Winter 2012-2013 Climate Winter 2012-2013 Climate ForecastForecast

Kyle DittmerHydrologist-Meteorologist

Columbia River Inter-Tribal Fish Commission Portland, Oregon

November 17th, 2012

Oregon-AMS Meeting, OMSI, Portland

2011-2012 Climate 2011-2012 Climate Forecast Forecast PerformancePerformance

…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) Observed Precipitation (% normal):Avg. (20-

yr) ObservedNovember Near Normal (-1.8 to + 1.8 degF) 0.6 -0.9 Above Normal (110 - 130%) 113% 117%         December Near Normal (-1.8 to + 1.8 degF) 0.5 -1.1 Above Normal (110 - 130%) 124% 44%         January Near Normal (-1.8 to + 1.8 degF) -0.3 -0.3 Near Normal (90 - 110%) 106% 146%         February Near Normal (-1.8 to + 1.8 degF) -1 -0.7 Near Normal (90 - 110%) 105% 71%

         

March Near Normal (-1.8 to + 1.8 degF) -1.3 -3.2Above Normal (110 - 130%)   111% 214%

      average: -0.3 -1.2  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 – Introduction – MethodsMethods

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”

http://solarscience.msfc.nasa.gov/images/ssn_predict_l.gif

SEA SURFACE TEMPERATURES SUGGEST “????”

http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images3/glbSSTMonMask.gif

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 1929-2012)

Summary: The Summary: The ForecastForecast

Month: Temperature (mean monthly): Avg. (20-yr) Precipitation (% normal): Avg. (20-yr)

November Near Normal (-1.8 to + 1.8 degF) 1 Near Normal (90 - 110%) 92%

December Near Normal (-1.8 to + 1.8 degF) 1 Below Normal (70 - 90%) 86%

January Near Normal (-1.8 to + 1.8 degF) 1 Near Normal (90 - 110%) 99%

February Near Normal (-1.8 to + 1.8 degF) 1 Below Normal (70 - 90%) 88%

March Near Normal (-1.8 to + 1.8 degF) 1 Near Normal (90 - 110%) 101%

…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.