Transverse banding associated with a decaying Mesoscale Convective System

August 7th, 2021 |

GOES-16 Mid-level Water Vapor (6.9 µm) and “Clean” Infrared Window (10.35 µm) images, with pilot reports of turbulence plotted in cyan/yellow [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) and “Clean” Infrared Window (10.35 µm) images, with pilot reports of turbulence plotted in cyan/yellow [click to play animation | MP4]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) revealed the formation of transverse banding along the eastern periphery of a decaying Mesoscale Convective System in the Upper Midwest during the morning hours on 07 August 2021. Transverse banding is a satellite signature that usually indicates an enhanced potential of turbulence (reference)— and there were indeed multiple reports of light-to-moderate turbulence within the 26-50,000 feet altitude range (cyan).


CIMSS Scientists have used machine-learning to create a predictive tool for moderate-or-greater (MOG) turbulence based in part on satellite imagery. The product for 1405 UTC on 7 August is shown below. A maximum is anchored on the MCS. This product is available online here. Training for this product is here.

Probability of Moderate-or-Greater turbulence, 1405 UTC on 7 August 2021 (Click to enlarge)

Chemtool facility fire in Rockton, Illinois

June 14th, 2021 |

GOES-16 "Red Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Fire Power and Fire Temperature derived products (above) showed the dark black smoke plume and thermal signature of a fire from an explosion at the Lubrizon Corporation Chemtool facility at Rockton in far northern Illinois on 14 June 2021. The thick smoke plume obscured the satellite’s view of the fire point source much of the time, preventing the continuous derivation of Fire Power and Fire Temperature products (and masking the thermal anomaly in the Shortwave Infrared images).

However, a comparison of Shortwave Infrared images from GOES-17 (GOES-West) and GOES-16 (below) revealed that the western satellite’s viewing angle allowed the thermal anomaly of the fire source (hot black-enhanced pixel) to be seen for a longer time period — even after the dark smoke plume had become well established.

Shortwave Infrared (3.9 µm) images from GOES-17 (left) and GOES-16 (right) [click to play animation | MP4]

Shortwave Infrared (3.9 µm) images from GOES-17 (left) and GOES-16 (right) [click to play animation | MP4]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images with plots of pilot reports (below) indicated that the smoke existed at altitudes of 2500 to 3000 feet, but was not restricting the surface visibility at sites that were downwind of the fire.

GOES-16 Near-Infrared "Vegetation" (0.86 µm) image, with plots of pilot reports and airport ceilings and visibility [click to enlarge]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images, with plots of pilot reports (yellow) and airport ceilings and visibility (cyan) [click to enlarge]

Closer views of GOES-16 Near-Infrared “Vegetation” images created using Geo2Grid (below) showed the southward transport of dark smoke as the fire continued to burn into the afternoon hours.

GOES-16 Near-Infrared "Vegetation" (0.86 µm) images [click to play animation | MP4]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images (credit: Tim Schmit, NOAA/NESDIS) [click to play animation | MP4]

Due to the very dark character of this particular smoke plume, it showed up much better against the more reflective surface in 0.86 µm imagery (compared to 0.64 µm “Red” Visible imagery), as seen in the image toggle below.

GOES-16 "Red" Visible (0.64 µm) and Near-Infrared "Vegetation" (0.86 µm) images at 1516 UTC (credit: Tim Schmit, NOAA/NESDIS) [click to enlarge]

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Vegetation” (0.86 µm) images at 1516 UTC (credit: Tim Schmit, NOAA/NESDIS) [click to enlarge]

The dark smoke plume was also evident in various GOES-16 RGB combinations, such as True Color, Day Land Cloud, and Day Snow Fog (below). True Color RGB images showed that the smoke eventually drifted over far western Indiana.

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

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

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

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

GOES-16 Day Snow Fog RGB images [click to play animation | MP4]

GOES-16 Day Snow Fog RGB images (credit: Tim Schmit/NOAA/NESDIS) [click to play animation | MP4]

 

 

 

Ice motion in Norton Sound, and an aircraft dissipation trail over the North Slope of Alaska

May 28th, 2021 |

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

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

GOES-17 (GOES-West) “Red” Visible (0.64 um) images (above) showed the motion of ice within Norton Sound — inbound early in the day, transitioning to outbound later in the day — on 28 May 2021. This ice motion was likely driven primarily by tidal motions within the Sound; for example, a plot of tide height for Unalakeet (below) depicted rising tide (water moving into the Sound) from 04-20 UTC followed by falling tide (water moving out of the Sound) after 20 UTC.

Plot of tide height at Unalakeet, Alaska on 28 May [click to enlarge]

Plot of tide height at Unalakeet, Alaska on 28 May [click to enlarge]

Farther inland over the Alaska North Slope, comparisons of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images at 1838 and 2015 UTC (below) revealed the formation and subsequent expansion of an “aircraft dissipation trail”. As an aircraft — likely headed to or from Prudhoe Bay — flew through a relatively thin cloud layer composed of supercooled water droplets, it caused glaciation of supercooled water droplets along its flight path (which then fell out of the cloud as snow).

