Typhoon Lionrock in the West Pacific

August 27th, 2016

Track of Typhoon Lionrock [click to enlarge]

Track of Typhoon Lionrock [click to enlarge]

Typhoon Lionrock (12W) in the West Pacific Ocean briefly intensified to Category 4 during the northeastward motion segment of its rather unusual track (above) — the intensity estimate from the Advanced Dvorak Technique peaked at 112.4 knots from 2140 UTC on 26 August to 0630 UTC on 27 August (plot | text).

During this period of intensification, 2.5 minute interval rapid-scan Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (below; also available as a large 85 Mbyte animated GIF) revealed complex patterns of cloud-top radial and transverse banding. Surface mesoscale vortices were also seen at times within the open eye feature.

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

A few hours later, the Category 3 intensity typhoon continued to exhibit a well-defined eye structure in both DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images around 18 UTC (below).

DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

During the nighttime hours preceding the intensification to Category 4, a comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below; courtesy of William Straka, SSEC) showed the eye of Lionrock at 1631 UTC on 26 August.

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

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

===== 28 August Update =====

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Typhoon Lionrock again intensified to a Category 4 storm on 28 August; a comparison of 2.5 minute interval rapid-scan Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images is shown above (also available as a large 68 Mbyte animated GIF).

323 reindeer killed by lightning in Norway

August 26th, 2016

GFS model fields of surface pressure, 6-hour precipitation, 850 hPa temperature, and 10-m wind [click to play animation]

GFS model fields of surface pressure, 6-hour precipitation, 850 hPa temperature, and 10-m wind [click to play animation]

GFS model fields from this site (above) showed a relatively compact storm that was deepening as it moved northeastward across southern and central Norway on 26 August 2016.

EUMETSAT Meteosat-10 Visible (0.75 µm) and Infrared Window (10.8 µm) images (below; also available as an MP4 animation) revealed the development of thunderstorms over southern Norway during the 0900-1300 UTC period. Cloud-to-ground lightning from one of these storms is believed to have killed 323 reindeer near the southeastern corner of the Hardangervidda National Park (which is located in the center of the visible and infrared satellite images).

Meteosat-10 Visible (0.75 µm, top) and Infrared Window (10.8 µm, bottom) images, with surface reports plotted in cyan [click to play animation]

Meteosat-10 Visible (0.75 µm, top) and Infrared Window (10.8 µm, bottom) images, with surface reports plotted in cyan [click to play animation]

The coldest cloud-top infrared brightness temperatures of the thunderstorms on the 1100 UTC image was -51º C, which corresponded to an altitude of around 10.5 km on the 1200 UTC Ørland rawinsonde report (below) — looking at the individual sounding profiles, Ørland to the north of Hardangervidda was still in the moist convective environment near the center of the storm system, while Stavanger to the south began to show the drier air aloft in the wake of the northeastward-moving storm.

Rawinsonde data from Stavanger and Orland, Norway [click to enlarge]

Rawinsonde data from Stavanger and Orland, Norway [click to enlarge]

A composite of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image swaths as viewed using RealEarth (below) showed the widespread thunderstorms across southern Norway on the earlier (eastern) 1103 UTC overpass, while the later (western) 1243 UTC overpass showed the effects of the mid-level drier air that was beginning to overspread the region as the center of the parent storm system moved northeast.

Suomi NPP VIIRS true-color image swaths [click to enlarge]

Suomi NPP VIIRS true-color image swaths [click to enlarge]

GOES-14 SRSO-R: pyrocumulus clouds over the Rey Fire in California

August 22nd, 2016

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

The GOES-14 satellite was in SRSO-R mode on 22 August 2016, providing images at 1-minute intervals over the western United States. A 3-panel comparison of Visible (0.63 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.7 µm) images (above; also available as a large 110 Mbyte animated GIF) showed that there were multiple bursts of pyrocumulus (pyroCu) clouds over the Rey Fire in southern California — while the bulk of the smoke was being transported westward over the offshore waters of the Pacific Ocean, smoke that was ejected to higher altitudes by the pyroCu clouds sent a plume of smoke drifting to the southeast.

The nearby Vandenberg rawinsonde data profile (below) suggests that the pyroCu clouds vertically lofted smoke to an altitude of at least 6.7 km (the 449 mb pressure level), where winds shifted to a northwesterly direction. However, since the pyroCu cloud-top IR brightness temperatures never even made it to -20º C (cyan color enhancement on the bottom panels), the smoke probably wasn’t much higher than the 6.7 km altitude (sounding data).

Vandenberg Air Force Base rawinsonde report [click to enlarge]

Vandenberg Air Force Base rawinsonde report [click to enlarge]

A comparison of Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images displayed using RealEarth (below) showed the dense plume of smoke drifting westward away from the active fire area (brighter shades of pink on the false-color image), along with a pyroCu cloud over the fire and the early stage of the southeastward-moving smoke plume aloft.

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

GOES-14 SRSO-R: wildfire in Idaho

August 21st, 2016

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4 animation]

The Pioneer Fire in central Idaho produced another pyroCumulonimbus (pyroCb) cloud on 21 August 2016 (the first was on 19 August). GOES-14 was in SRSO-R mode, and sampled the fire with 1-minute imagery (above; also available as a large 73 Mbyte animated GIF) — a large smoke plume was evident on 0.63 µm Visible images as it moved eastward; large fire hot spots (red pixels) were seen on 3.9 µm Shortwave Infrared images; on 10.7 µm Infrared Window images, the cloud-top IR brightness temperature cooled to -35º C (darker green enhancement) between 2249-2307 UTC as it moved over Stanley Ranger Station (KSNY), not quite reaching the -40º C threshold to be classified as a pyroCb.

However, a 1-km resolution NOAA-19 AVHRR 10.8 µm Infrared Window image (below; courtesy of René Servranckx) revealed a minimum cloud-top IR brightness temperature of -48.3º C (dark green color enhancement).

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

A larger-scale comparison of the NOAA-19 AVHRR visible, shortwave infrared and infrared window images is shown below.

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

===== 23 August Update =====

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

The Pioneer Fire continued to be very active on 22 August (exceeding 100,000 acres in total burn coverage since its start on 18 July), sending a large amount of smoke northeastward (OMPS Aerosol Index). During the following overnight hours, cold air drainage and the development of a boundary layer temperature inversion acted to trap a good deal of smoke in the Payette River valley to the west/southwest of Stanley KSNT. The active fire hot spots (black to yellow to red pixels) were evident on nighttime (1032 UTC or 4:32 AM local time) images (above) of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) data, while illumination from the Moon (in the Waning Gibbous phase, at 69% of Full) showed the ribbon of smoke trapped in the valley (note that this signal was not due to fog, since it did not show up in the VIIRS 11.45-3.74 µm brightness temperature difference or “fog/stratus product”).

During the subsequent daytime hours of 23 August, 1-minute GOES-14 Visible (0.63 µm) images (below; also available as a large 114 Mbyte animated GIF) showed the gradual ventilation of smoke from the Payette River valley as the temperature inversion eroded and mixing via winds increased.

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]