Record warmth in Alaska and Canada

March 19th, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm) images, with hourly surface temperatures plotted in cyan [click to play animation | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed that it was generally cloud-free across much of eastern Alaska and northwestern Canada on 19 March 2019 — the abundant solar insolation help to warm surface temperatures to record levels for the month of March at locations such as Sitka (high=67ºF) and Yakutat (high=60ºF) along the Alaska Panhandle, and at Yohin Lake (high=71ºF) in the Canadian Northwest Territories. The 70ºF at Klawock was the earliest occurrence of 70ºF on record for the state of Alaska, and the 71ºF at Yohin Lake was the earliest 70ºF on record for the Northwest Territores. In the eastern Interior of Alaska, daily temperature records for 19 March were set at Eagle (high=55ºF) and Northway (high=50ºF).

GOES-17 Air Mass RGB images from the AOS site (below) helped to highlight the anomalous mid-tropospheric ridge and warm lower-tropospheric temperatures over western North America — note the northwestward surge of green hues that are more characteristic of warm subtropical air masses south of the polar jet stream over the central Pacific Ocean. Note that GOES-17 was conducting a test of the Mode 6 scan schedule, so Full Disk images were available every 10 minutes.

GOES-17 Air Mass RGB images [click to play animation | MP4]

GOES-17 Air Mass RGB images [click to play animation | MP4]



Chemical plant fire near Houston, Texas

March 18th, 2019 |

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images (above) revealed the thermal anomaly or “hot spot” of a fire burning at the Intercontinental Terminals Company petrochemical plant in Deer Park, Texas on 18 March 2019. Although the thermal signature was often partially masked by the passage of high clouds overhead, it was still evident for much of the time period (0202-1457 UTC, or 9:02pm-9:57am CDT). The fire started around 1530 UTC (10:30am CDT) on 17 March.

Comparisons of 2-km resolution (at satellite subpoint) GOES-16 Shortwave Infrared and 375-meter resolution VIIRS Shortwave Infrared (3.74 µm) imagery from Suomi NPP (at 0741 UTC) and NOAA-20 (at 0835 UTC) are shown below. The thermal signature is better defined and more accurately located using the higher-resolution VIIRS imagery.

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0741 UTC [click to enlarge]

Shortwave Infrared images from Suomi NPP VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0741 UTC [click to enlarge]

Shortwave Infrared images from NOAA-20 VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0835 UTC [click to enlarge]

Shortwave Infrared images from NOAA-20 VIIRS (3.74 µm) and GOES-16 (3.9 µm) at 0835 UTC [click to enlarge]

A comparison of 1-km resolution NOAA-19 AVHRR and 2-km resolution GOES-16 Shortwave Infrared images at 1132 UTC is shown below. This happened to be at a time when the GOES-16 thermal signature was being masked by high clouds overhead. The fire was located northeast of the Houston Hobby (station identifier KHOU) and Ellington (station identifier KEFD) airports.

Shortwave Infrared images from NOAA-19 (3.7 µm) and GOES-16 (3.9 µm) at 1132 UTC [click to enlarge]

Shortwave Infrared images from NOAA-19 (3.7 µm) and GOES-16 (3.9 µm) at 1132 UTC [click to enlarge]

In a sequence of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below), the dark-colored smoke plume was most obvious in the Near-Infrared imagery — this is due to the fact that vegetation is more reflective at those wavelengths, helping to enhance the smoke/surface contrast. The smoke had drifted as far westward as Austin and Kerrville, a distance of over 100 miles.

GOES-16 "Red" Visible (0.64 µm), Near-Infrared "Vegetation" (0.86 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

===== 19 March Update =====

GOES-16 "Red" Visible (0.64 µm), Near-Infrared "Vegetation" (0.86 µm), and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

The Deer Park Fire continued to burn uncontrolled on 19 March — 1-minute Mesoscale Domain Sector GOES-16 Visible, Near-Infrared and Shortwave Infrared images (above) showed that while the passage of mid/upper-level clouds often obscured the dark-colored smoke plume, a signature of the hot thermal anomaly was seen almost continuously. Note that the color enhancement applied to the Shortwave Infrared imagery is different from the one used in the 18 March examples.

===== 22 March Update =====

GOES-16 "Red" Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

There was a brief re-ignition of the fire that began at 2035 UTC on 22 March, as shown by 1-minute GOES-16 Visible, Near-Infrared and Shortwave Infrared images (above). The thermal anomaly of the fire was only apparent for about 50 minutes — reaching a peak infrared brightness temperature of 48.4ºC at 2044 UTC — while the dark smoke continued to spread to cover a north-south distance of over 10 miles in 90 minutes, moving over Interstate 10 and the cities of Channelview and Highlands.

Signatures of fresh snowfall in the Dakotas

March 17th, 2019 |

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) depicted the signature of northwest-to-southeast oriented swaths of fresh snowfall (lighter gray shades) which had recently fallen on top of the aged snow pack across North Dakota on 17 March 2019. As discussed here, the surface of the preexisting snow cover had experienced rapid melting several days earlier, which increased its “water to ice crystal” ratio — making it appear darker, since water is a stronger absorber of radiation at the 1.61 µm wavelength.

A similar (albeit broader and more continuous) northwest-southeast swath of fresh snowfall was seen across South Dakota (below).

GOES-16 Near-Infrared "Snow/Ice" (1.61 µm) images [click to play animation | MP4]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

The radar-derived 24 hour precipitation ending at 12 UTC on 17 March is shown below.

24-hour precipitation ending at 12 UTC on 17 March [click to enlarge]

24-hour precipitation ending at 12 UTC on 17 March [click to enlarge]

Gas explosion and fire in Los Angeles, California

March 17th, 2019 |

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) revealed the southwestward motion of a dark smoke cloud resulting from a gas explosion and fire in South Los Angeles, California on the morning of 17 March 2019.

A sequence of 5-minute “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from both GOES-17 and GOES-16 (GOES-East) is shown below. It’s interesting to note that a distinct thermal anomaly (or fire “hot spot”) of 21.8ºC (darker orange enhancement) was apparent at 1502 UTC  and 1512 UTC in the GOES-16 Shortwave Infrared imagery — but not in the corresponding 3.9 µm images from GOES-17 (GOES-16 vs GOES-17: 1502 UTC | 1512 UTC).

In addition, the underlying mostly-urban landscape appeared a bit brighter in the GOES-16 Visible images, further enhancing the contrast between the dark smoke cloud and the surface (GOES-16 vs GOES-17 at 1517 UTC).

"Red" Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from GOES-17 and GOES-16 [click to play animation | MP4]

“Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images from GOES-17 and GOES-16 [click to play animation | MP4]