Hurricane Rosa

September 28th, 2018 |
GOES-15 Ifrared Window (10.7 µm, left) and GOES-17

GOES-15 Infrared Window (10.7 µm, left) and GOES-17 “Clean” Infrared Window (10.3 µm, right) images [click to play animation | MP4]

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

GOES-15 (GOES-West) Infrared Window (10.7 µm) and GOES-17 “Clean” Infrared Window (10.3 µm) images (above) showed Hurricane Rosa on the morning of 28 September 2018, after it had rapidly intensified to Category 4 intensity overnight (ADT | SATCON). Since GOES-17 was operating in a Mode 6 scan strategy, images were available every 10 minutes (compared to every 15 minutes from GOES-15, with 30-minute gaps during Full Disk scans every 3 hours). A notable warming trend was seen in the cloud tops surrounding the eye.

A toggle between DMSP-18 SSMIS Microwave (85 GHz) and GOES-15 Infrared Window (10.7 µm) from the CIMSS Tropical Cyclones site (below) showed the bands of heavier precipitation withing the central dense overcast surrounding the eye at 1333 UTC.

DMSP-18 SSMIS Microwave (85 GHz) and GOES-15 Infrared Window (10.7 µm) images [click to enlarge]

DMSP-18 SSMIS Microwave (85 GHz) and GOES-15 Infrared Window (10.7 µm) images [click to enlarge]

After sunrise, a comparison of GOES-15 Visible (0.63 µm) and GOES-17 “Red” Visible (0.64 µm) images (below) revealed an eye that was filled with low-level clouds.

GOES-15 Visible (0.63 µm, left) and GOES-17 "Red" Visible (0.64 µm, right) images [click to play animation | MP4]

GOES-15 Visible (0.63 µm, left) and GOES-17 “Red” Visible (0.64 µm, right) images [click to play animation | MP4]

An animation of the MIMIC-TC product (below) showed that Rosa went through an eyewall replacement cycle during the morning, and was downgraded to a Category 3 intensity at 15 UTC.

MIMIC-TC morphed microwave product, 0000-1545 UTC [click to enlarge]

MIMIC-TC morphed microwave product, 0000-1545 UTC [click to enlarge]

A Nebraska thunderstorm and a Wyoming wildfire, as viewed by GOES-15, GOES-17 and GOES-16

August 29th, 2018 |
Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right), with SPC storm reports plotted in red [click to play animation | MP4]

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right), with SPC storm reports plotted in red [click to play animation | MP4]

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

A comparison of Visible images from GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) (above) showed an isolated thunderstorm that developed in the Nebraska Panhandle late in the day on 29 August 2018. The storm produced hail (SPC storm reports), and also exhibited an Above Anvil Cirrus Plume. The images are displayed in the native projection of each satellite, with no re-mapping.

One other feature that was seen north of the thunderstorm was smoke which was being transported eastward from the Britania Mountain Fire in southeastern Wyoming. The smoke was more apparent on the GOES-17 and GOES-16 images as forward scattering increased toward sunset.

Shortwave Infrared imagery from the 3 satellites revealed important differences affecting fire detection: namely spatial resolution and viewing angle. The 3.9 µm detector on the GOES-15 Imager has a spatial resolution of 4 km (at satellite sub-point), compared to 2 km for the GOES-16/17 ABI. Given that the fire was burning in rugged mountain terrain, the view angle from each satellite had an impact on the resulting bire brightness temperature values. For example, the first indication of very hot (red-enhanced) pixels was at 1527 UTC from GOES-16/17, vs 1715 UTC from GOES-15; at the end of the day, the very hot fire pixels were no longer seen with GOES-15 after 2300 UTC, but continued to show up in GOES-17 imagery until 0042 UTC and in GOES-16 imagery until 0122 UTC.

Shortwave Infrared images from GOES-15 (3.9 µm, left), GOES-17 (3.9 µm, center) and GOES-16 (3.9 µm, right) [click to play animation | MP4]

Shortwave Infrared images from GOES-15 (3.9 µm, left), GOES-17 (3.9 µm, center) and GOES-16 (3.9 µm, right) [click to play animation | MP4]

Hail-producing thunderstorm in South Dakota

August 26th, 2018 |
Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play animation | MP4]

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right), with SPC storm reports plotted in yellow [click to play animation | MP4]

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

A comparison of Visible images from GOES-15 (GOES-West), GOES-17 and GOES-16 (GOES-East) (above) showed a severe thunderstorm that developed ahead of an advancing cold front (surface analyses) in central South Dakota late in the day on 26 August 2018. This storm produced hail as large as 4.0 inches in diameter (SPC storm reports), and also exhibited an above anvil cirrus plume (AACP) which is a signature often associated with severe thunderstorms.

The images are displayed in the native projection of each satellite, with no re-mapping. Note the important differences due to satellite scan strategy — the GOES-15 imager was initially performing a Full Disk scan, so imagery was only available every 30 minutes; the GOES-17 ABI was scanning at the standard “CONUS Sector” 5 minute interval; a GOES-16 ABI Mesoscale Domain Sector was providing images every 1 minute.

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]