Note that if drought conditions are not being experienced, or in the case of river flooding or heavy rain, this statement may be used to indicate river flows or flood potential.
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ESFOTX
IDZ001>004-026-027-WAZ031>038-041>044-042359-
HYDROLOGIC STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE SPOKANE, WA
951 AM PST TUE MAR 9 2010
THIS BULLETIN ADDRESSES THE EASTERN WASHINGTON AND NORTHERN IDAHO
WATER SUPPLY OUTLOOK.
...BELOW NORMAL RUNOFF VOLUMES FORECAST FOR EASTERN
WASHINGTON AND NORTH IDAHO RIVERS THIS SPRING AND SUMMER...
...WATER SUPPLY FORECAST BACKGROUND INFORMATION...
WATER SUPPLY FORECASTS IN THE INLAND NORTHWEST ARE DRIVEN BY A
COMBINATION OF FACTORS AFFECTING A LARGE AREA ACROSS WESTERN NORTH
AMERICA. TWO MAJOR RIVERS DRAIN THROUGH THE INLAND NORTHWEST. THE
COLUMBIA RIVER FLOWS OUT OF BRITISH COLUMBIA CANADA INTO THE
UNITED STATES NEAR NORTHPORT WASHINGTON. THE SNAKE RIVER BEGINS AT
JACKSON LAKE IN EASTERN WYOMING AND BRINGS WITH IT A LARGE AMOUNT OF
SNOWMELT AS IT WINDS THROUGH THE RUGGED IDAHO MOUNTAINS BEFORE
MERGING WITH THE COLUMBIA RIVER NEAR PASCO WASHINGTON. WATER SUPPLY
FORECASTS FOR THESE TWO RIVERS AND MANY SMALLER RIVERS THAT DRAIN
INTO THESE TWO RIVERS ARE ISSUED BY THE NATIONAL WEATHER SERVICE ON
A MONTHLY BASIS THROUGH JULY.
THERE ARE SEVERAL CONDITIONS WHICH AFFECT THESE WATER SUPPLY
FORECASTS. MOUNTAIN SNOWPACK IS THE MOST IMPORTANT FACTOR. THE SNOW
THAT ACCUMULATES IN THE MOUNTAINS SITS ESSENTIALLY AS A RESERVOIR
THROUGH THE WINTER. AS TEMPERATURES WARM ABOVE FREEZING IN THE
SPRING AND SUMMER THIS SNOW PACK BECOMES THE PRIMARY CONTRIBUTOR TO
STREAMFLOWS. ANOTHER IMPORTANT FACTOR IS PRECIPITATION IN THE
SPRING...EXISTING STREAMFLOW AND RESERVOIR LEVELS ALSO
PLAY AN IMPORTANT ROLE IN WATER SUPPLY FORECASTS. ALL OF THESE
CONDITIONS ARE MONITORED AND USED IN DETERMINING THE WATER SUPPLY
FORECASTS.
THE FORECASTS ISSUED ON THE PRODUCT REPRESENT THE MOST PROBABLE
FORECAST OF STREAMFLOW VOLUMES IN THOUSANDS OF ACRE FEET. 1 ACRE
FOOT IS DEFINED AS ENOUGH WATER TO COVER 1 ACRE OF LAND ONE FOOT
DEEP. 1 ACRE FOOT EQUALS 43560 CUBIC FEET OR 325850 GALLONS.
...PRECIPITATION AND TEMPERATURE SUMMARY...
PRECIPITATION TRENDS FOR FEBRUARY 2010 OVER THE REGION WERE
BELOW NORMAL FOR ALMOST ALL BASINS...WITH AREAS OF OKANOGAN AND
CHELAN COUNTY RECEIVING ABOVE NORMAL PRECIPITATION. BELOW NORMAL
PRECIPITATION ACROSS THE HSA HAS BEEN THE TREND SINCE NOVEMBER 2009
AS EL NINO PUSHED MUCH OF THE MOISTURE TO THE SOUTH ACROSS
CALIFORNIA. FOR THE 2009-2010 WATER YEAR ALL BASINS IN THE SPOKANE
HYDROLOGIC SERVICE AREA /HSA/ ARE BELOW NORMAL FOR PRECIPITATION.
TEMPERATURES FOR FEBRUARY 2010 WERE GENERALLY TWO TO 8 DEGREES
ABOVE NORMAL OVER MUCH OF THE INLAND NORTHWEST. THE TREND OF ABOVE
NORMAL TEMPERATURES THROUGHOUT THE WINTER HAS PREVENTED ACCUMULATION
OF LOW- AND MID-LEVEL SNOWPACK IN THE RIVER BASINS IN THE INLAND
NORTHWEST.
