HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE SACRAMENTO CA 1009 AM PST FRI MAR 9 2007
...BELOW AVERAGE SPRING FLOOD POTENTIAL FOR CALIFORNIA...
MUCH OF THE NORTHERN AND CENTRAL SIERRA NEVADA SAW ABOVE TO MUCH ABOVE AVERAGE PRECIPITATION AND SIGNIFICANT ACCUMULATION TO THE HIGH-ALTITUDE SNOWPACK DURING FEBRUARY. HOWEVER...SNOW WATER EQUIVALENTS REMAIN BELOW TO MUCH BELOW AVERAGE DUE TO A VERY DRY JANUARY...WITH THE BEST SNOWPACK CONDITIONS IN THE UPPER KLAMATH LAKE AND NORTHERN SACRAMENTO RIVER BASINS. MOST BASINS ARE PROJECTED TO RECEIVE BELOW AVERAGE APRIL THROUGH JULY RUNOFF. ALTHOUGH RESERVOIR STORAGE CONDITIONS ARE ABOVE AVERAGE FOR MUCH OF THE REGION DUE TO LAST YEAR'S EXCELLENT SPRING RUNOFF...THE BELOW AVERAGE SNOWPACK WATER EQUIVALENT AND/OR BELOW AVERAGE SEASONAL PRECIPITATION AMOUNTS RECEIVED SO FAR THIS SEASON INDICATE BELOW AVERAGE SPRING FLOOD POTENTIAL FOR THE REGION.
UPPER KLAMATH LAKE BASIN: THE WATER CONTENT OF THE SNOWPACK IS ABOUT 88 PERCENT OF THE MARCH 1 AVERAGE. SEASONAL PRECIPITATION SO FAR IS 94 PERCENT. THE MARCH THROUGH SEPTEMBER WATER SUPPLY FORECAST FOR THE UPPER KLAMATH LAKE INFLOW IS 81 PERCENT OF AVERAGE. THE SPRING FLOOD POTENTIAL OUTLOOK FOR THE UPPER KLAMATH LAKE BASIN IS BELOW AVERAGE.
NORTH COASTAL DRAINAGE: THE SEASONAL TOTAL PRECIPITATION RANGES FROM BELOW AVERAGE FOR THE NAPA BASIN TO NEAR AVERAGE FOR THE SMITH AND LOWER KLAMATH BASINS. THE TRINITY BASIN RECEIVED ABOUT 79 PERCENT OF THE SEASONAL PRECIPITATION TO DATE. SNOWPACK WATER EQUIVALENTS ARE ESTIMATED AT ABOUT 70 PERCENT OF THE APRIL 1ST AVERAGE IN THE TRINITY BASIN. THE APRIL THROUGH JULY FORECAST FOR THE TRINITY LAKE INFLOW IS 76 PERCENT. THE SPRING FLOOD POTENTIAL FOR THE NORTH COASTAL DRAINAGES IS BELOW AVERAGE.
SACRAMENTO DRAINAGE: ALTHOUGH PRECIPITATION WAS ABOVE AVERAGE IN FEBRUARY...THE SEASONAL AVERAGE IS BELOW AVERAGE PRIMARILY DUE TO A DRY JANUARY. SEASONAL AVERAGES ARE IN THE 76 TO 78 PERCENT RANGE FOR THE REGION. SNOWPACK WATER EQUIVALENT FOR THE SACRAMENTO DRAINAGE RANGES FROM 57 PERCENT FOR THE FEATHER RIVER...67 PERCENT FOR THE AMERICAN RIVER...68 PERCENT FOR THE UPPER SACRAMENTO...TO ABOUT 83 PERCENT FOR THE PIT RIVER DRAINAGE. RESERVOIR STORAGE IS ABOUT 113 PERCENT OF THE AVERAGE-TO-DATE. SEASONAL RUNOFF HAS BEEN MUCH BELOW AVERAGE THUS FAR...AVERAGING ABOUT 58 PERCENT FOR THE REGION. THE APRIL THROUGH JULY WATER SUPPLY FORECASTS VARY FROM 55 PERCENT FOR THE OROVILLE RESERVOIR INFLOW TO 80 PERCENT FOR THE NORTHERN SACRAMENTO RIVER BASINS. THE SPRING FLOOD POTENTIAL OUTLOOK FOR THE SACRAMENTO DRAINAGE IS BELOW AVERAGE BASED ON THE BELOW AVERAGE NORTHERN SIERRA SNOWPACK.
