West Pacific Super Typhoon Trami

September 24th, 2018 |

Himawari-8 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]

Himawari-8 “Clean” Infrared Window (10.4 µm) images (above) showed Typhoon Trami at Category 4 intensity during the 23-24 September 2018 period. The typhoon was going through an eyewall replacement cycle during this time — as seen on the MIMIC-TC product — which halted the period of rapid intensification that began early on 23 September (ADT | SATCON). Note the significant trochoidal motion (wobble) of the storm during the first half of the animation.

With the arrival of daylight late on 24 September UTC (25 September local time), the satellite presentation of then Category 5 Trami was quite striking, with surface mesovorticies within the large eye seen on both Visible and Infrared rapid-scan (2.5-minute interval) images (below). The deep-layer mean steering flow was also very light, allowing the forward motion of Trami to slow considerably.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play animation | MP4]

Trami was in an environment characterized by low values of deep-layer wind shear, as shown in an animation of Himawari-8 Infrared Window (10.4 µm) images from the CIMSS Tropical Ctclones site (below).

Himawari-8 Infrared Window (10.4 µm) images, with deep-layer wind shear analysis at 00 UTC [click to enlarge]

Himawari-8 Infrared Window (10.4 µm) images, with deep-layer wind shear analysis at 00 UTC [click to enlarge]

After nightfall on 25 September, and overpass of NOAA-20 provided VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images of Trami at 1634 UTC (below; courtesy of William Straka, CIMSS). Due to the very slow motion of the typhoon, strong winds had induced upwelling of cooler water from below the ocean surface — which in turn brought a gradual weakening of the storm to a Category 4 intensity. Ample illumination from a Full Moon demonstrated the “visible image at night” capability of the Day/Night Band.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]


Though the eye had become more cloud-filled, distinct surface mesovortices were still present — captured in stunning detail by an astronaut on the International Space Station:


Super Typhoon Mangkhut makes landfall in the Philippines

September 14th, 2018 |

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

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

Himawari-8 Infrared Window (10.4 µm) images (above) showed Super Typhoon Mangkhut making landfall as a Category 5 intensity storm over the far northern portion of Luzon in the Philippines just after 17 UTC on 14 September 2018 (1 am local time on 15 September). The eye quickly deteriorated and became cloud-filled after moving inland.

The MIMIC-TC morphed microwave product (below) indicated that Mangkhut was in the process of completing an eyewall replacement cycle shortly before making landfall.

westernMIMIC-TC morphed microwave product [click to enlarge]Mangkhut moved over waters of the western Philippine Sea having high values of Ocean Heat Content and Sea Surface Temperature during the final day preceding landfall (below).

Ocean Heat Content and Sea Surface Temperature data along the path of Mangkhut [click to enlarge]

Super Typhoon Jebi

August 31st, 2018 |

Himawari-8

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

West Pacific Typhoon Jebi underwent a period of very rapid intensification on 30 August 2018 (ADT | SATCON), reaching Category 5 Super Typhoon intensity. Himawari-8 rapid-scan (2.5 minute interval) “Clean” Infrared Window (10.4 µm) images (above) showed that Jebi began to exhibit an annular appearance with a nearly symmetric eyewall as it moved through the Northern Mariana Islands (north of Guam). The eye passed just south of the uninhabited volcanic island of Pagan around 16 UTC on 30 August.

Himawari-8 “Red” Visible images (below) revealed mesovortices within the eye of Jebi.

Himawari-8

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

Toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP (below) showed more detailed views of (1) the well defined eye, (2) surface mesovortices within the eye, and (3) storm-top gravity waves that were propagating away from the eyewall region. With the Moon in the Waning Gibbous phase (at 77% of Full), ample illumination was available to provide detailed “visible images at night” using the VIIRS DNB.

NOAA-20 Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1602 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1602 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1652 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and infrared Window (11.45 µm) images at 1652 UTC [click to enlarge]

Convective Rain Rate and Surface Rain Rate products derived from GCOM-W1 AMSR2 data (below) showed the heavy rainfall occurring within the eyewall region and a primary feeder band to the west. VIIRS and AMSR2 images courtesy of William Straka, CIMSS.

GCOM-W2 AMSR2 Convective Rain Rate and Surface Rain Rate products [click to enlarge]

GCOM-W2 AMSR2 Convective Rain Rate and Surface Rain Rate products [click to enlarge]

As Jebi tracked west-northwestward across the West Pacific, products from the CIMSS Tropical Cyclones site showed that it had been moving over waters having high values of Sea Surface Temperature and Ocean Heat Content (below).

Track of Jebi, with Sea Surface Temperature and Ocean Heat Content [click to enlarge]

Track of Jebi, with Sea Surface Temperature and Ocean Heat Content [click to enlarge]

A 48-hour animation of the MIMIC-TC product (below) showed the evolution of the Jebi from 29-31 August. The storm was completing an eyewall replacement cycle near the end of the animation, with the eye becoming distinctly larger.

MIMIC-TC product, 29-31 August

In a comparison of DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images at 1900 UTC (below), the Microwave data helped to better visualize the structure of the large eyewall in addition to a long, narrow feeder band wrapping inward toward the eye.

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

Hurricane Lane

August 22nd, 2018 |

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above; courtesy of William Straka, CIMSS) showed the eye of Hurricane Lane in the central Pacific Ocean at 1208 UTC on 22 August 2018, a few hours after it reached Category 5 intensity (SATCON). Surface mesovortices were evident within the eye, and storm-top gravity waves were seen propagating west-southwestward away from the eyewall.

