August 25, 2009
Good to Moderate Air Quality in U.S.; Dust in the Atlantic off East Coast; Another Tropical System Possibly Forming in the Caribbean
After several days of Code Green (Good) air quality across the nation, many areas observed Code Yellow (Moderate) PM2.5 conditions today, as shown in the loop of AQI values (below on left). AIRNow is experiencing some technical difficulties this evening, as AQI information is only available through 5 PM EDT. Fire activity is relatively quiet today. NOAA's Hazard Mapping System (HMS) reported an area of light smoke and haze stretching north-to-south across east Texas and along the borders of Oklahoma, Arkansas, Kansas, and Missouri this morning. By this afternoon, the plume had shifted to the east, and is visible along the Mississippi River Valley, from Illinois to the Gulf Coast, in today's MODIS Aqua true color image (below on right).
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The Midwestern haze/smoke plume was disperse enough to escape detection by MODIS AOD (below on upper left), but an area of high AOD is evident in the Atlantic, east of Florida. Could this be the Saharan dust predicted by Nikisa on Saturday? It sure looks like dust to me in today's MODIS true color image (below on right in Google Earth), although it seems to be arriving a bit late if transported by Hurricane Bill. The 5-day NAAPS forecast (below on lower left) suggests that we will be seeing more dust across Florida and the entire Caribbean this week, so we will have to keep an eye on the situation.
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Another situation in the Caribbean that bears watching is the possible development of Tropical Storm Danny. The National Hurricane Center has identified an area of low pressure (below) that has a high chance of developing into a tropical system sometime in the next 48 hours. The numerical forecast models are predicting that the system will form and approach the coast of the Southeastern United States in the Friday-Saturday time frame, and then possibly travel up the East Coast. Stay tuned to the Blog as we monitor the development of the system and track any possible impacts on air quality over the next week.
Update: At 11 AM EDT Wednesday, the National Hurricane Center officially designated the area of disturbed weather east of the Bahamas as Tropical Storm Danny.
Posted by Amy Huff at August 25, 2009 10:01 PM