1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of Hurricane Douglas — the first hurricane of the 2020 season in the East Pacific Ocean — on 22 July 2020. Douglas was the 4th latest formation of the first hurricane on record in this basin.

===== 23 July Update =====

Douglas intensified to a Category 3 storm during the nighttime hours — 1-minute GOES-17 Visible and Infrared images during the first 4 hours of daylight on 23 July (above) revealed mesovortices within the eye of the hurricane. The coldest cloud-top infrared brightness temperature during this time period was -76.6ºC, associated with an overshooting top within the eyewall just north-northwest of the eye at 1701 UTC (below).

A Suomi NPP VIIRS Infrared Window (11.45 µm) image viewed using RealEarth (below) showed Hurricane Douglas at 1035 UTC, about 1.5 hours after it reached Category 3 intensity.

Later in the day, a toggle between NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images (below) showed Douglas at 2233 UTC.

===== 24 July Update =====

A Mesoscale Domain Sector was once again positioned over Category 3 Hurricane Douglas at 1945 UTC on 24 July — 1-minute GOES-17 Visible and Infrared images are shown above.

View only this post Read Less

The main modern Mount St. Helens eruption was May 18, 1980 — yet there were also later paroxysmal eruptions, such as on June 12/13, 1980. Geostationary satellite imagery from NASA’s SMS-2 (Synchronous Meteorological Satellite) monitored two more Mount St. Helens eruptions on July 22th (local time), 1980, as shown above. Note that in “UTC-time”, the eruption took place on July 23rd. A similar side-by-side SMS-2 visible and infrared animation.  This may be the first* “rapid scan” imaging of a volcanic ash plume (with a 3-minute cadence for almost an hour), where “rapid scan” is defined as satellite imagery less than 5 min apart.

There is a long history of rapid scan imaging from geostationary imagers, including from SMS-1/2, ATS-1, ATS-3, GOES-1, GOES-7 series, GOES-8 series, GOES-14 , Meteosat, etc and of course, AHI and the GOES-R series ABI where 1-min imagery is routine. Here’s a page where users can search historical meso-scale sector locations from the University of Wisconsin-Madison SSEC Satellite Data Services.  

The monitoring of volcanic ash plumes and their attributes have greatly increased from 1980 to today. Moving from qualitative (somewhat after the fact imagery) to quantitative applications (that are much more timely)! Due to the large number of volcanoes, coupled with the increase in satellite observations, satellite observations are key in monitoring the world’s volcanoes for aviation safety and other uses. More on volcanic ash monitoring.

SMS-2

A similar loop as above (SMS-2 Visible and IR from July 23, 1980), but the in mp4 format. Both the day before and after, SMS-02 was in a routine scan mode of imagery every 30 minutes. The rapid scan imagery was just on July 23, 1980 for approximately one hour, starting at 00:14 UTC. 

This webpage allows to customize the loop speed of the SMS visible and infrared side-by-side animation. This uses the hanis software. 

The shadows from the plume are evident. 

A longer duration (4-hr) SMS-02 IR animation (mp4) or (animated gif). The red square represents the approximate location of Mount St. Helens.  Note the less than ideal image navigation. 

GOES-3

NOAA’s GOES-3 was also operating, although not in a rapid scan mode, so imagery was every 30 minutes. 

The two pulses are clearly evident. 

H/T

Thanks to Jean Phillips, the SSEC Data Services, and the Scott’s (Bachmeier and Lindstrom). NASA SMS-2 and NOAA GOES-3 data are via the University of Wisconsin-Madison SSEC Satellite Data Services. More GOES-R series information. 

* There may have been rapid scan satellite observations of volcanic ash plumes prior to this case in 1980, and if you know of any, please contact T. Schmit.

View only this post Read Less

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 the development of a large Mesoscale Convective System (MCS) that developed over North Dakota and began moving eastward into Minnesota on 17 July 2020 (surface analyses). These thunderstorms produced a variety of severe weather, and heavy rainfall with up to 6 inches in North Dakota and 4 inches in Minnesota.

1-minute GOES-16 Visible images (above) and Infrared images (below) include time-matched plots of SPC Storm Reports — of particular note was the wind gust of 101 mph (GOES-16 Visible / Infrared images) that occurred at a RAWS site in northeastern North Dakota around 2045 UTC, in the vicinity of a brief tornado. As the MCS continued to expand southward and eastward during the subsequent nighttime hours, it eventually produced damaging winds across northeastern South Dakota, much of Minnesota and northwestern Wisconsin.

Animations of CIMSS Clear Sky Convective Available Potential Energy (CAPE), Lifted Index (LI) and Total Precipitable Water (TPW) products (below), from this site, showed the rapid destabilization and moisture increase of the air mass south and southeast of the developing MCS; this corridor of moist and unstable air was feeding northward, helping to sustain MCS growth and propagation.

These severe thunderstorms with tall cloud tops provided a good demonstration of the parallax shift inherent in GOES imagery at higher latitudes. Time-matched comparisons of Infrared images from NOAA-20 at 1933 UTC and Suomi NPP at 2023 UTC with the corresponding images from GOES-16 (below) showed that the GOES images were shifted northwest of the more accurate NOAA-20/Suomi NPP images.  The superior 375-meter spatial resolution of the VIIRS instrument allowed subtle cloud-top gravity waves to be seen — and the VIIRS cloud-top infrared brightness temperatures were about 10ºC colder than those sensed by the ABI instrument. The 1933 UTC images were about 15 minutes prior to the tornado and 101-mph wind gust at Churches Ferry (located about 20 miles northwest of Devils Lake KDVL).

An image showing parallax correction vectors and distance for a 50,00 ft (15.2 km) cloud top feature at various points within the GOES-16 CONUS domain (below) is from this site — and indicated a southeastward correction of about 28-30 km (or 17-19 miles) over northern North Dakota. This is in good agreement with what was seen in the 2 VIIRS/ABI infrared image comparisons shown above.

View only this post Read Less

As a Mesoscale Convective System (MCS) over Kansas and Oklahoma decayed during the morning hours of 16 July 2020, GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) and Near-Infrared “Cirrus” (1.38 µm) images (above) depicted widespread transverse banding — tendrils of cirrus clouds oriented perpendicular to the upper-tropospheric wind flow — along the northern periphery of the MCS. An AIRMET was issued for that region (advising of moderate turbulence between 30,000 and 43,000 feet), and there were numerous Pilot Reports (PIREPs) of light to moderate turbulence in the general vicinity of these transverse banding features.

A GOES-16 Turbulence Probability product (below) did show scattered pockets of 25-35% probability in the transverse banding region. However, this product is designed to diagnose turbulence potential in the vicinity of features such as fronts and fields of convection.

Such transverse banding cloud features are frequently observed around the periphery of decaying MCSs (for example, June 2018 and July 2016) and in the vicinity of strong upper-tropospheric jet streaks (for example, February 2020 and March 2016).

View only this post Read Less