Wednesday, February 25, 2009

A Pair of Mild Days, then More Winter

Thursday and Friday will be a couple of mild days in central Virginia, with highs reaching the low to mid 60s. A storm system will spread much needed rain into the area late Friday, and the rain should continue into the weekend. Colder air will move into the state over the weekend, and there is some potential for snow in parts of the area. I'll have another update Thursday afternoon. For now, enjoy the early Spring weather!

New Sunspot in Cycle 24

A new sunspot has developed on the face of the Sun, which you can see as a “tiny” black speck (mind you, most sunspots are larger than Earth) in this SOHO image. There had not been a sunspot since Jan 9, 2009.

This is another spot in the new Solar Cycle 24, which further indicates a gradual increase in solar sunspot activity as the Sun transitions from the old solar cycle into the new one. A solar cycle typically lasts about eleven to twelve years, where there is a gradual increase in the flux of solar particles from the Sun to the Earth (sunspots are usually indicators of a release of magnetic energy) that reaches a peak when there is a greater chance for magnetic “superstorms” on Earth. When this happens, communications can experience interference or loss for GPS, power grids, satellites, etc. Aurora events can also become more frequent and intense at the poles. After reaching a peak, the sun’s magnetic flux toward Earth gradually weakens, and the Sun can go many weeks without a single sunspot occurring.

The last solar maximum occurred in 2000, with the minimum recently in 2008 when sunspots were few and far between.

You can view a plot of solar activity here, and another plot of the solar cycles from 1900 to the present here.

Here is a pretty useful site dedicated to monitoring the new Solar Cycle 24:

And, in case you’re wondering where the best Aurora viewing is right now (which rarely occurs in Virginia!), you can view the map here.

--Carrie