Severe thunderstorms in Argentina

December 10th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

A comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the development of thunderstorms well ahead of a cold front (surface analyses) that was moving northward across central Argentina on 10 December 2018. A Mesoscale Domain Sector had been positioned over that region in support of the RELAMPAGO-CACTI field experiment IOP15, providing imagery at 1-minute intervals. The northernmost storm (of a cluster of 3) featured a very pronounced overshooting top that was seen for several hours, briefly exhibiting infrared brightness temperatures as cold as -80ºC (violet enhancement) at 2133 UTC and 2134 UTC. Also noteworthy was the long-lived “warm trench” (arc of yellow enhancement) immediately downwind of the persistent cold overshooting top.

Plots of GOES-16 GLM Groups on the Visible and Infrared images (below) showed a good deal of lightning activity with this convection — especially in the leading anvil region east of the storm core. However, it is interesting to point out that there was a general lack of satellite-detected lightning directly over the large and persistent overshooting top. The GLM Groups were plotted with the default parallax correction removed, so the optical emissions of the lightning aligned with cloud-top features as seen on the ABI imagery.

GOES-16 "Red" Visible (0.64 µm, top) with GLM Groups and "Clean" Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top) with GLM Groups and “Clean” Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

A similar comparison of GOES-16 Visible and Near-Infrared “Snow/Ice” (1.61 µm) images (below) helped to highlight the formation of multiple Above-Anvil Cirrus Plume (AACP) features, which are signatures of thunderstorms that are producing (or could soon be producing) severe weather such as tornadoes, large hail or damaging winds. The appearance of gravity waves upshear (west) of the overshooting top was also very apparent.

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

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

Plot of severe weather reports [click to enlarge]

Plot of severe weather reports [click to enlarge]

There were several reports of hail with these particular thunderstorms (above), concentrated in the area between 35-36º S latitude and 62-65º W longitude. GOES-16 Visible images (below) showed this was the area under the path of the more northern storm with the prolonged overshooting top and the prominent AACP. This convection produced very large hail in Ingeniero Luiggi and General Villegas (located at 35.5º S, 64.5º W and 35º S, 63º W respectively) — see the tweets below for photos. On a side note, the large overshooting top began to take on an unusual darker gray appearance after 2230 UTC, possibly suggesting that boundary layer dust or particulate matter was being lofted to the cloud top by the very intense and long-lived updraft — the 18 UTC surface analysis showed that sites northwest of and south of the developing storms were reporting blowing dust.

GOES-16

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

Additional GOES-16 animations of these storms can be found on the Satellite Liaison Blog.

A zoom-in of NOAA-20 VIIRS True Color Red-Green-Blue (RGB) imagery at 1835 UTC viewed using RealEarth  (below) showed the 3 discrete thunderstorms in the vicinity of Santa Rosa.

NOAA-20 VIIRS True Color RGB image at 1835 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 1835 UTC [click to enlarge]

A toggle between NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1835 UTC (below) revealed the cold overshooting tops associated with each of the 3 thunderstorms. Also note the swath of wet soil in the wake of the southern storm, which appears darker in the True Color image and cooler (lighter shades of gray) in the Infrared image.

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1835 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1835 UTC [click to enlarge]

A toggle between NOAA-20 VIIRS Infrared Window (11.45 µm) images at 1835 UTC on 10 December and 0555 UTC on 11 December (below) showed the upscale growth into a large Mesoscale Convective System (MCS) that moved northeastward (eventually producing flooding in Rosario).

NOAA-20 VIIRS Infrared Window (11.45 µm) images at 1835 UTC on 10 December and 0555UTC on 11 December [click to enlarge]

NOAA-20 VIIRS Infrared Window (11.45 µm) images at 1835 UTC on 10 December and 0555 UTC on 11 December [click to enlarge]


===== 11 December Update =====

GOES-16

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

On the following day, GOES-16 Visible images (above) showed that additional severe thunderstorms developed across northern Argentina, in the general vicinity of a stationary front (surface analyses) east of Cordoba (SACO). Plots of GLM Groups (below) indicated that these storms produced a great deal of lightning.

GOES-16 "Red" Visible (0.64 µm) images, with GLM Groups plotted in red [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) images, with GLM Groups plotted in red [click to play MP4 animation]

The corresponding GOES-16 Infrared images, with and without plots of GLM Groups, are shown below. The coldest cloud-top infrared brightness temperatures were frequently colder than -80ºC, even reaching -90ºC (yellow pixels embedded within darker purple areas) from 1946, 1947 and 1948 UTC.