PRECIPITATION SUMMARY THROUGH 28 FEBRUARY 2009
AREA ..FEBRUARY 2010.. ..OCT 2009 - FEB 2010..
OBSD DEP PCT AV OBSD DEP PCT AV
COLUMBIA ABOVE COULEE 0.69 -1.31 34 9.33 -3.13 75
SNAKE RV AB ICE HARBOR 0.72 -0.89 45 6.74 -1.90 78
COLUMBIA AB THE DALLES 1.00 -1.11 48 9.77 -2.60 79
COLUMBIA AB CASTLEGAR 0.82 -2.01 29 13.27 -4.69 74
KOOTENAI 0.71 -1.23 37 10.00 -2.81 78
PEND OREILLE/ SPOKANE 1.51 -1.53 50 12.83 -4.59 74
NORTHEAST WASHINGTON 1.15 -0.44 72 8.64 -0.56 94
OKANOGAN 1.05 -0.32 77 6.87 -0.99 87
EAST SLOPES WASH CASC. 2.33 -2.60 47 20.79 -7.37 74
CENTRAL WASHINGTON 0.65 -0.21 76 4.44 -0.64 87
BURNT/ GRANDE RONDE 0.71 -0.69 51 6.88 -1.34 84
CLEARWATER 1.30 -1.57 45 11.54 -4.27 73
SOUTHEAST WASHINGTON 0.90 -1.05 46 7.51 -3.06 71
SELECTED PRELIMINARY LOCAL PRECIPITATION DATA FOR FEB 2010
STATION TOTAL NORMAL DEPART PCT AV
SPOKANE AP /GEIGER/ 1.28 1.51 -0.23 85
LEWISTON AP 0.49 0.95 -0.46 52
WENATCHEE AP 1.27 0.86 0.41 150
OMAK AP 1.84 1.24 0.60 148
MOSES LAKE AP 0.96 MM MM MM
PULLMAN AP MM 2.10 MM MM
EPHRATA AP MM 0.78 MM MM
MULLAN PASS AP 0.36 MM MM MM
COEUR D`ALENE 1.17 2.47 -1.30 47
BOUNDARY DAM 1.36 2.27 -0.91 60
PLAIN 1.80 3.62 -1.82 50
AVERY MM 3.70 MM MM
SANDPOINT MM 3.47 MM MM
...SNOWPACK SUMMARY...
SNOWPACK IN ALL THE INLAND NORTHWEST BASINS ARE EXPERIENCING
BELOW NORMAL SNOW WATER EQUIVLENT /SWE/ VALUES. THE LOWEST
SWE VALUES IN THE SPOKANE HYDROLOGIC SERVICE AREA /HSA/ ARE
FOUND IN THE COEUR D`ALENE LAKE/SPOKANE RIVER BASIN.
SNOWPACK TRENDS IN LOWER BRITISH COLUMBIA ARE VERY SIMILAR TO
THOSE IN WASHINGTON AND IDAHO. SNOWPACK IN THE NORTHERN
CONTRIBITUTING AREAS OF THE CANADIAN ROCKIES ARE SHOWING CLOSER TO
NORMAL
SWE VALUES WHICH HELPS BOOST THE FORECASTED FLOW FOR THE COLUMBIA
RIVER THROUGH THE SUMMER.
BASIN PCT AVE SWE
US BASINS /AS OF 4 MARCH 2010/
KOOTENAI RIVER IN MONTANA 66
FLATHEAD RIVER BASIN 70
UPPER CLARK FORK RIVER BASIN 68
LOWER CLARK FORK RIVER BASIN 51
IDAHO PANHANDLE REGION 66
SPOKANE 51
UPPER COLUMBIA 79
CHELAN/ENTIAT/WENATCHEE 76
CLEARWATER 52
SALMON 61
BRITISH COLUMBIA BASINS /AS OF 1 MARCH 2010/
COLUMBIA 83
KOOTENAY BASIN 71
OKANOGAN/KETTLE 86
SIMILKAMEEN 67
...STREAMFLOW SUMMARY...
AS OF 4 MARCH 2010...DATA FROM THE US GEOLOGICAL SURVEY INDICATES
THAT THE 28-DAY AVERAGE STREAMFLOW VALUES FOR MANY OF THE
NORTHERN LOCATIONS IN THE INLAND NORTHWEST ARE NEAR NORMAL. BELOW
NORMAL STREAMFLOW VALUES ARE INDICATED FOR MOST BASINS WITH
HEADWATERS IN THE STATES SUCH AS THE POTLACH...ST. MARIES...
