365 Days of Climate Awareness 161 – 2014 State of the Climate, North America

2014 US Climate Data

• Global atmospheric CO₂ concentration: 397.34ppm, +1.94 ppm from 2013
• Average air temperature: 54.0°F, 54^th all-time 1895-2021
• Average precipitation: 28.27”, 50^th wettest (78^th driest) 1895-2021
• Tornadoes: 886, 367 (29%) below the ten-year average 1253
• 8 named tropical cyclones: 6 hurricanes, 2 major (winds > 111 mph, 3-5 Saffir-Simpson)
• Atlantic ACE: 72.43 x 10⁴ kts²
• ENSO: Neutral, trending toward El Niño by year’s end

Larger Version

North American Conditions

• Warmer than average: Canada; western & southwestern US; Mexico
• Cooler than average: Midwestern and central southern US
• Drier than average: Yukon & Northwest Territories; southwestern & south central US
• Wetter than average: Saskatchewan, Manitoba & Ontario; northern & southeastern US; northern & south-central Mexico
• Wildfires: below-average wildfire activity
• Snow cover: Above average

The United States experienced another significant outbreak of frigid air in the first three months of the year, as the weakened polar jet stream veered away from its normal roughly west-to-east course, exposing much of Alaska and western Canada to unseasonably warm air, and much of the central and eastern US to arctic cold. The scale and persistence of this huge Rossby wave fluctuation in the jet stream contributed to a year of below-average temperatures in the US east of the Rockies. The pattern repeated in summertime, bringing cool, if not freezing, air to the southern regions of the United States.

For the second straight year the Atlantic hurricane season was very light. Despite the neutral ENSO, global sea surface temperatures (SSTs) in the tropical Atlantic’s Main Development Region (MDR) were quite high and conditions favored storm formation. It is highly likely that the ongoing disturbances in the polar jet stream, which extended into summer, affected the wind patterns farther south, helping generate the upper-level wind shear common to an El Niño which limits cyclone formation. By later in the year an El Niño was developing, which might have contributed as well.

Polar Vortex, late 2013 and early 2014

Atlantic Ocean Main Development Region (MDR) for tropical cyclones

Tomorrow: 2014 State of the World Climate.

Be brave, and be well.