July 9, 2012
Diminishing heatwave helps dwindle poor air quality
Northeasterly flow behind a frontal system early Monday gave a final boot to the unrelenting heatwave experienced over much of the east during the month of July thus far (bottom left,courtesy HPC). In fact, for the first time this month, daytime high temperatures remained below 94 degrees in Baltimore, according to observations at the Baltimore-Washington International Airport (bottom right, courtesy NWS).
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Peak ozone levels also receded this afternoon for the Northeast, Great Lakes, and Mid-Atlantic states, remaining in the Code Green (Good) to Code Yellow (Moderate) range (bottom left, courtesy AIRNow). Scatter Code Orange (Unhealthy for Sensitive Groups) ozone levels were recorded across Missouri, Oklahoma, and California, but all-in-all the nation saw much improvement in terms of air quality today. As Ray mentioned in yesterday's post, fire and smoke conditions out west are also improving and only isolated regions over the Southeast, Mid-Atlantic, Southern Plains, Pacific North/Southwest states reached Code Yellow (Moderate) PM25 AQI (bottom right, courtesy AIRNow).
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The MODIS sensor aboard NASA's Terra satellite indicates the majority of haze leftover from the heatwave's wrath has traversed east into the Atlantic, however there appears to be a swath of haze lingering over eastern North Carolina - Virginia, an area also being impacted by numerous wildfires (bottom left). This region also experienced the highest AOD today (bottom right).
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