Delta Fire pyroCumulonimbus cloud in California

September 5th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.3 µm) and Cloud Top Temperature product images displayed using AWIPS (above) showed the formation of a pyroCumulonimbus (pyroCb) cloud generated by the Delta Fire in Northern California late in the day on 05 September 2018. As the pyroCb cloud drifted eastward toward the California/Nevada border, Cloud Top Temperature values cooled to a minimum of -53ºC (lighter green enhancement) at 0300 UTC. Note the pulsing behavior of updrafts over the fire area: 2 distinct updraft pulses were apparent (at 0022 UTC and 0042 UTC), with the later pulse producing the pyroCb.



A longer animation of GOES-16 “Red” Visible, Shortwave Infrared and “Clean” Infrared Window images displayed using McIDAS (below) showed that the first hot (red) Shortwave Infrared pixels appeared at 2027 UTC. The fire caused a 5-mile section of Interstate 5 to be closed.

GOES-16 "Red" Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle), "Clean" Infrared Window (10.3 µm, bottom); Interstate 5 is plotted in cyan [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.3 µm, bottom) images; Interstate 5 is plotted in cyan [click to play animation | MP4]

GOES-17 (positioned at 89.5º W longitude during its post-launch checkout phase) had a more direct view of the pyroCb than GOES-16 (positioned over the Atlantic Ocean at 75.2º W longitude) — and GOES-17 “Red” Visible, Shortwave Infrared and “Clean” Infrared Window images are shown below. Unfortunately the default GOES-17 Western US Mesoscale Domain Sector was shifted farther to the south on this day, so 1-minute imagery of the pyroCb event was not available.

GOES-17 "Red" Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle), "Clean" Infrared Window (10.3 µm, bottom) images; Interstate 5 is plotted in cyan [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.3 µm, bottom) images; Interstate 5 is plotted in cyan [click to play animation | MP4]

* GOES-17 images shown here are preliminary and non-operational *

Stereoscopic View of Tropical Storm Gordon in the Gulf of Mexico

September 4th, 2018 |

GOES-16 (left) and GOES-17 (right) Visible (0.64 µm) imagery on 4 September 2018, starting at 1132 UTC (Click to play mp4 animation)


GOES-17 Data shown here are preliminary and non-operational!

Stereoscopic views (using GOES-16 and — preliminary and non-operational — GOES-17 Visible (0.64 µm) imagery) of strengthening Tropical Storm Gordon are shown above. The stereoscopic view shows an initially sheared storm, with the surface circulation apparent becoming somewhat less sheared as convection redevelops over the surface center. (To view in three dimensions: cross your eyes until 3 equal images are apparent, and focus on the image in the center). This animation will be updated periodically as more GOES-17 data become available. (Click here for animated gif)

For more information on this storm, consult the National Hurricane Center website, or the CIMSS Tropical Weather Website.

Tropical Storm Gordon

September 3rd, 2018 |

NOAA-20 Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0636 UTC [click to enlarge]

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

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0726 UTC [click to enlarge]

Potential Tropical Cyclone 7 was located between the Bahamas and Florida during the pre-sunrise hours on 03 September 2018. Toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 0636 UTC and Suomi NPP at 0726 UTC are shown above (courtesy of William Straka, CIMSS).

The storm became better organized and increased in intensity, and was named Tropical Storm Gordon at 1205 UTC. Animations of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) (below) showed Gordon as it moved across far southern Florida (where heavy rain and flash flooding occurred) and into the Gulf of Mexico during the daytime hours.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

===== 04 September Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed a series of widespread deep convective bursts within the northeast quadrant of the storm as it moved northeastward toward the Gulf Coast.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

The GOES-16 Rainfall Rate/QPE product (below) indicated rainfall rates of 2-3 inches per hour were possible from this convection, peaking in the 3-4 inch per hour range just after 1300 UTC. However, Infrared cloud-top brightness temperatures warmed dramatically as the convection moved onshore after about 22 UTC — and the Rain Rate product responded accordingly, with a significant decrease in hourly intensity.

GOES-16 Rain Rate product [click to play MP4 animation]

GOES-16 Rain Rate product [click to play MP4 animation]

Metop-A ASCAT surface scatterometer winds of 39 knots were sampled just northeast of the storm center at 1616  UTC (below).

GOES-16 Rain Rate product with Metop ASCAT winds [click to enlarge]

GOES-16 Rain Rate product with Metop-A ASCAT winds [click to enlarge]

Upper-tropospheric gravity waves in the wake of a decaying MCS

September 1st, 2018 |

GOES-16 Upper-level Water Vapor (6.2 µm) images [click to play MP4 animation]

GOES-16 Upper-level Water Vapor (6.2 µm) images [click to play MP4 animation]

A series of large Mesoscale Convective Systems (MCS) developed across Nebraska and Iowa during the nighttime hours before sunrise on 01 September 2018, which produced large hail and damaging winds (SPC storm reports). Storm-scale anticyclonic outflow aloft around the periphery of the decaying convection acted as a short-term barrier to the upstream southwesterly winds within the middle/upper troposphere, creating quasi-stationary gravity waves along their rear (westward) edges which persisted for several hours. These waves were most evident over eastern Nebraska and northeastern Kansas on GOES-16 Upper-level Water Vapor (6.2 µm) images (above).

6.2 µm Water Vapor images with plots of GOES-16 Derived Motion Winds (below) intermittently showed these high-altitude anticyclonic winds along the western edges of decaying convection — for example, at 0842 UTC, 0922 UTC, 0957 UTC, 1127 UTC, 1212 UTC and 1312 UTC.

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of Derived Motion Winds [click to play MP4 animation]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of Derived Motion Winds [click to play MP4 animation]

The quasi-stationary waves appeared to coincide with a few pilot reports of high-altitude turbulence: Clear Air Turbulence (CAT) was mentioned over northeastern Kansas at 37,000 feet and 39,000 feet, and “mountain wave action” was reported over southeastern Nebraska at 43,000 feet.

Pilot reports of turbulence [click to play animation]

Pilot reports of turbulence [click to play animation]

Higher resolution views of the convection were provided by VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from Suomi NPP at 0755 UTC and NOAA-20 at 0845 UTC (below). With ample illumination from the Moon (in the Waning Gibbous phase, at 67% of Full), the “visible image at night” capability of the Day/Night Band was well-demonstrated. The coldest cloud-top infrared brightness temperature associated with the MCS in western Iowa was -84ºC — and the effect of a similar “blocking wave” along the western/northwestern edge of that storm could be seen, which was effectively eroding the approaching high-altitude anvil cloud material from the Nebraska MCS. Note that the 0845 UTC NOAA-20 VIIRS images are incorrectly labeled as Suomi NPP.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]