ST JOE...CLEARWATER...SNAKE...GRAND RONDE...AND OKANOGAN RIVERS.
...FLOOD POTENTIAL OUTLOOK...
THE SHORT TERM FLOOD POTENTIAL IS BELOW NORMAL FOR ALL BASINS IN THE
AREA...THE CURRENT HYDROMETEROLOGICAL FORECAST INDICATED COOLER
TEMPERATURES OVER THE REGION FOR THE NEXT SEVERAL DAYS. AT THIS TIME
FLOODING IS NOT FORECASTED IN THE SPOKANE HSA. INTRESTED PARTIES
SHOULD CONTINUE TO MONITOR CURRENT RIVER FORECASTS AND STATEMENTS
FROM THE NATIONAL WEATHER SERVICE FOR SPECIFIC RIVER BASINS.
FOR THE LONGER TERM...ABOVE NORMAL TEMPERATURES THROUGHOUGHT THE
WINTER HAVE CONTRIBUTED TO EARLY MELING OF SNOW IN THE MID- AND
LOW-ELEVATION SNOWPACK OVER MUCH OF THE REGION...BASINS ALONG THE
BC/WA BORDER AND THE EASTERN SLOPES OF THE CASCADES ARE WELL BELOW
NORMAL WITH REGARD TO SEASONAL SWE...THE PROBABILITY OF SPRING
RUNOFF FLOODING IS LOW IN MOST AREAS...USERS IN AREAS TYPICALLY
IMPACTED BY SPRING SNOWMELT FLOODING SHOULD CONTINUE TO MONITOR
HYDROMETEOROLOGICAL DATA AND FORECASTS AS THE SEASON PROGRESSES.
...WEATHER AND CLIMATE OUTLOOK...
IN THE SHORT TERM...A BRIEF AND COOL BREAK PERIOD WILL IMPACT THE
REGION TODAY...WITH A FEW LINGERING VALLEY FLURRIES AND MOUNTAIN
SNOW SHOWERS. THE NEXT WEATHER SYSTEM ON WEDNESDAY WILL BRING MAINLY
CLOUDY CONDITIONS WITH MOUNTAIN SNOW SHOWERS AND A CHANCE OF VALLEY
AND BASIN FLURRIES. A DRYING AND WARMING TREND WILL RETURN LATE IN
THE WEEK WITH ANOTHER WEATHER SYSTEM EXPECTED FRIDAY NIGHT AND
SATURDAY.
THE EXTENDED 8-14 DAY OUTLOOK FROM THE NWS CLIMATE PREDICTION CENTER
SUGGESTS A RETURN TO ABOVE NORMAL TEMPERATURES AND BELOW NORMAL
PRECIPIATION. RIVER FLOODING IS NOT EXPECTED.
THE 30-90 DAY OUTLOOK ISSUED BY THE CLIMATE PREDICTION CENTER IN
WASHINGTON DC INDICATES AN ABOVE NORMAL CHANCE OF ABOVE NORMAL
TEMPERATURES OVER THE REGION WITH A TREND TOWARDS BELOW NORMAL
PRECIPIATION. AS OF 5 MARCH 2010 TEMPERATURES IN THE PACIFIC OCEAN
CONTINUE TO BE ABOVE NORMAL AS PART OF THE ON-GOING EL NINO EVENT
THAT HAS BEEN IN EFFECT THROUGHOUT THE WINTER OF 2009-2010. THE EL
NINO EVEN IS FORECASTED TO CONTINUE INTO SPRING 2010 AND DIMISH AS
WE MOVE INTO THE SUMMER. MORE INFORMATION ON THE CURRENT STATE OF EL
NINO/LA NINA CAN BE FOUND AT THE CLIMATE PREDICTION CENTER WEBSITE
AT HTTP://WWW.CPC.NOAA.GOV /ALL LOWER CASE/ .
...WATER SUPPLY OUTLOOK...
THE WATER SUPPLY FORECASTS FOR SUMMER 2010 IN THE SPOKANE HSA ARE FOR
WELL BELOW NORMAL FOR ALL RIVERS. THE BASINS WITH THE LOWEST
PERCENTAGE OF NORMAL FORECASTS ARE THE ST. JOE...COEUR
D`ALENE/SPOKANE ...AND SNAKE. THE SPRING THROUGH SUMMER FORECAST FOR
THE COLUMBIA RIVER AT THE DALLES IS FOR 67 PERCENT OF NORMAL.
