Harvey and GLM Lightning

August 25th, 2017 |

GOES-16 ABI Band 1 (0.47 µm) and color-coded GLM parallax-corrected observations of lightning groups for each 1 minute in the 5 minutes prior to the nominal time of the ABI image (red: oldest; yellow: latest), 1247-1332 UTC on 25 August 2017 (Click to enlarge)

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

The Geostationary Lightning Mapper (GLM) on GOES-16 allows observations of lightning associated with Hurricane Harvey in the Gulf of Mexico. The animation above, from 1247 to 1332 UTC on 25 August 2017, shows lightning group observations every minute, color-coded by time (red is the oldest, yellow is the most recent, corresponding to the nominal time of the ABI Image), superimposed on GOES-16 ABI Channel 1 Visible Imagery (0.47 µm). Most of the Hurricane lightning is in the outer bands of the storm, with very little in the central core. This distribution is not unusual.

(A similar animation from 1812-1857 UTC on 24 August 2017, when lightning was observed near the storm core, is here.)

(Thanks to Dave Santek, SSEC, for this animation!)

Added: The animation below (for 1352-1437 UTC on 25 August) is over simulated True-Color Imagery, and for this GLM plot, the latest 1-minute Groups plots (that correspond to the ABI Image time) are red, and the earliest are Yellow.

Simulated True Color Imagery from GOES-16 ABI and 1-minute GLM Group data overlain; red groups corresponding to the nominal image time and yellow groups are oldest, 1352-1437 UTC on 25 August 2017 (Click to enlarge)

Hurricane Harvey approaches the Texas Gulf Coast

August 25th, 2017 |
GOES-16

GOES-16 Low-Level Water Vapor Infrared (7.3 µm) images, 0217-1347 UTC on 25 August 2017 (click to play animation)

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

Low-Level Water Vapor Infrared imagery (7.34 µm) from GOES-16, above, shows Hurricane Harvey developing a distinct eye shortly after sunrise on 25 August 2017 after intermittent appearances of the eye during the night. Harvey is a strong Hurricane at 950 mb (as of 700 AM CDT according to the National Hurricane Center) and is approaching the central Gulf Coast of Texas. Strong upper-level outflow to the north and then east and south is apparent in the Water Vapor animation above, and an absence of dry air near the storm portends no significant weakening before the storm reaches the Coastline. Microwave estimates of Total Precipitable Water, below, from this site, continue to show extreme moisture amounts enveloping the storm.

MIMIC Total Precipitable Water estimates for the 24 hours ending 1300 UTC on 25 August 2017 (Click to enlarge)

Visible imagery, below, from after sunrise on 25 August 2017, show a symmetric storm with a visible eye. The “Cirrus Channel” near-infrared GOES-16 Channel (1.38), bottom, shows the extensive cirrus canopy from the storm covering much of the western Gulf of Mexico and adjacent states.

GOES-16

GOES-16 Visible Images (0.64 µm) images, 1242-1417 UTC on 25 August 2017 (click to play animation)

GOES-16 near-Infrared Images (1.38 µm) image, 1432 UTC on 25 August 2017 (Click to enlarge)

For the latest information on Harvey, consult the pages of the National Hurricane Center, or the CIMSS Tropical Weather Website. In addition to the flooding threat posed from Harveywith multiple days of rain, storm surge at the coast promises considerable inundation.

GOES-16 animation showing Clean Window IR (10.3 µm) and City Lights Background at night, True Color Imagery during the day, 1100-1900 UTC on 25 August 2017 (Click to enlarge)

A toggle between Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1853 UTC , below, provided a detailed view of the hurricane as it continued to near the Texas coast.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

Hurricane Harvey

August 24th, 2017 |

GOES-16

GOES-16 “Clean Window” Infrared (10.3 µm) images, 0432-1307 UTC on 24 August 2017 [click to play animation]

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

Overnight Satellite imagery from GOES-16, above, shows an increase in the size and convective activity with then-Tropical Storm Harvey. Harvey is forecast to make landfall on the Texas Gulf Coast (See the National Hurricane Center website for further details), and conditions favor strengthening. One of the favorable conditions is shown in the animation of Total Precipitable Water, below, from this site. There is abundant moisture surrounding the storm, extending into eastern and southeastern Texas. Flooding rains will likely precede and accompany this storm.

In addition to abundant moisture, Harvey’s projected path takes it over very deep very warm water (Link showing Oceanic Heat Content).

Note: Harvey achieved Hurricane Status at 1 PM CDT on 24 August 2017. Harvey continued to rapidly intensify during the day (ADT | SATCON).

GOES-16

MIMIC Total Precipitable Water, 24-hour animation ending at 1200 UTC 24 August 2017 [click to enlarge]

Harvey is a large storm. The GOES-16 “Cirrus Channel” 1.38 µm imagery, below, shows Harvey’s cirrus canopy covering much of the southwestern Gulf of Mexico. Cirrus from the storm should be visible from the south Texas Gulf Coast this morning.

