Along the central East coast today, there has been a code orange and yellow issued. This code orange, in Maryland, Washington D.C. and New Jersey, was forecasted and issued throughout mid-day, with Air Quality leveling off throughout the evening. The first image shows this code orange and yellow, centered around the Baltimore Metropolitan Area. The second image shows the very poor Air Quality forecast issued for the San Francisco Valley. There was a small amount of code purple issued in this area, which as in previous posts was caused by the large amounts of ozone in this region. The ground-level ozone is created by sunlight (ultraviolet) that endures a photochemical reaction when it reaches certain organic compounds and Oxides of Nitrogen (NOx).

There has still been a large concentration of fires in the Mississippi Valley, which are also causing poor air quality in this region. The first image shows the NOAA IDEA AOD values for this region, with the yellow and orange regions corresponding to areas of high AOD (dirtier air). This image also shows the locations of the fires in this region, with the small fire icon indicating the location of the fire. As you can clearly see, the AOD is higher to the east of the locations of the fire. The second image, showing a HYSPLIT trajectory of this smoke and air mass, shows that the change AOD has in fact been caused by the smoke coming from these fire locations, which has been moving eastward for the past 24 hours.

The following image is taken from the CALIPSO 532 nm Backscatter signal. The area of the image that I have circled shows the area that the satellite is passing through a cross section of the Mississippi Valley and the amount of particulates in the air.

The air quality story today across the US has improved from the last several days, with poorest conditions concentrated in the Mid-Atlantic Region. PM2.5 AQI levels remained in the moderate to Unhealthy for Sensitive Groups (USG) range for the eastern half of the US, while Ozone climbed to USG and Unhealthy throughout the Mid-Atlantic Region (bottom left,courtesy AirNow). Southerly winds across the eastern seaboard today continued to pump in moisture, and the air looked as sticky as it felt, as seen in today's 3pm EDT Hazecam (looking northeast towards downtown Baltimore) (bottom right).

According to NOAA's Hazard Mapping System, thin smoke from fires in northern New Mexico, Canada, and new large fires in western Ontario merged on the back, western side of a powerful weather system in northwestern Ontario. This same weather system may have helped to improve air quality conditions today for the Great Lakes Region, as it swept through a linear squall line feature, initiating a Derecho type wind event with widespread wind damage reports of winds estimated between 50-80 mph.

A spectacular image from today's GOES East Satellite's Visible channel was captured as the storms progressed southeast and exploded along the apex of a bowing segment and along another frontal boundary in the Ohio River Valley that formed in response to the aforementioned system's evolution (bottom middle).

Looking ahead, the Great Lakes and Mid-Atlantic Region will see a northwesterly wind shift over the next few days because of a High Pressure system forecast to drift south from Canada by the middle of the week. Nonetheless, the associated clearing skies and hot July sunshine may maintain a decent environment for Ozone levels to climb again, pushing AQI levels towards moderate to USG (bottom middle).

Finally, if you look closely at today's AirNow PM2.5 hourly map (bottom left), you can see a quick flash of an Unhealthy level in North Carolina around 11am. This is most likely due to the ongoing Honey Prairie fire in southeast Georgia and it looks like air quality conditions may get worse, as North Carolina's Air Quality Division forecasts Code Purples for Tuesday in southeast portions of the state (bottom right).

Today, DISCOVER-AQ flew again over Washington and Baltimore. The AQI in the area did not reach the forecasted Unhealthy for Sensitive Groups range and experienced an early morning decrease in light scattering (UMBC Nephelometer, left image) and MODIS Terra AOD (right image). By later in the afternoon, the light scattering increased again (see the UMBC lidar image below) and the HMS identification of smoke offshore (right).

Ozone was elevated across the state but was pretty uniform across the region with nearly all sites measuring about the same concentrations.

Wide bands of smoke were identified in the HMS image (left) and can be seen in the overlay of MODIS RGB, AIRNOW AQI and fire locations (right).

There were two USG readings in Ohio (Cleveland and Youngstown) and there is identifiable haze in the MODIS RGB. Curiously, the Google Earth map shows "Eriejarvi" as the lake name and I don't know when the Finns took over Canada. At least they took over Google.

Finally, in California, extensive areas of moderate ozone were seen in the LA Basin and in northern California near Sacramento. There was almost 60 ppb gradient in ozone from the airport on the coast and Riverside in the east.

Maryland experienced moderate AQI throughout the day today (top, left: AIRNow animation) but MDE (Maryland Department of Environment) has a code orange forecast for tomorrow due to a high pressure system that approaches bringing clear skies, warm temperatures and light surface winds. The exception would be the western portion of Maryland where MDE expects the air quality to remain within the upper moderate range. Today MODIS Terra AOD retrievals (top, right) show values between 0.2 and 0.4 while HMS (text) analysis reports an unknown source of haze over the Mid-Atlantic and Northeast.

