Wildfires in Idaho

August 24th, 2012 |
GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed the smoke plumes emanting from a number of large wildfires that were burning in parts of Idaho on 24 August 2012. Note that some of the low-altitude smoke was being channeled southward through valleys by strong northerly winds. The surface visibility at Salmon, Idaho (surface identifier KSMN) was reduced to 2 miles due to smoke, and at Dillon, Montana (station identifier KDLN) the surface visibility dropped to 1.25 miles.

The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes (as opposed to the standard 15-minute image interval).

MODIS true color image (viewed using Google Earth)

MODIS true color image (viewed using Google Earth)

A 250-meter resolution Aqua MODIS true color image from the SSEC MODIS Today site (above; viewed using Google Earth) showed a detailed view of the smoke plumes at 20:13 UTC.

Suomi NPP VIIRS 3.74 µm shortwave IR + 0.8 µm Day/Night Band images

Suomi NPP VIIRS 3.74 µm shortwave IR + 0.8 µm Day/Night Band images

During the following night-time hours, a comparison of AWIPS images of Suomi NPP VIIRS 3.74 µm shortwave IR and 0.8 µm Day/Night Band (DNB) data (above) demonstrated how the DNB imagery can detect the glow of the actively-burning fires (co-located with the black to yellow to red color enhanced “hot spots” on the shortwave IR image) in addition to the city lights across the region. Stray light contamination was affecting the far northeastern portion of the DNB image.

Record high temperatures and wildfires in Oklahoma

August 3rd, 2012 |

 

MODIS 0.65 µm visible channel image + Land Surface Temperature product

MODIS 0.65 µm visible channel image + Land Surface Temperature product

A comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel data and the corresponding MODIS Land Surface Temperature (LST) product (above) showed nearly cloud-free conditions and very hot LST values of 120 – 140 F (darker red color enhancement) across much of southern Oklahoma at 19:48 UTC or 2:48 PM local time on 03 August 2012. On this particular day, two notable temperature records were set at Oklahoma City:

 

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1145 PM CDT FRI AUG 3 2012

…NEW RECORD MAXIMUM TEMPERATURE SET AT OKLAHOMA CITY…
…NEW RECORD WARM MINIMUM TEMPERATURE AT OKLAHOMA CITY…

TODAYS MAXIMUM TEMPERATURE AT WILL ROGERS WORLD AIRPORT IN OKLAHOMA CITY WAS 113 DEGREES. THIS BREAKS THE PREVIOUS RECORD MAXIMUM
TEMPERATURE OF 109 DEGREES, SET ON THIS DATE IN 2011.

THIS ALSO TIES THE WARMEST MAXIMUM TEMPERATURE ON RECORD. THE RECORD WAS LAST REACHED ON AUGUST 11TH 1936.

THE MINIMUM TEMPERATURE OF 84 DEGREES IS ALSO THE WARMEST MINIMUM ON RECORD. THE PREVIOUS RECORD WARM MINIMUM OF 83 DEGREES WAS LAST REACHED ON AUGUST 13TH 1936.

TEMPERATURE RECORDS FOR OKLAHOMA CITY DATE BACK TO 1891.

 

The hot LST and air temperature values combined with dry fuels due to ongoing drought conditions created a very favorable environment for wildfire activity — and several fire smoke plumes were noted on GOES-13 0.63 µm visible channel images (below; click image to play animation). With the largest of the fires located east of Norman, Oklahoma (station identifier KOUN), a number of brighter white pyrocumulus clouds could be seen popping up through the lighter gray smoke plume.

GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

The dense smoke plume from the Norman fire showed up very well on the 19:52 UTC (2:52 pm local time) Aqua MODIS true color Red/Green/Blue (RGB) image (below, displayed using Google Earth).

Aqua MODIS true-color Red/Green/Blue (RGB) image

Aqua MODIS true-color Red/Green/Blue (RGB) image

The large fire east of Norman continued to burn into the the following night, exhibiting a pronounced “hot spot” (black to yellow to red color enhancement) on the 07:57 UTC (2:57 AM local time) Suomi NPP VIIRS 3.74 µm shortwave IR image (below). The flames from this fire also had a distinct bright signature on the corresponding 0.7 µm Day/Night Band image.

Suomi NPP VIIRS 11.45 µm IR, 3.74 µm shortwave IR, and 0.7 µm Day/Night Band images

Suomi NPP VIIRS 11.45 µm IR, 3.74 µm shortwave IR, and 0.7 µm Day/Night Band images

 

Historic Late April Nor’easter Storm

April 23rd, 2012 |
GOES-13 6.5 µm water vapor channel images (click image to play animation)

GOES-13 6.5 µm water vapor channel images (click image to play animation)

A historic late-April “nor’easter” storm affected much of the northeastern US during the 22 April23 April 2012 period. This storm produced heavy snowfall (as much as 23.3 inches at Laurel Summit, Pennsylvania), heavy rainfall (as much as 5.74 inches at New Boston, New Hampshire), and wind gusts as high as 94 mph at Mount Washington, New Hampshire. AWIPS images of 4-km resolution GOES-13 6.5 µm water vapor channel images (above; click image to play animation) showed the development of various features of the storm on 23 April, including a large and well-defined comma head, dry slot, and deformation zone.

By tracking the movement of various water vapor image features between consecutive images, atmospheric motion vectors can be calculated which give an indication of the wind direction and wind speed within the middle to upper troposphere. GOES-13 6.5 µm water vapor images with overlays of MADIS 1-hour interval water vapor winds are shown below  (click image to play animation).

