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Hurricane Barbara in the East Pacific

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the eye of Category 4 Hurricane Barbara on 02 July 2019. Mesovortices were briefly seen within the eye in the Visible imagery. Barbara was moving through an environment of low deep-layer wind shear and over warm water, factors favorable... Read More

GOES-17

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the eye of Category 4 Hurricane Barbara on 02 July 2019. Mesovortices were briefly seen within the eye in the Visible imagery. Barbara was moving through an environment of low deep-layer wind shear and over warm water, factors favorable for rapid intensification (ADT | SATCON).

DMSP-17 SSMIS Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed a closed eyewall at 1448 UTC.

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image [click to enlarge]

A 1700 UTC  GOES-17 “Red” Visible image with an overlay of Metop-A ASCAT winds (below) revealed surface scatterometer wind speeds as high as 76 knots just north of the eye.

GOES-17

GOES-17 “Red” Visible (0.64 µm) and Metop-A ASCAT winds [click to enlarge]

===== 03 July Update =====

GOES-17 "Red" Visible (0.64 µm, top) and "Clean" Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation | MP4]

Barbara maintained Category 4 intensity on 03 July — and 1-minute GOES-17 Visible and Infrared GOES-17 images (above) provided a better view of mesovortices within the eye.

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NUCAPS Profiles are back in AWIPS

Back in late March 2019, the Cross-track Infrared Sounder (CrIS) suffered an anomaly such that the mid-wave portion of the electromagnetic spectrum (a part that includes channels sensitive to water vapor) was not scanned properly. Thus, NUCAPS soundings created from Suomi-NPP were lost (link). Today, NUCAPS soundings created using NOAA-20 (which has the... Read More

1200 UTC Soundings from KGYX (Grey Maine) on 2 July 2019 and 1600 UTC NUCAPS sounding from nearby, showing changes in the thermodynamics (Click to enlarge)

Back in late March 2019, the Cross-track Infrared Sounder (CrIS) suffered an anomaly such that the mid-wave portion of the electromagnetic spectrum (a part that includes channels sensitive to water vapor) was not scanned properly. Thus, NUCAPS soundings created from Suomi-NPP were lost (link). Today, NUCAPS soundings created using NOAA-20 (which has the same instruments as Suomi-NPP) began flowing into AWIPS. Data from shortly after 1500 UTC were the first to appear.

NUCAPS Soundings over the northeastern United States at 1629 UTC on 2 July 2019 (Click to enlarge)

NUCAPS profiles from NOAA-20 are processed somewhat differently than those from Suomi-NPP as far as latency: NOAA-20 NUCAPS profiles show up more quickly — typically within an hour of the observations time — in AWIPS than NPP NUCAPS profiles did. This is important because the thermodynamic information in these mid-afternoon observations is important in judging destabilization relative to morning soundings.

When Suomi NPP was launched, two independent sets of electronics were present on CrIS; the ‘A’-side set of electronics were used until March; the ‘B’-side electronics have been used since June, and mid-wave observations from Suomi-NPP’s CrIS are now available at this site. However, NUCAPS soundings are not yet being created from Suomi-NPP because the A-side and B-side electronics have different statistical behavior that must be accounted for in the Regression used to start the NUCAPS processing.

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NWS Juneau, Alaska issues their first-ever Severe Thunderstorm Warning — based on satellite imagery

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed the development of thunderstorms over the far southern end of the Alaska Panhandle on 27 June 2019. These storms intensified as they moved southeastward toward the Misty Fjords area of Alaska (located east and southeast of Ketchikan PAKT) — and when... Read More

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

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

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed the development of thunderstorms over the far southern end of the Alaska Panhandle on 27 June 2019. These storms intensified as they moved southeastward toward the Misty Fjords area of Alaska (located east and southeast of Ketchikan PAKT) — and when a significant lightning jump was noted with the strongest storm, NWS Juneau issued their first-ever Severe Thunderstorm Warning at 0249 UTC. A few thunderstorm overshooting tops could be seen in the visible images (for example, at 0230 UTC).

The Severe Thunderstorm Warning polygon is shown below.

Severe Thunderstorm Warning polygon [click to enlarge]

Severe Thunderstorm Warning polygon [click to enlarge]

GOES-17 “Clean” Infrared Window (10.35 µm) images (below) revealed minimum cloud-top infrared brightness temperatures around -60ºC (darker red enhancement).

GOES-17 “Clean

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

A comparison of GOES-17 “Red” Visible (0.64 µm) images at 1-minute intervals with GOES-15 Visible (0.63 µm) images at 15-30-minute intervals (below) helps to underscore the importance of 1-minute imagery for identifying and tracking the pulse-type of thunderstorms that developed on this day. Also evident is the brighter appearance of the GOES-17 Visible imagery — the ABI instrument on the newer GOES-R Series benefits from on-orbit visible calibration, which mitigates the visible detector degradation that plagued the older GOES series.

GOES-17

GOES-17 “Red” Visible (0.64 µm, left) and GOES-15 Visible (0.63 µm, right) images [click to play animation | MP4]

Additional information about this severe thunderstorm event is available on a FDTD GOES Applications Webinar.

