Tropical Storm Matthew in the Windward Islands

September 28th, 2016 |

Note: Matthew was upgraded to a Hurricane at 1800 UTC on 29 September. See the National Hurricane Center Website for the latest information.

GOES-13 Visible (0.63 µm) and shortwave Infrared (3.9 µm) at 6-hour intervals, 23-28 September 2016 [Click to animate]

GOES-13 Visible (0.63 µm) and shortwave Infrared (3.9 µm) at 6-hour intervals, 23-28 September 2016 [Click to animate]

The area of disturbed weather that has been moving across the tropical Atlantic for the past week, shown above in six-hour steps using visible (0.63 µm) imagery during the day and shortwave infrared (3.9 µm) imagery at night, has developed into a strong tropical storm, named Matthew, as it moves through the Windward Islands. Matthew is embedded with the rich moisture source of the Intertropical Convergence Zone, as shown in the animation below of MIRS Total Precipitable Water, taken from this source. Matthew is also heading towards a region rich in moisture — it appears that dry air should not influence Matthew’s evolution in the near term.

Morphed MIRS Total Precipitable Water, 25-28 September 2016 [Click to animate]

Morphed MIRS Total Precipitable Water, 25-28 September 2016 [Click to animate]

Matthew’s predicted course into the Caribbean is over very warm water with high heat content (below, imagery from the CIMSS Tropical Weather site). Wind shear over the storm is low, with larger values to the west; the region of high shear in advance of Matthew has been preceding the storm for the past 72 hours and it is forecast to continue its retreat from Matthew. The forecast from the National Hurricane Center is for slow strengthening.

Observed Sea Surface Temperatures and Oceanic Heat Content [Click to enlarge]

Observed Sea Surface Temperatures and Oceanic Heat Content [Click to enlarge]

Wind Shear, 1500 UTC on 28 September [Click to enlarge]

Wind Shear, 1500 UTC on 28 September [Click to enlarge]

Late in the afternoon on the 28th, GOES-13 detected cloud tops cooler than -80º C associated with some of the overshooting tops (the purple enhancement). Overshooting tops can be detected automatically and shown at this website.

GOES-13 Infrared (10.7 µm) imagery, 1445-2045 UTC on 28 September 2016 [Click to animate]

GOES-13 Infrared (10.7 µm) imagery, 1445-2045 UTC on 28 September 2016 [Click to animate]


============== Added, 29 September 2016 =================

Suomi NPP overflew the eastern Caribbean early on 29 September, and the Day Night Band imagery, below, (from RealEarth) shows Matthew west of the Windward Islands. A lone lightning strike is visible in the convective clouds. There appears in this very low light image to be a low-level circulation exposed to the west of the deep clouds, suggesting a sheared storm.

Suomi NPP Day Night Band Visible (0.70 µm) imagery, ~0540 UTC on 29 September 2016 [Click to enlarge]

Suomi NPP Day Night Band Visible (0.70 µm) imagery, ~0540 UTC on 29 September 2016 [Click to enlarge]

A GOES-13 Visible Image animation from just after sunrise shows a the circulation center exposed to the west of the deep convection.

GOES-13 Visible (0.63 µm) imagery, 1045-1245 UTC on 29 September 2016 [Click to enlarge]

GOES-13 Visible (0.63 µm) imagery, 1045-1245 UTC on 29 September 2016 [Click to enlarge]

NOAA-19 overflew Matthew at about 1900 UTC on 29 September 2016, shortly after the storm was upgraded to a Hurricane, and visible imagery from that pass (data courtesy of the AOML Direct Broadcast antenna) shows far less evidence of a sheared storm. The Central Dense Overcast is above the surface circulation.

NOAA-19 Visible (0.63 µm) imagery, 1931 UTC on 29 September 2016 [Click to enlarge]

NOAA-19 Visible (0.63 µm) imagery, 1931 UTC on 29 September 2016 [Click to enlarge]

Post-Tropical Cyclone Hermine

September 5th, 2016 |

GOES-13 Visible (0.63 µm) images, with buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Visible (0.63 µm) images, with buoy/ship reports plotted in yellow [click to play animation]

GOES-13 (GOES-East) Visible (0.63 µm) images showed that the circulation of Post-Tropical Cyclone Hermine (NHC discussions) persisted off the US East Coast on 04 September (above; also available as an MP4 animation) and on 05 September 2016 (below; also available as an MP4 animation). On 04 September, the Royal Caribbean cruise ship Anthem of the Seas sustained some minor damage as it encountered strong winds and high waves in the northeastern quadrant of the storm (ship location | satellite images) while sailing from New Jersey to Bermuda.  Also of particular interest were the pair of mesovortices seen rotating around the main circulation center of the storm on 05 September. The GOES-13 satellite had remained in Rapid Scan Operations (RSO) mode during this period, providing images as frequently as every 5-7 minutes.