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

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

1-minute GOES-17 Day Cloud Phase Distinction RGB images created using Geo2Grid (below) showed the formation and growth of the aircraft dissipation trail.

GOES-17 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-17 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

===== 29 May Update =====

GOES-17 “Red” Visible (0.64 um) images, with plots of NAM12 model winds (green barbs) and Metop-A ASCAT winds (red bars) [ click to play animation | MP4]

GOES-17 “Red” Visible (0.64 um) images, with plots of NAM12 model surface winds (green barbs) and Metop-A ASCAT winds (red barbs) [click to play animation | MP4]

On the following day, 1-minute GOES-17 Visible images (above) showed a similar inbound/outbound diurnal shift in the direction of ice flow within Norton Sound. Plots of NAM12 model surface winds and Metop-A ASCAT surface scatterometer winds indicated that the ice motion was generally orthogonal to surface wind direction — which reaffirmed that tides were the primary factor influencing ice motion during those 2 days.

Thunderstorms northeast of Guam

April 2nd, 2021 |

Himawari-8 Band 13 Clean Window infrared imagery (10.41 µm) from 2300 UTC on 1 April through 1100 UTC 2 April (Click to enlarge)

The animation above shows Himawari full-disk imagery from 2300 UTC on 1 April through 1140 UTC on 2 April and depicts a cluster of thunderstorms over the Pacific Ocean far to the northeast of Guam.  A particular challenge in diagnosing atmospheric events over the open Pacific is the lack of data.  In this case, a timely NOAA-20 overpass (around 0300 UTC), below, allowed for the use of NOAA-Unique Combined Atmospheric Processing System (NUCAPS) profiles to describe the atmosphere in and around this ongoing convection.

NOAA-20 NUCAPS Sounding Availability points, 0300 UTC on 2 April 2020 (click to enlarge)

The toggles below shows Total totals index and Tropopause heights over the Pacific Ocean around Guam and northeastward over the developing convection.  Modest instability surrounds the convective cluster (TT values from 40-44);  somewhat more unstable air (TT > 46) is diagnosed to the northwest of the convection.   Tropopause heights surrounding the convection are high, around 200 mb.  Much lower tropopause heights are diagnosed over the northern part of the domain, and the more unstable TT values are in a region where the tropopause height is sloping.

HImawari-8 Clean Window infrared imagery (10.41 µm) overlain with NUCAPS-derived Total Totals indices (with and without labels) at 0312 UTC on 2 April 2021 (click to enlarge)

Himawari-8 Clean Window infrared imagery (10.41 µm) overlain with NUCAPS-derived estimates of tropopause heights, 0312 UTC on 2 April 2021 (Click to enlarge)


Himawari-8 infrared (Clean Window, 10.41 µm) imagery and NUCAPS-derived lapse rates, 925-700 mb, 0312 UTC on 2 April 2021

NUCAPS can also show you lapse rates within the atmosphere.  It is important when viewing lapse rates to consider that the vertical resolution of NUCAPS profiles is typically not greater than 10 layers within the tropopause.  The toggle above shows lapse rates from 925-700 mb; lapse rates from 850-500 mb are shown below. These domains are is a bit larger than the domain used in showing the tropopause height and Total Totals index above.  The 925-700 mb lapse rates show two regions:  relatively weak stability, with lapse rates around 5 or 6 C/km south of 30 N Latitude, and much stronger stability (Lapse rates closer to 3 C / km ) north of that latitude, to the east of Japan.

The 850-500 mb lapse rates similarly show two general regions:  not as stable south of 30 N, much more stable east of Japan.  There is a more concentrated region of lower stability, however, along the leading edge of the sloped tropopause, at 850-500 mb compared to 925-700 mb, and the 850-500 mb values show larger lapse rates in the air to the east of Japan.  This toggle shows the 925-700 and 850-500 mb lapse rates directly.

Himawari-8 infrared (Clean Window, 10.41 µm) imagery and NUCAPS-derived lapse rates, 850-500 mb, 0312 UTC on 2 April 2021

 


This region of the Pacific Ocean is scanned by both the Advanced Himawari Imager (AHI) on JMA’s Himawari-8 satellite and the similar Advanced Meteorological Imager (AMI) on KMA’s GK2A satellite.  The animation below combines visible imagery from the two satellites at 0100, 0110, 0230 and 0400 UTC to create a pseudostereocopic image of the convection.

Himawari-8 (left) and GK2A (right) visible imagery (0.64 µm) at 0100, 0110, 0230 and 0400 UTC 2 April (Click to enlarge)


Developing (and ongoing) thunderstorms are usually locations of turbulence. The CIMSS Turbulence product, shown below for the region from 0000 UTC to 0350 UTC, and available online here, does show elevated turbulence probabilities over the convection (located over the western part of the domain shown below).

Turbulence probability plotted on top of Himawari-8 grey-scale water vapor imagery, 0000 – 0350 UTC on 2 April 2021 (Click to enlarge)

Himawari-8 imagery in this blog post courtesy of JMA; GK2A imagery in the blog post courtesy of KMA. Thanks to Brandon Aydlett, WFO Guam, for alerting us to this interesting case.