Flood Potential Outlook
Issued by NWS Portland, OR

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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
150 PM PDT MONDAY JUNE 15 2015

...OREGON WATER SUPPLY OUTLOOK AS OF JUNE 15 2015...

THE OREGON WATER SUPPLY FOR THE SUMMER IS FORECAST TO BE BELOW-
NORMAL FOR OREGON. APRIL-SEPTEMBER RUNOFF VOLUME FORECASTS FOR
CENTRAL AND EASTERN OREGON RANGE FROM 15 TO 50 PERCENT OF AVERAGE.
FORECASTS FOR BASINS WEST OF THE CASCADES RANGE FROM 30 TO 60
PERCENT OF AVERAGE. WATER SUPPLY FORECASTS ARE BASED ON SEASONAL
SNOWPACK CONDITIONS...OBSERVED PRECIPITATION...AND OBSERVED
STREAMFLOW.

THE BIG STORY THIS WATER YEAR IS THE LACK OF SNOWPACK IN OREGON
MOUNTAINS...ESPECIALLY THE CASCADES. MANY NRCS SNOTEL STATIONS HAD
RECORD-LOW SEASONAL SNOWPACK...DUE TO ABOVE-AVERAGE TEMPERATURES AND
BELOW-AVERAGE PRECIPITATION. FOR WESTERN AND NORTH-CENTRAL
OREGON...BELOW-AVERAGE PRECIPITATION THIS SPRING CAUSED SIGNIFICANT
REDUCTIONS IN WATER SUPPLY VOLUME FORECASTS AND INCREASED DROUGHT
CONCERNS...WHICH ARE ALREADY A MAJOR ISSUE FOR THE REST OF THE STATE.

REFER TO THE SECTIONS BELOW AND THE LINKS PROVIDED FOR DETAILS
REGARDING SNOWPACK...PRECIPITATION...RESERVOIR CONDITIONS AND WATER
SUPPLY FORECASTS FOR INDIVIDUAL BASINS.

NOAA`S CLIMATE OUTLOOKS INDICATES THAT ABOVE-NORMAL TEMPERATURES ARE
LIKELY THROUGH THE SUMMER AND FALL...CONTINUING THE TREND OF ABOVE-
NORMAL TEMPERATURES SEEN THE PAST SEVERAL MONTHS. THE SUMMER OUTLOOK
FOR PRECIPITATION INDICATES INCREASED LIKELIHOOD OF BELOW-NORMAL FOR
NORTHWEST OREGON AND EQUAL CHANCES ELSEWHERE OF NORMAL...BELOW-
NORMAL...OR ABOVE-NORMAL PRECIPITATION FOR OREGON. HOWEVER...SUMMER
IS THE DRY SEASON FOR MOST OF OREGON...AND PRECIPITATION TOTALS WILL
NOT AFFECT WATER SUPPLY FORECASTS SIGNIFICANTLY. FOR MORE
INFORMATION ON SEASONAL OUTLOOKS AND EL NINO CONDITIONS...VISIT THE
CLIMATE PREDICTION CENTER WEB PAGE AT WWW.CPC.NCEP.NOAA.GOV.

SEVERAL COUNTIES ACROSS OREGON HAVE ONGOING DROUGHT ISSUES DUE TO
DRY CONDITIONS THE PAST TWO YEARS AND ESPECIALLY OVER THE PAST
SEVERAL MONTHS. DROUGHT DECLARATIONS ARE NOW IN EFFECT FOR THESE 19
COUNTIES: BAKER...COOS...CROOK...DESCHUTES...DOUGLAS...GILLIAM...
GRANT...HARNEY...JACKSON...JEFFERSON...JOSEPHINE...KLAMATH...
LAKE...LANE...MALHEUR...MORROW...UMATILLA...WASCO AND WHEELER.
DROUGHT CONDITIONS ARE LIKELY TO PERSIST OR WORSEN FOR MUCH OF THE
STATE THROUGH THE SUMMER. FOR THE LATEST DROUGHT INFORMATION...VISIT
DROUGHT.GOV AND WWW.OREGON.GOV/OWRD/PAGES/WR/DROUGHT.ASPX.

THIS IS THE LAST WATER SUPPLY OUTLOOK OF THE SEASON. HOWEVER...NWS
PORTLAND WILL ISSUE MONTHLY DROUGHT INFORMATION STATEMENTS STARTING
IN EARLY JULY.

============================================================
SNOWPACK ACROSS OREGON

AS OF EARLY JUNE...MOUNTAIN SNOW HAS COMPLETELY MELTED...OTHER THAN
ON THE CASCADES PEAKS. OREGON SNOWPACK THIS YEAR WAS THE LOWEST ON
RECORD...BASED ON DATA FOR THE PAST 35 YEARS. THE PRIMARY CAUSE
WASN`T A LACK OF PRECIPITATION BUT UNUSUALLY-WARM TEMPERATURES. MANY
SNOTEL STATIONS HAVE HAD LITTLE OR NO SNOWPACK SINCE JANUARY. SPRING
MELT OCCURRED 2 TO 3 MONTHS EARLIER THAN USUAL.

REFER TO THE FOLLOWING LINKS FOR MORE DETAILS.

