...WATER SUPPLY AND SPRING FLOOD POTENTIAL OUTLOOK FOR NEVADA ANDSource: http://www.wrh.noaa.gov/total_forecast/getprod.php?wfo=rev&sid=REV&pil=ESF
EASTERN CALIFORNIA AS OF FEBRUARY 8 2012...
ISSUED JOINTLY BY THE NATIONAL WEATHER SERVICE AND NATURAL RESOURCES
CONSERVATION SERVICE...
1A/SUMMARY...WATER SUPPLY OUTLOOK...
JANUARY BROUGHT MUCH NEEDED PRECIPITATION TO NORTHERN NEVADA AND THE
EASTERN SIERRA. PRECIPITATION WAS IN THE AVERAGE TO ABOVE AVERAGE
RANGE IN MOST OF THE REGION...THE EXCEPTIONS WERE EASTERN...
NORTHWEST AND SOUTHERN NEVADA WHICH WERE DRIER THAN NORMAL. AS
WELCOME AS THIS PRECIPITATION WAS...MUCH MORE IS NEEDED THIS SEASON
TO OVERCOME AN OVERALL VERY DRY WATER YEAR FOR NEVADA AND EASTERN
CALIFORNIA. THE MOISTURE DEFICIT THAT NOW EXISTS WILL BE DIFFICULT
TO OVERCOME.
PERSISTENT HIGH PRESSURE HAS BUILT BACK INTO THE REGION IN EARLY
FEBRUARY CAUSING ALL BUT THE MOST POTENT PACIFIC STORMS TO BE
DIVERTED FAR TO THE NORTH. A SUBSTANTIAL TURN AROUND IN THIS
WEATHER PATTERN WILL BE NEEDED SOON TO END THE SEASON AT EVEN
AVERAGE SNOWPACK CONDITIONS...AND AS OF EARLY FEBRUARY THIS KIND OF
CHANGE DOES NOT APPEAR TO BE ON THE HORIZON. ABOUT DOUBLE AVERAGE
PRECIPITATION OVER THE NEXT TWO MONTHS WOULD BE NEEDED TO JUST REACH
AVERAGE SNOW CONDITIONS BY EARLY APRIL...TYPICALLY THE END OF
THE SNOW ACCUMULATION SEASON. ALTHOUGH THERE CAN BE SOME ADDITIONAL
ACCUMULATIONS INTO MAY...NORMALLY STORMS AFTER MID APRIL DO NOT
CONTAIN THE MOISTURE THAT MID TO LATE WINTER STORMS DO. SO...
CATCHING UP THAT LATE IN THE SEASON IS VERY UNLIKELY.
WITHOUT A SIGNIFICANT CHANGE TO WETTER CONDITIONS OVER THE NEXT FEW
WEEKS...RUNOFF CONDITIONS WILL BE WELL BELOW AVERAGE FOR NEVADA AND
EASTERN CALIFORNIA THIS SPRING AND SUMMER. WATER USERS WILL NEED TO
KEEP A CLOSE EYE ON THIS SITUATION AS THE REST OF THE YEAR UNFOLDS.
1B/SUMMARY...SPRING FLOOD POTENTIAL OUTLOOK...
SPRING FLOOD POTENTIAL IN NEVADA AND EASTERN CALIFORNIA DEPENDS ON
SEVERAL FACTORS...INCLUDING 1/SNOWPACK...2/SOIL MOISTURE...
3/RESERVOIR STORAGE...4/TIMING OF MELT...5/AIR TEMPERATURES DURING
MELT AND 6/RAIN DURING THE MELT PERIOD.
AS OF EARLY FEBRUARY...SNOWPACK IS WELL BELOW AVERAGE THROUGHOUT THE
REGION. PRECIPITATION HAS BEEN LIGHT...AND SOILS REMAIN DRY. SO...
UNLESS THERE IS A DRASTIC CHANGE OVER THE NEXT FEW WEEKS...SPRING
FLOOD POTENTIAL WILL BE LOW. AS THE WET SEASON CAN EXTEND INTO
EARLY APRIL...CHANGE IS POSSIBLE...THOUGH NOT LIKELY. IF SNOWPACK
SIGNIFICANTLY INCREASES...SOILS BECOME WET AND IT IS WARM AND WET
DURING THE MELT SEASON...SPRING FLOODING COULD OCCUR.
2/SNOWPACK...
EARLY FEBRUARY SNOWPACK CONDITIONS FOR NEVADA AND EASTERN CALIFORNIA
CONTINUED TO LAG FAR BEHIND AVERAGE. MANY WATERSHEDS WERE AT OR
NEAR RECORD LOWS. THE HIGHEST SNOWPACK WAS ON THE OWYHEE RIVER
BASIN AT 64 PERCENT OF AVERAGE. THE TRUCKEE AND LOWER HUMBOLDT
RIVER BASINS WERE LOWEST AT 31 PERCENT OF AVERAGE.
