CIMSS Satellite Blog, CIMSS

Tropical Depression Flossie near Hawai’i

By Scott Bachmeier • 5 August 2019

An animation that cycles through GOES-17 (GOES-West) “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Upper-level Water Vapor (6.2 µm) images (above) showed Tropical Depression Flossie just northeast of Hawai’i on 05 August 2019. Note that (1) the exposed low-level circulation center (LLCC) was very apparent in the visible imagery, (2)... Read More

GOES-17 “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Upper-level Water Vapor (6.2 µm) images [click to play animation | MP4]

An animation that cycles through GOES-17 (GOES-West) “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Upper-level Water Vapor (6.2 µm) images (above) showed Tropical Depression Flossie just northeast of Hawai’i on 05 August 2019. Note that (1) the exposed low-level circulation center (LLCC) was very apparent in the visible imagery, (2) deep convection offset to the east/northeast of the LLCC exhibited cloud-top infrared brightness temperatures as cold as -83ºC , and (3) a series of gravity waves were propagating westward away from the convection, moving toward Hawai’i.

GOES-15 Infrared imagery and deep-layer wind shear data from the CIMSS Tropical Cyclones site (below) showed that the tropical cyclone was in an environment of strong shear, which was responsible for the displacement between the exposed LLCC and the convection. In addition to the wind shear, the weakening trend of the system was also due to its motion over cold Sea Surface Temperatures and low Ocean Heat Content.

GOES-15 Infrared Window (10.7 µm) images, with contours and streamlines of deep-layer wind shear [click to enlarge]

GOES-15 Infrared Window (10.7 µm) images, with contours and streamlines of deep-layer wind shear at 18 UTC [click to enlarge]

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Severe thunderstorms in the Dakotas, as viewed by 4 GOES

By Scott Bachmeier • 3 August 2019

With GOES-14 undergoing its annual INR testing and evaluation, it afforded the ability to monitor features such as severe thunderstorms in the western Dakotas from 4 GOES — GOES-17 (GOES-West) at 137.2ºW, GOES-15 at 128ºW, GOES-14 at 105ºW and GOES-16 (GOES-East) at 75.2ºW longitude (above). These storms produced hail as large as 2.0 inches... Read More

Visible images from GOES-17, GOES-15, GOES-14 and GOES-16, with SPC Storm Reports plotted in red [click to play animation | MP4]

With GOES-14 undergoing its annual INR testing and evaluation, it afforded the ability to monitor features such as severe thunderstorms in the western Dakotas from 4 GOES — GOES-17 (GOES-West) at 137.2ºW, GOES-15 at 128ºW, GOES-14 at 105ºW and GOES-16 (GOES-East) at 75.2ºW longitude (above). These storms produced hail as large as 2.0 inches in diameter and damaging winds to 75 mph (SPC Storm Reports). The images are displayed in the native projection of each satellite.

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Record 24-hour rainfall in Nome, Alaska

By Scott Bachmeier • 3 August 2019

The MIMIC Total Precipitable Water (TPW) product (above) showed a northward-moving atmospheric river that was responsible for producing a record 24-hour rainfall amount of 2.47 inches (62.7 mm) ending at 10 pm AKDT on 02 August (06 UTC on 03 August 2019). Some of the poleward transport of moisture was aided by the approach... Read More

MIMIC Total Precipitable Water product [click to play animation | MP4]

The MIMIC Total Precipitable Water (TPW) product (above) showed a northward-moving atmospheric river that was responsible for producing a record 24-hour rainfall amount of 2.47 inches (62.7 mm) ending at 10 pm AKDT on 02 August (06 UTC on 03 August 2019). Some of the poleward transport of moisture was aided by the approach of a Gale Force low (surface analyses).

Blended TPW values reached 2.7 inches near Nome at 1537 UTC on 02 August — and broad areas of TPW greater than 200% of normal (yellow) were seen across the Bering Sea as the atmospheric river approached the Seward Peninsula (below).

Blended Total Precipitable Water and Percent of Normal [click to play animation | MP4]

Blended Total Precipitable Water and Percent of Normal TPW [click to play animation | MP4]

In a plot of surface data from Nome, Alaska over the 02-03 August period (below), heavy rain was reported at 1222 UTC on 02 August.

Time series of surface data from Nome, Alaska [click to enlarge]

A plot of rawinsonde data from Nome at 12 UTC on 02 August (below) revealed a TPW value of 37.7 mm (1.48 inches), which is among the top 10 TPW amounts on record for that site.

Plot of rawinsonde data from Nome at 12 UTC on 02 August [click to enlarge]

Rainfall totals since Thursday AM around Alaska. At any one place most of the rain fell in ~24 hours: any amounts over 1.5″ are very significant. Note: not all of these totals are completely accurate: instrument, reporting & decoding all sources of error. #akwx @Climatologist49 pic.twitter.com/xqJalsCOKv

— Rick Thoman (@AlaskaWx) August 3, 2019

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Eruption of Ulawun in Papau, New Guinea

By Scott Bachmeier • 3 August 2019

The Ulawun volcano erupted just after 09 UTC on 03 August 2019 — retrieved Volcanic Ash Height images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed values generally in the 16-18 km range, with some portions of the umbrella cloud as high as 18-20 km. An advisory issued by the Darwin VAAC estimated the maximum volcanic... Read More

Volcanic ash height [click to play animation | MP4]

The Ulawun volcano erupted just after 09 UTC on 03 August 2019 — retrieved Volcanic Ash Height images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed values generally in the 16-18 km range, with some portions of the umbrella cloud as high as 18-20 km. An advisory issued by the Darwin VAAC estimated the maximum volcanic ash height to be 63,000 feet or 19.2 km.

Volcanic Ash Loading and Effective Radius products (below) indicated that there were high amounts of large ash particles within the volcanic cloud as it drifted southwestward.