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

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

GOES-16 "Clean" Infrared Window (10.3 µm) images, with GLM Groups plotted cyan [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images, with GLM Groups plotted cyan [click to play MP4 animation]

A NOAA-20 VIIRS True Color RGB image (below) showed the cluster of thunderstorms east of Cordoba at 1817 UTC.

NOAA-20 VIIRS True Color RGB image at 1817 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB image at 1817 UTC [click to enlarge]

A toggle between NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1817 UTC (below) showed the easternmost storm which produced a tornado at Santa Elena.

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1817 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 1817 UTC [click to enlarge]



Industrial and ship plumes in supercooled clouds

December 4th, 2018 |

MODIS and VIIRS

MODIS and VIIRS “Fog/stratus” BTD images [click to enlarge]

A sequence of nighttime MODIS and VIIRS “Fog/stratus” infrared Brightness Temperature Difference (BTD) images (above) revealed long plumes (darker shades of red) streaming southwestward for over 200 miles from their industrial point sources in the Mesabi Range of northeastern Minnesota on 03 December 2018.

During the subsequent daytime hours, a comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) images (below) showed signatures of these Mesabi Range plumes along with others emanating from industrial or power plant sources. A few ship tracks were also apparent across Lake Superior.

Particles emitted from the exhaust stacks at power plants and industrial sites (as well as ships) can act as efficient cloud condensation nuclei, which causes the formation of large numbers of supercooled water droplets having a smaller diameter than those found within the adjacent unperturbed supercooled clouds — and these smaller supercooled cloud droplets are better reflectors of incoming solar radiation, thereby appearing brighter in the Near-Infrared and warmer (darker gray) in the Shortwave Infrared images.

GOES-16

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

On the following night, another sequence of MODIS and VIIRS “Fog/stratus” infrared Brightness Temperature Difference (BTD) images (below) highlighted a number of industrial and power plant plumes across Minnesota, northern Wisconsin and the Upper Peninsula of Michigan. The curved shape of many of these plumes resulted from boundary layer winds shifting from northerly to westerly as the night progressed.

MODIS and VIIRS "Fog/stratus" BTD images [click to enlarge]

MODIS and VIIRS “Fog/stratus” BTD images [click to enlarge]

During the following daytime hours on 04 December, a comparison of VIIRS Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images (below) showed 2 plume types across eastern Nebraska. There were several of the brighter/warmer plumes similar to those noted on the previous day across Minnesota/Wisconsin/Michigan — but one large plume originating from industrial sites just east of Norfolk (KOFK) had the effect of eroding the supercooled cloud deck via glaciation (initiated by the emission of particles that acted as efficient ice nuclei) and subsequent snowfall. This is similar to the process that creates aircraft “distrails” or “fall streak clouds” as documented here, here and here.

VIIRS Visible (0.64 µm), Near-Infrared

VIIRS Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images [click to enlarge]


Farther to the east over Ohio and Pennsylvania, another example of the 2 plume types was seen (below) — one plume originating from an industrial site near Cleveland was glaciating/eroding the supercooled cloud and producing snowfall, while another bright/warm supercooled droplet plume was moving southeastward from a point source located west of Indiana County Airport KIDI.

The Cleveland plume was captured by an overpass of the Landsat-8 satellite, with a False Color Red-Green-Blue (RGB) image viewed using RealEarth providing great detail with 30-meter resolution (below). A small “overshooting top” can even be seen above the industrial site southeast of Cleveland, with the swath of glaciated and eroding cloud extending downwind (to the southeast) from that point.

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

Coincidentally, Landsat-8 also captured another example of a glaciating cloud plume downwind of the Flint Hills Oil Refinery south of St. Paul, Minnesota on 03 December (below). The erosion/glaciation of supercooled cloud extended as far south as Albert Lea, Minnesota. Similar to the Cleveland example, a small “overshooting top” was seen directly over the plume point source.

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

===== 08 December Update =====

The effect of this industrial plume glaciating and eroding the supercooled water droplet clouds over northern Indiana was also seen in a comparison of Terra MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Infrared Window (11.0 µm) images (below).

