Flood Potential Outlook
Issued by NWS Portland, OR

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FGUS76 KPQR 062100

Water Supply Outlook
National Weather Service Portland OR
200 PM PDT Tuesday June 6 2017


The water supply forecast for the summer of 2017 is above-average
statewide.  April through September runoff-volume forecasts range
from 100 to 170 percent of average, with above-average forecasts for
most rivers basins in Oregon, except near-average forecasts for a
few basins in coastal western Oregon and northeast Oregon.

Snowpack as of June 5th is limited to elevations above 5500 feet in
the Cascades and 7000 feet in eastern Oregon mountains, with minimal
area of snow coverage remaining. This year`s above-average seasonal
snowpack peaked in March and April.

The June 2017 outlook by the Climate Prediction Center calls for
enhanced possibility of below-average precipitation in western
Oregon, with equal chances of near, above, or below-average
precipitation for central and eastern Oregon. The temperature
outlook for June and through the summer calls for an enhanced
possibility of above-average temperatures for Oregon. For more
details, visit www.cpc.ncep.noaa.gov.

Refer to the sections below and links provided for details regarding
snowpack, precipitation, reservoir conditions, and water supply
forecasts for individual basins.

This is the final water supply outlook for the season. The next
outlook is scheduled to be issued February 2018.

Snowpack across Oregon

Some snow remains above 5500 feet in the Cascades and above 7000
feet in eastern Oregon mountains. Seasonal snowpack peaked at 120 to
150 percent of average in March and April.

Additional snowpack information:

NOAA National Weather Service - Northwest River Forecast Center

USDA Natural Resources Conservation Service

Precipitation and Temperatures across Oregon

Precipitation for the 2017 water year thus far (Oct 1, 2016 through
May 31, 2017) ranges from 120 to 150 percent of average in Oregon,
but May precipitation was below-average, especially so in central
and eastern Oregon. May temperatures were 1 to 3 degrees above-
average across the state.

Details on precipitation and temperatures:

NOAA National Weather Service - Northwest River Forecast Center

NOAA NWS - California-Nevada River Forecast Center (Klamath basin)


Reservoir storage increased somewhat in May, adding to the major
increases through the spring. As of early June, most irrigation
reservoirs around the state are 95 to 100 percent full. Note that
Owyhee Reservoir, Oregon`s largest irrigation reservoir, filled to
100 percent of capacity in late April and remains full as of early

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

Additional reservoir information:


Observed Streamflow

Observed streamflow in May 2017 was above-average for nearly all
Oregon rivers and especially high for rivers draining the Cascades.

Visit waterwatch.usgs.gov for details on observed streamflow. Water
year and monthly runoff data is available at www.nwrfc.noaa.gov for
several locations in Oregon.

Forecast Streamflow and Seasonal Runoff Volumes

Forecasts for April-September runoff volume range from 100 to 170
percent of average, with the highest values generally in
southwestern and eastern Oregon and the lowest values in northwest
Oregon. Seasonal forecasts have trended upward through the spring.

The June 5th forecast for the Columbia River at The Dalles, which is
a good index of conditions across the Columbia Basin, is 132 percent
of average for April-September, an increase of 3 percent from the
forecast on May 4th.

Details on basin-scale water supply forecasts:

NOAA National Weather Service - Northwest River Forecast Center

USDA Natural Resources Conservation Service


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