CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Laura during the the 12-hour period after it intensified from a Tropical Storm to a Hurricane in the southern Gulf of Mexico at 1215 UTC on 25 August 2020. Numerous convective overshooting tops were observed, some exhibiting cloud-top infrared brightness temperatures as cold as -87ºC.

A comparison of NOAA-20 MiRS Microwave (88 GHz), GOES-16 “Red” Visible (0.64 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images at 1851 UTC (below) revealed a curved convective band wrapping around the eye of Laura.

NOAA-20 MIRS Microwave (88 GHz), GOES-16 “Red” Visible (0.64 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images at 1851 UTC [click to enlarge]

In a toggle between Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1943 UTC (below), the coldest cloud-top infrared brightness temperature was -91.9ºC in the Suomi NPP image (compared to -87.0ºC on the GOES-16 image). The northwestward parallax displacement associated with GOES-16 imagery over the southern Gulf of Mexico was also apparent.

Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1943 UTC [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/38092

CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images — with and without an overlay of GLM Flash Extent Density (above) showed Tropical Storm Marco as it intensifies to a Category 1 hurricane at 1630 UTC on 23 August 2020. A pronounced semi-circular convective burst was seen to develop near the storm center shortly before 19 UTC.

A toggle between time-matched Infrared images from Suomi NPP and GOES-16 (below) indicated that the coldest cloud top infrared brightness temperature on the Suomi NP VIIRS image was -86.8ºC, compared to -81.5ºC from the GOES-16 ABI instrument. The northward parallax displacement associated with GOES-16 imagery over the Gulf of Mexico was also apparent.

Infrared images from Suomi NPP and GOES-16 [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/38010

CIMSS Satellite Blog

GOES-17 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images  [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a pyrocumulonimbus (pyroCb) cloud that was spawned by the Castle Fire in California on 23 August 2020.

The coldest pyroCb cloud-top infrared brightness temperatures were around -50ºC –according to 00 UTC rawinsonde data from Las Vegas, Nevada (below) indicated that this temperature corresponded to altitudes around 12 km.

Plot of 00 UTC rawinsonde data from Las Vegas, NV [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/38007

CIMSS Satellite Blog

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Near-Infrared (1.61 µm and 2.25 µm) images along with the VIIRS Active Fires product (credit: William Straka, CIMSS) [click to enlarge]

A comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Near-Infrared (1.61 µm and 2.25 µm) images along with the VIIRS Active Fires product (above) showed nighttime visible reflectance and thermal signatures of the many wildfires burning across Northern California at 1001 UTC or 3:01am PDT on 20 August 2020. A closer view is available here.

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Fire Temperature Red-Green-Blue (RGB) and “Red” Visible (0.64 µm) images (below) displayed the thermal signatures and smoke plumes associated with the Northern California fires.

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

GOES-17 True Color RGB images created using Geo2Grid (below) provided a closer view of the dense residual smoke and new smoke plumes across Northern California.

GOES-17 True Color RGB images [click to play animations | MP4]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37987

CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) displayed the well-defined eye of Category 4 Hurricane Genevieve in the East Pacific Ocean on 18 August 2020.

A GOES-16 Visible image at 1617 UTC (below) includes plots of Metop-A ASCAT scatterometer surface winds — the highest wind was 69 knots just northeast of the storm center.

GOES-16 “Red” Visible (0.64 µm) image, with plots of ASCAT scatterometer surface winds [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37976

CIMSS Satellite Blog

 

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.35 µm, bottom) images, with hourly plots of surface reports [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed 2 pulses of pyro-convection emanating from a wildfire that was burning between between Kremmling (K20V) and Berthoud Pass (K0CO) in Colorado on 14 August 2020. The cloud of the second pulse, originating around 2300 UTC, exhibited infrared brightness temperatures of -40ºC and colder  (shades of blue in the 10.35 µm images) — assuring the heterogeneous nucleation of all supercooled water droplets to form ice crystals, and thereby meeting the criteria of a pyrocumulonimbus (pyroCb). The pyroCb then drifted east-southeastward across Colorado.

