Can't Beat the Heat

If you're an Oklahoma resident, then chances are you're already all too familiar with the star portrayed in the image to the right. That star is of course our Sun, which has been on full display in mostly clear skies for all but a handful of days during the past two months. Though the spectacular NASA image shows an active, chaotic sun, with prominences and flares leaping up from the surface, the sun is currently much calmer. The sun goes through regular 11 year cycles of activity; during peaks, sunspots are numerous, and flares cause geomagnetic storms that result in disruptions to satellite communications and radio here on Earth, along with beautiful auroral displays (commonly known as the 'northern lights', or 'southern lights' for friends from the southern hemisphere).

The last solar maximum occurred around 2003, and we are now nearing the end of one of the deepest solar minimums in the last century. During a solar minimum such that which we are currently experiencing sunspots all but disappear from the surface of the sun, and the total solar output received at the Earth decreases by about 1 Watt per square meter, which may sound impressive, but is only 0.07% of the average solar energy Earth receives (approximately 1366 Watts per square meter). While some have done studies that have suggested that changes in the solar cycle may influence climate patterns here on Earth, the climate forcing caused by the solar cycle is far less than that of greenhouse gases added to the atmosphere since the start of the industrial revolution.

While the current solar minimum may have rendered the sun calm by astronomical standards, when it comes to Oklahoma's current weather, the sun has been anything but calm. As of July 10, much of Oklahoma is in the grip of a powerful heat wave, with no relief in sight for the coming week. Triple-digit readings have been common across much of the state, with temperatures as high as 115 F observed in the panhandle.

Shown to the left is a meteogram from the Buffalo Mesonet site for 24 hours ending on the afternoon of July 9. A meteogram is a plot of weather data over time. Meteograms are useful tools that allow meteorologists to view weather trends over time, and clearly identify the time and magnitude of significant weather events (such as frontal passages, severe storms, or heat bursts) at a given observation site. This particular meteogram image tells the tale of two sweltering, humid, breezy days of triple-digit heat, the second of which saw temperatures soar above 110 F. If you look during the afternoon of the first day, you can see a jump in the temperature for several hours at the same time as a significant drop in dewpoint--these are the kinds of interesting details that meteograms let you catch that might go unnoticed on other plots. While the current heat wave is impressive, it is far from the hottest that Oklahoma has seen. According to Mesonet records, the highest temperature ever recorded in Oklahoma history is 120 F – a mark which has been reached six times, most recently in Freedom, OK, on June 27, 1994. Nor is the current heat wave anywhere near the longest we've seen, a title likely held by 1980, when Oklahoma City topped out in the triple digits on 50 separate days (as of July 12, OKC has had highs in the triple digits just 7 times during 2009). If you're working (or playing) outside during the heat wave, be sure to take precautions to prevent heat-related illnesses such as heat stroke and heat exhaustion. The National Weather Service recommends remaining well-hydrated and seeking shelter in air-conditioned areas during periods of excessive heat, as well as limiting exposure to the sun, and making sure that any pets or livestock you may own have access to plenty of water. To monitor the heat wave and keep up to date on the latest weather conditions, check out the official site tune in to your local NOAA weather radio station (see this page for more information), or check the weather service website at http://www.weather.gov. For more information on the Sun and the solar cycle, the author recommends the resources and links at SpaceWeather.com. And of course, if it's weather data you're looking for, there's no better place than right here on HOOT to find it!

Story is © Nate Snook, 2009