Archive for February, 2010

Circumzenithal Arc and Thundersnow

Saturday, February 6th, 2010

Thursday afternoon, 04 February 2010, cirroform clouds filled the sky ahead of an approaching winter storm. At first I noticed a couple of parhelia, also known as “sundogs.” A while later, I saw a circumzenithal arc high in the southwestern sky. By the time I walked home to get a digital camera, the phenomenon had disappeared. See what you missed by looking at a gallery of photos of circumzenithal arcs taken by other photographers.

Friday morning, snow started falling around 10:00 a.m.; 24 hours later, snow is still falling and the National Weather Service has posted a winter storm warning effective until 10:00 p.m. Saturday, 36 hours after the storm began. So far, some parts of the Washington, D.C. metropolitan region have recorded up to 30″ of snow! Overnight, my neighborhood lost power twice: the first time, the power was off for about 30 minutes; the second time, the power was off for several hours. During the second outage, it was pitch black outside. I saw numerous lightning flashes, but never heard thunder. Meteorologists call this phenomenon “thundersnow.” Essentially, thundersnow is a thunderstorm during a strong winter storm.

Groundhog Day

Monday, February 1st, 2010

According to legend, if the groundhog sees his shadow on February 2nd then there will be six more weeks of winter; if he doesn’t see his shadow then there will be an early spring. Reality check: The fact of the matter is there will be six more weeks of winter regardless of what the groundhog sees!

For places located in the Northern Hemisphere, the first day of astronomical spring occurs on the March Equinox, when the subsolar point crosses the Earth’s equator. The March Equinox occurs on 20 March 2010 at 17:32 UTC. Do the math: There are six- to seven more weeks of winter between Groundhog Day and the March Equinox. Truth be told, numbers don’t lie.

Here’s a cold fact to warm your heart: On January 24th, the daily average high temperature in Washington, D.C. begins increasing from its lowest point annually. Yippee — winter’s icy grip may be slipping!

Teacher Tips: Visit Groundhog Day, the official website of the Punxsutawney Groundhog Club. Follow the hyperlink to “Teachers” for pointers to related activities and lesson plans.

Editor’s Note: Punxsutawney Phil saw his shadow, and we know what that means … sigh!

Posted from Arlington, Virginia, United States.