365 Days of Climate Awareness 163 – 2015 State of the Climate, North America

2015 US Climate Data

• Global atmospheric CO₂ concentration: 399.34ppm, +2.01 ppm from 2014
• Average air temperature: 55.8°F, 9^th all-time 1895-2021
• Average precipitation: 30.53”, 12^th wettest (116^th driest) 1895-2021
• Tornadoes: 1117, 134 (11%) below the 1991-2010 average 1251
• 11 named tropical cyclones: 4 hurricanes, 2 major (winds > 111 mph, 3-5 Saffir-Simpson)
• Atlantic ACE: 68.11 x 10⁴ kts²
• ENSO: Strong El Niño

Larger Version

North American Conditions

• Warmer than average: Central & western Canada; Alaska; western US (especially southern California and the Pacific Northwest); southeastern US; Mexico (then-record)
• Cooler than average: Eastern Canada;
• Drier than average: Canada; California; western & southern Mexico
• Wetter than average: Alaska; central & southern US; mid-Atlantic eastern US; north-central Mexico
• Wildfires: 4.1 million ha/10.1 million acres burnt in US (third-most at the time); 2.14 million ha/5.3 million acres burnt in Canada (then-record)
• Snow cover: 90% of average snowfall in US; near-record snowfall in eastern Canada

Atlantic cyclone activity was slightly below the 1981-2010 averages (12.1 named storms, 6.4 hurricanes, 2.7 major), as expected during an El Niño year, but were at the top end of NOAA’s predicted range (6-11 named storms; 3-6 hurricanes; 0-2 major). About half of the season’s ACE (68.11), roughly 65% of the 1980-2010 average 104, was due to Hurricane Joaquin which did not impact the continental US. Tornado activity was similar, slightly but not significantly below average, consistent with El Niño conditions but not extremely so.

Among other measures of Arctic sea ice, such as extent (February maximum extent 14.54 million km², 7% below the 1981-2010 average), a combination of satellite and drift-buoy measurements are used to estimate the age and thickness of sea ice throughout the basin. Arctic sea ice has been thinning, from an average of 3 m throughout much of the basin to 1-2 m in the eastern portion. Likewise multi-year ice has shrunk. Older ice tends to be denser and less brittle. Ice of 4 or more years’ age has diminished from nearly 20% of total cover in 1985 to around 5% by 2015.

2015 US Percentage Area Very Warm vs Very Cold (top 10th percentile of each)

2015 US Percentage Area Very Wet vs Very Dry (top 10th percentile of each)

Arctic Ocean Percentage of Sea Ice Cover by Age, 1985 - 2015

Tomorrow: 2015 state of the world climate.

Be brave, and  be well.