GOES-13 Visible (0.63 µm) images, with buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Visible (0.63 µm) images, with buoy/ship reports plotted in yellow [click to play animation]

===== 06 September Update =====

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship data plotted in yellow [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship data plotted in yellow [click to play animation]

On 06 September, the circulation of Post-Tropical Cyclone Hermine continued to move very slowly westward toward the Northeast US coast as it gradually weakened (above; also available as an MP4 animation). A 1600 UTC GOES-13 Visible image with plots of Metop ASCAT winds along with surface/buoy/ship reports is shown below — the maximum ASCAT surface scatterometer wind speeds were 33 knots in the western semicircle of the storm.

GOES-13 Visible (0.63 µm) image at 1600 UTC, with ASCAT winds and surface/buoy/ship reports [click to enlarge]

GOES-13 Visible (0.63 µm) image at 1600 UTC, with ASCAT winds and surface/buoy/ship reports [click to enlarge]

As of 18 UTC, all coastal Tropical Storm Warnings were discontinued by the National Hurricane Center (final advisory).

===== 07 September Update =====

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

An animation of hourly MIMIC Total Precipitable Water (TPW) product images covering the 04-07 September period {above) showed that the remnant circulation of what was formerly Post-Tropical Cyclone Hermine still contained relatively high values of TPW (in the 50-60 mm or 2.0-2.4 inch range) as it edged closer to the coast on 07 September.

 

Hurricane Hermine

September 1st, 2016 |

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

Hermine was upgraded to a Hurricane over the Gulf of Mexico around 20 UTC on 01 September 2016. GOES-13 (GOES-East) Visible (0.63 µm) images (above) showed improvement in the appearance of curved banding structures around the eye late in the day. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes. Note that Hurricane Hermine developed from Tropical Invest 99L, which was sampled by 1-minute GOES-14 imagery beginning on 25 August; unfortunately, the 1-minute Super Rapid Scan Operations for GOES-R (SRSO-R) test period ended at 1115 UTC on 29 August (however, imaging of the evolution of Tropical Depression 9 to Hurricane Hermine continued at 15-minute intervals).

The corresponding GOES-13 Infrared Window (10.7 µm) images (below) revealed the eventual formation of a distinct eye, with bursts of convection exhibiting cloud-top IR brightness temperatures in the -75º to -80º C range (shades of white to violet pixels) in the western and southern semicircles of the eyewall region. Hermine became the first hurricane to make landfall in Florida since Wilma in 2005.

GOES-13 Infrared Window (10.7 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

A Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image visualized using RealEarth (below) provided a detailed view of the curved banding around the western and southern portion of the eye.

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

A comparison of DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images around 2315 UTC (below) depicted a much larger eye presentation on microwave vs infrared — the microwave image showed the curved banding structure around an eye that was still not well-organized.

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

While Hermine passed over waters exhibiting warm Sea Surface Temperature values in the eastern Gulf of Mexico, the Ocean Heat Content values were only modest (below).

Sea Surface Temperature and Ocean Heat Content values [click to enlarge]

Sea Surface Temperature and Ocean Heat Content values [click to enlarge]

The high values of Total Precipitable Water (TPW) associated with Hermine were evident on hourly composites of morphed TPW from MIRS sensors (below). Rainfall amounts exceeded 22 inches in Florida (WPC storm summary)

Morphed Total Precipitable Water derived from MIRS sensors [click to play animation]

Morphed Total Precipitable Water derived from MIRS sensors [click to play animation]


===== Post-landfall Update, 02 September =====
 

Suomi-NPP overflew Hermine shortly after 0700 UTC on 02 September, after its 0530 UTC landfall near St. Mars FL. The toggle below shows the VIIRS 0.7 µm Day/Night Band and the 11.45 µm Infrared Window imagery. Both show the asymmetric nature of the storm. Rain and clouds extend quite a distance to the south and east of the storm, but not far to the west. The infrared imagery shows cold cloud tops surrounding the storm center southeast of Tallahassee, with very cold cloud tops also over Tampa FL and near Savannah GA with bands associated with the storm. Cloud detail is missing in the Day/Night Band image because of the lack of lunar illumination — a New Moon occurred early on 01 September — however, high-altitude mesospheric airglow waves (references: 1 | 2 | 3) can be seen off the east coast of Florida and Georgia, excited by Hermine’s bands of strong thunderstorms.