GOES-13 6.5 µm water vapor images + MADIS 1-hour water vapor winds (click image to play animation)

GOES-13 6.5 µm water vapor images + MADIS 1-hour water vapor winds (click image to play animation)

Satellite-derived water vapor winds can also be used to calculate an upper-tropospheric (150-300 mb) divergence product (below), which in this case showed persistent divergence aloft over much of the northeastern US on 23 April. This upper-level divergence created an environment that favored upward vertical motion within the atmospheric column, helping to enhance and prolong the ongoing precipitation over those areas.

GOES-13 water vapor images + Upper-level divergence derived from water vapor winds

GOES-13 water vapor images + Upper-level divergence derived from water vapor winds

A series of 1-km resolution MODIS 11.0 µm IR and POES AVHRR 12.0 µm IR images (below; click image to play animation) indicated that enhanced areas of colder clouds (some exhibiting a banding structure) developed over the region of persistent upper level divergence.

MODIS 11.0 µm IR + POES AVHRR 12.0 µm IR images

MODIS 11.0 µm IR + POES AVHRR 12.0 µm IR images

The 10-km resolution GOES-13 sounder Total Column Ozone (TCO) product (below; click image to play animation) revealed an anomalously large area of elevated TCO covering much of the eastern US, indicative of a lowered tropopause associated with the large upper-level trough of low pressure.

GOES-13 sounder Total Column Ozone + RUC 500 hPa geopotential heights

GOES-13 sounder Total Column Ozone + RUC 500 hPa geopotential heights

===== 24 April Update =====

MODIS 6.5 µm visible channel image + MODIS false-color RGB image

MODIS 6.5 µm visible channel image + MODIS false-color RGB image

A comparison of the 1-km resolution MODIS 0.65 µm visible channel image at 16:09 UTC (12:09 pm local time) with a corresponding false-color Red/Green/Blue (RGB) image created using the MODIS 2.1 µm “snow/ice detection” channel (above) helped to identify high-elevation areas with significant snow cover remaining after the passage of the storm — snow appears brighter white on the visible image, and darker red on the false-color image. Note that cirrus clouds appear as a lighter shade of red in the RGB image.

A 250-meter resolution MODIS true color image from the SSEC MODIS Today site (below; viewed using Google Earth) showed even better detail of the snow-covered high terrain.

MODIS true-color RGB image (viewed using Google Earth)

MODIS true-color RGB image (viewed using Google Earth)

“County Line Fire” in northern Florida

April 7th, 2012 |
GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

McIDAS images of 1-km resolution GOES-13 0.63 µm visible channel data (above; click image to play animation) showed the large smoke plume emanating from the so-called “County Line Fire” that was burning in the Pinhook Swamp area (along the Baker and Columbia County line) of the Osceola National Forest in far northern Florida on 07 April 2012. Strong easterly winds early in the day promoted a long westward fetch of smoke transport toward the Florida Panhandle region, but a change in wind direction along with a reduction in wind speeds allowed the smoke to become more densely concentrated around the burn area later in the day. The smoke was reducing surface visibility and causing air quality problems (see the US Air Quality blog) at some locations across northern Florida.

A 250-meter resolution MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below; viewed using Google Earth) showed a closer view of the source region of the smoke plume.

MODIS true-color Red/Green/Blue (RGB) image (viewed using Google Earth)

MODIS true-color Red/Green/Blue (RGB) image (viewed using Google Earth)

Even though the smoke was quite thick over the fire source region, a comparison of AWIPS images of MODIS 0.65 µm visible channel and 3.7 µm shortwave IR channel data (below) showed how the fire “hot spot” (red to yellow to black color enhancement) could still easily be detected with the shortwave IR imagery.

MODIS 0.65 µm visible image + MODIS 3.7 µm shortwave IR image

MODIS 0.65 µm visible image + MODIS 3.7 µm shortwave IR image

A sequence of 1-km resolution MODIS and POES AVHRR 3.7 µm shortwave IR images (below) showed the diurnal change in size of the fire hot spot signature (red to yellow to black color enhancement).

MODIS and POES AVHRR 3.7 µm shortwave IR images

MODIS and POES AVHRR 3.7 µm shortwave IR images

A comparison of 4-km resolution GOES-13 3.9 µm shortwave IR imagery with 1-km resolution MODIS 3.7 µm shortwave IR imagery in the early afternoon hours (below) demonstrated the advantage of higher spatial resolution for more accuately determining the exact location of the County Line fire in far northern Florida, as well as the ability to detect a few of the smaller fires that were burning at that time in other parts of Florida and southern Georgia.

MODIS 3.7 µm shortwave IR + GOES-13 3.9 µm shortwave IR images

MODIS 3.7 µm shortwave IR + GOES-13 3.9 µm shortwave IR images

Finally, a comparison of 375-meter resolution Suomi NPP VIIRS 3.74 µm shortwave IR and 11.450 µm longwave IR images (below) provided even greater detail about the location and size of the fire. Even though the core portion of the fire was hot enough to exhibit a “hot spot” on the longwave IR image, the superior high temperature sensitivity of the shortwave IR channel gave a much more accurate view of the full areal coverage of the most intense portion of the fire (red color enhancement) as well as the location of active fire lines (black enhacement) out ahead of the main fire hot spot.

Suomi NPP VIIRS 3.74 µm shortwave IR and 11.450 µm longwave IR images

Suomi NPP VIIRS 3.74 µm shortwave IR and 11.450 µm longwave IR images