Hurricane Nate makes landfall in Louisiana and Mississippi

October 7th, 2017 |

GOES-16 Visible (0.64 µm. left) and Infrared Window (10.3 µm, right) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-16 Visible (0.64 µm. left) and Infrared Window (10.3 µm, right) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

1-minute interval Mesoscale Sector GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the large central dense overcast (which exhibited cloud-top infrared brightness temperatures of -80ºC and colder, violet colors, and at times -90ºC and colder, yellow enhancement) and subsequent smaller convective bursts associated with Hurricane Nate on 07 October 2017.

After having moved north-northwestward at speeds up to 24 mph — quite possibly the fastest-moving tropical cyclone on record in the Gulf of Mexico — Nate made its initial landfall (as a Category 1 storm) in Louisiana near the mouth of the Mississippi River at 00 UTC on 08 October 2017 [note: Nate’s second landfall was around 0530 UTC near Biloxi, Mississippi]. A few reports of damaging winds and tornadoes were noted ahead of and during Nate’s landfall; a listing of other wind gusts can be seen here.

Earlier in the day, DMSP-17 SSMIS Microwave (85 GHz) imagery was hinting at the development of a closed eye structure beneath the central dense overcast seen on GOES-13 Infrared Window (10.7 µm) imagery (below).

GOES-13 Infrared Window (10.7 µm) and DMSP-17 SSMIS Microwave (85 GHz) images around 1215 UTC [click to enlarge]

GOES-13 Infrared Window (10.7 µm) and DMSP-17 SSMIS Microwave (85 GHz) images around 1215 UTC [click to enlarge]

Even though Nate passed over very warm water in the Gulf of Mexico (below), the fast forward motion of the storm limited its ability to take advantage of those warm waters and rapidly intensify.

Sea Surface Temperature and Ocean Heat Content analyses from 06 October, with an overlay of the 07 October path of Hurricane Nate ending at 12 UTC [click to enlarge]

Sea Surface Temperature and Ocean Heat Content analyses from 06 October, with an overlay of the 07 October path of Hurricane Nate ending at 12 UTC [click to enlarge]

Tropical Storm Nate forms near Nicaragua

October 5th, 2017 |

GOES-16 ABI Band 2 Visible (0.64 µm) Imagery, 1127 – 1324 UTC on 5 October 2017 (Click to animate)

GOES-16 Visible Imagery, above, shows convection (imagery at 1-minute intervals) surrounding Tropical Storm Nate, just onshore in northeastern Nicaragua.

GOES-16 ABI “Clean Window” Infrared (10.3 µm) Imagery, 4 October 2017 at 2300 UTC through 1130 UTC on 5 October 2017 (Click to animate)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

The Tropical Depression (#16) in the western Caribbean Sea has strengthened to become a minimal Tropical Storm, acquiring the name Nate. The animation from GOES-16, above, shows disorganized convection over the entire basin, stretching into the Pacific Ocean south of central America. (The sheared remains of Pacific Tropical Storm Ramon are also present south of Mexico). The animation below, from 0000-1300 UTC on 5 October 2017, shows the mid-level Water Vapor Infrared Imagery (6.95 µm) from GOES-16. Convection develops over the center of Nate, over Nicaragua, at the end of the animation.

GOES-16 ABI “Mid-Level Water Vapor” Infrared (6.95 µm) Imagery, 0000-1300 UTC on 5 October 2017 (Click to animate)

Microwave Imagery, below, from SSMI/S at around 1000 UTC on 5 October, (from this site) suggests that Nate is centered very near the coast of Nicaragua. Nate is forecast to move north into the Gulf of Mexico; its path through the northwest Caribbean suggests strengthening is possible if Nate remains far enough from land. Very warm water is present in the northwest Caribbean; that warmth extends to great depth as shown by this plot of Oceanic Heat Content; that warmth extends into the central Gulf of Mexico.

85 GHz Brightness Temperatures, 1000 UTC on 5 October 2017 (Click to enlarge)

Nate formed at a time when the Moon was Full. Thus, Suomi NPP Day Night Band Visible Imagery showed excellent illumination. The image below is from 0627 UTC on 5 October.

Suomi NPP Day Night Band Visible (0.7 µm) Imagery, 0627 UTC on 5 October 2017 (Click to enlarge)

Total Precipitable Water in advance of Nate is plentiful, as shown in the loop below (from this site). There is dry air over the continental United States, however, associated with a strong High Pressure System. Easterly winds south of that system are apparent in Scatterometer winds from early in the morning on 5 October.

MIMIC Morphed Total Precipitable Water, 1200 UTC 4 October – 1100 UTC 5 October 2017 (Click to enlarge)

The Active Atlantic Basin in August and September

October 4th, 2017 |

ABI “Clean Window” Infrared (10.3 µm) Image, 1800 UTC on 8 September 2017, showing Katia, Irma and Jose, from left to right (Click to animate as a YouTube Video)

The YouTube link, above, shows the GOES-16 “Clean Window” (10.3 µm) Infrared Imagery over the Atlantic, showing the evolution of Hurricanes Franklin through Maria, from 7 August through 1 October. (The original mp4 video (250 Meg) is available.)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

September 2017: a record-setting month in terms of Atlantic tropical cyclone ACE

October 4th, 2017 |

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

The Accumulated Cyclone Energy (ACE) for September 2017 set a new record for any month over the North Atlantic basin:

Two significant contributors to this record ACE value were long-lived and very intense Hurricane Irma and Hurricane Maria.

Hurricane Irma – Ace: 66.6 – Duration: 13 Days

Montage of Hurricane Irma GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Irma GOES-13 infrared images, with and without storm track/intensity [click to view]

One noteworthy statistic of Hurricane Irma: during its 3 days and 3 hours as a Category 5 hurricane (above), the storm had an intensity of 160 knots or 185 mph for 37 consecutive hours — which set a new world record. GOES-16 “Clean” Infrared Window (10.3 µm) images during this period of 185 mph intensity (below) showed a well-defined eye, with cold cloud-top infrared infrared brightness temperatures (occasionally -80ºC or colder, denoted by the violet color enhancement) within the adjacent eyewall region.

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

Hurricane Maria – Ace: 44.6 – Duration: 14 Days

Montage of Hurricane Maria GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Maria GOES-13 infrared images, with and without storm track/intensity [click to view]

One noteworthy aspect of Hurricane Maria was its intensification to a Category 5 storm on 18 September (above) — just before making landfall on the island of Dominica — and less than 48 hours before making landfall over southeastern Puerto Rico as a high-end Category 4 storm. GOES-16 Infrared Window (10.3 µm) images at 1-minute (pre-landfall) and 30-second (post-landfall) time intervals (below) showed that while the eye of Maria quickly eroded as the tropical cyclone moved northwestward across the island and interacted with its rugged terrain, deep convection of the eyewall region persisted over much of Puerto Rico during the transect. Note that the last hourly surface observations from Roosevelt Roads (TJNR) and San Juan (TJSJ) were from 04 UTC and 09 UTC, respectively — after which times power and communications to weather equipment (such as the San Juan radar) were lost.

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

Hurricane Jose – Ace: 42.2 – Duration: 17 Days

Montage of Hurricane Jose GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Jose GOES-13 infrared images, with and without storm track/intensity [click to view]

Although not as intense as Irma or Maria, the long duration of Hurricane Jose allowed it to achieve an ACE value nearly as high.

Individual storm montage images are available here on the CIMSS Tropical Cyclones site.