SAN JOAQUIN DRAINAGE: SNOWPACK CONDITIONS IN THE SAN JOAQUIN DRAINAGE ARE BELOW AVERAGE SO FAR THIS YEAR. THE WATER EQUIVALENT OF THE SNOWPACK VARIES FROM 55 PERCENT OF THE APRIL 1ST AVERAGE FOR THE TUOLUMNE RIVER BASIN TO 64 PERCENT FOR THE MOKELUMNE BASIN. SEASONAL PRECIPITATION RANGE FROM 61 PERCENT FOR THE MERCED RIVER BASIN TO 83 PERCENT FOR THE MOKELUMNE. RESERVOIR STORAGE IS ABOUT 119 PERCENT OF AVERAGE...AGAIN A RESULT OF LAST YEAR'S EXCELLENT CARRYOVER. IT IS ANTICIPATED THAT RESERVOIRS SHOULD BE ABLE TO HANDLE RUNOFF FROM SNOWMELT THIS SPRING. SEASONAL RUNOFF IS ABOUT 38 PERCENT OF AVERAGE. THE APRIL THROUGH JULY WATER SUPPLY FORECASTS ARE AVERAGING ABOUT 60 PERCENT FOR THE REGION. BECAUSE OF THE BELOW AVERAGE SNOWPACK...THE SPRING FLOOD POTENTIAL IS BELOW AVERAGE FOR THE SAN JOAQUIN DRAINAGE.
TULARE LAKE DRAINAGE: SNOWPACK CONDITIONS ARE BELOW TO MUCH BELOW AVERAGE IN THE TULARE LAKE DRAINAGE. SNOWPACK WATER CONTENT VARIES FROM 76 PERCENT OF THE APRIL 1ST AVERAGE FOR THE KAWEAH RIVER BASIN...51 PERCENT FOR THE KINGS...AND ONLY 37 PERCENT FOR THE KERN. ALTHOUGH MANY STATIONS RECORDED ABOVE AVERAGE PRECIPITATION DURING FEBRUARY...THE SEASONAL AVERAGE PRECIPITATION FOR THE REGION IS ABOUT 60 PERCENT. RESERVOIR STORAGE VARIES FROM 65 PERCENT FOR THE TULE AT SUCCESS TO 111 PERCENT FOR THE KERN AT ISABELLA. SEASONAL RUNOFF IS ABOUT 44 PERCENT OF AVERAGE. BECAUSE OF THE BELOW AVERAGE CONDITION OF THE SNOWPACK...THE SPRING FLOOD POTENTIAL FOR THE TULARE LAKE DRAINAGE IS BELOW AVERAGE.
CENTRAL AND SOUTH COAST DRAINAGES: THE FLOOD POTENTIAL FOR THIS REGION IS BELOW AVERAGE AS SEASONAL PRECIPITATION HAS BEEN MUCH BELOW AVERAGE SO FAR THIS YEAR.
SOUTHEASTERN CALIFORNIA DESERTS...EAST SLOPE SIERRA NEVADA IN INYO COUNTY: THE SEASONAL PRECIPITATION RECEIVED THUS FAR IS MUCH BELOW AVERAGE. SNOWPACK WATER EQUIVALENT IS ESTIMATED AT ABOUT 37 PERCENT OF THE APRIL 1ST AVERAGE FOR THE OWENS RIVER BASIN. THE FLOOD POTENTIAL IS BELOW AVERAGE FOR THE REGION THIS SPRING.
SOUTHEASTERN CALIFORNIA DESERTS...EASTERN INYO COUNTY...DESERT AREAS OF SAN BERNARDINO COUNTY...EASTERN RIVERSIDE AND IMPERIAL COUNTIES: SEASONAL PRECIPITATION SO FAR HAS BEEN MUCH BELOW AVERAGE. THE POTENTIAL FOR SPRINGTIME FLOODING IS PRIMARILY CAUSED BY PERIODS OF HEAVY RAINFALL INSTEAD OF SNOWMELT. HENCE...THE FLOOD POTENTIAL IS BELOW AVERAGE THIS SPRING. HOWEVER...LARGE AND SMALL STREAM FLOODING CAN STILL OCCUR AS THE RESULT OF PROLONGED HIGH INTENSITY RAINFALL THROUGHOUT THESE AREAS.
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