PM2.5 levels (top left, courtesy AIRNow) in the Valley in California reached Code Orange (Unhealthy for Sensitive Groups) today due to a build up of smoke from wood burning due to stagnate air that is a result of a high pressure system and low wind speeds over the area. This area has experienced elevated PM2.5 levels throughout the winter due to an unusually dry winter that has limited the dispersion of pollutants; storms help disperse pollutants and clean the air. PM2.5 levels reached Code Orange in Oregon as well. Code Yellow (Moderate) PM2.5 levels in Oregon, Washington, Idaho, and in the Great Lakes and Mid-Atlantic regions. NOAA's Hazard Mapping System (HMS, top right) reports no visible smoke over the countries. Much of the fires in the country were located in Texas, Georgia, and Florida. The OMI tropospheric NO2 map (bottom) shows high NO2 levels in Wisconsin and moderate NO2 levels in California and Texas.

Today, moderate air quality over the country was pretty much good except in the Mid-Atlantic and Great Lakes regions were moderate concentrations were read (top left). In Addition to the region mentioned, California also reached moderate and unhealthy levels for sensitive groups in a couple of stations throughout the day. On the other hand, HMS reported some fires scattered over the US, some of the producing light and no significant smoke in Texas, Florida, Kansas and Nebraska (top left).

As a special feature, Earth Observatory reported the First Fire Images from the new VIIRS ). VIIRS was launched on October 28, 2011, on the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite and produced its first image on November 21. By January 19, 2012, the sensor acquired its first measurements of fires. These measurements and others from VIIRS are still preliminary, and scientists and engineers will continue testing and calibrating the measurements over the coming weeks before data are released for public use.
It took longer to acquire the first VIIRS fire measurements because the sensor had to cool enough to accurately observe thermal infrared energy. These images show a few of the fires detected on January 19. The top image shows a smoky fire burning in the mountains east of San Diego, California. The lower image shows widespread agricultural burning in South Sudan, East Africa. In both cases the fires are marked in red.
The images indicate that the VIIRS sensor is in good health and that it appears to be detecting fires accurately. In both images, the fire detections line up with plumes of smoke. In the South Sudan image, the fires are burning in areas where black, charred ground points to recent fire activity. Flying over the same areas at about the same time, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite also detected fires in both California (bottom left) and South Sudan (bottom right).

Today the air quality in the US was relatively good. There were no reports on blowing dust over the Southern States and HMS reported a few fires in Florida but the light smoke posed no problems for the air quality in the region. Moderate levels of PM2.5 was observed over the Midwest and also in the West Coast, mainly in California and Oregon where code orange was also observed.

Extensive cloud coverage remains over most of the US, as can be seen in today's GASP AOD animation. High AOD was observed over Florida for a little while which could be due to the fires but some cloud contamination cannot be discarded.

PM2.5 levels (top left, courtesy AIRNow) reached Code Orange (Unhealthy for Sensitive Groups) in northern California. Code Yellow (Moderate) PM2.5 levels were repored in the Northwest, Great Lakes regions and in Texas. Dust from the southern and western parts of the state, as well as smoke from agricultural fires in Mexico and Central America contributed to the Code Yellow PM2.5 levels in Texas (Texas Commission on Environmental Quality).  NOAA's Hazard Mapping System reported earlier in the day that remnant dust from Texas was observed over Louisiana and Alabama. The LANCE AIRS dust score mapping (top right) reports dust over Louisiana, Mississippi, Alabama, and Georgia. HMS reports no visible smoke from fires across the country. Much of the fires currently ongoing were observed along the Plains States and in the South. The OMI tropospheric NO2 map (bottom) reports high NO2 levels in Texas and moderate NO2 levels in the Mid-Atlantic.

Some leftovers of the dust storm in Texas, as reported by Ray yesterday, could still be observed in the South today, according to the analysis from the HMS team at NOAA. They observed in the morning satellite images some remnant dust blowing over central Louisiana extending towards central Alabama.

From AIRNow-tech data we can see an increase in PM2.5 concentrations with respect to yesterday in some cities in Louisiana (below).

MODIS Aqua shows lots of cloud coverage over the Southern States but some high AOD was retrieved offshore from Houston and over Southwest Louisiana (left). HMS also reported some fires with associated light smoke (right).

AIRNow animation loop shows scattered regions across the US that experienced moderate levels of PM2.5 this Monday. Baltimore in particular has experienced increasing levels of PM2.5 since Saturday but MDE forecast is of good levels tomorrow.

While it is no excuse, we are off at the American Meteorological Association's annual meeting and lost connectivity with the world for a day. To catch up, on Sunday most of the country was covered in cloud and snow so the MODIS Aqua image is pretty white, except for that smudge through North Texas. The METAR observations for 13:00UTC show winds of 35-45 knots in the lower left corner of the plot below.

But the wind gusts got to near hurricane strength east of Abilene and the SRH website at NOAA discusses the event in some detail. Gusts exceeded 70 mph in that area (below left). There is some rather dramatic TV video of the event from Fox News in Lubbock and, of course, youtubes of people who drove through it abound (see below). There were many car crashes and probably some by people holding up their cell phones while trying to video the dust as they were driving. The gust front is seen nicely on this video on Accuweather.

On the right below is the daily average AQI for the US showing that the dust registered on the AQI but there were other areas (near Yuma Arizona and Montreal Canada) that had high PM2.5.

The comparison between the MODIS Aqua image (left) and MODIS Terra (right) points out the Terra calibration issue at the eastern edge of the swath. But what I really was interested in was the overlay of the AIRS dust score from the LANCE webmapping service. AIRS is an infrared spectrometer that can see spectral signatures of the minerals that make up dust. AIRS did see the dust storm but not all of it. AIRS sensitivity, however, it at higher altitudes in the troposphere so it is possible that the low dust was not picked up and this was dust which got up in the troposphere.

The PM was also elevated in Calexico in the Imperial Valley (below) and in Quebec Canada (below that).

Numerous agriculture fires in Florida burning south of Lake Okeechobee generated thin smoke plumes which eventually merged into a large swath of thin smoke surrounding the lake. Today's MODIS Terra image overlaid with the HMS fire analysis shows a light layer of smoke moving north over the lake (bottom left). Not surprisingly, AOD measurements from MODIS Terra were elevated around the same region (bottom right).

PM2.5 across Florida remained in the Code Green (Good) range except for locations near the fires, which rose to Code Yellow (Moderate) AQI (bottom left, courtesy AIRNow). Over the next several days, a few weather systems brining showers are forecast to pass only over northern Florida, suggesting that dry weather conditions will persist and increase the threat of fires in this region. Fortunately, onshore wind flow across the peninsula has increased relative humidity, (low humidity = good precursor for fire development) yet wind speeds have remained calm, making it difficult to disperse smoke plumes (bottom right).

Elsewhere, PM2.5 AQI across the Pacific coast were climbing again today, notably Washington and Montana, reaching Code Yellow (Moderate) and Code Orange (Unhealthy for Sensitive Groups) (bottom left, courtesy AIRNow). The southern valleys of California were also one of the worst air quality locations in the United States today, climbing to Code Orange AQI as well (bottom right, courtesy AIRNow).