While much of the lower 48 and Canada have experienced a bitter cold January, we are experiencing unusually warm temperatures here in Alaska. We’re not alone though, it’s also been warmer than average in northern Europe and western Russia. Afternoon temperatures across Alaska yesterday (on January 23) were warm, with temperatures in the 30s, 40s, and even 50s across south central and southwest Alaska. Only north of the Brooks Range did temperatures fall to the single digits above and below zero! These warmer-than-average January temperatures are not in themselves unusual, what’s really odd is how long they’ve stuck around. Warm air advection events, sometimes called the ‘Pineapple Express’ or ‘Chinooks’, are not uncommon during Alaskan winters – but they usually only last a few days before a return to more normal and cooler temperatures.
Below is a cool map (from NOAA Climate.gov) showing differences from average air temperature across the northern hemisphere for early January. Temperatures far below average are dark blue; temperatures far above average are dark red (with average being defined as the 1981-2010 30-yr ‘climate normal’).
So, what’s to blame for these long-lasting contrasting temperature extremes? Tough to say, but climate researchers have been pointing the finger at undulations of the jet stream, and the much-hyped polar vortex. Click these links to find out more about these topics.
If you live and work in south central Alaska, you might be interested in some local climate data for the past month (through Jan 23). The following climate plots are for long-term weather stations in south central Alaska. What they show are observed daily temperatures (red=daily high, blue=daily average, green=daily low), the range of ‘normal temperatures’ (grey area), and cumulative precipitation (dotted line), which has mostly been in the form of rain. The range of ‘normal temperatures’ represents long-term average high/low temperatures for the 30-year period 1981-2010.
Some interesting things to note: Average daily temperatures that are…Anchorage: 12 degrees F above ‘normal’, Homer: 13 degrees F above ‘normal’, Pt. Alsworth: 18 F degrees above ‘normal’, King Salmon: 17 F degrees above ‘normal’, Seward: 7 degrees F above ‘normal’. Really warm low temperatures that, on several days, were only a few degrees lower than the daily average temperature. Lots of precipitation (Seward has already gotten over 10 inches this month - 125% of normal) but unfortunately not much snow at low elevations. Dang, even Alyeska is closed (check out the last 14 years of snowfall below)!
Chuck Lindsay - Southwest Alaska Network Inventory & Monitoring Program, National Park Service