GOES-16 “Cirrus Channel” (1.38 µm) Imagery, 1307 UTC on 24 August 2017 (Click to enlarge)

Suomi NPP overflew the southern Gulf after midnight on 24 August 2017, and the VIIRS  Day/Night Band Imagery, below, shows a few lightning streaks in the storm that is barely illuminated by airglow. Cloud-top heights computed from VIIRS data (Link) shows a large central dense overcast with heights exceeding 50000 feet. ATMS 88-GHz Imagery at the same time is shown here. Morphed Microwave imagery (from this site) hints at the development of a ragged eye shortly after sunrise on 24 August. (Animation). (A DMSP SSMI 85 GHz still image from near the end of the MIMIC animation is here).

Suomi NPP Day Night Band Visible (0.70 µm) Imagery over Tropical Storm Harvey, 0747 UTC on 24 August 2017 (Click to enlarge)

ATMS 88-GHz Imagery at the same time is shown here. Morphed Microwave imagery (from this site) hints at the development of a ragged eye shortly after sunrise on 24 August. (Animation). An 85 GHz still image from the end of the animation is shown below.

85 GHz Microwave imagery over Tropical Storm Harvey, 1300 UTC on 24 August 2017 (Click to enlarge)

Later in the day, a toggle between 1912 UTC Visible (0.64 µm) and Infrared Window (11.45 µm) Suomi NPP VIIRS images, below, provided a detailed view of the hurricane.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

For more information on Hurricane Harvey, a storm that people along the Texas Gulf Coast should be monitoring closely, consult the website of the National Hurricane Center, or the CIMSS Tropical Weather Website.

Total solar eclipse of 21 August 2017 – a satellite perspective

August 21st, 2017 |

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

GOES-16 CONUS Sector images (at 5-minute intervals)

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play animation]

During the total solar eclipse of 21 August 2017,  the lunar umbra was evident on imagery from the GOES-16  0.5 km resolution (at satellite sub-point) “Red” Visible band (0.64 µm) (above) and 1.0 km resolution Near-Infrared “Vegetation” band (0.86 µm) (below).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images [click to play animation]

The shadow was also prominent in other Visible and Near-Infrared bands, as shown in a 4-panel comparison of GOES-16 “Blue” Visible (0.47 µm, upper left), “Red” Visible (0.64 µm, upper right), “Vegetation” (0.86 µm, lower left) and “Snow/Ice” (1.61 µm, lower right) images (below).

GOES-16

GOES-16 “Blue” Visible (0.47 µm, upper left), “Red” Visible (0.64 µm, upper right), “Vegetation” (0.86 µm, lower left) and “Snow/Ice” (1.61 µm, lower right) images [click to play animation]

GOES-16 true-color Red/Green/Blue (RGB) images from the SSEC Geostationary Satellite site (below) showed another view of the shadow. A GOES-16 Full-Disk true-color animation (courtesy of  Kaba Bah, CIMSS) is available here; a composite of eclipse shadow images can be seen here.

GOES-16 true-color RGB images [click to play animation]

GOES-16 true-color RGB images [click to play animation]

The 3.9 µm Shortwave Infrared band is also sensitive to reflected solar radiation — particularly that which is reflected from land surfaces and cloud tops composed of small spherical supercooled water droplets (and to a lesser extent, small ice crystals) — which causes this band to sense warmer (darker gray to black) brightness temperatures compared to the other ABI infrared bands. Therefore, a loss of sunlight within the eclipse shadow will lead to cooling (lighter shades of gray) 3.9 µm brightness temperatures (below).

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

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

Taking a closer look at eastern Missouri and southern Illinois as the solar eclipse shadow was passing over that region shortly after 1800 UTC (1:00 pm local time), GOES-16 “Red” Visible (0.64 µm) images (below) revealed that the pronounced decrease of incoming solar radiation appeared to temporarily suppressed the development of widespread boundary layer cumulus clouds. Note that increase in hourly surface temperatures was also halted, with some locations even experiencing a slight cooling (1-3 ºF) due to reduction of heating within the lunar umbra.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-16 Shortwave Infrared (3.9 µm) images (below) also showed a slight cooling — seen as a lighter shade of red enhancement — across the region.

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-16 Mesoscale Sector images (at 1-minute intervals)

GOES-16 "Red" Visible (0.64 µm) images, with station identifiers plotted in yellow [click to play animation]

1-minute GOES-16 “Red” Visible (0.64 µm) images, with station identifiers plotted in yellow [click to play animation]

A “floating” Mesoscale Sector provided 1-minute imagery during the eclipse (above).

Polar-orbiting satellite images (Terra MODIS, and Suomi NPP VIIRS)

Terra MODIS Visible (0.65 µm). Land Surface Temperature product, Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra MODIS Visible (0.65 µm), Land Surface Temperature product, Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]

A toggle between Terra MODIS Visible (0.65 µm), Land Surface Temperature product, Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images (above) showed the eclipse shadow as it was centered over western Nebraska around 1748 UTC. Without a time series of MODIS Land Surface Temperature product images, it is difficult to gauge the exact amount of surface cooling brought about within the shadow of totality. A large-scale high resolution Terra MODIS Visible image is available here (courtesy of Liam Gumley, SSEC).

Suomi NPP VIIRS Visible (0.64 µm), Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

A comparison of Suomi NPP VIIRS Visible (0.64 µm), Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) showed the shadow center over eastern Tennessee around 1833 UTC. A closer comparison of Day/Night Band and Infrared images (below) revealed the  presence of cloud features that made it difficult to see a signature of any city lights that may have come on in the Nashville TN (KBNA) metropolitan area.

Suomi NPP VIIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]