On a side note, a larger-scale view of GOES-17 Visible imagery (below) showed a curious thin elongated feature moving southwestward from Yukon across the Alaska Panhandle to the Gulf of Alaska, which became more obvious later in the day as the lower sun angle increased forward scattering. This feature was casting a shadow onto the marine boundary layer stratus clouds over the Gulf of Alaska (0250 UTC image).

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

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

This feature was also apparent in GOES-17 Near-Infrared “Cirrus” (1.38 µm) images (below), since that spectral band excels at the detection of atmospheric particles that are efficient scatterers of light (such as cirrus ice crystals, dust, smoke and volcanic ash/sulfate). In fact, this was a streamer of high-altitude sulfate from the Raikoke eruption on 21 June — and this thin volcanic filament could be unambiguously identified earlier in Cirrus imagery than in Visible imagery (for example, over Yukon at 1950 UTC, before forward scattering became large enough to aid identification at visible wavelengths).

GOES-17 Near-Infrared “Cirrus” (1.38 µm) images [click to play animation | MP4]

GOES-17 Near-Infrared “Cirrus” (1.38 µm) images [click to play animation | MP4]

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Ulawun volcano erupts in Papau New Guinea

The Ulawun volcano erupted just after 0430 UTC on 26 June 2019 — a comparison of Himawari-8 Visible (0.64 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.4 µm) images (above) showed the thermal anomaly (yellow to red 3.9 µm pixels) preceding the eruption and the development of a well-defined... Read More

Himawari-8 Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and Infrared Window (10.4 µm, right) images [click to play animation | MP4]

Himawari-8 Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and Infrared Window (10.4 µm, right) images [click to play animation | MP4]

The Ulawun volcano erupted just after 0430 UTC on 26 June 2019 — a comparison of Himawari-8 Visible (0.64 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.4 µm) images (above) showed the thermal anomaly (yellow to red 3.9 µm pixels) preceding the eruption and the development of a well-defined umbrella cloud after the eruption. The coldest cloud-top infrared brightness temperature was -83.6ºC in conjunction with a prominent overshooting top at 0600 UTC. Note the eastward-moving cloud material that originated from this overshooting top — judging from Merauke/Mopah, Indonesia rawinsonde data (plot | data), the westerly winds required for such transport existed in the stratosphere at altitudes of 20-24 km. The pocket of warmer cloud-top 10.4 µm brightness temperatures associated with this stratospheric cloud material was the warmest at (-57.2ºC) at 0640 UTC (which, with the adjacent -82.7ºC overshooting top, created a cold/warm couplet whose magnitude was 25.5ºC). In addition, concentric gravity waves propagating outward across the volcanic cloud top were evident on the imagery.

Himawari-8 Infrared Window images (below) showed that the volcanic cloud dissipated fairly quickly. The eastward drift of the stratospheric cloud material also became difficult to follow after a couple of hours — even in Low-level Water Vapor (7.3 µm) imagery (which is also sensitive to SO2 absorption).

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Shortwave Infrared (3.9 µm) images (below) revealed a thermal anomaly or “hot spot” (yellow to red pixels) for several hours leading up to the 0430 UTC volcanic eruption.

Himawari-8 Shortwave Infrared (3.9 um) images [click to play animation | MP4]

Himawari-8 Shortwave Infrared (3.9 µm) images [click to play animation | MP4]

Regarding the intensity of the thermal anomaly, a plot of volcano radiative power (VRP) and volcanic cloud longwave infrared brightness temperature (below) showed that the VRP exceeded 1 GW several hours prior to the formation of the eruption umbrella cloud.

Plot of volcano radiative power (red) and volcanic cloud longwave infrared brightness temperature (green), courtesy of Mike Pavolonis (NOAA/NESDIS) [click to enlarge]

Time series plot of volcano radiative power (red) and volcanic cloud longwave infrared brightness temperature (green), courtesy of Mike Pavolonis (NOAA/NESDIS) [click to enlarge]

Himawari-8 False Color RGB imagery along with radiometrically retrieved Ash Height, Ash Effective Radius and Ash Loading products (below) revealed a volcanic cloud characterized by high ash loading of large particles, having height values generally in the 16-20 km range (with a maximum height of 22 km).

False Color RGB (top left), Ash Height (top right), Ash Effective Radius (bottom left) and Ash Loading (bottom right) [click to play animation | MP4]

False Color RGB (top left), Ash Height (top right), Ash Effective Radius (bottom left) and Ash Loading (bottom right), courtesy of Mike Pavolonis (NOAA/NESDIS) [click to play animation | MP4]

An oblique view of of the Ulawun volcanic cloud was provided by GOES-17 “Red” Visible (0.64 µm) images (below). This view accentuated the vertical extent of overshooting tops, and the large solar angle helped to highlight the cloud-top gravity waves. The 3-dimensional aspect of the two distinct eruption pulses (with umbrella clouds at two different altitudes) along with the westward-drifting stratospheric plume were a bit more obvious in the GOES-17 images.

GOES-17 "Red" Visible <em>(0.64 µm)</em> images [click to play animation | MP4]

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

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