August 16 , 2011ccc.atmos.colostate.edu/pdfs/CDA_16_Aug_2011.pdf · NIDIS Weekly Climate, Water and...
Transcript of August 16 , 2011ccc.atmos.colostate.edu/pdfs/CDA_16_Aug_2011.pdf · NIDIS Weekly Climate, Water and...
August 16th, 2011
-Assessment of current water conditions
- Precipitation Forecast
- Recommendations for Drought Monitor
Temperature Departure from Normal08/8/2011 – 08/14/2011
VIC Soil Moisture Percentiles14 August 2011
eMODIS VegDRI – 08/07/2011
Cortez Reference ET – SW CO
Center Reference ET - SLV
Avondale Reference ET – AR Basin
NIDISWeeklyClimate,WaterandDroughtAssessmentSummary
UpperColoradoRiverBasinAugust16,2011
PrecipitaEonandSnowpack
Water‐year‐to‐date(WYTD),mostoftheUpperColoradoRiverBasin(UCRB)receivednearoraboveaverageprecipitaEon.TheUpperandLowerGreenRiverbasinshavereceivedover200%oftheiraverageWYTDprecipitaEoninmanyspots.ThesouthernporEonoftheUCRBhasbeendrier,seeingaround70to100%ofaverage.Fig.1showsthataccumulatedprecipitaEonto‐dateforAlamosaintheSanLuisValleyhasbeenmuchbelownormalsinceApril.AttheendofAugust,Alamosanormallyreceivesjustover6inches,butthisWYTD,theyhaveonlyreceivedjustover2inchesandcouldbeseeingtheirdriestwateryearonrecord.
ForthemonthofAugustsofar,precipitaEonhasfavoredColoradoeastoftheUCRB—muchoftheplainsandFrontRangehavereceivedbetween0.5to3.5inchesofraininthelasttwoweeks.Lastweek,thunderstormswerespoYythroughouttheUCRBandeasternplainsofCO(Fig.2).IsolatedareasinsoutheastandnortheastCOreceivedaroundaquarterinchtonearly2inchesofprecipitaEonfortheweek,whilemostoftheFrontRangewasdry.MostoftheUCRBandSanLuisValleyreceivedlessthanaquarterinchfortheweek.
Fig.1:Water‐year‐to‐dateaccumulatedprecipitaEonatAlamosa,CO. Fig.2:August7–13precipitaEonininches.
StreamflowandWaterSupplyAsofAugust14th,about92%oftheUSGSstreamgagesintheUCRBrecordednormal(25th–75thpercenEle)orabovenormal7‐dayaveragestreamflowswith60%ofthegagesrecordingflowsabovethe75thpercenEle(Fig.3).KeygagesontheColoradoRiverneartheCO‐UTstatelineandtheGreenRiveratGreenRiver,UThaveabovenormal7‐dayaveragestreamflowatthe84thand89thpercenEles,respecEvely(Fig.4).StreamflowontheSanJuanRivernearBluff,UTisatthe25thpercenEle.
AferlargestoragevolumeincreasesthroughouttheUCRBforthemonthofJuly,allofthemajorreservoirs’storagevolumesarenowdecreasing,withFlamingGorge,LakeGranby,andLakeDillonseeingonlyminordecreases.AllofthemajorreservoirsaboveLakePowellarecurrentlyabovetheiraverageAugustlevels.ThisApril–Julyperiodwasthe3rdweYestwithregardtoinflowsintoLakePowellsinceoperaEonsatGlenCanyonDambeganin1963.Powell’scurrentlevelisthehighestAugustlevelit’sbeensince2001.
Fig.3:7‐dayaveragedischargecomparedtohistoricaldischargeforAugust14th.
Fig.4:USGS7‐dayaveragedischargeoverEmeattheCO‐UTstateline(top),GreenRiver,UT(middle)andBluff,UT(boYom).
WaterDemandLastweek,thenorthernporEonoftheUCRBexperiencednearaveragetemperatureswhiletheFourCornersareaconEnuedtoseeaboveaveragetemperatures.TheFrontRangeandsoutheastCOwerealsowarmerthanaveragefortheweek.ThewarmertemperatureshavecontributedtohigherreferenceevapotranspiraEon(refET)indroughtstrickenareas.IntheFourCorners,refETiscurrentlyjustaboveaverage,ontrackwiththedrieryears.IntheSanLuisValleyrefETiscurrentlytrackingabovethehighestrefETyear,duringthedroughtof2002—soprecipitaEonfallingtherecouldbequicklylosttotheatmosphereagain.VeryhighrefETratesarealsoseenintheArkansasRiverbasin,thoughimprovementshavebeenseenoverthepastcoupleofweeks(Fig.5).
SoilmoisturecondiEonsremainpoorfortheSanLuisValleyandsoutheastCO.SoilmoistureisaboveaverageformuchofnorthernUTandthenorthernmountainsofCOwhilesoilshavebeguntodryoutinnortheastCO.SatelliteimageryofvegetaEoncondiEonsshowverydryvegetaEonwithliYlegrowthintheSanLuisValleyandsoutheastCO(Fig.6).VegetaEonscondiEonsaremoistforthenorthernporEonoftheUCRB,slightlydryintheFourCornersarea,andarenearaverage,butgejngdrier,fornortheastCO.
PrecipitaEonForecastAweakupperleveldisturbancewillmoveacrosstheUCRBearlyTuesdayandsparkisolatedshowersandthunderstormsoverhigherelevaEons.Moisturewillbeonthedecline,sothethreatofheavyrainwillremainlowthroughouttheday.ThisdryingtrendwillconEnuethroughoutWednesdayandtherestoftheweek.Bythisweekendmonsoonalmoisturewillagaintrytoworknorthward,butitdoesnotappearasthoughitwillmakeitveryfar.ScaYeredthunderstormswillbemostnumerousinthesouthernareasofthebasinaroundtheFourCornersareaandintheSanJuanmountains.ThisacEvitywillbeonthedecreasebyearlynextweekasaPacifictroughsweepsthroughandsupressesmonsoonalmoisturebacktothesouth.
Fig.5:ReferenceevapotranspiraEonsinceApril1statAvondale,COintheArkansasRiverbasin.
Fig.6:August14thVegDRImap,basedonsatellite‐derivedobservaEonsofvegetaEon.
DroughtandWaterDiscussion
NochangesarerecommendedintheUCRBforthecurrentU.S.DroughtMonitor(USDM)map(Fig.7).VeryliYlechangeshavebeenseenaroundtheFourCornersarea,sotheD0/D1thereissElljusEfied.
StatusquoisalsorecommendedforsoutheastCO.ThoughprecipitaEonmapsshowsomeaccumulaEonsaroundfarsoutheastCO,someoftheseobservaEonsseemquesEonableandtheregionsEllremainsverydry.
OneareatowatchinthecomingweeksaheadisnortheastCO—aroundMorgan,Washington,andYumacounEes.SomeslightprecipitaEondeficitsareshowingupintheareawithSPIslessthan‐1onthe60dayandwateryearEmeperiods.VegDRIandtheVICsoilmoistureproductarealsoshowingsomedryvegetaEonandsoilsintheregion.StatusquoisrecommendedatthisEme,butanintroducEonofD0couldbewarrantedinthenearfuture.
DroughtcategoriesandtheirassociatedpercenEles
Fig.7:August9threleaseofU.S.DroughtMonitorfortheUCRB