GOES-14 SRSO-R: central Montana wildfire

August 15th, 2015

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm shortwave IR images [click to play MP4 animation]

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm shortwave IR images [click to play MP4 animation]

A comparison of 4-km resolution GOES-15 (GOES-West), GOES-14, and GOES-13 (GOES-East) 3.9 µm shortwave infrared images (above; click to play MP4 animation; also available as a 9.4 Mbyte animated GIF) showed the development and evolution of the “hot spot” (dark black to yellow to red color enhancement) associated with a small wildfire that formed near the border of Fergus and Petroleum counties in central Montana during the afternoon hours on 15 August 2015. With GOES-15 Routine Scan mode “SUB-CONUS” sectors, images were available up to 6 times per hour (at :00, :11, :15, :30, :41, and :45); with GOES-13 in Rapid Scan Operations (RSO) mode, images were available up to 8 times per hour (at :00, :07, :15, :25, :30, :37, :45, and :55). The GOES-14 satellite had been placed into Super Rapid Scan Operations for GOES-R (SRSO-R) mode, providing images at 1-minute intervals to emulate what will be available with mesoscale sectors from the ABI instrument on GOES-R.

For the central Montana wildfire, the first unambiguous signature of a darker black wildfire hot spot began to appear on each satellite after about 1945 UTC, with the first color-enhanced pixels (signifying a shortwave IR brightness temperature of 331.9 K) showing up on the 2026 UTC GOES-14 image. The hottest fire pixel  on the GOES-15 images was 336.5 K at 2130 UTC, while the hottest fire pixel on GOES-13 images was 329.8 K at 2125 UTC. From 2120 to 2130 UTC, the hottest GOES-14 fire pixels were 341.2 K (the saturation temperature of the 3.9 µm detectors on that satellite).

With the finer spatial resolution of the shortwave IR detectors on the polar-orbiting MODIS (1-km) and VIIRS (375-meter) instruments, a fire hot spot was first detected on the 1857 UTC VIIRS image (below).

Terra/Aqua MODIS and Suomi NPP VIIRS 3.7 µm shortwave IR images [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS 3.7 µm shortwave IR images [click to enlarge]

Hail damage to Delta Flight 1889 over Nebraska

August 7th, 2015

GOES-13 Sounder Lifted Indices [click to play animation]

GOES-13 Sounder Lifted Indices [click to play animation]

Hail associated with a line of rapidly developing thunderstorms near the borders of Kansas, Nebraska and Colorado heavily damaged Delta Flight 1889 bound from Boston to Salt Lake City, forcing an emergency landing in Denver (media report). An excellent blog post on the radar presentation of the system is here. What did the satellite data show? GOES Sounder Derived Product Image (DPI) values of Lifted Index (LI), above, (realtime images available here) showed instability over the High Plains of Colorado throughout the day. At 2000 UTC, for example, values greater than -8º C prevailed (subsequent cloud development prevented the retrieval of LI values using the Sounder). GOES Sounder DPI of Convective Available Potential Energy (CAPE), below, (realtime images available here) also indicated strong destabilization during the late afternoon (1600, 1800 and 2000 UTC are shown in the animation). The 08 August/00 UTC rawinsonde report from North Platte, Nebraska had LI and CAPE values of -5ºC and 1592 J/kg, respectively.

GOES Sounder Convective Available Potential Energy (CAPE), 1600 - 2000 UTC 7 August 2015  [click to enlarge]

GOES Sounder Convective Available Potential Energy (CAPE), 1600 – 2000 UTC 7 August 2015 [click to enlarge]

LAP (Legacy Atmospheric Profiles) from GOES-13 (from here) also showed strong instability in between extensive cloud cover: the imagery at 1600 UTC on 7 August for CAPE and LI is shown below.

GOES-13 LAP estimates of Lifted Index (LI) and Convective Available Potential Energy (CAPE), 1600 UTC 7 August 2015  [click to enlarge]

GOES-13 LAP estimates of Lifted Index (LI) and Convective Available Potential Energy (CAPE), 1600 UTC 7 August 2015 [click to enlarge]

Given the instability present, rapid thunderstorm development should not surprise (the region was under a Severe Thunderstorm Watch, and a Mesoscale Convective Discussion had been issued specifically mentioning the possibility of severe hail). The visible animation from GOES-13, below, from 1900 UTC on 7 August through 0145 UTC on 8 August, showed rapid convective growth, and the damaging convective cell is quite apparent growing northward over northwestern Kansas at the end of the animation.

GOES-13 Visible imagery (0.63 µm) 1900 UTC 7 August - 0145 UTC 8 August [click to animate]

GOES-13 Visible imagery (0.63 µm) 1900 UTC 7 August – 0145 UTC 8 August [click to animate]

A slower animation of GOES-13 visible images from 0045-0130 UTC is shown below.

