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Ash fall streak from the Sheveluch volcano in Kamchatka

In a comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 12 May 2019 (above), a dark volcanic ash fall streak was evident in the Visible image, which extended over 100 miles southward from the Sheveluch volcano on the Kamchatka... Read More

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

In a comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 12 May 2019 (above), a dark volcanic ash fall streak was evident in the Visible image, which extended over 100 miles southward from the Sheveluch volcano on the Kamchatka Peninsula of Russia. This feature was a layer of volcanic ash that had been deposited on top of existing snow cover — note that most of the dark ash fall streak exhibited much cooler infrared brightness temperatures compared to the bare ground of the interior valley to the west (since the ash streak existed on top of a higher-altitude area of snow cover).

This ash fall streak was a result of an explosive eruption of the volcano over a month earlier, on 10 April — the volcanic ash plume could be seen moving southward in Himawari-8 Visible (0.64 µm) images (below).

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

An interesting aspect of this long-lived ash fall streak was that a portion of it was apparently covered by a layer of fresh snowfall at some point after the eruption — and a 7-day sequence of Suomi NPP VIIRS True Color Red-Green-Blue (RGB) images viewed using RealEarth (below) suggested that this layer of new snow was melting with the aid of the high May sun angle, gradually revealing more of the original length of the ash fall streak.

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Note that there was another small volcanic plume moving south-southwestward from Sheveluch in the 09 May VIIRS True Color image — retrieved quantities of ash probability, height, loading and effective radius for this volcanic plume (source) are shown below.

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

This type of volcanic ash fall streak frequently occurs on the snow-covered Kamchatka Peninsula — here is an example from March 2013.

Thanks go out to Santiago Gassó for bringing this interesting feature to our attention.

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Record May snowfall in Duluth, Minnesota

Several snowfall records have already been broken for the Duluth area. The table in the image shows a list of these records. Stay tuned as the Monthly snowfall total and daily snowfall for today (5/9) are likely to change. #mnwx #mnclimate pic.twitter.com/nYbGyV6kZt — NWS Duluth (@NWSduluth) May 9, 2019 GOES-16 (GOES-East)... Read More


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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the cloudiness associated with a midlatitude cyclone (surface analyses) that moved across the Upper Midwest on 08 May09 May 2019.  The system produced accumulating snowfall from extreme eastern South Dakota to central/northeastern Minnesota, northwestern Wisconsin and Upper Michigan — storm total accumulations were as high as 10.6 inches at Duluth, Minnesota (observations), 10.4 inches at Poplar, Wisconsin, 5.0 inches at Atlantic Mine, Michigan and 3.0 inches at Astoria, South Dakota (NOHRSC maps of snowfall/snowdepth). Note that the NW-SE oriented band of snowfall straddling the South Dakota/Minnesota border may have been enhanced by upslope flow as northeasterly surface winds encountered rising terrain of the Coteau des Prairies.

GOES-16 Mid-level Water Vapor (6.9 µm) images (below) showed the formation of a SW-NE oriented deformation zone across Minnesota — forcing for ascent was further aided by a stretched lobe of 500 hPa vorticity and 310 K potential vorticity that moved northeastward across the region during this period, along with a favorably-coupled 250 hPa jet streak configuration. Cloud features within the deformation zone across eastern South Dakota into southern/central Minnesota had an appearance resembling convective elements/bands in both the Visible and Water Vapor imagery.

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of surface weather type (yellow) and GLM Groups (red) [click to play animation | MP4]

Although lightning was not widespread — and thunder was not explicitly reported in any first-order station observations — there were isolated small clusters of GOES-16 GLM Groups detected, first over northeastern, then central and finally over southwestern Minnesota between 2256 and 0036 UTC (below), indicating the presence of thundersnow.

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

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of surface weather type (yellow) and GLM Groups (red) [click to enlarge]




Through occasional breaks in the clouds later in the day on 09 May, GOES-16 Day Cloud Phase Distinction Red-Green-Blue (RGB) images (below) revealed the stationary signature of fresh snow cover (darker green) across central to northeastern Minnesota and far northwestern Wisconsin (glaciating cloud tops also appear as shades of green).

GOES-16 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

===== 10 May Update =====

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

GOES-16 Visible images (above) showed two swaths of snow cover remaining across northeastern Minnesota (where reported snow depths were 1-2 inches) and northwestern Wisconsin (where reported snow depths were 4-5 inches) on the morning of 10 May.

Comparisons of GOES-16 Land Surface Temperature (LST) and Visible images at 1401 UTC and 1501 UTC (below) indicated that LST values were as much as 10ºF colder within the areas of snow cover (brighter shades of cyan) compared to adjacent bare ground.

