Super Typhoon Yutu makes landfall on Tinian and Saipan

October 24th, 2018 |

Himawari-8 “Clean Window” Infrared (10.41 µm) Imagery, 0900-1540 UTC on 24 October 2018 (Click to animate)

Himawari-8 Clean Window Infrared (10.41 µm) imagery shows Super Typhoon Yutu poised to hit Tinian and Saipan in the Marianas Islands, to the northeast of Guam. The 0900 UTC Advisory from the Joint Typhoon Warning Center shows a storm with sustained winds of 145 knots, with strengthening forecast. JMA estimates a surface pressure of 905 hPa! (Link)

(Himawari data courtesy JMA and the NWS Pacific Region)

Update: Landfall on Tinian and Saipan occurred just before 1500 UTC; a closer view using 2.5 minute rapid scan Himawari-8 imagery can be seen here (station plot PGSN is Saipan, where reliable observations ceased after 1452 UTC).

Added: From William Straka, CIMSS. NOAA-20 had a fortuitous overpass, almost directly over Tinian at landfall. The Day Night Band Visible (0.7 µm) Imagery (with a full moon) and 11.45 µm infrared imagery is shown below).

NOAA-20 VIIRS Day Night Band visible (0.7 µm) imagery and I05 infrared (11.45 µm) imagery, 1551 UTC on 24 October 2018 (Click to enlarge)

CIMSS helps manage a Direct Broadcast (DB) antenna at the National Weather Service on Guam, and that antenna received both NOAA-20 and GCOM data as the eye was over, or close to, Tinian.  Microwave imagery from The Advanced Microwave Scanning Radiometer 2 (AMSR-2) on JAXA’s GCOM satellite, below, (courtesy Kathy Strabala, CIMSS) at 36.5 GHz and 89.0 GHz, reveals cloud and rainband structures that infrared imagery cannot.  In particular, the 89.0 GHz imagery suggests the formation of an outer eyewall ouside the very compact inner eye.  This typically is the start of an eyewall replacement cycle.

GCOM AMSR-2 imagery at 36.5 and 89.0 GHz, 1601 UTC on 24 October 2018 (Click to enlarge)

The DB antenna also processed data from NOAA-20, the same overpass as shown above, zoomed in over Tinian. The antenna is able to capture data over much of the western Pacific Basin, as the Day Night Band visible image shows below. A true color image from the previous overpass on Guam, 12 hours earlier, during daytime (0311 UTC on 24 October), is here.

NOAA-20 VIIRS Day Night Band visible (0.7 µm) imagery, 1544 UTC on 24 October 2018 (Click to enlarge)

Hurricane Walaka

October 1st, 2018 |

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 (GOES-West) Infrared Window (10.7 µm) images (above) showed the formation of a well-defined eye of Hurricane Walaka during a period of rapid intensification (ADT | SATCON) from 0000-2330 UTC on 01 October 2018; Walaka was classified a Category 5 hurricane as of the 02 October 00 UTC advisory. Walaka was moving over very warm water with Sea Surface Temperatures of 30ºC.

A 1536 UTC DMSP-16 SSMIS Microwave (85 GHz) image from the CIMSS Tropical Cyclones site (below) revealed a small eye (reported to be 20 nautical miles in diameter at 21 UTC).

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

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

A side-by-side comparison of JMA Himawari-8 and GOES-15 Infrared Window images (below) showed Walaka from 2 different satellite perspectives — the superior spatial resolution of Himawari-8 (2 km, vs 4 km for GOES-15) was offset by the much larger viewing angle. Cloud-top infrared brightness temperatures were -80ºC and colder (shades of violet) from both satellites early in the animation, but warmed somewhat into the -70 to -75ºC range by 00 UTC on 02 October.

Infrared Window images from Himawari-8 (10.3 µm, left) and GOES-15 (10.7 µm, right) [click to play animation | MP4]

Infrared Window images from Himawari-8 (10.3 µm, left) and GOES-15 (10.7 µm, right) [click to play animation | MP4]

===== 02 October Update =====

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]

Walaka remained classified as a Category 5 hurricane until the 15 UTC advisory on 02 October, when it was assigned Category 4 status after some weakening as a result of an overnight eyewall replacement cycle. A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above; courtesy of William Straka, CIMSS) showed the storm at 1240 UTC or 2:40 am local time.

GOES-15 Infrared Window (10.7 µm) images (below) showed the northward motion of Waleka. Given that the storm was forecast to pass very close to Johnston Atoll, the US Coast Guard was dispatched to evacuate personnel on Johnston Island.

GOES-15 Infrared Window (10.7 µm) images; the white circle shows the location of Johnston Atoll [click to play animation | MP4]

GOES-15 Infrared Window (10.7 µm) images; the white circle shows the location of Johnston Atoll [click to play animation | MP4]

The MIMIC-TC product (below) showed the eyewall replacement cycle during the 0000-1445 UTC period.

MIMIC-TC morphed microwave product [click to play animation]

MIMIC-TC morphed microwave product [click to play animation]

Around 1830 UTC, a toggle between GOES-15 Infrared (10.7 µm) and GPM GMI Microwave (85 GHz) images (below) showed a small eye, with evidence of a larger outer eyewall suggesting that another eyewall replacement cycle was taking place.

GOES-15 Infrared Window (10.7 µm) and GPM GMI Microwave (85 GHz) images [click to enlarge]

GOES-15 Infrared Window (10.7 µm) and GPM GMI Microwave (85 GHz) images [click to enlarge]

Hurricane Florence

September 9th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) iimages [click to play MP4 animation]

After previously weakening from a Category 4 hurricane (on 04 September) to a tropical storm on 07 September (track/intensity), Florence re-intensified to become a Category 1 hurricane at 15 UTC on 09 September 2018. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.63 µm) are shown above, with the corresponding “Clean” Infrared Window (10.3 µm) images shown below. An eye structure appeared for brief intervals during the day, but was often masked by cloud debris from a series of convective bursts within the surrounding eyewall.

GOES-16

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

GPM GMI Microwave (85 GHz) image at 1811 UTC [click to enlarge]

GPM GMI Microwave (85 GHz) image at 1811 UTC [click to enlarge]

GPM GMI (above) and DMSP-16 SSMIS (below) Microwave (85 GHz) images from the CIMSS Tropical Cyclones site revealed that the eye was still partially open at 1811 UTC and 1945 UTC.

DMSP-16 SSMIS Microwave (85 GHz) image at 1845 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1845 UTC [click to enlarge]

===== 10 September Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with GLM Group lightning [click to enlarge]

GOES-16 GLM lightning Groups (aggregates of GLM lightning Events) are plotted on “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below), courtesy of Dave Santek, SSEC.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with GLM Group lightning [click to enlarge]

Overlapping GOES-16 and GOES-17 Mesoscale Domain Sectors were positioned over Hurricane Florence beginning at 1200 UTC (providing imagery at 30-second intervals) — Visible animations are shown below.

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

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-17

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

Longer animations of 30-second GOES-16 Visible and Infrared images viewed using AWIPS (below) provided a better view of  the mesovortices within the eye. Florence rapidly intensified (ADT | SATCON) to a Category 4 hurricane during this period.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16

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

One particularly large mesovortex rotated around the eastern edge of the eye after 2100 UTC, significantly eroding the eyewall (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16

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

Later in the early evening hours, GOES-16 Infrared imagery (below) showed an area of pronounced cloud-top warming and a thinning of cloud material just south of the eyewall, as Florence began to undergo an eyewall replacement cycle.

GOES-16

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

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]