GOES-13 Visible imagery (0.63 µm) 0045 UTC 8 August - 0130 UTC 8 August [click to animate]

GOES-13 Visible imagery (0.63 µm) 0045 UTC 7 August – 0130 UTC 8 August [click to animate]

GOES-15 Visible imagery (0.63 µm) 1900 UTC 7 August - 0145 UTC 8 August [click to animate]

GOES-15 Visible imagery (0.63 µm) 1900 UTC 7 August – 0145 UTC 8 August [click to animate]

GOES-15 also viewed the rapid development of convection. The animation from 1900 UTC on 7 August 2015 through 0145 UTC on 8 August is shown above; the animation from 0000 UTC through 0145 UTC is shown below. Convective development over northwest Kansas was racing northward.

GOES-15 Visible imagery (0.62 µm) 1900 UTC 7 August - 0145 UTC 8 August [click to enlarge]

GOES-15 Visible imagery (0.62 µm) 0000 UTC 8 August – 0145 UTC 8 August [click to enlarge]

GOES-13 Infrared (10.7 µm) brightness temperatures confirmed the quick growth of the convection. The animation below showed strong cooling starting around 0115 UTC in extreme northwest Kansas. Coldest brightness temperatures at 0100 UTC (200.2 K or -73ºC) dropped to 196.2 K (-77ºC) at 0115 UTC, then to 194.0 K (-79ºC) at 0130 UTC, 192.8 (-80.4ºC) at 0145 and 192.2 K (about -81ºC!) at 0200 UTC. The rocking animation at bottom testifies to how quickly the developing convection was able to close the gap in convection through which the aircraft was attempting to fly.

GOES-13 Infrared imagery (10.7 µm) 0015 UTC 8 August - 0215 UTC 8 August [click to animate]

GOES-13 Infrared imagery (10.7 µm) 0015 UTC 8 August – 0215 UTC 8 August [click to animate]

Rocking animation of GOES-13 Infrared imagery (10.7 µm) 0015 UTC 8 August - 0215 UTC 8 August [click to enlarge]

Rocking animation of GOES-13 Infrared imagery (10.7 µm) 0015 UTC 8 August – 0215 UTC 8 August [click to enlarge]

The side-by-side comparisons shown below of GOES-15 (left) and GOES-13 (right) 10.7 µm Infrared and 0.63 µm Visible images also help to demonstrate the value of more frequent images for monitoring the rapid development of such features. GOES-15 was in Rapid Scan Operations (RSO) mode, providing up to 10 images every hour (at :00, :11, :15, :22, :30, :41, :45, :52, :55, and :57), while GOES-13 was in Routine Scan mode, providing up to 4 images every hour (at :00, :15, :30. and :45). Unfortunately, there were 30-minute gaps in both GOES-15 (between 0030 and 0100 UTC) and GOES-13 (between 0015 and 0045 UTC) during the time that the new line of thunderstorms began to rapidly build northward across far northwestern Kansas, between the 2 pre-existing areas of thunderstorm activity.

GOES-15 (left) and GOES-13 (right) 10.7 µm Infrared images [click to play animation]

GOES-15 (left) and GOES-13 (right) 10.7 µm Infrared images [click to play animation]

GOES-15 (left) and GOES-13 (right) 0.63 µm Visible images [click to play animation]

GOES-15 (left) and GOES-13 (right) 0.63 µm Visible images [click to play animation]

In addition to the animated GIFs, MP4 versions of the Infrared and Visible images are available here and here.

The flight positions of Delta 1889 are superimposed on a composite animation of GOES-13 Infrared (10.7 µm)and Goodland, Kansas radar reflectivity, below (courtesy of Rick Kohrs, SSEC).

Delta Flight 1889 position, GOES-13 Infrared images, and Goodland, Kansas radar reflectivity [click to play QuickTime movie]

Delta Flight 1889 position, GOES-13 Infrared images, and Goodland, Kansas radar reflectivity [click to play QuickTime movie]

Long-track Tornado over southwestern Manitoba

July 27th, 2015

Color-enhanced Infrared (10.7 µm) imagery from GOES-15 (left) and GOES-13 (right), times as indicated  [click to play animation]

Color-enhanced Infrared (10.7 µm) imagery from GOES-15 (left) and GOES-13 (right), times as indicated [click to play animation]

A strong tornado (rated a high-end EF-2) touched down near Pierson, Manitoba at around 0130 UTC on 28 July or 8:30 pm local time on 27 July (Press Report) and persisted until about 0355 UTC or 10:55 pm local time (near Virden Manitoba). The animation above shows GOES-15 (left) and GOES-13 (right) Infrared imagery from 0000 UTC through 0430 UTC. The strong storm lifting northward over southwestern Manitoba is apparent, with an enhanced-V signature especially noticeable in the GOES-13 imagery.

