Fires and blowing dust across the Upper Midwest and southern Manitoba

April 29th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with surface station identifiers plotted in cyan [click to play MP4 animation]

The combination of strong winds and low relative humidity prompted the SPC to forecast elevated to critical fire weather potential across parts of the Upper Midwest on 29 April 2018. A Mesoscale Domain Sector was positioned over the region, providing data at 1-minute intervals — and “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) revealed the smoke plumes and thermal anomalies or “hot spots” (black to yellow to red pixels) associated with some of these larger fires. The most prominent fires were located in southeastern Manitoba later in the day (including the largest fire EA015, which was listed as Out of Control).

On the Visible images, also note the hazy signature of blowing dust that developed from the northern Red River Valley of North Dakota and Minnesota into southern Manitoba — with winds gusting in excess of 50 knots, the surface visibility dropped to 3 miles at Grafton ND (KGAF) and Winnipeg International Airport (located just northwest of station CXWN in southern Manitoba).

Time series of surface observation data at Grafton, North Dakota [click to enlarge]

Time series of surface observation data at Grafton, North Dakota [click to enlarge]

Time series plot of surface weather data at Winnipeg, Manitoba [click to enlarge]

Time series plot of surface observation data at Winnipeg, Manitoba [click to enlarge]


Refinery Explosion and Fire in Superior WI

April 26th, 2018 |

GOES-16 ABI “Red Visible” (0.64 µm) from 1532-2027 UTC on 26 April 2018 (Click to enlarge)

Explosions at an oil refinery in Superior WI on 26 April 2018 (news link) produced a black plume of smoke visible in the GOES-16 “Red Visible” Band, the highest resolution (0.5 km at nadir) band on GOES-16. The plume is first visible at about 1717 UTC, and it then streams southeastward over northwest Wisconsin. Areas immediately downwind of the refinery were evacuated due to air quality concerns.

The explosion and subsequent fire was not sufficiently hot to be detected by the shortwave infrared 3.9 µm channel on GOES-16. However, the smoke plume is obvious in this animation, cooler than the background by 3-4ºC, and yellow in the enhancement chosen.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Vegetation” (0.86 µm, right) images [click to animate]

The dark smoke plume was also evident on Near-Infrared “Vegetation” (0.86 µm) images (above), aided by the additional contrast between the dark plume and the lighter gray appearance of the land surface.

GOES-16 Natural Color images [click to animate]

GOES-16 Natural Color RGB images [click to animate]

The GOES-16 Natural Color Red-Green-Blue (RGB) product (above) was also useful for identifying and tracking the smoke plume.

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

250-meter resolution Aqua MODIS True Color and False Color images from the MODIS Today site (above) provided a detailed view of the smoke plume at 1842 UTC. In the False Color image, snow cover and lake ice appear as shades of cyan.

ACSPO SSTs in AWIPS at WFO Guam

April 24th, 2018 |

ACSPO SSTs constructed from AVHRR, MODIS and VIIRS data from various overpasses at Guam on 18 April 2018 (Click to enlarge)

Sea Surface Temperatures (SSTs) produced from the Advanced Clear-Sky Processor for Oceans (ACSPO) are now being created in real time at the National Weather Service Forecast Office on Guam (where the National Weather Service day begins). The algorithm is applied to data broadcast from polar orbiter satellites and received at the Direct Broadcast antenna sited at the forecast office.  Because there are so many polar orbiters broadcasting data — NOAA-18, NOAA-19, Metop-A, Metop-B, Suomi-NPP, Terra, Aqua — cloudy pixels on one pass are typically filled in with data from a subsequent pass.  When ACSPO software for NOAA-20 is available, data from that satellite will be incorporated as well.  The result is a very highly calibrated, accurate depiction of high spatial resolution tropical Pacific SSTs.  A composite created every 12 hours from the imagery is also available at the forecast office.

 

Contrails off the coast of Southern California

April 23rd, 2018 |

As pointed out by NWS San Diego, an interesting pattern of contrails formed off the coast late in the day on 23 April 2018. A comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm), Near-Infrared “Cirrus” (1.37 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed signatures during the daylight hours — Visible images revealed contrail shadows being cast upon the low-altitude cloud tops at 0142 and 0147 UTC — with an Infrared signature persisting after sunset. These contrails were likely caused by military aircraft performing training exercises, since chaff was seen with radar in that same area on the previous day.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left), Near-Infrared “Cirrus” (1.37 µm, center) and “Clean” Infrared Window (10.3 µm, right) images [click to play animation | MP4]

A better post-sunset signature was seen on a NOAA-15 Infrared Window (10.8 µm) image at 0212 UTC (below). A comparison with the corresponding GOES-16 “Clean” Infrared Window (10.3 µm)  image displayed a significant northwestward GOES-16 displacement due to parallax — and the 1.1 km spatial resolution of AVHRR data resulted in a clearer contrail signature.

NOAA-15 AVHRR Infrared Window (10.8 µm) and GOES-16 ABI

NOAA-15 AVHRR Infrared Window (10.8 µm) and GOES-16 ABI “Clean” Infrared Window (10.3 µm) images [click to enlarge]

The pattern of contrails could also be followed after sunset using GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) imagery (below).

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

The GOES-16 Water Vapor weighting function plots (below) displayed a bi-modal distribution for all 3 spectral bands, with peaks near 300 hPa and 500 hPa. The absence of a distinct contrail signature on the 6.2 µm imagery suggests that these features were located closer to the 500 hPa pressure level.

GOES-16 Water Vapor weighting functions, calculated using rawinsonde data from San Diego CA [click to enlarge]

GOES-16 Water Vapor weighting functions, calculated using rawinsonde data from San Diego CA [click to enlarge]