Terra MODIS Visible (0.65 µm), Near-Infrared

Terra MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Infrared Window (11.0 µm) images [click to enlarge]

===== 09 December Update =====



During the following daytime hours, GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed a number of plumes from industrial sites (many of which were likely refineries) streaming southeastward and eastward over the Gulf of Mexico on 09 December. Note the lack of a plume signature in the 10.3 µm imagery.
GOES-16 "Red" Visible (0.64 µm), Near-Infrared "Snow/Ice" (1.61 µm), Near-Infrared "Cloud Particle Size" (2.24 µm), Shortwave Infrared (3.9 µm) and "Clean" Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Thunderstorms over Argentina

November 29th, 2018 |

Suomi NPP VIIRS True Color RGB image at 1753 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB image at 1753 UTC [click to enlarge]

A Suomi NPP VIIRS True Color Red-Green-Blue (RGB) image viewed using RealEarth (above) showed numerous thunderstorms developing across the foothills of the Andes in western Argentina on 29 September 2018, in advance of a cold front that was moving northward.

Closer views of VIIRS True Color and Infrared Window (11.45 µm) images from Suomi NPP at 1753 UTC and NOAA-20 at 1843 UTC (below) depicted several cold overshooting tops (darker red enhancement) associated with the more vigorous thunderstorm updrafts.

Suomi NPP VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1753 UTC [click to enlarge]

Suomi NPP VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1753 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1843 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Windoe (11.45 µm) images at 1843 UTC [click to enlarge]

In support of the RELAMPAGO-CACTI field experiment, a GOES-16 (GOES-East) Mesoscale Domain Sector had been positioned over the region, providing 1-minute imagery — animations of “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and “Clean” Infrared Window (10.3 µm) imagery (below) showed the upscale development of the convection from 1300-2330 UTC. The largest storms were in the vicinity of and to the south of Mendoza (SAME) and Rio Cuarto (SAOC).

GOES-16

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

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

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

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

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

Toward the end of the day, a closer look at one storm along the southeastern end of the large convective complex (below) showed that it exhibited awell-defined enhanced-V signature around 20 UTC and shortly thereafter produced a long-lived Above-Anvil Cirrus Plume (AACP). Both are signatures of storms that often produce large hail, damaging winds or tornadoes.

GOES-16 "Red" Visible (0.64 µm, top), Near-Infrared :Snow/Ice" (1.61 µm, center) and "Clean" Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top), Near-Infrared :Snow/Ice” (1.61 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play MP4 animation]

The AACP exhibited a colder (around -55ºC, shades of orange) infrared brightness temperature than the anvil beneath it (-40 to -50ºC, green to yellow enhancement), due to the atmospheric temperature profile aloft as seen on 12 UTC rawinsonde data from nearby Santa Rosa (below). The sounding profile suggests that the AACP was at or perhaps above the tropopause.

Plot of 12 UTC Santa Rosa rawinsonde data [click to enlarge]

Plot of 12 UTC Santa Rosa rawinsonde data [click to enlarge]

GOES-17 / GOES-16 True Color Composite

November 26th, 2018 |
GOES-17 / GOES-16 True Color RGB composite [click to enlarge]

GOES-17 / GOES-16 True Color RGB composite [click to enlarge]

* GOES-17 imagery posted here is preliminary and non-operational *

A composite of GOES-17 and GOES-16 True Color Red-Green-Blue (RGB) imagery (above) was created by blending a total of 59 north-south swaths — each swath within +/- 23 minutes of “local Noon” (for example, the blue swaths using GOES-16) — during the period beginning at 1115 UTC on 26 November (over the eastern Atlantic Ocean and far western Africa, using GOES-16) and ending at 0200 UTC on 27 November 2018 (over the western Pacific Ocean, using GOES-17). Since the GOES-16/17 ABI does not have a true “Green” (0.51 µm) spectral band, that component of the RGB image is simulated using other Near-Infrared bands.

For perspective, the GOES-17/GOES-16 True Color composite is overlaid on a global “Blue Marble” background (below), which helps to emphasize the total areal coverage provided by the GOES-R constellation.

GOES-17 / GOES-16 True Color RGB composite [click to enlarge]

GOES-17 / GOES-16 True Color RGB composite [click to enlarge]

Notable Northern Hemisphere features seen in the imagery include (1) a pair of strong mid-latitude cyclones in the North Atlantic, (2) a large storm in the Gulf of Alaska with a trailing cold front moving inland along the west coast of North America, (3) two storms in the West Pacific, and (4) convective cloud bands along the Intertropical Convergence Zone (ITCZ) in the tropical Atlantic and Pacific basins (below).

Surface analyses from 12 UTC on 26 November to 00 UTC on 27 November [click to enlarge]

Surface analyses from 12 UTC on 26 November to 00 UTC on 27 November [click to enlarge]

Kudos to Rick Kohrs (SSEC) for masterfully perfecting the blending technique to create these composite GOES images.