* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As southern California experienced a record-setting heatwave, 2 large wildfires were burning in San Luis Obispo and Santa Barbara counties on 08 July 2017: the Alamo Fire and the Whittier Fire. GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plumes and hot spots (red pixels) associated with these 2 fires.

The dense smoke plumes also exhibited a signature on the Near-Infrared “Cirrus” (1.37 µm) images (below), even though they were not composed of ice crystals (note that 10.3 µm Infrared Window brightness temperatures of the smoke plumes were warmer than -20º C, cyan color enhancement, the entire day). This example demonstrates that in a dry atmosphere, the “Cirrus” imagery will also be able to detect the presence of any airborne particles that are efficient scatterers of light (which includes smoke, dust and volcanic ash).

During  the nighttime prior to sunrise, with the benefit of ample illumination from a Full Moon, a long smoke plume streaming southwestward from the Alamo Fire was clearly seen on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0910 UTC or 2:10 am local time (below). A very bright glow — larger than that of some nearby city lights — was co-located with the large hot spot on the corresponding Shortwave Infrared (3.74 µm) image.

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GOES-16 data (and products) posted on this page are preliminary, non-operational data and are undergoing testing

The San Francisco Bay Area National Weather Service office Tweeted out an image (as noted by the Media) during the early morning of 7 July of the GOES-16 Fire Temperature, a GOES-16 Baseline Product (link) above a massive fire in Oakland (News Report). The animation above shows the evolution of the fire as detected by the 3.9 µm Brightness Temperature shown in AWIPS. The first indication of a fire appeared around 1200 UTC; the fire was difficult to discern after 1330 UTC.

GOES-16 Baseline Products include Fire-Detection products: Fire Temperature, Fire Power, and Fire Area. These products returned values from 1222 to 1247 UTC, when the fire was at its most intense. The table below shows the values as noted in AWIPS.  The fire peaked in terms of Power and Area at 1237 UTC.  The animation below is for Fire Temperature, and only one area is indicated (Fire Power and Fire Area caused the same region to show a non-zero values, the same values noted in the table below). GOES-16 Engineers and Scientists are investigating why the pixel size below does not match the correct pixel sizes above in the 3.9 µm imagery.

Time	Fire Temperature (K)	Fire Power	Fire Area (Square Meters)
1222 UTC	892 K	86	4000
1227 UTC	873 K	92	4000
1232 UTC	849 K	153	4671
1237 UTC	833 K	167	5402
1242 UTC	889 K	137	4000
1247 UTC	1041 K	94	4000

 

The fire was hot enough that it emitted detectable near-infrared 1.61 µm radiation, as shown below (animation). The brightest pixel, pointed to by the red arrow, over downtown Oakland in Alameda County (outlined in magenta) shows an albedo of 4.2% before sunrise!

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GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing

Tropical Depression #4 formed in the tropical Atlantic on 5 July 2017 (Click here for National Hurricane Center advisories on the system). The Depression is not forecast to strengthen, and two GOES-16 products give evidence to its weakened state. The animation of GOES-16 Band 4 (1.38 µm “Cirrus Channel”), above, shows a general decrease in the high clouds associated with this system (located north of 10º North Latitude and between 40º and 50º West Longitude), meaning convection is not strong. A closer view reveals intricate cirrus transverse banding around the periphery of the system during the early part of the day. In addition, the 10.3 µm “Clean Window” image, below, overlain on top of the GOES-16 Baseline Total Precipitable Water (TPW) Product, shows dry air west of the circulation. A Saharan Air Layer (SAL) analysis from here that uses Meteosat data, shows dry air moving towards the system from the east as well (Link). A toggle between GOES-13 Infrared Window, Meteosat-10 SAL product, and MIMIC TPW imagery can be seen here.

Refer to the National Hurricane Center website, or the CIMSS Tropical Weather website, for more information on this sytem.

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* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As seen on the map of SPC storm reports from 21 June 2017 (above), nighttime thunderstorms (during the pre-dawn hours of 22 June) produced a swath of hail (as large as 2.0 inches in diameter) that damaged emerging crops at some locations across eastern South Dakota and southwestern Minnesota (NWS Aberdeen summary).

Nearly 2 weeks later, on 04 July, the hail damage swath was still apparent on GOES-16 imagery. In a comparison of “Blue” Visible (0.47 µm), “Red” Visible (0.64 µm) and Near-Infrared “Vegetation” (0.86 µm ) images (below), the northwest-to-southeast oriented hail damage swath was best seen on the 0.64 µm imagery (in part due to its higher spatial resolution, which is 0.5 km at satellite sub-point); healthy vegetation is more reflective at 0.86 µm, so the crop-damaged hail swath appears slightly darker in those images.

A signature of the hail damage swath was also seen in Near-Infrared “Snow/Ice” (1.61 µm) and Shortwave Infrared (3.9 µm) images (below). The hail damage swath warmed more quickly on the 3.9 µm imagery — exhibiting a darker black appearance with time — compared to the adjacent fields of healthy crops.

Why was the hail damage swath also seen on the 1.61 µm “Snow/Ice” (Band 5) imagery? A look at the Spectral Response Functions for GOES-16 ABI  bands 3, 4, 5 and 6 — plotted with the reflectance of asphalt, dirt, grass and snow (below) — show that the 1.61 µm Band 5 happens to cover a portion of the radiation spectrum where there is a minor peak in grass relectance (denoted by the green plot).

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Regarding the warmer temperatures seen on GOES-16 Shortwave Infrared images, the 1-km resolution Aqua MODIS Land Surface Temperature product at 1738 UTC (above) revealed a 10º F difference between the warmer hail damage swath (which appeared to be about 100 miles in length) and adjacent fields of undamaged crops. A similar result was noted on 03 July by NWS Aberdeen (below).

Monitoring for fires using GOES-16 and noted area ~10F warmer than surroundings – dry/dead crops from the 6/22 Castlewood hailstorm #SDWX pic.twitter.com/d2AeYos84W

— NWS Aberdeen (@NWSAberdeen) July 4, 2017

A comparison of before (21 June) and after (02 July) Aqua MODIS true-color Red/Green/Blue (RGB) images from the SSEC MODIS Direct Broadcast site (below) clearly shows the hail damage path.

On 05 July a closer view of the hail scar was seen using a Suomi NPP VIIRS true-color RGB image from RealEarth (below).

Incidentally, on 02 July the Sentinel-2A satellite provided 10-meter resolution true-color imagery of the hail swath:

Meant to share this a while ago. Sentinel 2A passed over the area 7/2/17. Zoomed to Castlewood. Hires: https://t.co/9edCkrqXob #sdwx #mnwx pic.twitter.com/vqkSs4og6f

— Carl Jones (@northflwx) July 13, 2017

===== 07 July Update =====

The hail damage swath was also evident on a 30-meter resolution Landsat-8 false-color RGB image from 07 July:

Other examples of satellite-observed hail damage swaths can be seen here and here.

 

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