Rapid Intensification of Hurricane Maria just to the east of the Leeward Islands

September 18th, 2017 |

GOES-16 “Clean Window” Infrared 10.3 µm imagery, 1600-2017 UTC on 18 September 2017 (Click to animate). Note: The Label states GOES-17 in error, and the time annotation becomes stuck for a time.

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

Hurricane Maria underwent rapid intensification on 18 September as it moved through very warm waters to the east of the Leeward Islands. The animation of GOES-16 “Clean Window” Infrared Imagery (10.3 µm), above, shows the rapid development of a warm concentric eye between 1640 and 1940 UTC. The toggle below, between 1600 UTC and 2000 UTC, testifies to a great increase in organization and strength. Click here for an mp4 animation from 1400 UTC to 2100 UTC on 18 September showing the intensification in the Visible (0.64 µm) channel from ABI.

GOES-16 “Clean Window” Infrared 10.3 µm imagery, 1600 and 2017 UTC on 18 September 2017 (Click to enlarge). Note: The Label states GOES-17 in error.

The storm is in an environment of very low shear (below) and moving towards warm water that is quite deep as depicted by large values of Oceanic Heat Content (bottom). (Maps found at this site).

850-250 hPa wind shear, 1800 UTC on 18 September 2017 (Click to enlarge)

Oceanic Heat Content analysis, 1800 UTC on 18 September 2017. (Click to enlarge). Note the relative cool wake north of the Leeward Islands left behind by Hurricane Irma.

Geostationary Lightning Mapper (GLM) data over Maria for the two hours ending 2045 UTC on 18 September (from this site; click here for infrared imagery), shows lightning within the southern eyewall of the storm.

GLM Group Observations in 3-minute intervals plotted on top of GOES-16 Visible (0.64 µm) Imagery, 1830-2045 UTC on 18 September 2017 (Click to enlarge)

For more information on this dangerous storm, refer to the webpages of the National Hurricane Center, or to the CIMSS Tropical Weather website. People in the Leeward Islands in particular should pay close attention to this storm.

Tropical Storm Maria upgraded to Hurricane Maria in the central Atlantic

September 16th, 2017 |

GOES-16

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

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

On 16 September 2017, GOES-16 “Clean” Infrared Window (10.3 µm) images (above) showed the early stages of development of Tropical Storm Maria in the central Atlantic Ocean (located at 12.3 ºN latitude, 52.6 ºW longitude at 2100 UTC). Convective bursts exhibited cloud-top infrared brightness temperatures in the -77 ºC to -79 ºC range (brighter white enhancement). The hourly surface report from TBPB (along the left edge of the images) is Bridgetown in Barbados.

Unfortunately, the initial National Hurricane Center forecast track (below) takes Maria to Major Hurricane intensity over or near islands that were recently heavily impacted by Hurricane Irma. Maria is forecast to remain in an environment of low wind shear and move over waters characterized by warm SST and high OHC values (source), which all favor intensification.

Initial NHC forecast track [click to enlarge]

Initial NHC forecast track [click to enlarge]

===== 17 September Update =====
GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to animate]

GOES-16 Visible (<strong0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to animate]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Widow (10.3 µm) images (above) revealed a steady trend of organization during the day on 17 September, which allowed Maria to intensify to Category 1 Hurricane status at 2100 UTC. Note the large convective burst which expanded just west of the center of circulation after 1700 UTC — cloud-top infrared brightness temperatures were impressively cold, in the -80ºC to -89ºC range (violet shades of color enhancement).

===== 18 September Update =====
GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to animate]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to animate]

A GOES-16 Mesoscale Sector was positioned over Hurricane Maria, providing imagery at 1-minute intervals — Visible (0.64 µm) and Infrared Window (10.3 µm) images (above) captured the formation of an obvious eye feature beginning around 1615 UTC. Maria rapidly intensified (CIMSS SATCON) from a Category 1 to a Category 4 Hurricane east of Le Lamentin, Martinique (TFFF) during this daylight sequence of 1-minite images; the eye then went on to approach the small island of Dominica (TDCF is the identifier of their Canefield Airport) — and in fact Maria was upgraded to Category 5 intensity as the eye was just east of Dominica at 00 UTC on 19 September (NHC advisory). AWIPS imagery of the 1-minute GOES-16 Infrared data is available here.

This small-diameter “pinhole eye” was also evident earlier in the day on DMSP microwave imagery at 1040 UTC, and again at 1843 UTC.

Irma over Florida as seen by Suomi NPP and GOES-16

September 11th, 2017 |

Suomi NPP VIIRS Infrared 10.8 µm imagery, 0709 UTC on 11 September 2017 (Click to enlarge)

Suomi NPP overflew Florida and Hurricane Irma shortly after 0700 UTC on Monday 11 September. The 10.8 µm Infrared Image from the VIIRS Instrument, above, shows cold cloud tops and strong convection over much of central Florida (Orlando International Airport received 3″ of rain between 0300 and 0600 UTC on 11 September — time series plot of surface data).  The center of Irma at this time was about 55 miles northeast of Tampa.

