Average Temperature for 11 western states including Washington, Oregon, California, Nevada, Idaho, Utah, Arizona, Montana, Wyoming, Colorado, and New Mexico. Data were obtained from the National Climatic Data Center, the Center for Climate Prediction, and the National Oceanic Atmospheric Administration cooperative network.
Surface temperatures vary more than air temperatures during the day, but they both are fairly similar at night. The dip and spike in surface temperatures over the pond show how water maintains a fairly constant temperature day and night, due to its high heat capacity. The temperatures displayed do not represent absolute temperature values.
Using an "ensemble" of 18 global climate models and the moderate "A1B" emissions scenario, researchers at the NOAA Earth System Research Laboratory (ESRL) predict warming in the Southwest at the end of this century of approximately 7-8 degrees F for summer (June-August) and 5-7 degrees F for winter (December-February).
The greenhouse gas effect functions by trapping in the atmosphere heat from the Sun’s radiation. The greenhouse gases can be thought of as creating a one-way mirror—they allow the short wavelength energy emitted by the Sun to pass through the atmosphere and warm the Earth’s surface, but they do not allow all the longer wavelength energy radiated by the Earth back to space.
The top graph shows the positive relationship between Annual frequency of large (>400 hectare) wildfires (bars) and average spring and summer temperatures (line) in Western U.S. forests. Using the same x-axis, the bottom graph shows the first principal component of the center timing of streamflow in snowmelt dominated streams (pink = early, white = average, blue = late).
Multi-model means of surface warming (compared to the 1980–1999 base period) for the SRES scenarios A2 (red), A1B (green) and B1 (blue), shown as continuations of the 20th-century simulation. The latter two scenarios are continued beyond the year 2100 with forcing kept constant. An additional experiment, in which the forcing is kept at the year 2000 level is also shown (orange).