Growing season's gone...
Posted October 31, 2011
A cold air mass that rushed into the region behind a front early Friday morning kept our daytime highs way below normal Friday and Saturday and set us up for what turned out to be a widespread freeze early Sunday morning. Clear skies, dry air, and winds that diminished rapidly through the evening allowed for lows that mainly dipped into the 29-33 degree range across our viewing area, as seen in the map (first image above) from the Raleigh NWS office. The area was under freeze warnings and frost advisories, but they will be the last ones issued due to the freeze bringing the 2011 growing season to an end. In historical terms, this was right on time. The average "first freeze" date for the Raleigh-Durham airport, for example, is October 29th, with a standard deviation of about +/- nine days, and this year's first freeze there came in on the morning of the 30th. The range of dates so far for RDU is an earliest freeze on October 3rd in 1974, and a latest first freeze on November 28th in 2009.
This time of year is also within the broad period of the Taurid meteor shower, which has peaks in mid October and early November, but may produce a couple of especially bright meteors on any given night. I happened to catch a fairly nice on early Sunday morning just as I arrived at work, although it was not so bright as to be classified a fireball. Just the same, when you're out on clear nights over the next couple of weeks, keep your eyes on the sky and you might see one.
Finally, there have been a few auroral displays in recent weeks that reached a little farther south than normal, and others that were in the typical regions but were especially nice. I thought I'd pass along a photo of one that occurred back on the 24th, but is especially fitting for Halloween. It was taken by Mike Hollingshead in Blair, Nebraska, and he happened to shoot it (very nicely) in a graveyard! You can see a larger version of the photo and another shot or two by going to the Spaceweather.com site and clicking on the tombstone photo there, and then on the medium size pictures that appear to get the highest-resolution images. You can find lots of other really nice recent aurora images at Spaceweather as well - just look for the "Aurora Gallery" links.