Suomi NPP includes a Day/Night Band on the VIIRS Instrument, allowing night-time visible imagery that is illuminated by the Moon.  The Day/Night Band Near Constant Contrast product from the same time as the infrared image above, but zoomed out, is shown below. In addition to the cloud structures, this band can help identify power outages. Tampa and Miami city lights are still visible. Key West is dark. A zoomed-in view of Key West (here) shows very little illumination.

Suomi NPP Day/Night Band Image over the southeast United States showing Hurricane Irma over Florida, 0710 UTC on 11 September 2017 (Click to enlarge)

In addition, GOES-16 “Clean” Infrared Window (10.3 µm) images with surface wind gusts (in knots) are shown below during the night and the following day into the evening on 11 September 2017, as Irma was eventually downgraded to a Tropical Storm and then a Tropical Depression (NHC Discussions) as it moved northward across the Florida peninsula and into southern Georgia and South Carolina.

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

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with surface wind gusts in knots (Click to animate)

GOES-16 Water Vapor animations, below, show the evolution of the Hurricane as it transitions to an extratropical cyclone. At the start of the animations, near 0400 UTC on 11 September, the convection in the center of the hurricane is apparent between Tampa and Cape Canaveral. That central convection diminishes with time as it moves northeast and as the extratropical transition continues.

GOES-16 Mid-level Water Vapor (6.95 µm), 0442-1702 UTC on 11 September 2017 (Click to animate)

GOES-16 Upper-level Water Vapor (6.19 µm), 0427-1647 UTC on 11 September 2017 (Click to animate)

Hurricane Irma moves through the Florida Keys

September 10th, 2017 |

GOES-16 ABI Infrared Imagery from the Clean Window (10.3 µm), 0122-1342 UTC (Click to animate)

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

GOES-16 Infrared Imagery, above, shows Hurricane Irma moving north on a wobbly path (displaying trochoidal motion) through the Florida Keys. The eye of the storm moved between Key West (surface data plot) and Marathon (surface data plot) around sunrise on 10 September. Also note the development of well-defined transverse banding well to the northwest and north of the storm center — a cloud signature often associated with high-altitude turbulence. (In addition, GOES-16 Infrared images during 09-10 September with plots of surface wind gusts in knots is available here). Irma is a storm increasingly affected by wind shear, as evidenced by the asymmetries in the upper level clouds. and as noted in the 1200 UTC 10 September 2017 Wind Shear analysis below (Source).

Wind shear (850-250 hPa) analysis, 1200 UTC 10 September, over GOES-13 Visible Imagery (0.64) (Click to enlarge)

 

Irma is being influenced by a mid-latitude system and is gradually starting the extended process of extratropical transition. The drying associated with the mid-latitude system is very apparent over the Gulf of Mexico in the animation of 6.95 µm (Mid-level Water Vapor) Infrared Imagery from GOES-16, below.

 

GOES-16 Mid-Level Water Vapor (6.95 µm) Infrared Imagery, 0230 -1445 UTC on 10 September 2017 (Click to animate)

MIMIC TPW, below (source), shows the convergence of residual Atlantic frontal moisture from the east (into northern Florida) and Hurricane Irma’s moisture fro the the Caribbean (into southern Florida) (Click to animate).

MIMIC Total Precipitable Water (Click to animate)

MIMIC Total Precipitable Water (Click to animate)

Suomi NPP overflew Irma at 0740 UTC on 10 September, and Day/Night Band Visible Imagery (0.70 µm) is toggled with Infrared Imagery (11.45 µm) over the eye, below.

Suomi NPP Imagery over the eye of Irma: Day/Night Band Visible (0.70 µm) and Infrared (11.45 µm), 0740 UTC on 10 September (Click to enlarge)

Suomi NPP Imagery: Day/Night Band Visible (0.70 µm) and Infrared (11.45 µm), 0740 UTC on 10 September (Click to enlarge)

During the subsequent daytime hours, VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1855 UTC, below, showed the eye of Category 3 Hurricane Irma about 40 minutes prior to landfall at Marco Island, Florida.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (Click to enlarge)

 

A toggle through 6 different Suomi NPP Channels near the time of landfall (0.41 µm, 0.64 µm, 0.86 µm, 1.38 µm, 1.61 µm and 10.8 µm) is shown below.

Suomi NPP VIIRS Imagery at 1852 UTC on 10 September 2017: 0.41 µm, 0.64 µm, 0.86 µm, 1.38 µm, 1.61 µm and 10.8 µm) (Click to enlarge)