Hurricane Florence off the coast of North Carolina

September 13th, 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]

A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) showed Category 2 Hurricane Florence off the coast of North Carolina at 0646 UTC on 13 September 2018. GCOM AMSR2 Microwave (89 GHz), Convective Rain Rate and Surface Rain Rate (below) indicated that the southern and southeastern portions of the eye and eyewall had become fragmented. (VIIRS and AMSR2 imagery courtesy of William Straka, CIMSS)

GCOM AMSR2 Microwave (89 GHz), Convective Rain Rate and Surface Rain Rate [click to enlarge]

GCOM AMSR2 Microwave (89 GHz), Convective Rain Rate and Surface Rain Rate [click to enlarge]

In a toggle between DMSP-17 SSMIS Microwave (85 GHz) and GOES-16 Infrared Window (10.3 µm) images from the CIMSS Tropical Cyclones site (below), microwave imagery revealed the very large internal core of the hurricane at 1216 UTC.

DMSP-17 SSMIS Microwave (85 GHz) and GOES-16 Infrared Window (10.3 µm) images [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) and GOES-16 Infrared Window (10.3 µm) images [click to enlarge]

The Metop-A satellite passed over the western edge of Florence, with ASCAT sensing surface winds as high as 66 knots along the western edge of the storm core (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm) image at 1427 UTC, with plots of buoy reports and Metop-A ASCAT surface scatterometer winds [click to enlarge]

Comparisons of Visible and Infrared Window images from Terra MODIS (1538 UTC), NOAA-20 VIIRS (1804 UTC) and Suomi NPP VIIRS (1854 UTC) are shown below.

Terra MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images at 1538 UTC [click to enlarge]

Terra MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images at 1538 UTC [click to enlarge]

NOAA-20 VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1804 UTC [click to enlarge]

NOAA-20 VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1804 UTC [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1854 UTC [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1854 UTC [click to enlarge]

As Florence approached the coast, it moved over Gulf Stream waters as warm as 82-85ºF, as seen in a comparison of 12 September MODIS Sea Surface Temperature product and 13 September MODIS Visible images (below).

12 September Terra MODIS Sea Surface Temperature product and 13 September Terra MODIS Visible (0.65 µm) image [click to enlarge]

12 September Terra MODIS Sea Surface Temperature product and 13 September Terra MODIS Visible (0.65 µm) image [click to enlarge]

The strong winds associated with Florence created large waves which induced upwelling of colder water from below the ocean surface:


Overlapping GOES-16 (GOES-East) Mesoscale Domain Sectors were providing images every 30 seconds; “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) animations are shown below. Note that a secondary eyewall began to form following a convective burst which developed southwest of the eye around 1920 UTC (Visible | Infrared) — and as the new eyewall convection quickly wrapped around to the north, Cape Lookout, North Carolina (Buoy CLKN7) recorded a peak wind speed of 73 knots at 20 UTC and 21 UTC.

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]

The large pattern of upper-tropospheric outflow was quite apparent on GOES-16 Near-Infrared “Cirrus” (1.37 µm) images (below) — spanning a distance of approximately 1000 miles.

GOES-16 Near-Infrared "Cirrus" (1.37 µm) images [click to play MP4 animation]

GOES-16 Near-Infrared “Cirrus” (1.37 µm) images [click to play MP4 animation]

Hurricane Florence continues to approach the southeastern US

September 11th, 2018 |

GOES-16

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

Hurricane Florence maintained Category 4 intensity on the morning of 11 September 2018 — and 1-minute (initially 30-second, until 1345 UTC) Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) and “Clean” Infrared Window (10.3 µm) images (below) showed improving eye structure after the tropical cyclone completed an eyewall replacement cycle during the preceding nighttime hours (MIMIC TC). A distinct pattern of transverse banding was also evident within the northern semicircle of Florence on Infrared imagery.

GOES-16

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

DMSP-18 SSMIS Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed a large eye at 1015 UTC, and also at 1103 UTC.

