National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Portland, OR
Versions: 1 2
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FGUS76 KPQR 110028
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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
525 PM PST FRI MAY 10 2013

...OREGON WATER SUPPLY OUTLOOK AND SPRING FLOOD POTENTIAL AS OF MAY
10 2013...

THE OREGON WATER SUPPLY FOR THE COMING SPRING AND SUMMER IS FORECAST
TO BE NEAR-NORMAL FOR NORTHWEST OREGON AND PORTIONS OF NORTHEAST
OREGON...AND BELOW-NORMAL FOR MUCH OF SOUTHWEST...CENTRAL AND
EASTERN OREGON...ESPECIALLY SOUTH-CENTRAL AND SOUTHEAST BASINS.
WATER SUPPLY FORECASTS ARE BASED ON SNOWPACK CONDITIONS AND OBSERVED
PRECIPITATION THUS FAR THIS WINTER AND SPRING. BELOW-NORMAL
PRECIPITATION JANUARY THROUGH APRIL HAS PUSHED SEVERAL OREGON BASINS
TO DROUGHT CONDITIONS. THE NATIONAL DROUGHT MONITOR INDICATES
MODERATE DROUGHT /D1/ CONDITIONS FOR MUCH OF SOUTH-CENTRAL AND
SOUTHEAST OREGON...AND ABNORMALLY DRY CONDITIONS /D0/ FOR MOST OF
THE REST OF THE STATE.

SPRING SNOWMELT FLOODING IN OREGON IS UNLIKELY DUE TO A SNOWPACK
THAT WAS GENERALLY BELOW-NORMAL AND MUCH OF WHICH HAS ALREADY
MELTED. NOTE THAT SPRINGTIME /MAY-JUNE/ FLOODING IS TYPICALLY
LIMITED TO BASINS EAST OF THE CASCADES AND IS USUALLY CAUSED BY A
COMBINATION OF RAINFALL AND SNOWMELT.

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 OUTLOOK FOR MAY-JULY CALLS FOR A CONTINUED ENHANCED
POSSIBILITY OF BELOW-NORMAL PRECIPITATION. FOR MORE INFORMATION ON
SEASONAL OUTLOOKS...VISIT THE CLIMATE PREDICTION CENTER WEB PAGE AT
WWW.CPC.NCEP.NOAA.GOV.

THE NEXT UPDATE OF THIS OUTLOOK WILL BE ISSUED BY JUNE 11TH.

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SNOWPACK ACROSS OREGON

SNOWPACK AS OF EARLY MAY WAS GENERALLY BELOW-NORMAL ACROSS THE
STATE. WINTER SNOW ACCUMULATION WAS BELOW-NORMAL IN MOST
BASINS...AND SPRING SNOWMELT HAS COME EARLIER THAN USUAL. ACROSS THE
SOUTHERN PART OF THE STATE...THE SNOW HAS ALMOST COMPLETELY MELTED.
BASIN SNOWPACK FOR THE CASCADES AND NORTHEAST MOUNTAINS RANGE FROM
50 TO 90 PERCENT OF NORMAL. 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.WCC.NRCS.USDA.GOV/SNOWCOURSE/SC-SNOWPACK.HTML

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PRECIPITATION ACROSS OREGON

SEASONAL PRECIPITATION TOTALS ARE NEAR-NORMAL IN WESTERN OREGON AND
BELOW-NORMAL IN CENTRAL AND EASTERN OREGON FOR THE FIRST SEVEN
MONTHS OF THE 2013 WATER YEAR /OCT-APR/...RANGING FROM 70 TO 95
PERCENT. APRIL WAS THE FOURTH MONTH IN A ROW OF BELOW-NORMAL
PRECIPITATION ...WITH BASIN AVERAGES RANGING FROM 40 TO 80 PERCENT
OF NORMAL. FOR MANY OREGON LOCATIONS...THE 2013 JANUARY-APRIL
PRECIPITATION TOTALS ARE SOME OF THE LOWEST ON RECORD FOR THAT SAME
4-MONTH PERIOD. VISIT THE FOLLOWING LINKS FOR MORE DETAILS ON
PRECIPITATION TOTALS.

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

USDA - NATURAL RESOURCES CONSERVATION SERVICE
WWW.WCC.NRCS.USDA.GOV/SNOW/SNOTEL-PRECIP-REPORT.HTML

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MAJOR IRRIGATION RESERVOIRS

AT THE CLOSE OF APRIL...RESERVOIR STORAGE REPRESENTS ABOUT 83
PERCENT OF AVERAGE...AND IS ABOUT 63 PERCENT OF STORAGE CAPACITY.
THE CURRENT STORAGE IS 79 PERCENT OF STORAGE FOR THIS SAME TIME LAST
YEAR. RESERVOIR DATA IS PROVIDED COURTESY OF THE NATURAL RESOURCES
CONSERVATION SERVICE.

VISIT THE FOLLOWING LINK FOR MORE INFORMATION:
WWW.WCC.NRCS.USDA.GOV/WSF/WSF-RESERVOIR.HTML

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CURRENT AND FORECAST STREAMFLOW

OBSERVED STREAMFLOW FOR APRIL WAS BELOW-NORMAL IN OREGON. VISIT
WATERWATCH.USGS.GOV FOR MORE DETAILS ON OBSERVED STREAMFLOW.

FORECAST STREAMFLOW VOLUMES FOR THE SPRING AND SUMMER ARE GENERALLY
BELOW-NORMAL AND RANGE FROM 25 TO 95 PERCENT OF NORMAL...WITH THE
LOWEST PERCENTAGES IN SOUTHEAST AND SOUTH-CENTRAL OREGON...INCLUDING
THE OWYHEE BASIN AND PORTIONS OF THE KLAMATH. THE ONLY BASINS NEAR
NORMAL ARE THE WILLAMETTE AND THE UMATILLA. THE FORECAST FOR THE
COLUMBIA RIVER AT THE DALLES...WHICH IS A GOOD INDEX OF CONDITIONS
IN THE COLUMBIA BASIN...IS 95% OF AVERAGE FOR THE APRIL-SEPTEMBER
PERIOD.

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.OR.NRCS.USDA.GOV/WSF/

BRYANT
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National Weather Service Weather Forecast Office
