Red Sky At Morning; S.T. Warning?

The old adage "Red Sky At Morning; Sailors Take Warning" couldn't have been more appropriate than it was this morning here in State College, PA. Except this time, I have to change it to "Red Sky At Morning; Severe Thunderstorm Warning."

About 30 minutes after my webcam snapped the beautiful shot above, a line of severe thunderstorms roared through the area, some clocked at well over 100 mph according to the NEXRAD Storm Attributes Table on AccuWeather.com Professional. At the time of the picture, a Severe Thunderstorm Watch was being issued by the government's Storm Prediction Center. This was followed up by multiple severe thunderstom warnings, including one for Centre County, home to AccuWeather and WeatherMatrix. Click on the image below for a large radar movie of the storm moving through central Pennsylvania, courtesy AccuWeather.com RadarPlus. More movies are available here.

Dozens of downed tree reports were received by NOAA; a plot is shown below for yesterday and today.

So what about the folklore about red skies -- is it fact or fiction? Turns out, the saying takes advantage of a fairly common weather pattern in the mid-latitudes in the Northern Hemisphere, for example here in the United States. Meteorologists disagree on the interpretation of this saying, for one reason because it's not clear in what portion of the sky the red was occurring.

Generally, this is the interpretation: Dry air contains lots of dust particles, which cause red sunrises and sunsets. In the United States, where weather moves from west to east, the existence of a mass of dry air to your east ("red sky at morning") would indicate that the dry weather was moving away (and, in the everlasting atmospheric dance, moist air would follow). If this dry air were to your west, causing a "red sky at night", then dry air would move over you in the short term, in other words, don't worry about bad (stormy) weather tomorrow.

Here's one more for the road:

Seagull, seagull, sit on the sand,
It's a sign of rain when you are at hand

If you want to read more about nautical weather proverbs like that one, check out this site.

PHOTO BY SEAROSE3