Strange Weather in Southwest, Southeast

Today some weather briefs including an unusually "nice" Spring in the Southeast, and Pressure records broken in the Southwest. According to an email from William Schmitz of the Southeast Regional Climate Center (a division of NOAA), 2008 was the 10th latest year that Columbia, South Carolina ever took to reach 90 degrees (in the last 130 years of record, anyway*). It happened this year on May 28th. In Raleigh, North Carolina, it took until June 1st; only 21 of their years of record showed later dates.

In other odd weather news, Chris Burt, author of "Extreme Weather", a comprehensive weather book to which I frequently refer (2007 Edition is out!), writes that Yuma, Arizona dipped to its lowest pressure ever - and it's not all that low. Turns out the Southwest is known for high pressure, and the 29.33" Hg experienced by Yuma on May 22nd** shattered their all-time record of 29.37" in 1937.

This all sounds odd to me, because pressure readings like that, or even lower, are commonplace here in the Northeast when winter or tropical storms come barrelling through, but that's just part of the U.S. pressure climatology (see NCDC map of pressure records below).

In nearby Las Vegas, they recorded their lowest May pressure on record, as did Sacramento, California. The Las Vegas NWS explained... "THIS WAS THE RESULT OF AN UNSEASONABLY STRONG LOW PRESSURE SYSTEM WHICH DROPPED DOWN OUT OF THE PACIFIC NORTHWEST AND SETTLED OVER NORTHWEST ARIZONA AND SOUTHERN NEVADA TODAY."

*This station's record may include data from more than one, possibly incompatible, locations. It reflects the longest available record for the Columbia Area.

**Note that lower pressure readings are listed on that page, but not "Sea-Level Pressure" which is what meteorologists use.