GOES-16 Land Surface Temperature and “Red” Visible (0.64 µm) images at 1401 UTC [click to enlarge]

GOES-16 Land Surface Temperature and “Red” Visible (0.64 µm) images at 1501 UTC [click to enlarge]

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Severe thunderstorms over the southern Plains

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images viewed using AWIPS (above) showed the development of a large severe thunderstorm in the Texas Panhandle near Lubbock on 05 May 2019. A GOES-16 Mesoscale Domain Sector was positioned over the region, providing images at 1-minute intervals. A persistent quasi-stationary pulsing overshooting top... Read More

GOES-16

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images viewed using AWIPS (above) showed the development of a large severe thunderstorm in the Texas Panhandle near Lubbock on 05 May 2019. A GOES-16 Mesoscale Domain Sector was positioned over the region, providing images at 1-minute intervals. A persistent quasi-stationary pulsing overshooting top was evident in both the Visible and Infrared imagery, and cloud-top infrared brightness temperatures were as cold as -80ºC at times — judging from 00 UTC Amarillo rawinsonde data, this represented an altitude of around 13 km. In addition, the presence of north-to-south oriented stable wave clouds in the Visible imagery marked the western edge of a residual convective outflow boundary from the previous evening.

The storm also exhibited very prominent Enhanced-V and Above-Anvil Cirrus Plume signatures — a toggle between 0015 UTC Visible and Infrared images (below) illustrated these two signatures.

GOES-16 "Red" Visible (0.64 µm) and "Clean" Infrared Window (10.3 µm) images at 0015 UTC on 06 May [click to enlarge]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images at 0015 UTC on 06 May [click to enlarge]

GOES-16 Visible and Infrared images with plots of SPC storm reports viewed using McIDAS (below) showed that this individual thunderstorm produced tornadoes, large hail and damaging winds. Beginning at 2200 UTC, there was an overlap of both GOES-16 Mesoscale Domain Sectors over the Texas Panhandle, which provided imagery at 30-second intervals.

GOES-16 "Red" Visible (0.64 µm, left) and "Clean" Infrared Window (10.3 µm, right) images, with plots of SPC storm reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with plots of SPC storm reports [click to play animation | MP4]

===== 07 May Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm, top left), Near-Infrared “Snow/Ice” (1.61 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play animation | MP4]

1-minute GOES-16 imagery (above) revealed another example of a supercell thunderstorm exhibiting Enhanced-V and Above-Anvil Cirrus Plume signatures north-northeast of Fort Stockton, Texas (station identifier KFST) on 07 May; these storms developed east of a dry line that was located in Far West Texas (surface analyses).

GOES-16 Visible and Infrared images with plots of SPC storm reports are shown below.

GOES-16 "Red" Visible (0.64 µm, left) and "Clean" Infrared Window (10.3 µm, right) images with plots of SPC storm reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images with plots of SPC storm reports [click to play animation | MP4]

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Cyclone Fani makes landfall in India

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed the intensification of Cyclone Fani to a high-end Category 4 storm on 02 May 2019 (ADT | SATCON | PGTW advisory), before eventually making landfall in northeastern India at 0230 UTC on 03 May. During its life cycle, Fani moved over warm sea surface temperature values of... Read More

EUMETSAT-8 Meteosat-8 Infrared Window (10.8 µm) umages [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed the intensification of Cyclone Fani to a high-end Category 4 storm on 02 May 2019 (ADT | SATCON | PGTW advisory), before eventually making landfall in northeastern India at 0230 UTC on 03 May. During its life cycle, Fani moved over warm sea surface temperature values of 29-30ºC — and deep-layer wind shear of only 5-10 knots on 02 May provided an environment favorable for rapid intensification.

Once inland, Fani was in the process of rapidly weakening to a Category 1 storm as it passed over Bhabaneswar (VEBS), and surface wind gusts to 75 knots were reported at that site (below).

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) showed snapshots of Fani from 19 UTC on 01 May (over the Bay of Bengal) to 07 UTC on 03 May (after landfall).

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

A comparison of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP on 02 May (below) showed Fani shortly after it had reached Category 4 intensity.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

A toggle between a DMSP-17 SSMIS Microwave image at 1230 UTC and a Meteosat-8 Infrared Window image at 1300 UTC  from the CIMSS Tropical Cyclones site (above) showed the eye and totally closed eyewall of Fani when it was at its peak intensity on 02 May. However, the MIMIC TC product (below) indicated that the eastern portion of the eyewall started to erode as Fani approached the coast and began to undergo an eyewall replacement cycle.

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

On 30 April, VIIRS DayNight Band (0.7 µm) images (below, courtesy of William Straka, CIMSS) revealed widespread mesospheric airglow waves (reference) within the western semicircle of the storm, along with numerous bright lightning streaks associated with convection south of the storm center.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]

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