Cold Winds Rising
2014-09-21 18:38:55.000 – Tom Padham, Weather Observer/Meteorologist
Some of the first rime ice of the season
This week has seen some very large temperature swings on the summit, with temperatures falling as low as a chilly 14 degrees and into the relatively mild lower 50s. Three separate cold fronts will have crossed the summit by tomorrow, with temperatures falling about 25 degrees in roughly 30 hours from the time of this writing. Icing conditions are also looking to make a return to the higher summits late tomorrow, with a much more wintry scene expected by Tuesday. A few snow showers are also not out of the question during the evening Tuesday.
So when does winter really begin to set in on the summit? By late September the average temperature begins creeping closer to freezing, with 36 a daily average for the last two days of the month. This means a good portion of the day is spent below freezing (likely at night). September also averages about 2 inches of snowfall, with so far the summit only seeing a trace but still there is more than a week left in the month. Average wind speeds also begin creeping upwards, as the jet stream strengthens and storms begin becoming a bit stronger than what is typically seen in the summer. By October 9th, the average daily temperature has reached 32 degrees, and a typical day on the summit is spent mostly below freezing. Monthly snowfall also jumps up to nearly 18 inches, and so sometime in early October is when one could consider the true start to the winter season on the summit. Not too far off!
Tom Padham, Weather Observer/Meteorologist