NOAA`S NATIONAL WEATHER SERVICE - NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/SNOW/

USDA - NATURAL RESOURCES CONSERVATION SERVICE
WWW.NRCS.USDA.GOV/WPS/PORTAL/NRCS/MAIN/OR/SNOW/

============================================================
PRECIPITATION AND TEMPERATURES ACROSS OREGON

SEASONAL PRECIPITATION TOTALS RANGE FROM 50 TO 90 PERCENT FOR THE
2015 WATER YEAR THUS FAR. NOTABLY...MAY PRECIPITATION WAS ABOVE-
NORMAL FOR MOST OF CENTRAL AND EASTERN OREGON...AS MUCH AS 200
PERCENT OF AVERAGE...BUT WAS BELOW-NORMAL FOR WESTERN OREGON...ONLY
30 TO 50 PERCENT.

WARM TEMPERATURES HAD A BIG IMPACT ON SNOWPACK THIS WINTER...WITH
MONTHLY TEMPERATURES AS HIGH AS 10 DEGREES ABOVE AVERAGE FOR THE
PAST FEW MONTHS. AFTER A MONTH OF NEAR-NORMAL TEMPERATURES IN
APRIL...TEMPERATURES IN MAY WERE BACK ABOVE-NORMAL...GENERALLY 2 TO
5 DEGREES.

VISIT THE FOLLOWING LINKS FOR MORE DETAILS ON PRECIPITATION AND
TEMPERATURES.

NOAA`S NATIONAL WEATHER SERVICE - NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/WATER_SUPPLY/WY_SUMMARY/WY_SUMMARY.PHP

NOAA`S NATIONAL WEATHER SERVICE - CALIFORNIA NEVADA RFC
(KLAMATH BASIN ONLY) WWW.CNRFC.NOAA.GOV/WATER_RESOURCES_UPDATE.PHP

============================================================
MAJOR IRRIGATION RESERVOIRS

RESERVOIR STORAGE REMAINS WELL BELOW CAPACITY...GENERALLY 20 TO 60
PERCENT OF CAPACITY IN EASTERN OREGON...65 TO 90 PERCENT FOR CENTRAL
OREGON...AND 30 TO 60 PERCENT IN WESTERN OREGON. WITH THE LOW
SNOWPACK AND BELOW-NORMAL SPRING RAINFALL...RESERVOIR INFLOW THROUGH
THE SPRING MONTHS WAS LOW. OF PARTICULAR NOTE...OWYHEE RESERVOIR...
THE LARGEST IRRIGATION RESERVOIR IN OREGON...ONLY HAS 133 THOUSAND
ACRE FEET...19 PERCENT OF CAPACITY. MOST CORPS OF ENGINEERS
RESERVOIRS IN THE WILLAMETTE VALLEY AND SOUTHWEST OREGON DID NOT
FILL TO SUMMER FULL-POOL LEVELS. ONE POSITIVE NOTE ON RESERVOIR
STORAGE IS THAT MOST MUNICIPAL WATER SUPPLY RESERVOIRS...INCLUDING
BULL RUN AND SCOGGINS IN NORTHWEST OREGON...ARE FILLED TO NORMAL
CAPACITY FOR THIS TIME OF YEAR.

RESERVOIR DATA IS PROVIDED BY THE NATURAL RESOURCES CONSERVATION
SERVICE...THE BUREAU OF RECLAMATION...AHD THE US ARMY CORPS OF
ENGINEERS.

VISIT THE FOLLOWING LINKS FOR MORE RESERVOIR INFORMATION:
WWW.WCC.NRCS.USDA.GOV/BASIN.HTML
WWW.USBR.GOV/PN/HYDROMET/SELECT.HTML
WWW.NWD-WC.USACE.ARMY.MIL/NWP/TEACUP/WILLAMETTE/

============================================================
CURRENT AND FORECAST STREAMFLOW

OBSERVED STREAMFLOW FOR MAY WAS BELOW-AVERAGE IN WESTERN AND
NORTHEAST OREGON AND NEAR-NORMAL IN CENTRAL AND SOUTHEAST OREGON.
STREAMFLOW THE FIRST HALF OF JUNE HAS BEEN LOW ON ALL OREGON
RIVERS...AND FLOWS ARE TRENDING DOWN MUCH EARLIER THAN USUAL TO
SUMMER BASEFLOW LEVELS. DUE TO RECENT DRY CONDITIONS...MANY RIVERS
IN WESTERN OREGON ARE AT OR NEAR DAILY RECORD LOW STREAMFLOWS AS OF
MID JUNE.

VISIT WATERWATCH.USGS.GOV FOR MORE DETAILS ON OBSERVED STREAMFLOW.

FORECAST STREAMFLOW VOLUMES FOR THE SPRING AND SUMMER (GENERALLY
APRIL THROUGH SEPTEMBER) RANGE FROM 15 TO 60 PERCENT OF AVERAGE FOR
OREGON BASINS AND ARE LOWEST IN SOUTHEAST OREGON. FORECASTS FOR MOST
WESTERN AND NORTHEAST OREGON BASINS HAVE DECLINED 10 TO 20 PERCENT
OVER THE PAST 2 MONTHS DUE TO DRY AND WARM SPRING CONDITIONS.

THE FORECAST FOR THE COLUMBIA RIVER AT THE DALLES...WHICH IS A GOOD
INDEX OF CONDITIONS ACROSS THE COLUMBIA BASIN...IS 68% OF AVERAGE
FOR THE APRIL-SEPTEMBER PERIOD...A DECLINE OF 4% FROM THE FORECAST A
MONTH AGO.

VISIT THE FOLLOWING LINKS FOR MORE DETAILS ON BASIN-SCALE WATER
SUPPLY FORECASTS:

NOAA`S NATIONAL WEATHER SERVICE - NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/WS/

USDA - NATURAL RESOURCES CONSERVATION SERVICE
WWW.WCC.NRCS.USDA.GOV/WSF/

BRYANT
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