BELOW ARE THE STREAM FLOW VOLUME FORECAST FOR SPECIFIC RIVERS
AND SITES AS OF 5 MARCH 2010.
WATER SUPPLY FORECASTS
/IN THOUSANDS OF ACRE FEET/
STREAM AND STATION PERIOD FORECAST NORMAL PCT
...COLUMBIA RIVER...
MICA RESERVOIR INFLOW BC JAN-JUL 8800 9619 92
FEB-JUL 8620 9372 92
APR-SEP 11500 12500 92
REVELSTOKE BC JAN-JUL 12600 13880 91
ARROW LAKES INFLOW JAN-JUL 18500 20960 88
FEB-JUL 17900 20230 88
APR-SEP 22400 25110 89
BIRCHBANK BC JAN-JUL 32300 38930 83
APR-SEP 36200 43500 83
GRAND COULEE WA JAN-JUL 47300 62900 75
APR-SEP 48500 63990 76
ROCK ISLAND DAM WA JAN-JUL 52100 68910 76
APR-SEP 52900 69540 76
...KOOTENAI RIVER...
LIBBY RES INFLOW MT JAN-JUL 4440 6306 70
APR-AUG 4410 6248 71
APR-SEP 4680 6638 71
LEONIA ID APR-JUL 4950 7041 70
APR-SEP 5710 8125 70
BONNERS FERRY ID APR-JUL 5400 7619 71
...KOOTENAY RIVER...
KOOTENAY LAKE INFLOW BC JAN-JUL 12000 16010 75
APR-SEP 12400 16450 75
...PRIEST/KETTLE RIVERS...
PRIEST RIVER ID APR-JUL 585 814 72
KETTLE NR LAURIER WA APR-SEP 1430 1972 73
...PEND OREILLE RIVER...
PEND OREILLE LAKE INFLOW ID APR-SEP 8590 13910 62
APR-JUL 7870 12740 62
BOX CANYON DAM WA APR-SEP 8810 14090 63
...COEUR D`ALENE/SPOKANE RIVERS...
CDA RIVER AT ENAVILLE ID APR-SEP 365 778 47
APR-JUL 345 739 47
COEUR D`ALENE LAKE INFLOW APR-JUL 1130 2552 44
SPOKANE RIVER AT SPOKANE WA APR-SEP 1450 2744 53
ST JOE RIVER AT CALDER ID APR-SEP 630 1205 52
APR-JUL 590 1136 52
...OKANAGAN/SIMILKAMEEN/METHOW RIVERS...
OKANOGAN NR TONASKET WA APR-SEP 1190 1766 67
SIMILKAMEEN NR NIGHTHAWK WA APR-JUL 860 1350 64
APR-SEP 925 1450 64
METHOW NR PATEROS WA APR-SEP 665 985 68
...WENATCHEE/CHELAN RIVERS...
LAKE CHELAN INFLOW WA APR-SEP 850 1185 72
WENATCHEE NR PESHASTIN WA APR-SEP 1110 1635 68
...SNAKE RIVER...
HELLS CANYON ID APR-JUL 2490 6493 38
APR-SEP 3870 7977 49
LOWER GRANITE RES INFLOW JAN-JUL 17000 30020 57
FEB-SEP 17000 30370 56
APR-JUL 12100 21550 56
APR-SEP 13600 24140 56
...GRANDE RONDE/CLEARWATER RIVERS...
GRANDE RONDE NR TROY OR MAR-JUL 1170 1578 74
APR-JUL 965 1274 76
CLEARWATER NR SPALDING ID JAN-JUL 5500 9683 57
APR-JUL 4340 7435 58
APR-SEP 4580 7849 58
THESE FORECASTS ARE SELECTED FROM THOSE PREPARED BY: NATIONAL
WEATHER SERVICE...NATURAL RESOURCE CONSERVATION SERVICE...AND B.C.
HYDRO AND POWER AUTHORITY. FOR VARIOUS PROJECT INFLOWS...THE
FORECASTS HAVE BEEN COORDINATED WITH THE U.S. ARMY CORPS OF
ENGINEERS AND THE U.S. BUREAU OF RECLAMATION.
FOR FURTHER DETAILS ON THE WATER SUPPLY FORECAST VISIT
HTTP://WWW.NWRFC.NOAA.GOV/WATER_SUPPLY/WS_FCST.CGI /LOWER CASE/.
THE NEXT WATER SUPPLY OUTLOOK FOR EASTERN WASHINGTON AND NORTHERN
IDAHO WILL BE ISSUED THE WEEK OF APRIL 5TH.
$$
ROWDEN
