November 29, 2015

Air Quality Stagnation Advisory in the Pacific Northwest

The National Weather Service issued an air stagnation advisory in the Pacific Northwest until Monday. PM2.5 AQI levels ranged from Moderate to Unhealthy for Sensitive Groups (Code Yellow to Orange, Airnow animation) because cold air trapped wood smoke and carbon monoxide near the surface by warm air aloft.

NOAA Hazard Mapping System Fire and Smoke Product reported that despite the continuing numerous seasonal fires detected across portions of the North Central, Northwestern US and Southwestern Canada, little in the way of smoke was visible in satellite imagery.

November 27, 2015

Fires near Still Air in Pacific Northwest

The Weather Service issued an Air Stagnation Advisory for eastern Washington and northern Idaho through the weekend as the high pressure seen in the NWS surface analysis below left strengthens low level inversions, preventing aerosols from mixing out so they just build up near the ground. The concern seems to be smoke from the fires in the area seen in the HMS fire and smoke product below right.

The EPA AQI map below left shows only minor impacts from the smoke so far, but that may not last. Unfortunately, the cloud cover in the area, shown in the MODIS Aqua image below right, makes satellite views of the area more difficult.

November 24, 2015

Widespread poor air quality and winter weather conditions

A majority of the nation experienced varying levels of poor air quality today. The Great Lakes and Mississippi Valley regions had consistent Moderate, code yellow AQI (AirNow, top left). The Pacific Northwest had Moderate and Unhealthy for Sensitive Groups AQI. The contributors to this could be small patches of smoke and sulfates, as shown in the NAAPS AOD profile (top right). The Very Unhealthy AQI reported in southern California is likely due to the presence of dust or sand. The winter weather conditions are also not helping with the poor air quality (NOAA, bottom left). The snow and light winds can cause slightly stagnant conditions which can trap particles in the air. The AOD also appears to be elevated for these regions (VIIRS, bottom right).

November 23, 2015

Swath of Snow in the Mid-West, Moderate to Unhealthy Air Quality Conditions West

An early morning snapshot today from the Suomi NPP satellite's VIIRS instrument illustrated a blanket of snow across the mid-west after this weekend's snowstorm (top left, courtesy NOAA). In terms of air quality, most of the nation experienced good conditions, while much of the Pacific Northwest and Southwest climbed to Code Yellow, Moderate conditions, including a few pockets of Code Orange, Unhealthy for Sensitive Groups (top right, courtesy AirNow). Today's worst air quality conditions were recorded in northern California, peaking briefly at Code Red , Unhealthy, PM2.5 levels (bottom left). In addition, today's Aqua satellite overpass illustrated slightly elevated aerosol optimal depth (AOD) near the aforementioned Unhealthy air quality region (bottom right).

November 22, 2015

Code Yellow to Red PM2.5 AQI Levels in California; Freezing Temperatures for Eastern US

EPA's Airnow AQI animation shows Moderate to Unhealthy PM2.5 AQI levels reported in California, as light winds and little mixing favored fine particle (PM2.5) formation. These conditions persisted throughout the weekend. Yesterday's VIIRS AOD retrievals show values reaching max values of approximately 0.5 over this region.

Coldest temperatures of the season are expected for much of the eastern U.S. into Tuesday. In the wake of a strong cold front, the coldest temperatures of the season will impact locations from New York and southern New England down to parts of the eastern Gulf Coast. Temperatures will warm a few degrees for Tuesday, but still remain 5 to 10 degrees below average. Scattered lake effect snow showers are forecast southeast of the Great Lakes through Tuesday. Across the West, the beginnings of a colder and snowier pattern will begin to set up on Monday with the approach of a sharp upper level trough and cold front.

November 20, 2015

Smoke in Idaho and Califonia

The HMS fire and smoke product, shown below left, indicates many fires in the Pacific Northwest and Southwest. While these are not classified as large fires, nor are they producing smoke dense enough to be seen on the map, they nonetheless add up, producing Moderate to Unhealthy for Sensitive Groups AQIs (yellow to orange) in the EPA AQI loop below right. The elevated AQI levels in the San Joaquin Valley have prompted several Air Quality Action Days in the region.

The NWS wind speed map for the afternoon shows low winds for these areas, which would have left the smoke more or less in place.

November 18, 2015

Extensively Cloudy Skies Limit Detection

There is a great number of fires burning in Florida, Texas, the Northwest US, and Southwestern Canada again, however, mostly cloudy skies throughout the nation limited satellite imagery for today. The NOAA IDEA animation, top left, shows the vast cloud coverage over the US, and Canada. No smoke was detected for the most part, only very small patches of light density smoke were seen (HMS image, top right). The air quality was mostly good throughout the nation, with the exception of a few sporadic areas, mostly California, which was affected by a thin area of lingering dust being blown around (AQI animation, bottom left).