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]

Hurricane Bud

June 12th, 2018 |

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

East Pacific Hurricane Bud peaked at Category 4 intensity (ADT | SATCON) around 06 UTC on 12 June 2018 (just 4 days after Hurricane Aletta reached the same intensity) — and a GOES-16 (GOES-East) Mesoscale Sector was positioned over the storm about an hour before that time, providing “Clean” Infrared Window (10.3 µm) images at 1-minute intervals (above).

A post-sunrise comparison of 1-minute GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images is shown below.

GOES-16 "Red" Visible (0.64 µm, left) and "Clean" Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Ocean Heat Content and Sea Surface Temperature analyses, with the track of Hurricane Bud ending at 12 UTC on 12 June [click to enlarge]

Ocean Heat Content and Sea Surface Temperature analyses, with the track of Hurricane Bud ending at 12 UTC on 12 June [click to enlarge]

As mentioned in the NHC discussion at 15 UTC, Bud was beginning to move over water having lower values of Ocean Heat Content and Sea Surface Temperature (above), which would lead to rapid weakening — in fact, an erosion of the northern eyewalll was seen in DMSP-16 SSMIS Microwave imagery at 1105 UTC (below).

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

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

Hurricane Aletta

June 7th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Tropical Storm Aletta was upgraded to Hurricane Aletta at 21 UTC on 07 June 2018. As was the case on 06 June, a GOES-16 Mesoscale Domain Sector centered over the tropical cyclone provided 1-minute data — and an eye eventually became apparent on  “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) imagery (above).

DMSP-15, DMSP-17 and GPM GMI Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed an increase in organization of the eye structure as the day progressed.

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-15 SSMI Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

DMSP-17 SSMIS Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

GPM GMI Microwave image [click to enlarge]

===== 08 June Update =====

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

Aletta went through a period of rapid intensification (ADT | SATCON), reaching Category 4 status by 15 UTC on 08 June. 1-minute GOES-16 Infrared (10.3 µm) images (above) showed the eye becoming more well-defined during the pre-dawn hours.

After sunrise, GOES-16 Visible images (below) initially hinted at the presence of mesovortices within the eye of Aletta.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Aletta had been moving over relatively warm water and within an environment characterized by low values of deep-layer wind shear (below) — both  of which were favorable factors for intensification. An animation of the deep-layer wind shear over the East Pacific Ocean during 06-07 June is available here.

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Sea Surface Temperature and Deep-Layer Wind Shear products [click to enlarge]

Aletta peaked in intensity later in the day on 08 June (ADT | SATCON) — as pointed out by NHC “This is also consistent with GOES-16 measurements of increased inner-core lightning observed to be occurring to the east of the eastern eyewall, which some research suggests corresponds to a halting of the intensification process”. GOES-16 Infrared (10.3 µm) imagery with GLM Group Density counts are shown below.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) with GLM Group Density counts [click to play MP4 animation]

Cyclone Kelvin makes landfall in Australia

February 18th, 2018 |

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface plots at Broome [click to play Animated GIF | MP4 also available]

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface plots at Broome, Australia [click to play Animated GIF | MP4 also available]

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (above) showed Cyclone Kelvin as it made landfall in Western Australia as a Category 1 storm on 18 February 2018. Kelvin continued to intensify shortly after making landfall, with estimated winds of 80 gusting to 100 knots — and a distinct eye feature could be seen in the Visible and Infrared imagery (as well as Broome radar data).

A longer animation of Himawari-8 Infrared Window (10.4 µm) images (below) revealed a very large convective burst as Kelvin meandered near the coast early on 17 February — periodic cloud-top infrared brightness temperatures of -90 ºC or colder were seen. After making landfall, the eye structure eventually deteriorated by 18 UTC on 18 February.

Himawari-8 Infrared Window (10.4 µm) images, with hourly surface plots [click to play MP4 | Animated GIF also available]

Himawari-8 Infrared Window (10.4 µm) images, with hourly surface plots [click to play MP4 | Animated GIF also available]

The MIMIC-TC product (below) showed the development of Kelvin’s compact eye during the 17 February – 18 February period; the eye was well-defined around the time of landfall (2147 UTC image on 17 February), and persisted for at least 18 hours (1556 UTC image on 18 February) until rapidly dissipating by 21 UTC.

MIMIC-TC morphed microwave imagery [click to enlarge]

MIMIC-TC morphed microwave imagery [click to enlarge]

Himawari-8 Deep Layer Wind Shear values remained very low — generally 5 knots or less — prior to, during and after the landfall of Kelvin, which also contributed to the slow rate of weakening. In addition, an upward moisture flux from the warm/wet sandy soil of that region helped Kelvin to intensify after landfall; land surface friction was also small, since that portion of Western Australia is rather flat.

Himawari-8 Water Vapor images, with Deep Layer Wind Shear product [click to enlarge]

Himawari-8 Water Vapor images, with Deep Layer Wind Shear product [click to enlarge]

The eye of Cyclone Kelvin could also be seen in Terra MODIS and Suomi NPP VIIRS True-color Red-Green-Blue (RGB) images, viewed using RealEarth (below). The actual times of the Terra and Suomi NPP satellite overpasses were 0154 UTC and 0452 UTC on 18 February, respectively.

Terra MODIS and Suomi NPP VIIRS True-color RGB images [click to enlarge]

Terra MODIS and Suomi NPP VIIRS True-color RGB images [click to enlarge]