Presentation on theme: "Winter 2012-2013 Climate Forecast Kyle Dittmer Hydrologist-Meteorologist Columbia River Inter-Tribal Fish Commission Portland, Oregon November 17th, 2012."— Presentation transcript:
Winter Climate Forecast Kyle Dittmer Hydrologist-Meteorologist Columbia River Inter-Tribal Fish Commission Portland, Oregon November 17th, 2012 Oregon-AMS Meeting, OMSI, Portland
Climate Forecast Performance …but what about snow events?! Forecast three events…1 to 5 inches each, December to early March. Observed EIGHT snow events…9.5 inch seasonal total. Month:Temperature (mean monthly):Avg. (20-yr)ObservedPrecipitation (% normal):Avg. (20-yr)Observed NovemberNear Normal (-1.8 to degF) Above Normal ( %)113%117% DecemberNear Normal (-1.8 to degF) Above Normal ( %)124%44% JanuaryNear Normal (-1.8 to degF)-0.3 Near Normal ( %)106%146% FebruaryNear Normal (-1.8 to degF)-0.7Near Normal ( %)105%71% MarchNear Normal (-1.8 to degF) Above Normal ( %) 111%214% average: average:112%118% Water Supply Forecast (MEI method): Columbia R. at The Dalles, Jan.-July: 117 MAF (issued Oct 2011), 109%. Observed: 129 MAF. Error ±9%. 132 MAF (issued April 2012), 130%. Observed: 129 MAF. Error ±2%.
Introduction – Methods Forecast uses a holistic, integrated big picture view. Big-picture: Solar Forcing (e.g., sunspot cycles) does influence our global weather patterns. In memoriam: Dr. Landscheidt, 1922 – 2004, of Germany. Track ENSO with the Multi-variable ENSO Index. Sea-Surface Temperature Departure Forecasts. Hydro-Climate approach: Water year 2013 volume forecast uses regressed Multi-variable ENSO Index vs. historic runoff for the Columbia R. at The Dalles. Average of 20 water years = the volume forecast. Pattern recognition is key: El Niño & ENSO-neutral.
SUNSPOT COUNTS – SUGGEST EL NIÑO
SEA SURFACE TEMPERATURES SUGGEST ????
ENSO SIGNAL SUGGESTS ENSO-NEUTRAL WINTER WEATHER MEI tracks the Sea-Level Pressure, surface winds (2D), Sea-surface Temperature, Air Temperature, and fraction of Cloud cover.
PDO SIGNAL...THE COLD PHASE GETS COLDER!
ENSEMBLE STREAMFLOW FORECAST Blue line = long-term average (WY )
Summary: The Forecast …but what about snow events?! Expect FOUR events…1 moderate (2-5 inch), 3 minor (1 inch) (70-80% likely), January through mid-March. EXPECT HIGH VARIABILITY IN THE WEATHER...BUT NOT EXTREME – HEAVY RAIN EVENTS, FLOODS, etc. WATER SUPPLY FORECAST: 102 MAF or 95%, COLUMBIA RIVER AT THE DALLES, JANUARY - JULY.