1. Winter 2017-2018 Climate Forecast
TMT – Annual Year-End Review
25th Winter Weather Meeting, OMSI and Oregon AMS, Portland
Kyle Dittmer
Hydrologist-Meteorologist
Columbia River Inter-Tribal Fish Commission Portland, Oregon
Professor of Earth Science
PCC – Southeast Campus, Portland, Oregon
December 12th, 2017

2. CRITFC website, http://www.critfc.org
Columbia River Inter-Tribal Fish Commission - CRITFC
CRITFC website,

3. 2016-2017 Portland Climate Forecast Performance
…but what about Snow events?!
Forecasted four events…two moderate, two minor (6-inch seasonal total), December to February.
Observed five snow events: Dec. 8 (minor), 14 (moderate); Jan. 7 (minor), (major); and March 6 (minor)…a 11-inch seasonal total. 

4. 2016-2017 Government Camp Climate Forecast Performance
Water Supply Forecast (MEI method): Columbia R. at The Dalles, Jan.-July: 111 MAF (issued Oct. 2016), 109%. Observed: 137 MAF. Error ±19% MAF (issued April 2017), 100%. Observed: 137 MAF. Error ±26%.

5. Introduction – Methods
CRITFC 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, of Germany (1922 – 2004).
Track ENSO with the Multi-variable ENSO Index: MEI.
NOAA’s Sea-Surface Temperature departure forecasts.
Hydro-Climate approach: Use a regression: Multi-variable ENSO Index ( ) vs. historic runoff for the Columbia River at The Dalles, then compute a 2018 Water Supply Forecast.
Select the “right” mixture of 20 past Water Years (next slide).
Pattern recognition is key: both La Niña and ENSO-Neutral years.

6. Introduction – Methods
Ensemble forecasting – 20 past water years:
NWRFC TDA WSF forecast (updated Dec. 11): 113 MAF

7. SUNSPOT COUNTS – “LA NIÑA”

8. NOAA SEA SURFACE TEMPERATURES - “LA NIÑA”

9. MEI SIGNAL SUGGESTS “LA NIÑA”
MEI tracks the Sea-Level Pressure, surface winds (2D), Sea-surface Temperature, Air Temperature, and fraction of Cloud cover (updated Dec. 11)

10. PDO SIGNAL...THE COLD PHASE CONTINUES

11. ENSEMBLE STREAMFLOW FORECAST
Blue line = long-term average (WY )

12. NOAA’s 30-90 day Probability Forecast
NOAA’s Climate Prediction Center (updated Nov. 30th)

13. NOAA’s Climate Prediction Center (updated Nov. 9th)
NOAA’s ENSO Forecast
NOAA’s Climate Prediction Center (updated Nov. 9th)

14. Summary: the CR Gorge Hood River
Expect many snow events…or 135% of normal (NOV-FEB); seasonal total 35-inches.
NOV 2.5-inch (up to 8), DEC 11-inch (up to 22), JAN 11-inch (up to 24), FEB 8-inch (up to 17), MAR 2-inch

15. Summary: the mountains
Government Camp
Expect a seasonal total of: 266-inches or 119% of normal (NOV-MAY).

16. Summary: the Portland Forecast
EXPECT HIGH VARIABILITY – INTENSE RAIN EVENTS, FLOODS, FOG, WIND STORMS, GORGE WIND, FREEZING RAIN, etc.
WATER SUPPLY FORECAST: 112 MAF (±14 MAF) or 109%, COLUMBIA RIVER AT THE DALLES, JANUARY - JULY.
…but what about Snow events?!
Expect FIVE events: 3 moderate (3-4 inch), 2 minor (1-inch).
DEC 1-inch (up to 2.5), JAN 3.5-inch (up to 8.5), FEB 1.5-inch (up to 4), and MAR 0.5-inch (up to 1)
(80% - 95% likely)