DMSP-18 SSMIS Microwave (85 GHz) and GOES-16

DMSP-18 SSMIS Microwave (85 GHz) and GOES-16 “Clean” Infrared Window (10.3 µm) images at 1015 UTC [click to enlarge]

GOES-16 Upper-level Water Vapor (6.2 µm) images with Derived Motion Winds (below) revealed that a well-defined high altitude outflow channel had developed northwest of Florence, helping the storm to maintain its intensity.

GOES-16 Upper-level Water Vapor (6.2 µm) images, with Derived Motion Winds [click to play MP4 animation]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with Derived Motion Winds [click to play MP4 animation]

1-minute GOES-16 True Color Red-Green-Blue (RGB) images (courtesy of Kathy Strabala, CIMSS; details) are shown below. A larger-scale RGB animation beginning at sunrise is available here (courtesy of Rick Kohrs, SSEC).

GOES-16 natural color RGB images [click to play MP4 animation]

1-minute GOES-16 True Color RGB images, 1330-1440 UTC [click to play MP4 animation]

Taking a closer look at the center of Florence later in the day, 1-minute GOES-16 data (below) showed mesovortices within the eye on Visible imagery, along with a narrow radial band of colder (darker red) cloud-top infrared brightness temperatures about 30-50 miles from the inner edge of the eyewall.

GOES-16

GOES-16 “Red” Viisible (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]

===== 12 September Update =====

Florence remained at Category 4 intensity early in the day as it continued its northwestward motion toward the southeast coast of the US on 12 September. A 20-hour period of 1-minute GOES-16 Infrared images (from 0000-2015 UTC) is shown below.

1-minute GOES-16

1-minute GOES-16 “Clean” Infrared Window (10.3 µm) images, from 0000-2015 UTC [click to play MP4 animation]

Nighttime toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 are shown below (courtesy of William Straka, CIMSS). Bright lightning-illuminated cloud areas can be seen on the DNB images distant to the north and northwest of the storm center; with minimal illumination from the Moon (which was in the Waxing Crescent phase, at only 10% of Full), Florence was illuminated primarily via airglow. On the Infrared images, a coarse pattern of transverse banding was evident along the far southern and western periphery of the storm.

Suomi NPP VIIRS Day/Night Band and Infrared Window images [click to enlarge]

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

NOAA-20 VIIRS Day/Night Band and Infrared Window images [click to enlarge]

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

A sequence of Terra/Aqua MODIS and Suomi NPP VIIRS Infrared images (below) showed dramatic changes in the cold central dense overcast (CDO) of Florence between 02 and 18 UTC.

Infrared Window images from Terra MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from Terra MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

During the morning hours, 1-minute GOES-16 Visible and Infrared images (below) once again displayed a distinct eye and eyewall structure, with surface mesovortices evident within the eye. A curious linear standing wave — extending radially outward to the northeast of the storm center — developed from about 13-15 UTC (best seen on Infrared images).

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]

ASCAT surface scatterometer winds from Metop-A (below) were as strong as 76 knots just northeast of the eye at 1450 UTC.

GOES-16

GOES-16 “Red” Visible (0.64 µm) image with Metop-A ASCAT surface scatterometer winds [click to enlarge]

A stereoscopic animation using GOES-16 and GOES-17 imagery is shown below — to view in three dimensions, cross your eyes until 3 equal images are apparent, then focus on the image in the center. *Note: GOES-17 images shown here are preliminary and non-operational*

Stereoscopic animation using GOES-16 and GOES-17

Stereoscopic animation using GOES-16 and GOES-17 “Red” Visible (0.64 µm) imagery [click to play animation]

During the afternoon hours, GOES-16 Visible and Infrared images (below) showed that the eye presentation  was beginning to deteriorate as Florence weakened to Category 3 intensity by 21 UTC.

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]

The MIMIC Total Precipitable Water product (below) indicated that high TPW values associated with Florence began to move inland along the US East Coast by the end of the day.

MIMIC Total Precipitable Water product [click to enlarge]

MIMIC Total Precipitable Water product [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]