 

GOES-15 (GOES-West) Infrared Window (10.7 µm) images (below) revealed a significant amount of trochoidal motion as Lane moved northwestward during the 21 August – 22 August period. The storm weakened somewhat to Category 4 intensity as of 15 UTC on 22 August.

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

Hurricane Lane was near the limb of the Full Disk view of both Himawari-8 and GOES-17, as seen in a comparison of “Red” Visible (0.64 µm) images from the two satellittes (below).

* GOES-17 images shown here are preliminary and non-operational *

“Red” Visible (0.64 µm) images from Himawari-8 (left) and GOES-17 (right) [click to play animation | MP4]

DMSP-16/17 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site are shown  below.

DMSP-16 SSMIS Microwave (85 GHz) image at 1411 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1411 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1717 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1717 UTC [click to enlarge]

Since forming as Tropical Depression 14E on 14 August. Lane had been moving westward over water having only modest Ocean Heat Content but Sea Surface Temperature values of 27-28ºC (below).

Track of Hurricane Lane, with maps of Ocean Heat Content and Sea Surface Temperature [click to enlarge]

Track of Hurricane Lane, with maps of Ocean Heat Content and Sea Surface Temperature [click to enlarge]

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

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1150 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1150 UTC [click to enlarge]

Hurricane Lane remained at Category 4 intensity during the early hours of 23 August — however, the satellite presentation began to deteriorate as the eye became cloud-filled as seen in toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 1150 UTC (above) and Suomi NPP at 1240 UTC (below). An interesting narrow “warm trench” signature became very pronounced within the northwestern quadrant of Lane on the later Suomi NPP Infrared image.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1240 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1240 UTC [click to enlarge]

GOES-15 Visible (0.63 µm, left) and Infrared Window (10.7 µm, right) images, with hourly plots of data from Buoy 51002 [click to play animation | MP4]

GOES-15 Visible (0.63 µm, left) and Infrared Window (10.7 µm, right) images, with hourly plots of data from Buoy 51002 [click to play animation | MP4]

GOES-15 Visible (0.63 µm) and Infrared Window (10.7 µm) images after sunrise (above) showed that the eye of Lane moved over Buoy 51002 — located about 200 miles southwest of the Big Island of Hawai’i — just after 19 UTC (below). The peak wind gust measured by the buoy was 93 knots or 107 mph ay 1830 UTC; the lowest wind and air pressure values were recorded while in the eye from 1930-2110 UTC.

Plot of wind speed/gust and air pressure data from Buoy 51002

Plot of wind speed/gust and air pressure data from Buoy 51002

At 1703 UTC Buoy 51002 was located just west of the eye, beneath strong convection of the eyewall as seen on a DMSP-17 SSMIS Microwave (85 GHz) image (below).

DMSP-17 SSMIS Microwave (85 GHz) image at 1703 UTC, with and without plots of buoy data [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1703 UTC, with and without plots of buoy data [click to enlarge]

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 2334 UTC or 1:34 pm HST on 23 August is shown below.

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

===== 24 August Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image (above) showed Category 3 Hurricane Lane at 1211 UTC or 2:11 am HST on 24 August. Thin tendrils of high-altitude transverse banding can be seen along the western and northern periphery of the storm.

GOES-15 Infrared Window (10.7 µm) images (below) showed the development of the transverse banding as Lane eventually weakened to a Category 1 storm during the course of the day; a rapid warming of the cloud-top infrared brightness temperatures began around 2100 UTC. Even though the Ocean Heat Content and Sea Surface Temperature in the waters immediately west of Hawai’i were still fairly high, the hurricane was moving into an environment of increasingly unfavorable deep-layer wind shear which acted to decouple the low-level and mid-level circulations and hasten the weakening process.

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Visible (0.63 µm) images (below) provided a slightly closer look at the storm during the daylight hours.

GOES-15 Visible (0.63 µm) images [click to play animation | MP4]

GOES-15 Visible (0.63 µm) images [click to play animation | MP4]

A dramatic difference was seen between Suomi NPP VIIRS Day/Night Band images at 1211 UTC and 2315 UTC (below), as Lane weakened from a Category 3 to a Category 1 hurricane in this 11-hour period.In spite of the rapid weakening, very heavy rainfall continued across much of the State, with 24-hour amounts exceeding 20 inches at some locations on the Big Island of Hawai’i. Note that the Low-Level Circulation Center (LLCC) of Lane had become exposed on the later 2315 UTC image (in spite of a thin veil of cirrus overhead), and was located to the southwest of the rapidly-dissipating convection that was closer to the islands.

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

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

===== 25 August Update =====

On the islands, the highest wind gust associated with Lane was 74 mph — and storm total rainfall amounts greater than 50 inches were recorded, with Hilo setting a record 3-day accumulation of 31.85 inches and a record 4-day accumulation of 36.76 inches. Rainfall rates on the Big Island exceeded 19 inches in 24 hours on 23 July.

Time series of surface reports from Hilo, Hawai'i [click to enlarge]

Time series of surface reports from Hilo, Hawai’i [click to enlarge]

Hourly images of the MIMIC Total Precipitable Water (TPW) product during the period 22-25 August (below) showed the circulation of Lane transporting high amounts of moisture across the Hawaiian Islands. TPW values of 60 mm (2.4 inches) or more were also seen in rawinsonde data from Hilo on many of these days.

MIMIC Total Precipitable Water product during 22-25 August [click to play animation | MP4]

MIMIC Total Precipitable Water product during 22-25 August [click to play animation | MP4]

A toggle between Suomi NPP VIIRS Day/Night Band images from 24 August / 2315 UTC and 25 August / 1152 UTC (below) showed a slow north/northwestward motion of the exposed LLCC of what had further weakened to Tropical Storm Lane.

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

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