/ws/

NOAA NWS - California-Nevada RFC (Klamath basin)
www.cnrfc.noaa.gov/water_resources_update.php

USDA Natural Resources Conservation Service
www.wcc.nrcs.usda.gov/wsf/

$$