National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Portland, OR
Versions: 1 2
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FGUS76 KPQR 112234
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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
330 PM PST THU APR 11 2013

...OREGON WATER SUPPLY OUTLOOK AND SPRING FLOOD POTENTIAL AS OF
APRIL 11 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 CURRENT SNOWPACK CONDITIONS AND
OBSERVED PRECIPITATION THUS FAR THIS WINTER. BELOW-NORMAL
PRECIPITATION JANUARY THROUGH MARCH HAS PUSHED SEVERAL OREGON
BASINS CLOSER TO DROUGHT CONDITIONS. NOT SURPRISINGLY...THE
POTENTIAL FOR SPRING SNOWMELT FLOODING IN OREGON AS OF EARLY APRIL
IS BELOW-NORMAL. 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 TEMPERATURE AND PRECIPITATION OUTLOOK FOR THE SPRING CALLS
FOR CONTINUED ENSO-NEUTRAL CONDITIONS IN THE TROPICAL PACIFIC. BASED
ON THIS AND OTHER CLIMATE FACTORS...THERE IS A SLIGHTLY-ENHANCED
POSSIBILITY OF BELOW-NORMAL TEMPERATURES AND PRECIPITATION FOR
APRIL-JUNE. 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 MAY 10TH.

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SNOWPACK ACROSS OREGON

SNOWPACK AS OF EARLY APRIL WAS GENERALLY BELOW-NORMAL ACROSS THE
STATE EXCEPT FOR NEAR-NORMAL SNOWPACK IN THE NORTH OREGON CASCADES
IN THE VICINITY OF MT. HOOD. BASIN SNOWPACK TOTALS RANGE FROM 20 TO
100 PERCENT OF NORMAL...LOWEST IN THE MALHEUR AND OWYHEE BASINS IN
SOUTHEAST OREGON. MARCH SNOW ACCUMULATION WAS BELOW NORMAL...WITH
SIGNIFICANT MELT IN MANY BASINS IN LATE MARCH AND EARLY APRIL. 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.OR.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 EASTERN OREGON FOR THE FIRST SIX MONTHS OF THE 2013
WATER YEAR /OCT-MAR/...RANGING FROM 85 TO 115 PERCENT. HOWEVER...
MARCH WAS THE THIRD 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-MARCH PRECIPITATION TOTALS
ARE SOME OF THE LOWEST ON RECORD FOR THAT SAME 3-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/SEA_WY_SUMMARY.CGI

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

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MAJOR IRRIGATION RESERVOIRS

AT THE CLOSE OF MARCH...RESERVOIR STORAGE REPRESENTS ABOUT 90
PERCENT OF AVERAGE...AND IS ABOUT 65 PERCENT OF STORAGE CAPACITY.
THE CURRENT STORAGE IS 78 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 MARCH 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 35 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 AREAS
NEAR-NORMAL ARE IN THE WILLAMETTE BASIN AND A COUPLE OF BASINS IN
NORTHEAST OREGON. THE FORECAST FOR THE COLUMBIA RIVER AT THE
DALLES...WHICH IS A GOOD INDEX OF CONDITIONS IN THE COLUMBIA
BASIN...IS 97% 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