The coldest pyroCb infrared brightness temperature was -46ºC, which corresponded to an altitude near 11 km according to rawinsonde data from Denver (below).

Plot of rawinsonde data from Denver [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37969

CIMSS Satellite Blog

Himawari-8 True Color RGB images [click to play animation | MP4]

JMA Himawari-8 True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed the gray to tan hues of a narrow west-to-east oriented volcanic ash cloud following an eruption of Mount Sinabung on 10 August 2020.

A sequence of Terra MODIS False Color RGB, Ash Probability, Ash Loading, Ash Height and Ash Effective Radius products from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) showed the characteristics of the ash plume at 0415 UTC.

Terra MODIS False Color RGB, Ash Probability, Ash Loading, Ash Height and Ash Effective Radius [click to enlarge]

A plot of 00 UTC rawinsonde data from Medan (below) helped to explain the different ash height and ash transport characteristics — the higher-altitude portion of the ash plume was transported westward by easterly flow above the 500 hPa (5.9 km) level, while the lower-altitude portion moved eastward due to westerly winds below 500 hPa.

Plot of 00 UTC rawinsonde data from Medan, Indonesia [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37950

CIMSS Satellite Blog

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the eastward progression of a Mesoscale Convective System (MCS) that produced a long swath of damaging winds (SPC Storm Reports) or derecho from eastern Nebraska to Indiana on 10 August 2020. The highest measured wind gust was 112 mph in eastern Iowa at 1755 UTC.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

In a comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC (below), the higher spatial resolution of the VIIRS instrument detected infrared brightness temperatures as cold as -84ºC, compared to -76ºC with GOES-16 (the same color enhancement is applied to both images). The northwest parallax offset associated with GOES-16 imagery at this location was also evident.

Comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC [click to enlarge]

GOES-16 Visible/Infrared Sandwich Red-Green-Blue (RGB) and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports, is shown below. The probability contours are produced from a deep-learning algorithm used to identify patterns in ABI and GLM imagery that correspond to intense convection. It is trained to highlight strong convection as humans would identify it. Work is ongoing to incorporate this storm-top information into NOAA/CIMSS ProbSevere.

GOES-16 Visible/Infrared Sandwich RGB and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports (credit: John Cintineo, CIMSS) [click to play animation | MP4]

A comparison of Terra MODIS True Color RGB images (source) from before (28 July) and after (11 August) the derecho (below) revealed very large swaths of wind-damaged crops (lighter shades of green) across Iowa.

Comparison of before (28 July) / after (11 August) Terra MODIS True Color RGB images centered over Iowa [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37938

CIMSS Satellite Blog

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) showed widespread smoke from biomass burning across parts of Brazil (south of the Amazon River) on 09 August 2020. Most of this smoke was created by extensive burning during the previous day and evening — but later in the animation, several new smoke plumes can be seen growing from new fire activity.

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37931

CIMSS Satellite Blog

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

A sequence of 3 VIIRS True Color Red-Green-Blue (RGB) images from Suomi NPP and NOAA-20 as visualized using RealEarth (above) showed plumes of blowing dust moving off the coast of Namibia and South Africa on 07 August 2020.

EUMETSAT Meteosat-11 Visible (0.6 µm) images (below) displayed the motion of the dust plumes during the daytime hours.

Meteosat-11 Visible (0.6 µm) images [click to play animation | MP4]

A plot of surface data from Luderitz, Namibia (station identifier FYLZ) is shown below; it showed that winds gusted to 36 knots (41 mph) at 08 UTC.

Plot of surface data from Luderitz, Namibia [click to enlarge]

H/T to Santiago Gassó for bringing this event to our attention.