A closer view of the tornadic supercell is shown below, with overlays of surface reports (metric units). The pulsing nature of the overshooting tops is evident in the fluctuation of the coldest cloud-top IR brightness temperatures (the coldest of which was -69º C, darker black color enhancement, on the 0300 UTC GOES-15 and 0315 UTC GOES-13 images). There are different apparent positions of the storms based on the satellite that views them because of parallax shifts. Such shifts are especially pronounced at higher latitudes with very tall storms.

GOES-15 (left) and GOES-13 (right) 10.7 µm Infrared images, with surface reports [click to play animation]

GOES-15 (left) and GOES-13 (right) 10.7 µm Infrared images, with surface reports [click to play animation]

A 1-km resolution Terra MODIS 11.0 µm Infrared image at 0331 UTC is shown below; the minimum cloud-top IR brightness temperature was -73º C.

Terra MODIS 11.0 µm Infrared image [click to enlarge]

Terra MODIS 11.0 µm Infrared image [click to enlarge]

GOES-13 Visible (0.63 µm) imagery, times as indicated  [click to play animation]

GOES-13 Visible (0.63 µm) imagery, times as indicated [click to play animation]

Visible imagery from GOES-13 (above) and GOES-15 (below) showed the overshooting tops associated with the tornadic thunderstorm, as well as the rapidly expanding cirrus shield.

GOES-15 Visible (0.62 µm) imagery, times as indicated  [click to play animation]

GOES-15 Visible (0.62 µm) imagery, times as indicated [click to play animation]

A closer view of the tornadic supercell from GOES-15 vs GOES-13 is shown below, with overlays of surface reports (metric units). The overshooting tops are again apparent on the images, along with an above-anvil plume (which is easier seen on the GOES-13 images, due to a more favorable forward-scattering viewing geometry). The robust convective development was first seen on the 2030 UTC images, in the vicinity of the Saskatchewan/Manitoba/North Dakota border region.

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images, with surface reports [click to play animation]

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images, with surface reports [click to play animation]

As an area of low pressure was deepening over eastern Montana, warm and humid air was surging northward into far southern Saskatchewan and Manitoba (surface analyses). GOES sounder derived product images (available from this site) of Convective Available Potential Energy (CAPE), Lifted Index, and Total Precipitable Water (below) showed that the environment across southern Manitoba was becoming increasingly unstable and moist leading up to the time of convective initiation.

GOES sounder CAPE derived product images [click to play animation]

GOES sounder CAPE derived product images [click to play animation]

GOES sounder Lifted Index derived product images [click to play animation]

GOES sounder Lifted Index derived product images [click to play animation]

GOES sounder Total Precipitable Water derived product images [click to play animation]

GOES sounder Total Precipitable Water derived product images [click to play animation]

Wildfires continue in the interior of Alaska

July 25th, 2015

GOES-15 visible (top) and shortwave IR (bottom) images [click to play animation]

GOES-15 visible (top) and shortwave IR (bottom) images [click to play animation]

Wildfires continued to burn across parts of the interior of Alaska during the 22-25 July 2015 period, as is shown in GOES-15 (GOES-West) 0.63 µm visible channel and 3.9 µm shortwave IR images (above; click to play animation; also available as an MP4 movie file). Also of interest is: (1) the diurnal change of intensity and areal coverage of the fire hot spots (darker black to red pixels on the shortwave IR images), with the fires dying down at night, and (2) the change in direction of smoke transport, from westward on 22 July to eastward on 24 July. The switch in smoke transport direction was the result of changing winds associated with a broad area of low pressure moving across Alaska during that period (surface analyses).

A more detailed view of the fire hot spots was provided by 375-meter resolution (mapped onto a 1-km AWIPS grid) Suomi NPP VIIRS 3.74 µm shortwave IR images (below; click to play animation).

Suomi NPP VIIRS shortwave IR images [click to play animation]

Suomi NPP VIIRS shortwave IR images [click to play animation]

Many of the fires were burning in the general vicinity of the Utopia Creek, Indian Mountain airport (station identifier PAIM); a time series of surface observation from that site (below) showed that visibility was 1 mile or less due to smoke at times on 25 July.

Time series of surface observation from Utopia Creek, Indian Mountain airport [click to enlarge]

Time series of surface observation from Utopia Creek, Indian Mountain airport [click to enlarge]

Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images viewed using the SSEC RealEarth web map server are shown below.

Suomi NPP VIIRS true-color images [click to enlarge]

Suomi NPP VIIRS true-color images [click to enlarge]