Colorado weather and climate update: a bit more than halfway through the water year (Or: What s going on with the weather?? ) Russ S. Schumacher Colorado State Climatologist Director, Colorado Climate Center Department of Atmospheric Science, Colorado State University Along with: Zach Schwalbe, Becky Bolinger, Peter Goble, Nolan Doesken Summit County State of the River, May 2018
Looking back to Water Year 2017... 30 th wettest water year on record Schumacher: Summit County State of the River 2
7 months through this water year: Schumacher: Summit County State of the River 3
At the halfway point of the water year: Schumacher: Summit County State of the River 4
Statewide precipitation, October - March 1976-77 2001-02 Schumacher: Summit County State of the River 5
Colorado basin precipitation, October - March 1976-77 6th-driest Oct-March on record for Colorado basin Schumacher: Summit County State of the River 6
And to make matters worse, it s been warm, especially west of the divide Warmest Nov-Jan on record for all of the southwestern states Schumacher: Summit County State of the River 7
And to make matters worse, it s been warm, especially west of the divide February (especially) was closer to normal for temperature, so now only the 4 th warmest Oct- March period statewide Schumacher: Summit County State of the River 8
Statewide average temperature, October - March Fifth-warmest Oct-March on record for Colorado Last year was warmest Schumacher: Summit County State of the River 9
April 2018 Precipitation Temperature The storm on April 7-9 was a big one for Summit County! From https://wrcc.dri.edu/wwdt/current.php Schumacher: Summit County State of the River 10
Annual average precipitation Schumacher: Summit County State of the River 11
Average monthly precipitation Schumacher: Summit County State of the River 12
Water-year precip: Dillon (wettest) This year Average (driest) Schumacher: Summit County State of the River 13
Water-year precip: Georgetown (wettest) This year Average (driest) Schumacher: Summit County State of the River 14
Water-year precip: Climax (wettest) This year Average (driest) Schumacher: Summit County State of the River 15
Water-year precip: Grand Junction (wettest) Average This year (driest) Schumacher: Summit County State of the River 16
Water-year precip: Gunnison (wettest) Average This year (driest) Schumacher: Summit County State of the River 17
Water-year precip: Cortez (wettest) Average (driest) This year Schumacher: Summit County State of the River 18
Snowpack: a tale of two halves of the state... Caveat: snowpack values after mid-april can be rather misleading... https://www.nrcs.usda.gov/wps/portal/nrcs/main/co/snow/products/ Schumacher: Summit County State of the River 19
Summit Ranch (9400 ft) Grizzly Peak (11,100 ft) Schumacher: Summit County State of the River 20
Copper Mountain (10,550 ft) Vail Mountain (10,300 ft) Schumacher: Summit County State of the River 21
Upper Colorado River basin San Miguel, Dolores, Animas, and San Juan basins Barely hanging on above 2002... From NRCS Schumacher: Summit County State of the River 22
The jet stream: a big driver of weather! From earth.nullschool.net Valid last night Schumacher: Summit County State of the River 23
ENSO (El Niño / Southern Oscillation) One of the biggest drivers of seasonal climate over North America is ENSO, the periodic variation of ocean temperatures in the Pacific Ocean Its effect is to shift where the jet stream tends to be, how wavy it is, etc. This year, we have been in La Niña conditions: cool ocean near South America, warm in the western Pacific Typically, this brings warm and dry conditions to southern CO, and cool and (relatively) wet conditions to northern CO, and that s what we ve seen, especially after January La Niña conditions are expected to wane this spring, returning to near neutral (but forecasts of ENSO in the spring aren t as good as they are in the fall/winter) Schumacher: Summit County State of the River 24
Jet stream-level, November through January Was the pressure at jet-stream level above or below normal for Nov-Jan? Large ridge of high pressure over the west, leading to the record warm and dry conditions Jet stream even farther north than usual for La Niña Schumacher: Summit County State of the River 25
Jet stream-level, February-April More typical of La Niña, favoring northern mountains, with high pressure over southern Colorado Schumacher: Summit County State of the River 26
Current situation Strong spring storm ongoing http://weather.cod.edu/forecast Schumacher: Summit County State of the River 27
NWS 7-day precipitation forecast http://www.wpc.ncep.noaa.gov/qpf/p168i.gif Schumacher: Summit County State of the River 28
NWS 7-day precipitation forecast Schumacher: Summit County State of the River 29
May-June-July outlook Schumacher: Summit County State of the River 30 http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead14/interactive/index.php
May-June-July outlook Schumacher: Summit County State of the River 31 http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead14/interactive/index.php
CoAgMET COLORADO CLIMATE CENTER 75 stations 10 coming soon on west slope 44 5-minute stations interactive mapping through erams includes time series charts site photos coagmet.colostate.edu
CoAgMET COLORADO CLIMATE CENTER 75 stations 10 coming soon on west slope 44 5-minute stations interactive mapping through erams includes time series charts site photos coagmet.colostate.edu
COLORADO CLIMATE CENTER new website features at climate.colostate.edu Data Access Climate Maps (coming soon) Climate Normals Climate Extremes Tools 2/13
Intermountain West drought early warning system We lead monthly webinars on the drought situation in the intermountain west (now doing them every 2 weeks while in drought): next one is Tuesday (May 8) Register at http://climate.colostate.edu/webinar_r egistration.html See graphics at http://climate.colostate.edu/~drought/ Schumacher: Summit County State of the River 35
And finally, the all-important question: Do you have a rain gauge? Schumacher: Summit County State of the River 36
If you are interested in weather and the variations in precipitation, please join the Community Collaborative Rain, Hail and Snow Network http://www.cocorahs.org or see me today Schumacher: Summit County State of the River 37
CoCoRaHS data, 7 August 2017 Over 6 north of Stratton, almost nothing north of Yuma We always need more observers! Schumacher: Summit County State of the River 38
CoCoRaHS data in Hurricane Harvey, August 2017 Schumacher: Summit County State of the River 39
Thank you! http://climate.colostate.edu/ russ.schumacher@colostate.edu Follow us on Facebook and Twitter! @ColoradoClimate Schumacher: Summit County State of the River 40
Schumacher: Summit County State of the River 41
(extra slides) Schumacher: Summit County State of the River 42
Precipitation monthly importance Schumacher: Summit County State of the River 43
CPC s outlooks for the winter season how did they do? Forecasts Issued mid- November for Dec-Jan-Feb Observations Schumacher: Summit County State of the River 44
Growing season summaries at long-term stations: Avondale (2017) http://climate.colostate.edu/2 017ET/et_summary_avn_ano m.html Schumacher: Summit County State of the River 45
Ensemble weather forecasts Schumacher: Summit County State of the River 46
Ensemble weather forecasts Beyond 10 days, probably don t pay too much attention...the models will generally just revert to near the average conditions for the time of year Schumacher: Summit County State of the River 47
Ensemble weather forecasts Beyond 10 days, probably don t pay too much attention...the models will generally just revert to near the average conditions for the time of year...beyond this, the best we can hope for is above, near, or below normal Schumacher: Summit County State of the River 48
Ensemble weather forecasts Schumacher: Summit County State of the River 49