#sentinel2 had a not-so-centered overpass, but some of the northern plumes seem to me like sand although there are plumes coming of the pan further inland. #highlatitudedust @sheffield_dust @jobullard https://t.co/pBaIQf2Z3v pic.twitter.com/4hwnR59CNa

— Santiago Gassó (@SanGasso) August 9, 2020

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37928

CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed clusters of thunderstorms that developed along and just behind a cold front moving eastward across Minnesota on 08 August 2020. In addition, a decaying Mesoscale Convective System in southeastern North Dakota eventually revealed curved cloud features associated with a Mesoscale Convective Vortex.

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

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GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

A toggle between time-matched NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images (below) demonstrated the northwestward parallax displacement of GOES-16 cloud-top features (note: the same color enhancement enhancement has been applied to both images). Due to the 375-meter spatial resolution of VIIRS imagery, it was able to sense overshooting top infrared brightness temperatures as cold as -77.8ºC (compared to -65.7ºC with GOES-16). The higher resolution VIIRS image also provided a clearer depiction of the cloud-top gravity waves and transverse banding.

NOAA-20 VIIRS Infrared Window (11.45 µm) and GOES-16 “Clean” Infrared Window (10.35 µm) images [click to enlarge]

A GOES-16 Infrared image with parallax displacement vectors and magnitudes (in km) from this site is shown below. For a 50,000 foot cloud top over southern Minnesota, the parallax adjustment was to the southeast at a distance of 21 km (13 miles) — this corresponded well to what was seen in the NOAA-20/GOES-16 comparison above.

GOES-16 Infrared image, with parallax displacement vectors (green) and magnitudes (red, in km) [click to enlarge]

 

 

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37918

CIMSS Satellite Blog

NOAA-20 852-mb Temperatures, ca. 1750 UTC on 7 August 2020.  Inset:  Global Map of where the data sit (Click to enlarge)

A previous blog post (link) detailed how to access NOAA CLASS to create Gridded NUCAPS (NOAA-Unique Combined Atmospheric Processing System) imagery from those data.  (You can also view some gridded NUCAPS fields here;  click here to see the 850-mb field of Temperature from that site, it is very similar to the imagery above).   This post details how to use the CSPP QuickLooks software package to create imagery at different levels.  These QuickLook fields give good information quickly and at many different levels for Direct Broadcast data.

Download the Sounder QuickLook software for Linux from the CIMSS website here.  Documentation is also available at the download website.  The files to download are shown in this graphic. The package is self-contained and requires only unzipping and un-tarring.

After downloading, define the $CSPP_SOUNDER_QL_HOME variable as the directory where the package sits on your unix platform.  Then, set up the environment with the command:  source $CSPP_SOUNDER_QL_HOME/cspp_sounder_ql_env.sh.

This software package works on NUCAPS EDR (Environmental Data Records) files created at Direct Broadcast sites by CSPP (that are also available after some time from CLASS), and those files can be found at websites such as this one: ftp://ftp.ssec.wisc.edu/pub/eosdb/ — underneath this are directories for NOAA-20 (‘j01’) and Suomi-NPP (‘npp’). For example, NOAA-20 data from 7 August 2020 from the ~1747 UTC overpass is at ftp://ftp.ssec.wisc.edu/pub/eosdb/j01/crisfsr/2020_08_07_220_1747/ (This website is not preserved forever but will go away after about a week. The directory includes an edr subdirectory that contains the files needed; a typical filename looks like this:  NUCAPS-EDR_v2r0_j01_s202008071752319_e202008071753017_c202008071830250.nc; it is the EDR for NOAA-20 and it contains data on 7 August 2020 from 1752 through 1753 UTC. The directory will include up to about 18 of these EDRs (the number depends on how long the satellite is within view of the Direct Broadcast antenna at CIMSS).

How do you create the QuickLooks?

