From the Moon to the Sun: Cool Astronomy Events This Weekend!

We have a couple of interesting astronomical events this weekend, from the Moon to the Sun. The Full Moon is Saturday night, rising in the east in Richmond at 7:40 PM.
This will be a rare perigee full moon, meaning that the Moon is at its closest proximity to the earth in its elliptical orbit around us. As a result of literally being closer to the Earth and also being a Full Moon, it will be 14% bigger and 30% brighter than when the Moon is at apogee (farthest away from Earth in its elliptical orbit).

In addition, there is an optical illusion that occurs when the moon is at the horizon: it looks to our eyes to be huge, even though it really isn't (camera photos can prove this illusion by showing the moon is the same size at the horizon as when it's higher aloft)!

(Image above: Lloyd Kaufman & James H. Kaufman)
So this combination of literally being bigger and brighter plus merely appearing to be bigger should lead to a great Full Moon viewing Saturday at sunset. It looks like cloud-cover on Saturday should be moving out of the area by sunset, so hopefully we'll get to see this Full Moon on the eastern horizon as it rises.

Our second astronomical note for this weekend is the Vernal Equinox.
This is the official astronomical start of Spring on Sunday at 7:21 PM EDT.
This is the exact moment when the Sun's most direct rays are over the Earth's Equator. After this, the most direct rays continue to creep northward into the Northern Hemisphere, leading us into our Spring and Summer months until the Autumnal Equinox, when the most direct rays are back over the Equator on their trek southward into the Southern Hemisphere.

Rainfall Summary March 15-16, 2011

Last night's rainfall was beneficial for most of us in central Virginia, with a swath of a half inch to an inch of rain cutting through the heart of the Commonwealth. Everywhere in green on this map received at least a half inch of rainfall:

This was great rain for the metro areas, too, with Richmond International Airport picking up 0.76" officially, with higher totals Downtown and into the West End. Petersburg received a half inch last night.

This puts our year-to-date rainfall in Richmond at 7.67", about an inch below the normal year-to-date tally of 8.65". Last night's rain certainly helped close some of the gap as we lag behind in rainfall this year with continued moderate drought conditions. However, with no rain in our forecast for the next week, we'll fall behind again.

Tornado Preparedness Day

Today was Tornado Preparedness Day in Virginia, where tens of thousands of people practiced their tornado safety plan. A test tornado warning was issued by the National Weather Service office in Wakefield, Virginia, at 9:45 A.M. Here are a couple of quick facts about tornadoes in the Commonwealth. The average number of tornadoes per year in Virginia is 10, with 2008 being an exceptionally active year with 39 tornadoes. The number of tornadoes per 10,000 square miles is displayed for the whole U.S. in the next graphic. While Virginia typically doesn't see many tornadoes on an average year, there will be years (like 2008) that will be very active. It's also important to remember that tornadoes have occurred in every month of the year, so have a plan, and always be ready for when severe weather moves through central Virginia.