Typhoon Kammuri in the West Pacific Ocean, with record cold cloud-top temperatures

November 30th, 2019 |

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

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

2.5-minute interval JMA Himawari-8 AHI “Clean” Infrared Window (10.4 µm) images (above) showed a large canopy of cold cloud-top infrared brightness temperatures (BTs) associated with Category 1 Typhoon Kammuri in the West Pacific Ocean on 30 November 2019. Between 00 UTC and 05 UTC, many of the pulsing overshooting tops exhibited BTs -100ºC or colder (shades of red embedded in black on the coldest end of the scale). — the coldest BT was -103.55ºC at 02:59:44 UTC.

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 0421 UTC as viewed using RealEarth (below) revealed an area of very cold cloud-top infrared BTs (highlighted by the yellow region near the center of the storm). The coldest BT within that yellow area was -109.35ºC — which would qualify as the coldest cloud-top temperature on record as sensed by a meteorological satellite (Weather Underground).

 NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 0420 UTC [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images at 0421 UTC [click to enlarge]

The NOAA-20 VIIRS Infrared image at 0421 UTC is shown below with 2 different color enhancements — the darker blue colors of the 160-to-200 K enhancement help to highlight the colder BT regions (including the coldest 163.8 K or -109.35ºC pixel).

NOAA-20 VIIRS Infrared Window (11.45 µm), with different color enhancements (credit: William Straka) [click to enlarge]

NOAA-20 VIIRS Infrared Window (11.45 µm) image at 0421 UTC, with 2 different color enhancements (credit: William Straka, CIMSS) [click to enlarge]

On the closest (time-wise) Himawari-8 Infrared image at 04:22:15 UTC, the coldest cloud-top BT was -102.5ºC. In a toggle between magnified Himawari-8 Visible and Infrared images at that time (below), the -102.5ºC BT was located within the northernmost cluster of red pixels (where shadowing and texture in the Visible image highlighted the overshooting top).

Himawari-8 Visible (0.64 µm) and Infrared (10.4 µm) images at 0422 UTC [click to enlarge]

Himawari-8 Visible (0.64 µm) and Infrared (10.4 µm) images at 0422 UTC [click to enlarge]

The nearest upper air site was Babelthuop Airport/Koror on Palau Island, located south of the storm — the coldest temperature in their 00 UTC rawinsonde data (below) was -81.9ºC at an altitude of 16.7 km. Assuming that the overshooting top cooled at a lapse rate of around 7.5ºC per km of ascent beyond the -81.9ºC tropopause (reference), the altitude of the coldest -109.35ºC cloud top was likely near 19.5 km.

Plots of 00 UTC and 12 UTC rawinsonde data from Koror, Palau Island [click to enlarge]

Plots of 00 UTC and 12 UTC rawinsonde data from Koror, Palau Island [click to enlarge]

During the daylight hours on 30 November, Himawari-8 “Red” Visible (0.64 µm) images (below) revealed widespread cloud-top gravity waves which were moving outward away from intense convection with overshooting tops near the storm center. Many of these gravity waves were propagating along the tops of tendrils of transverse banding — especially within the southern semicircle of Kammuri.

Himawari-8

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

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Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1604 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1604 UTC (credit: William Straka, CIMSS) [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from Suomi NPP at 1604 UTC (above) and NOAA-20 at 1654 UTC (below) showed mesospheric airglow waves propagating southward in the DNB images.

NOAA-20 Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1654 UTC (credit: William Straka, CIMSS) [click to enlarge]

NOAA-20 Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1654 UTC (credit: William Straka, CIMSS) [click to enlarge]

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6.9 µm) images, with contours of Deep-Layer Wind Shear [click to enlarge]

Himawari-8 Water Vapor (6.2 µm) images, with contours of Deep-Layer Wind Shear [click to enlarge]

Himawari-8 Water Vapor (6.2 µm) images with contours of Deep-Layer Wind Shear (above) indicated that Kammuri was moving through an environment of low to moderate shear. Himawari-8 Water Vapor images with plots of satellite-derived Atmospheric Motion Vectors (below) showed a well-defined outflow channel north of the tropical cyclone.

Himawari-8 Water Vapor (6.9 µm) images, with Derived Motion Winds [click to enlarge]

Himawari-8 Water Vapor (6.2 µm) images, with plots of Derived Motion Winds [click to enlarge]


Himawari-8 (courtesy JMA) and GEO-KOMPSAT-2A (courtesy KMA) visible imagery were combined to create stereoscopic imagery of the storm on 30 November, as shown below from 0000 to 0800 UTC (with missing data between 0100 and 0400 UTC).  View the 3-dimensional image by crossing your eyes and focusing on the third image that becomes apparent in between the two images shown.

Visible (0.64 µm) Imagery from Himawari-8 (left) and GK2A (right) from 0000 to 0800 UTC on 30 November 2019 (Click to animate)

Pyrocumulonimbus cloud in eastern Australia

November 22nd, 2019 |

Himawari-8 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.4 µm, bottom) [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.4 µm, bottom) [click to play animation | MP4]

JMA Himawari-8 AHI “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed the development of a pyrocumlonimbus (pyroCb) cloud produced by bush fires northwest of Sydney, Australia (station identifier YSSY) on 22 November 2019 (surface analyses). In the 3.9 µm images, hot thermal signatures of the bush fires (darker black to red pixels) were apparent; in addition, the cloud tops of the pyroCb cloud appeared warmer (darker gray) than surrounding convective cloud tops. The pyroCb exhibited cloud-top 10.4 µm brightness temperatures colder than -40ºC.

VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as viewed using RealEarth are shown below. Cloud-top 11.45 µm brightness temperatures of the pyroCb were in the -70 to -75ºC range on the later 0407 UTC Suomi NPP image.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

The coldest Himawari-8 10.4 µm brightness temperature (BT) associated with the southernmost thunderstorm was -67.0ºC at 0520 UTC (with the northern pyroCb storm, closer to the fire complex, reaching -66.9ºC at 0500 UTC).  According to 00 UTC rawinsonde data from nearby Williamtown (below), those BTs were 2-3ºC colder than the coded tropopause temp of -64.5ºC at 12.6 km. The VIIRS 11.45 µm BTs were nearly 10ºC colder than the tropopause, suggesting significant penetration of overshooting tops into the lower stratosphere.
Plot of rawinsonde data from Williamtown, New South Wales [click to enlarge]

Plot of rawinsonde data from Williamtown, New South Wales [click to enlarge]

Severe turbulence over coastal South Carolina

November 15th, 2019 |

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of pilot reports and SIGMET boundaries [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence and SIGMET boundaries [click to play animation | MP4]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images (above) revealed the presence of elongated W-E oriented billow clouds, many of which exhibited small-scale ripples that were oriented N-S along the billow cloud tops, over coastal areas of South Carolina and North Carolina on 15 November 2019. An initial SIGMET (November 1) was issued covering airspace over Georgia and South Carolina — Severe Turbulence (plotted in red) was reported at 41,000 feet and at 35,000 feet. A second SIGMET (November 2) was later issued covering airspace over South Carolina and North Carolina.

The same GOES-16 Water Vapor images which include isotachs of RAP40 model maximum wind (at any level) are shown below — most of the Moderate to Severe turbulence reports were occurring within the speed gradient along the poleward (left) edge of a SW-NE oriented jet stream flowing parallel to the coast.

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of pilot reports, SIGMET boundaries, and isotachs of RAP40 model maximum wind [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence, SIGMET boundaries, and isotachs of RAP40 model maximum wind [click to play animation | MP4]

More detailed views of the billow-top ripples were provided by a Terra MODIS Visible image at 1600 UTC, and NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared images as visualized using RealEarth (below).

Terra MODIS Visible (0.65 µm) image, with plots of pilot reports and SIGMET boundaries [click to enlarge]

Terra MODIS Visible (0.65 µm) image, with pilot reports of turbulence and SIGMET boundaries [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images, with pilot reports of turbulence [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images, with pilot reports of turbulence [click to enlarge]

Lake-effect, river-effect and bay-effect cloud bands producing snowfall

November 13th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Day Cloud Phase Distinction RGB images on 07 November [click to play animation | MP4]

During the course of multiple intrusions of arctic air across the Lower 48 states during early November 2019, a variety of lake-effect, river-effect and bay-effect cloud features were generated — many of which produced varying intensities of snowfall. GOES-16 (GOES-East) “Red” Visible (0.64 µm), “Clean:” Infrared Window (10.35 µm) and Day Cloud Phase Distinction Red-Green-Blue (RGB) images on 07 November (above) showed lake-effect clouds streaming south-southeastward across Lake Superior. The Day Cloud Phase Distinction RGB images (in tandem with the Infrared images) helped to highlight which cloud features had glaciated and were therefore more capable of producing moderate to heavy lake-effect snow; the dominant band yielded 5-10 inches of snowfall in the central part of northern Michigan.

On 11 November, GOES-16 Nighttime Microphysics RGB images (below) displayed lake-effect clouds originating from the still-unfrozen waters of Fort Peck Lake in northeastern Montana — these clouds did produce a brief period of light snowfall downstream at Glendive (KGDV). On this particular morning, the lowest temperature in the US occurred in north-central Montana, with -30ºF reported north of Rudyard.

GOES-16 Nighttime Cloud Phase Distinction RGB images on 11 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB images on 11 November [click to play animation | MP4]

On 12 November, cold air moving southward across the Lower Mississippi Valley produced horizontal convective roll clouds which were evident in GOES-16 Nighttime Microphysics RGB and subsequent Visible images after sunrise (below) — one of these narrow cloud bands was likely enhanced by latent heat fluxes as it passed over the comparatively-warm waters of the Mississippi River, and produced accumulating snowfall in downtown Memphis. Note that since Memphis International Airport KMEM was located just east of the cloud band, no accumulating snow was reported there (only a brief snow flurry around 1430 UTC).

GOES-16 Nighttime Microphysics RGB and "Red" Visible (0.64 µm) images on 12 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB and “Red” Visible (0.64 µm) images on 12 November [click to play animation | MP4]

Aqua MODIS Sea Surface Temperature values along parts of the Mississippi River were as warm as the mid-40s F (below).

MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]

Aqua MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]


On 13 November, as the cold air was moving off the US East Coast, GOES-16 Infrared images (below) revealed bay-effect cloud plumes which developed over Chesapeake Bay and Delaware Bay — the Chesapeake Bay plume produced brief periods of light snow at Oceana Naval Air Station in Virginia Beach KNTU from 06-10 UTC (and possibly contributed to snowfall farther south at Elizabeth City, North Carolina KECG).

GOES-16 "Clean" Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

Terra MODIS Sea Surface Temperature values in Chesapeake Bay and Delaware Bay were in the lower to middle 50s F where the bay-effect cloud plumes were originating (below).

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]