1. Move the EDR files to your machine, and that’s easily done with wget ftp://ftp.ssec.wisc.edu/pub/eosdb/j01/crisfsr/2020_08_07_220_1747/edr/NUCAPS-EDR*.  Of course, the yyyy_mm_dd_jdy_hhmm value (2020_08_07_220_1747 above) changes with each satellite overpass!
2. Create a list of the files in that directory, i.e., files=$CSPP_SOUNDER_QL_HOME/data/NUCAPS-EDR*
3. Invoke the shell script from $CSPP_SOUNDER_QL_HOME/scripts/ql_level2_image.sh "$files" NUCAPS --dset temp --pressure 850.   This will create an image, shown above, that is a temperature mapping at the closest pressure level to 850 mb in the NUCAPS retrieval. (Pressure levels in the Radiative Transfer Model that is used by NUCAPS are listed here;  in the map label above, note that values are truncated, not rounded).  You can also map dewpoint temperature (dwpt), relative humidity (relh) and mixing ratio (wmix). By default, temperature scaling matches the bounds of the image, but you can specify the bounds if needed, using --plotMin=250.0 --plotMax=300.0, for example.  The time of the image is the time of the first scan line — for this ascending pass, it’s the southernmost line.  In this QuickLook image, the airmass difference between the relatively cool air over Ohio/Indiana and the warmer air to the south is apparent.

You can also create a QuickLook SkewT/logP plots for each scan. This produces one SkewT per ScanLine, at the mid-point along the scanline that contains 30 separate profiles.   The sounding below was produced by this command:

./ql_level2_skewt.sh ./data/NUCAPS-EDR_v2r0_j01_s202008071755119_e202008071755417_c202008071831450.nc NUCAPS

NOAA-20 NUCAPS Sounding from 1755 UTC on 7 August 2020 at 41.93º N, 75.81º W (Click to enlarge)

The SkewT has characteristics that suggest the presence of clouds.  What did this particular sounding look like in AWIPS?  That’s shown below.  In AWIPS, the sounding also terminated at about 550 mb, and the temperature and dewpoint lines above that level match the Quick Look sounding shown above.

NSharp AWIPS presentation of NOAA-20 NUCAPS Sounding at 41.93 N, 75.81 W at ~17UTC on 7 August 2020 (Click to enlarge)

NUCAPS Sounding Availability points from this NOAA-20 pass are shown below. The sounding point — in yellow — that is circled in blue is the one shown above. The sounding just to the east of that point — a green point that gives useful information down into the boundary layer — is shown here. Quick Looks choose the mid-point sounding along the line, and sometimes, as in this case, the retrieval that produced the profile did not converge.

NOAA-20 NUCAPS Sounding Availability Points from AWIPS, 1732 UTC on 7 August 2020 (Click to enlarge). The sounding shown above is from the point circled in blue.  This is in the middle of the 30 sounding points along the horizontal line of available profiles.

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37888

CIMSS Satellite Blog

Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Active Fires product (credit: William Straka. CIMSS) [click to enlarge]

A sequence of Suomi NPP VIIRS Day/Night Band (0.7 µm), Near-Infrared (1.61 µm and 2.25 µm), Shortwave Infrared (3.75 µm) and Active Fires product at 2335 UTC on 04 August 2020 (above) showed nighttime reflective and thermal signatures of the fire that was burning about 8.5 hours following a large explosion that occurred at 1508 UTC in Beirut, Lebanon.

Plots of Spectral Response Functions (SRFs) for similar spectral bands on the GOES-R series ABI instrument (1..61 µm, 2.24 µm and 3.9 µm) are shown below — note that the 1.61 µm and 2.24 µm SRF curves are located close to the peak emitted radiance of very hot features such as large fires.

Plots of Spectral Response Functions for GOES-R series ABI 1..61 µm, 2.24 µm and 3.9 µm spectral bands [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37877

CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the 10-hour period leading up to the time when Tropical Storm Isaias re-intensified to Category 1 hurricane intensity on 03 August 2020. The center of Isaias passed near Buoy 41004 (below) — ahead of the storm, there was a wind gust to 62 knots (71 mph) at 21 UTC, and after the storm  center had passed there was a wind gust to 68 knots (78 mph).

