VISIT: Meteorological Interpretation Blog

Dust off the coast of Africa!

Earlier this morning, a large areal extent of dust advected off the coast of Africa. The new National Oceanic and Atmospheric Administration  – 20 (NOAA-20) satellite, launched into orbit back in November 2017, captured the dust via Day/Night Band (DNB) product at 0323Z, 1 August 2018. DNB illuminates atmospheric features, senses emitted and reflected light sources (i.e. dust and clouds in this case), during the nighttime. Notice in the DNB image below, the opaque, milky white features that resemble dust along the African coast and west of Africa. Corresponding cloud cover over the ocean and over land are also seen.

Although the DNB image above is only a static image, in animation of the dust can be seen later in the day, via geostationary data (higher temporal resolution). Clicking on the video below shows dust advecting west, towards the U.S., between 13-16Z, 1 August 2018. Products seen within animation are the GeoColor and Dust products, identifying dust in milky brown and pink colors, respectively.

Satellite observations of dust and forecasting dust can assist in assessing convective initiation, hurricane development/dissipation processes, along with determining visibility levels. As dust advects westward the next few days, Weather Forecast Offices (WFO’s) will determine how dust levels will impact their County Warning Areas (CWA’s), especially along the southeastern U.S. and Puerto Rico (U.S. territory).

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Carr Fire

It has been a very active fire season in California. Another fire burning in the state, is the Carr Fire, located in Shasta County, just west of Redding, CA. Over 44,000+ acres have burned with only 3% containment as of 27 July 2018. According to sources, the mechanical failure of a vehicle is presumed to be the cause of the fire.

The Carr Fire was observed by the Near-Constant Contrast (NCC) product, derived from the Day/Night Band (DNB, 0.7um) sensor, apart of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on-board the Suomi-National Polar-orbiting Partnership (S-NPP) satellite. The NCC produces ‘nighttime visible’ satellite imagery, and in this case (see NCC image below, at 0909Z, 27 July 2018), observes emitted city lights, emitted lights from the fires, reflected light from fog and low stratus clouds, along with the reflected light from nearby smoke.

Additionally, a comparison between NCC (bottom-left) and the GOES-16 infrared imagery (3.9um, bottom-right) at ~1050Z, 27 July 2018, is seen below. The NCC highlights the emitted lights from cities and towns, emitted lights from the Carr Fire, along with atmospheric features described earlier.

However, how do users clearly discriminate between emitted lights produced from fire to emitted lights exhibited by cities and towns? This is where GOES-16 3.9um imagery complements NCC.  GOES-16 3.9um can be used to identify ‘fire hotspots’, that emanate high brightness temperature values, near the surface. In the infrared imagery, the ‘fire hotspots’ are clearly discerned, and are seen embedded within the black ellipse.

For more updates on the Carr Fire, click on the following link.

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Typhoon Jongdari

By late weekend, Typhoon Jongdari is forecasted to make landfall along Japan’s southern islands. Typhoon Jongdari is expected to strengthen, with an initial northeast storm motion, then elicit a circuitous path, moving westward, within the next 24-hours. The typhoon is anticipated to be at Category 1 hurricane strength (74-95 miles per hour), just before landfall. Heavy rain, strong winds, storm surge and flooding is to be expected.

This morning, Near-Constant Contrast (NCC) data, derived from the Suomi National Polar-orbiting Partnership (S-NPP) satellite observed Typhoon Jongdari at 1617Z, 26 July 2018 (0117, 27 July 2018, local time in Japan). The NCC, a derived product of the Day/Night Band (DNB) utilizes a sun/moon reflectance model to illuminate and sense emitted (i.e. city lights) and reflected (i.e. clouds) light sources during the nighttime.

The first NCC image (below) is a large scale view of the storm, while the second NCC image, is a small scale perspective of Typhoon Jongdari, highlighting the convective cloud tops (areas of heavy precipitation), near and around Jongdari’s circulation. Notice the magnitude of Typhoon Jongdari, and how close the typhoon is to the country of Japan. Emitted lights from Japan, and ambient cloud cover can be seen in the following images.

Large Scale

Small Scale

For the latest updates on Typhoon Jongdari, click on the following link.

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Ferguson Fire, CA

The Ferguson Fire erupted last Friday, 13 July 2018 at ~2030 local time.  The fire is near Yosemite National Park, burned 22,000+ acres, and is only 7% contained, as of 20 July 2018. The cause of the fire is unknown and under investigation, while several communities have been evacuated from the area, and one fatality has been confirmed. Expected 3-5 day forecast for Central California is to be hot, hazy, with light and variable winds, that could potentially enhance the fire.

The Suomi National Polar-orbiting Partnership (S-NPP) satellite and the Geostationary Operational Environmental Satellite – 16 (GOES-16) observed the wildfire event, identifying the areal extent of the fire (emitted lights from the fire, seen via Near-Constant Contrast (NCC)) and associated fire ‘hotspots’ (GOES-16 3.9um). NCC and GOES-16 3.9um observed the Ferguson Fire at 0941Z (0241 local time), 20 July 2018.

NCC 

Note the areal extent of the fire (embedded in the white ellipse) but additionally, emitted lights from nearby towns/cities can be seen via NCC.

To discern emitted lights that are from cities/towns to emitted lights from the fire, that is where GOES-16 3.9um complements NCC. GOES-16 3.9um, not only shows the fire location, but indicates the relatively cool brightness temperatures of the fire. See the brightness temperature (degrees Celsius), sampled, in the following satellite image.

GOES-16 3.9um

As the day progressed through late morning, fire temperatures increased significantly, due to increasingly hot, ambient temperatures and dry conditions. See the brightness temperature (degrees Celsius), sampled, in the following satellite image.

GOES-16 3.9um of Ferguson Fire at 1622Z (0922 local time), 20 July 2018. 

For more updates on the Ferguson Fire, click the following link.

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Pawnee Fire, CA

In the late afternoon on 23 June 2018, the Pawnee Fire in Northern California initiated and has now spread to 11,000+ acres. As of this morning 26 June 2018, the fire is located a few miles north of Clearlake, CA and has forced thousands of people to evacuate the area, where 20+ structures have been destroyed. The fire is currently 5% contained and the cause of the fire is still under investigation. Additionally, Northern California is currently experiencing ‘D-0’ drought conditions (abnormally dry conditions), according to the US Drought Monitor. The latest California drought conditions can be seen below.

Polar-orbiting satellite imagery observed the Pawnee Fire, along with the Lions Fire, nearby. One of the polar-orbiting satellite products, the Near-Constant Contrast (NCC), illuminates atmospheric features and senses emitted and reflected light sources during the nighttime. The following two NCC images show the ‘Morning Before’ and the ‘Morning After’ the Pawnee Fire started. The first NCC image (shown below) is taken at 0948Z (0248 local time), 23 June 2018. Notice the emitted city lights along Northern California, and no discernible fires in the area.

Morning Before – 23 June 2018

The second NCC image is taken at 0928Z (0228 local time), 24 June 2018. Notice the emitted lights produced from the two fires, seen within the two red circles. The Pawnee Fire is located in the top-left part of the image, and the Lions Fire in the bottom-right part of the image. Areal extent of both fires can be inferred from the satellite imagery, wherein thousands of acres have been burned. Also notice the uniform, fog and low stratus clouds, along the California coast.

Morning After – 24 June 2018

The 3-5 day forecast for the area, is projected to be in the upper 80’s (air temperature), sunny, dry, with light to moderate winds, that could amplify the fire even further. More details on the Pawnee Fire can be accessed via the following link and via Inciweb website.

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