Poor air quality was also observed in California, Arizona, New Mexico, Utah and Nevada where unhealthy (code red) levels of PM2.5 were reported (bottom, left). Also according to HMS analysis (map), smoke from the recent fires in New Mexico, Oklahoma and Southeast US were observed all over the Central Plains and Midwest which correlates with the poor air quality and the high AOD observed today over that region (bottom, right).

PM2.5 levels (top left, courtesy AIRNow) reached Code Red (Unhealthy) in Georgia today. Code Orange (Unhealthy for Sensitive Groups) PM2.5 levels were reported in South Carolina, Georgia, Ohio, Indiana, Tennessee, and Pennsylvania. Moderate (Code Yellow) levels were reported throughout the Great Lakes, Mid-Atlantic, South, and Mississippi Valley regions, as well as in California. Ozone levels (top right, courtesy AIRNow) throughout the night ranged from Code Orange to Code Yellow in southern California. In the daytime, Code Red ozone levels were reported in southern California, with Code Orange levels being reported throughout the state. Code Orange ozone levels were reported along the Texas-Oklahoma border and in Georgia. Code Yellow ozone levels were reported throughout the Pacific Southwest, Plains Sates, Mississippi Valley, and Great lakes regions. Fires in New Mexico continue to emit smoke as NOAA's Hazard Mapping System (HMS, bottom left) reports smoke over much of the central part of the country in the Plains States, Mississippi Valley, and Great Lakes region. A patch of smoke was also observed by HMS stretching over North Carolina, South Carolina, Georgia, and Alabama.The MODIS Terra AOD map (IDEA, bottom right) reported high AOD over Georgia and South Carolina.

Today, a lot of air quality activity especially in the eastern US. According to EPA moderate to unhealthy levels for sensitive groups were reached in Mid-Atlantic, Mississippi Valley and Southeast region (top left). Ozone levels registered a significant increase during the afternoon in several regions. Levels jump from moderate to unhealthy for sensitive groups in the Mid-Atlantic and Mississippi Valley regions as well as California State (top right). Particularly, the increase of Ozone levels during the afternoon in Aladino MD is indicated in the AQI plot from Clear Air Partners (bottom).

The large wildfires south of Reindeer Lake in Saskatchewan continue to emit moderately dense to dense smoke which is currently moving the southwest (top left). Remnant smoke from these fires is moving to the east through central Manitoba where it varies to dense smoke over Lake Winnipeg. The light smoke continues to the east passing over the majority of Ontario and into the southern region of Quebec where it dissipates as it approaches the US border.
In Addition, moderate to dense smoke is still detected from fires in Georgia and New Mexico (top right). Due to the smoke in New Mexico high AOD was detected by MODIS as can be seen in the GASP animation (bottom left).

Across the northern tier of the US today, mid and upper level winds (bottom left, courtesy SPC) helped steer smoke from Canadian wildfires near Ontario, towards the Great Lakes Region, causing moderate to USG (Unhealthy for Sensitive Groups) AQI (bottom right).

According to NOAA's Hazard Mapping System, the Las Conchas and Pancheco fires in northwestern New Mexico continued to emit dense smoke, which took a northeasterly track into south-central Colorado. The Southeast and Mid-Atlantic states also experienced moderate to USG AQI levels, but may have gotten a little relief after a frontal system initiated a band of storms across parts of the Eastern coast. Elevated AOD is visible on the RGB image from Terra today (bottom middle) along the eastern coast of Georgia and the Carolinas, but once you travel further inland, much of the AOD gets lost in the clouds associated with the band of storms.

After an unusually devastating 2011 tornado season, and historical flooding of the Mississippi River, wild weather made headlines yet again today. A monstrous plume of dust rolled over the mountains impacting Phoenix, Arizona and surrounding communities during the early evening hours yesterday. The impressive dust storm, also known as a "haboob" , was caused from a microburst during an afternoon thunderstorm near Tucson, Arizona. In brief, a microburst is an intense downdraft inside a thunderstorm that descends rapidly to the ground, initiating powerful wind divergence at the surface. These naturally occurring phenomena prompt dangerous wind events alone, but when coupled with loose sand on the desert floor, a wall of dust can sweep through an area causing zero visibility, delayed air traffic, and knock out electricity for miles.

The billowing dust cloud prompted an Ozone Health Watch today across Phoenix and surrounding cities, and air quality forecasters reported nearly every PM 10 level in the forecast area exceeded standards.