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<br />John Benz. private meteorolo2ist. BDR En2ineerin2 <br />. John Henz gave this presentation and opened with a discussion about the tornado in Holly and <br />presented radar reflectivity and velocity data. 1964 was last time Holly was hit by a tornado. The <br />County Sheriffs office and the NWS coordinated for quick response and warning of this event. <br />. 2006 reeap - Spring snowmelt produced some heavy breathing in the mountain communities but <br />no serious flooding. Summer monsoon was a "Mon-sooner" with start on July 1. In Tucson <br />started June 28 compared to July 4 average start date. Significant flash flood events: July 2 to July <br />15 and again August 1-17. Big December 20-30 snowstorms. <br />. La Nina building - There will be lingering storminess into Spring. The SW Mountain storm track <br />will aid basins south ofI-70 with wet spring snow. Upslope rains could impact eastern plains into <br />mid-May. Summer looks "average" as we transition from EI Nino into weak La Nina pattern by <br />fall. <br />. Snowmelt flood threats - Purgatoire River below Trinidad, Arkansas River below La Junta <br />. Rest of state average to below average risk A word of caution: since spring storms could still <br />impact SE plains into mid-May we need to be vigilant. <br />. Summer flood threat - Lower than last year from monsoon. The Monsoon will be average with a <br />"mon-Iatter" starting July 4-10 and ending before Labor Day. However, severe thunderstorms <br />with hail may return and produce urban flooding threats late May to mid-June, mid-July and early- <br />mid August. <br />. Long Range Outlook - La Nina dominated storm tracks into December and January. This will <br />favor average to above average winter snows in northern and central mountains and Rio <br />Grande/Sange de Cristo's. This could make below average snow in SW mountains. There will be <br />less snow in South Platte Front Range and fewer big storms on eastern plains next winter. <br />. Will La Nina die early and give way to a Mar-Dee El Nino or Not? <br />If La Nina persists - we could experience 1-3 dry years again in a row. If this is true then dry <br />conditions with above normal temperatures are likely statewide for 2008. Snowpacks could be <br />average to below average if we have two dry years in a row. <br />. If El Nino returns - after a brief La Nina then a very different scenario plays out. If EI Nino <br />comes back in 2008 we could face a very wet May-July with a nasty monsoon followed by a <br />couple of wet winters. Snow packs would be on the higher side of average except northern <br />mountains. <br />. Klaus Wolter at the NOAA <br />Climate Prediction Center <br />has done good work <br />characterizing the EI Nino <br />and La Nina years through <br />the Multivariate ENSO <br />Index. Henz posed the <br />question is this a good <br />barometer for change and <br />heavy precipitation years in Colorado? Henz then showed years with standard departures in the <br />plus 1.5 and above range and how they correlate well to years between 1951-2006 where Colorado <br />had: high snowpack, significant rains, and significant floods in those years. <br /> <br />A2enev Reports <br /> <br />- 7 - <br /> <br /> <br /><ll <br />.3 3 MULTIVARIATE ENSO INDEX <br />"" <br />~ 2 <br />'" <br />co <br />'0 <br /><ll <br />N 0 <br />:a <br />"" <br />'" -1 <br />'0 <br />s:: <br />.s -2 <br />'" <br /> <br />1950 <br /> <br />1955 1960 <br /> <br />1965 1970 1975 1980 1965 1990 1995 2000 2005 2010 <br /> <br />Flood Protection. Water Project Planning and Finance. Stream and Lake Protection <br />Water Supply Protection. Conservation Planning <br />