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]



Winter storm affecting the southern Plains to the Mid-Atlantic

December 10th, 2018 |

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly plots of surface weather type [click to play MP4 animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly plots of surface weather type [click to play MP4 animation]

A large storm produced significant winter weather impacts from the southern Plains to the Mid-Atlantic states during the 07 December10 December 2018 period. GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed the progression of the storm during that 3-day interval.

As much as 10-11 inches of snow fell in the Lubbock, Texas area during 07-08 December. A sequence of  Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) showed the snow cover melting from 09-10 December. Snow cover absorbs radiation at the 1.61 µm wavelength, so it appears very dark on those images.

Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared

Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images [click to enlarge]

Portions of northern and northeastern Arkansas received ice accrual of up to 0.5 inches due to freezing rain — those areas with snow and ice on the ground can be seen in a comparison of Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below).

Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images [click to enlarge]

Significant snowfall resulted across the central Appalachians and Mid-Atlantic, especially for so early in the winter season — 1-minute Mesoscale Domain Sector “Red” Visible (0.64 µm) images (below) revealed embedded convective elements and banding that helped to enhance snowfall rates across that region on 09 December. GLM Groups are also plotted on the images; however, there was no satellite signature of lightning associated with the convective elements until 2130 UTC in north-central North Carolina.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with plots of hourly surface weather type in yellow and GLM Groups in red [click to play MP4 animation]

 

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

GOES-16

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

Once clouds cleared the eastern US on 11 December, the areal coverage of snow cover across the central Appalachians and Mid-Atlantic states could be seen in a comparison of GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above). Note the darker areas seen on 1.61 µm imagery over parts of eastern Kentucky and also from north-central North Carolina into south-central Virginia: those are areas where the snow cover also received a thin glaze of ice from a period of freezing drizzle/rain.

Mesoscale vortices in Oregon and Idaho

December 7th, 2018 |

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

As noted by NWS Boise, a pair of mesoscale vortices were apparent over far southeastern Oregon and far southwestern Idaho on 07 December 2018. A comparison of GOES-17 and GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (below) showed that even with the larger GOES-16 viewing angle (or satellite zenith angle), the features could still be seen rather well.

GOES-17 and GOES-16

GOES-17 and GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Topography in feet [click to enlarge]

Topography in feet [click to enlarge]

A look at the local topography (above) indicated that the low altitude quasi-stationary Oregon vortex was located within the Owyhee River valley, just northeast of the Rome airport KREO. With high pressure centered over the Idaho/Montana border (surface analyses), the low-level southerly/southeasterly flow seen in a plot of 12 UTC rawinsonde data from Boise, Idaho (below) was being channeled between the higher terrain surrounding the valley; interactions with that terrain likely caused the Oregon vortex to form. The Idaho vortex was moving toward the northeast — Boise rawindsonde data showed southwest winds at 727 hPa or an altitude of 2700 feet. The 2 vortices wre quite small, having a diameter of only

12 UTC rawinsonde data from Boise, Idaho [click to enlarge]

12 UTC rawinsonde data from Boise, Idaho [click to enlarge]

The pair of vortices likely formed just before or right around sunrise, since there was no signature seen in earlier nighttime MODIS or VIIRS “Fog/stratus” infrared Brightness Temperature Difference (BTD) images {below).

MODIS and VIIRS

MODIS and VIIRS “Fog/stratus” infrared BTD images [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]