LAST YEAR THIS YEAR
BASIN PERCENT OF AVERAGE PERCENT OF AVERAGE
LAKE TAHOE ............................. 136 ................ 35
TRUCKEE RIVER........................... 124 ................ 31
CARSON RIVER ........................... 124 ................ 33
WALKER RIVER ........................... 138 ................ 37
NORTHERN GREAT ......................... 113 ................ 32
UPPER HUMBOLDT RIVER ................... 117 ................ 46
LOWER HUMBOLDT RIVER ................... 116 ................ 31
CLOVER VALLEY & FRANKLIN RIVER ......... 103 ................ 33
SNAKE RIVER ............................ 120 ................ 59
OWYHEE RIVER ........................... 96 ................ 64
EASTERN NEVADA ......................... 151 ................ 38
3/PRECIPITATION...
MUCH OF NEVADA AND EASTERN CALIFORNIA HAD REASONABLY GOOD
PRECIPITATION DURING JANUARY. HOWEVER...IT WAS NOT ENOUGH TO
OVERCOME AN EXCEEDINGLY DRY NOVEMBER AND DECEMBER...LEAVING THE
REGION WITH A LARGE MOISTURE DEFICIT. JANUARY PRECIPITATION WAS
HIGHEST ON THE OWYHEE RIVER BASIN AT 167 PERCENT OF AVERAGE AND
LOWEST IN THE LOWER COLORADO RIVER BASIN AT 15 PERCENT. FOR THE
2012 WATER YEAR...WHICH BEGAN OCTOBER 1 2011...PRECIPITATION WAS
HIGHEST ON THE SNAKE AND OWYHEE RIVER BASINS AT 85 PERCENT OF
AVERAGE AND LOWEST ON THE LOWER COLORADO BASIN AT 45 PERCENT.
JANUARY WATER YEAR
BASIN PERCENT OF AVERAGE PERCENT OF AVERAGE
LAKE TAHOE ............................ 93 ................ 52
TRUCKEE RIVER ......................... 87 ................ 51
CARSON RIVER .......................... 88 ................ 49
WALKER RIVER .......................... 106 ................ 56
NORTHERN GREAT ........................ 67 ................ 49
UPPER HUMBOLDT RIVER .................. 118 ................ 78
LOWER HUMBOLDT RIVER .................. 92 ................ 61
CLOVER VALLEY AND FRANKLIN RIVER ...... 154 ................ 80
SNAKE RIVER ........................... 137 ................ 85
OWYHEE RIVER .......................... 167 ................ 85
EASTERN NEVADA ........................ 69 ................ 76
LOWER COLORADO RIVER .................. 15 ................ 45
4/RESERVOIRS...
RESERVOIR STORAGE IN NORTHERN NEVADA AND EASTERN CALIFORNIA REMAINS
IN GOOD SHAPE. AS OF FEBRUARY 1...RESERVOIR STORAGE WAS HIGHEST ON
THE WALKER RIVER BASIN AT 152 PERCENT OF AVERAGE. THE LOWER
COLORADO RIVER BASIN WAS LOWEST AT 70 PERCENT OF AVERAGE.
BASIN PERCENT OF CAPACITY PERCENT OF AVERAGE
LAKE TAHOE ............................. 64 ................ 130
TRUCKEE RIVER .......................... 73 ................ 134
CARSON RIVER ........................... 68 ................ 115
WALKER RIVER ........................... 76 ................ 152
LOWER HUMBOLDT RIVER ................... 66 ................ 136
OWYHEE RIVER ........................... 69 ................ 126
LOWER COLORADO RIVER ................... 60 ................ 70
5/STREAMFLOW...
STREAMFLOW FOR NEVADA AND EASTERN CALIFORNIA IS FORECAST TO BE WELL
BELOW AVERAGE THIS SEASON. STREAMFLOW FORECASTS ARE HIGHEST FOR THE
LOWER COLORADO RIVER BASIN AT 62 PERCENT OF AVERAGE AND LOWEST FOR
THE LOWER HUMBOLDT RIVER BASIN AT 25 PERCENT.
