CBRFC April 2010 Water Supply Webinar 10am, May 7, 2010 Kevin Werner These slides: PLEASE MUTE YOUR PHONES

Outline April Weather Review Snow States Weather / Climate forecast Water Supply Forecasts Peak Flow Forecasts Web Reference:

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Web Reference: Snow: Apr 6 (above) May 6 (right)

Web Reference: Snow: Upper Green Basin (above Flaming Gorge)

Web Reference: Snow: Colorado Mainstem (above Cameo)

Web Reference: Snow: San Juan Basin

Web Reference: Snow: Bear River

Web Reference: Snow: Six Creeks in Salt Lake County

Web Reference: Snow: Lower Colorado

Web Reference: Waterwatch.usgs.gov

Last 5 days… Web Reference:

Forecast Precipitation Web Reference: Dry for the weekend Storm pattern expected for early next week for northern half of basin.

Forecast Precipitation: Next Week’s Storm Storm pattern centered on Monday / Tuesday (May 10-11). Total precipitation amounts up to 1.5 inches

El Nino Update Web Reference: and iri.columbia.edu/climate/ENSOhttp://

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Web Reference: May 1, 2010 Water Supply Forecasts Highlights: Some improvement particularly in northern Great Basin, parts of Green and upper Colorado Improvements on the order of 5-10% from April storm activity Gunnison, San Juan, and southern Great Basin essentially unchanged from April

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Web Reference: waterwatch.usgs.gov

Web Reference: and waterwatch.usgs.govwww.cbrfc.noaa.gov/gmap/gmapm.php?wcon=checked

Web Reference: and Waterwatch.usgs.govwww.cbrfc.noaa.gov/gmap/gmapm.php?wcon=checked

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Lake Powell SWE vs Inflow Below is a scatter plot of the % average of the snow water equivalent for this index for April 7 and the % average of the April-July volumes for the years As you can see by the diagonal line, the snow index is not necessarily a good indicator of run-off volume. In fact, as the % average snow decreases the resulting volume becomes much less. This is likely due to losses such as sublimation, evaporation, and bank storage which can become more pronounced in drier years. Our ESP model (see below) takes these, and other hydrologic factors, into consideration. Plugging this year’s current index value into the equation gives a result of 62%, or 4.9 maf.

Web Reference: and waterwatch.usgs.govwww.cbrfc.noaa.gov/gmap/gmapm.php?wcon=checked

Web Reference: and waterwatch.usgs.govwww.cbrfc.noaa.gov/gmap/gmapm.php?wcon=checked

Online Publication Web Reference:

May 1, 2010 Peak Flow Forecasts Still in development Coming Soon (probably later today) Low flood risk potential in upper basin Likely peak flows have increased (up to ~15%) since April Weather patterns over the next month will greatly influence actual peak flows Web Reference:

Updates: Automatic update customized to what you need. p/govdelivery.html

More Resources Wateroutlook.nwrfc.noaa.gov Podcast versions of webinars available (CBRFC homepage -> podcasts Tentative June water supply & peak flow webinar: 1pm June 7 Separate Peak Flow Forecast webinar as required or requested 2010 forecast verification webinar and 2011 look ahead webinars will be scheduled in October / November

CBRFC Open House Objective: Improve understanding / communication of forecast process and forecast usage August 18, 2010 – Lower Basin Focused section: Aug 19 – Upper Basin Focused section: Aug 17 Salt Lake City, UT More details to come

Kevin Werner CBRFC Service Coordination Hydrologist Phone: Feedback, Questions, Concerns always welcome….