Suomi NPP Day/Night Band Visible (0.70 µm) and Infrared Window (11.45 µm) images at 0723 UTC on 2 September [click to enlarge]

Suomi NPP Day/Night Band Visible (0.70 µm) and Infrared Window (11.45 µm) images at 0723 UTC on 2 September [click to enlarge]

A toggle between before-landfall (0319 UTC Terra MODIS) and after-landfall (0814 UTC POES AVHRR) Infrared images, below, shows the expected trend of warming cloud-top IR brightness temperatures and a consolidation into a more compact storm circulation.

11.0 µm Terra MODIS (0319 UTC) and 12.0 µm POES AVHRR (0814 UTC) Infrared images [click to enlarge]

11.0 µm Terra MODIS (0319 UTC) and 12.0 µm POES AVHRR (0814 UTC) Infrared images [click to enlarge]

===== 03 September Update =====

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

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

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0707 UTC on 03 September (above; courtesy of William Straka, SSEC) showed that Hermine — still being classified as a Tropical Storm — continued to produce mesospheric airglow waves as it moved off the East Coast of the US. Numerous bright white streaks were also evident on the Day/Night Band image, due to cloud illumination from intense lightning activity.

During the following daylight hours of 03 September, GOES-13 (GOES-East) Visible (0.63 µm) images (below: also available as an MP4 animation) showed the circulation of post-tropical cyclone Hermine. In eastern North Carolina, winds gusts as high as 80 mph were recorded, with rainfall amounts as great as 8.54 inches (NWS Newport/Morehead City); the storm also produced a few tornadoes (SPC Storm Reports). In southeastern Virginia, winds gusted to 73 mph (NWS Wakefield). A few of the heavier rainfall amounts for individual states are listed here.

GOES-13 Visible (0.63 µm) images, with surface and buoy wind barbs plotted in yellow and wind gusts (knots) plotted in red [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface and buoy wind barbs plotted in yellow and wind gusts (knots) plotted in red [click to play animation]

A Suomi NPP VIIRS true-color image visualized using RealEarth (below) showed the clouds associated with Hermine at 1827 UTC.

Suomi NPP VIIRS true-color image [click to enlarge]

Suomi NPP VIIRS true-color image [click to enlarge]

GOES-14 SRSO-R: Tropical Disturbance near the Caribbean

August 25th, 2016 |

GOES-14 Visible (0.63 µm) images [click to play animated gif]

GOES-14 Visible (0.63 µm) images [click to play animated gif]

GOES-14 SRSO-R Imagery is being produced over the Greater Antilles on 25 August 2016 to monitor a tropical wave (Invest 99L) that is moving towards Florida and the southeast United States. The visible animation above shows a highly sheared system: a low-level circulation center (LLCC) is evident north of Hispaniola and east of the Turks and Caicos, but strong convection (overshooting tops are readily apparent) is displaced well to the east of the system. There is also considerable convection over Hispaniola.

A 2-panel comparison of GOES-14 Visible and Infrared Window images, below (also available as a large 200 Mbyte animated GIF), provided a slightly closer view of the LLCC feature.

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

Wind shear analyses from the CIMSS Tropical Weather site, below, show the surface circulation is within a small ribbon of relatively strong shear. Development chances will increase if the wind shear relaxes. A GOES-13 Visible image with overlays of satellite winds and wind shear is available here.

Wind Shear Analysis, 1200 UTC on 25 August 2016 [click to play animated gif]

Wind Shear Analysis, 1200 UTC on 25 August 2016 [click to enlarge]

Metop-A overflew the system at about 0200 UTC on 25 August (link to orbit path), and winds near Tropical Storm Force cover a wide swath of the southwestern Atlantic. Even if this system does not develop into a Tropical Depression, gusty winds and abundant moisture (see the animation of MIRS Total Precipitable Water from this site, below) herald a weekend when it’s appropriate to pay attention to the weather because of the potential for rain and winds.

Morphed Observations of Total Precipitable Water from MIRS, 0000 UTC 24 August - 1500 UTC 25 August [click to play animated gif]

Morphed Observations of Total Precipitable Water from MIRS, 0000 UTC 24 August – 1500 UTC 25 August [click to play animated gif]

===== 28 August Update =====

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

Invest 99L developed into Tropical Depression 09 around 21 UTC on 28 August. A comparison of 1-minute GOES-14 Visible (0.63 µm) and Infrared Window (10.7 µm) images, above (also available as a large 94 Mbyte animated GIF), showed the tropical depression as it moved westward through the Florida Straits.