PERCENT OF AVERAGE
MOST PROBABLE FORECAST
BASIN /50 PERCENT CHANCE OF EXCEEDANCE/
LAKE TAHOE ............................................. 51
TRUCKEE RIVER .......................................... 50
CARSON RIVER ........................................... 34
WALKER RIVER ........................................... 53
NORTHERN GREAT ......................................... 45
UPPER HUMBOLDT RIVER ................................... 38
LOWER HUMBOLDT RIVER ................................... 25
CLOVER VALLEY AND FRANKLIN RIVER ....................... 36
SNAKE RIVER ............................................ 54
OWYHEE RIVER ........................................... 44
EASTERN NEVADA ......................................... 41
LOWER COLORADO RIVER ................................... 62
6/ DROUGHT STATUS...
AS OF JANUARY 31 2012...THE UNITED STATES DROUGHT MONITOR CLASSIFIED
ALL OF NORTHEAST AND CENTRAL CALIFORNIA...AS WELL AS MOST OF
NEVADA...AS IN A MODERATE DROUGHT. THE EXCEPTIONS WERE EXTREME
NORTHEASTERN AND SOUTHEASTERN NEVADA WHICH WERE CLASSIFIED AS
ABNORMALLY DRY.
IMPACTS FROM THE DROUGHT IN NEVADA AND EASTERN CALIFORNIA INCLUDE...
HIGH FIRE DANGER...DESPITE THE LATE JANUARY PRECIPITATION...FUELS
REMAIN VERY DRY THROUGHOUT THE REGION. THE RECORD WINTER DRYNESS WAS
TO BLAME FOR THE DEVASTATING FIRE WHICH OCCURRED JANUARY 19-20 SOUTH
OF RENO WHICH DESTROYED 29 HOMES AND CAUSED THOUSANDS TO EVACUATE.
WINTER SPORTS IMPACTS...THE STORMS IN LATE JANUARY GREATLY AIDED THE
WINTER SPORTS INDUSTRY IN THE SIERRA AND ELSEWHERE IN NEVADA...BUT
MUCH MORE IS NEEDED TO KEEP IT THRIVING THROUGH MID APRIL.
POSSIBLE WATER SUPPLY DEFICITS...ALTHOUGH RESERVOIR STORAGE IS
GENERALLY IN GOOD SHAPE...WATER SUPPLY COULD BECOME AN ISSUE
THROUGHOUT THE REGION THIS SPRING AND SUMMER IF SIGNIFICANT
PRECIPITATION DOES NOT OCCUR OVER THE NEXT FEW WEEKS. WATER SUPPLY
CONCERNS WOULD BE HIGHEST ON BASINS WITHOUT SIGNIFICANT RESERVOIR
STORAGE.
7/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA...
THE OUTLOOK FOR FEBRUARY 15 TO 21...IS FOR WELL BELOW NORMAL
PRECIPITATION AND BELOW NORMAL TEMPERATURES THROUGHOUT THE REGION.
FEBRUARY PRECIPITATION IS EXPECTED TO BE BELOW NORMAL SOUTH OF A
LINE FROM ABOUT ALTURAS CALIFORNIA TO ELY NEVADA...WITH NEAR NORMAL
PRECIPITATION EXPECTED NORTH OF THIS LINE. FEBRUARY TEMPERATURES
ARE EXPECTED TO BE NEAR NORMAL THROUGHOUT CALIFORNIA AND NEVADA.
THE LONG RANGE OUTLOOK FOR THE MONTHS OF MARCH THROUGH MAY IS FOR
NEAR NORMAL PRECIPITATION THROUGHOUT THE REGION. TEMPERATURES
DURING THIS PERIOD ARE EXPECTED TO BE ABOVE NORMAL IN ALL BUT
NORTHWEST NEVADA AND EASTERN CALIFORNIA...WHERE THEY ARE EXPECTED TO
BE NEAR NORMAL.
8/ FOR MORE DETAILED WATER SUPPLY AND STREAMFLOW FORECAST
INFORMATION FOR NEVADA AND EASTERN CALIFORNIA...PLEASE REFER TO THE
FOLLOWING WEB SITES /NOTE...ALL LETTERS IN WEB SITE ADDRESSES ARE
LOWER CASE/...
NWS CALIFORNIA NEVADA RIVER FORECAST CENTER...
HTTP://WWW.CNRFC.NOAA.GOV/WATER_SUPPLY.PHP
NEVADA NATURAL RESOURCES CONSERVATION SERVICE...
HTTP://WWW.NV.NRCS.USDA.GOV/SNOW/
CALIFORNIA DEPT. OF WATER RESOURCES...
HTTP://CDEC.WATER.CA.GOV/
NWS CLIMATE PREDICTION CENTER LONG RANGE OUTLOOK MAPS...
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/FORECASTS/
U.S. DROUGHT PORTAL...INCLUDING U.S. DROUGHT MONITOR...
HTTP://DROUGHT.GOV/
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