Plot of wind speed (blue), wind gust (red) and air pressure (green) at Buoy 41004

GOES-16 Infrared images with and without an overlay of GLM Flash Extent Density (below) showed that there was some lightning activity associated with areas of deep convection around the center of Isaias.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with and without an overlay of GLM Flash Extent Density [click to play animation | MP4]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37832

CIMSS Satellite Blog

Himawari-8 Ash RGB images, from 25 July to 01 August 2020 [click to play animation | MP4]

JMA Himawari-8 Ash Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed the nearly continuous volcanic cloud emanating from Nishinoshima during the 1-week 25 July to 01 August period. The direction of plume transport switched from northwesterly/westerly to southerly/southeasterly during this time, which is explained by the transition in wind direction within much of the troposphere as revealed by rawinsonde data from nearby Chicijima (below).

Plots of rawinsonde data from Chichijima [click to enlarge]

VIIRS True Color RGB images from NOAA-20 and Suomi NPP [click to enlarge]

After the transition to southerly transport, VIIRS True Color RGB images from NOAA-20 and Suomi NPP as visualized using RealEarth (above), the surface visibility at Iwo Jima RJAW dropped to 4 miles on 01 August (below) as the hazy volcanic plume drifted across the area.

Time series plot of surface observation data from Iwo Jima [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37820

CIMSS Satellite Blog

GOES-16 images from all 16 ABI spectral bands [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) images from all 16 of the ABI spectral bands (above) revealed a variety of signatures of the Mars 2020 Perseverance Rover launch from Kennedy Space Center in Florida on the morning of 30 July 2020. Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images provided the best thermal signature of hot combustion byproducts (water vapor and carbon dioxide) in the wake of the ULA Atlas V rocket booster engines. Closer to the launch site, thermal and reflective signatures of the lower-altitude rocket condensation cloud were seen drifting slowly westward in imagery from all 16 spectral  bands.

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37801

CIMSS Satellite Blog

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

JMA Himawari-8 “Red” Visible (0.64 µm) images (above) showed trains of vortices extending downwind (southeast) of the Kuril Islands on 28-29 July 2020. One unusual aspect of these vortices was the development of small cloud elements within the cloud-free “holes”.

H/T to Santiago Gassó for alerting us to this interesting case.

Himawari animation (fwd/bkwd) confirms it, condensation starts inside the clean holes which remain as cloud after the surrounding dissipates. @CIMSS_Satellite @GOESguy https://t.co/BLx2hqKdEo pic.twitter.com/PW6xNHQsWd

— Santiago Gassó (@SanGasso) July 29, 2020

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37807

CIMSS Satellite Blog

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Potential Tropical Cyclone Nine as it moved northeastward across the Caribbean Sea on 29 July 2020. In Puerto Rico, Luis Muñoz Marin Airport in San Juan (TJSJ) had a wind gust to 44 knots (51 mph) around 19 UTC. Numerous pulsing overshooting tops were seen, with some exhibiting cloud-top infrared brightness temperatures as cold as -89ºC — according to plots of rawinsonde data from San Juan, Puerto Rico (below), such temperatures were about 10ºC colder than that of the tropopause. Note the significant increase in moisture from the 12 UTC to the 00 UTC soundings, as PTC9 moved closer to Puerto Rico.

Plots of rawinsonde data from San Juan, Puerto Rico [click to enlarge]

GOES-16 Infrared images with an overlay of GLM Flash Extent Density (below) revealed a modest amount of lightning activity associated with some of the larger clusters of convection.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37794

CIMSS Satellite Blog

GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed  Category 1 Hurricane Douglas as it moved just north of Hawai’i during the day on 26 July 2020 (the boundary of the Mesoscale Sector was abruptly shifted westward at 1658 UTC). The coldest cloud-top infrared brightness temperatures were around -80ºC.

The apparent storm center was shifted north of the actual surface center location, due to the presence of southerly/southwesterly deep-layer wind shear as shown by a 20 UTC analysis from the CIMSS Tropical Cyclones site (below).

GOES-17 “Clean” Infrared Window (10.35 µm) images, with analysis of deep layer wind shear at 20 UTC [click to enlarge]

from CIMSS Satellite Blog https://cimss.ssec.wisc.edu/satellite-blog/archives/37741