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)

Hurricane Irma moves along the north coast of Cuba

September 9th, 2017 |

GOES-16 “Clean Window” Infrared Imagery (10.3 µm) from 0357 to 1202 UTC on 9 September 2017 (Click to animate)

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

Hurricane Irma hit Cuba as a category 5 Storm late on 8 September 2017. The animation above shows the storm paralleling the north coast of Cuba; outer rainbands are moving into southern Florida. Irma is forecast to turn northwest and north during the day on 9 September, and then move up along the Gulf Coast of Florida, threatening the entire Florida Peninsula with Hurricane-force winds. Irma’s prolonged proximity to the Cuban landmass has affected the storm’s structure and its satellite presentation.  (Compare this animation above to one from 8 September in this blog post). The microwave animation, below, (source) suggests that the disruption to the storm might include the eyewall, and the central pressure of the storm has increased.

Morphed Microwave Imagery of Irma for the 24 hours ending around 0900 UTC on 9 September 2017 (Click to enlarge)

 

850-250 hPa Wind Shear over Irma, 0900 UTC on 9 September (Click to enlarge)

Wind shear in the atmosphere, shown above as 850-250 mb wind shear (Source), remains very low over the storm.   Shear will increase over the storm during the day however as it moves north.  This could slow any intensification that might occur as the storm moves over the very warm waters of the Florida Straits and eastern Gulf of Mexico, where Sea-Surface Temperatures are 30-32 C.

The latest Geostationary Lightning Mapper data over the storm (from this source) as the sun rises, shows little lightning over the center of Irma.

GOES-16 Visible (0.64 µm) Imagery at 15-minute intervals underneath plots of GLM Group Activity in 3-minute intervals, 0945-1200 UTC9 September 2017 (Click to enlarge)

William Straka, CIMSS, provided the Suomi NPP Visible (from the Day Night Band) and Infrared Imagery below.

Suomi NPP VIIRS Day Night Band Visible (0.7 µm) from 0619 UTC on 9 September 2017 (Click to enlarge)

Suomi NPP VIIRS Infrared Imagery (11.45 µm) from 0619 UTC on 9 September 2017 (Click to enlarge)

A zoomed-in, annotated view of the eye is below. (Click here for an image with no labels)

Annotated Suomi NPP VIIRS Day Night Band Visible (0.7 µm) from 0619 UTC on 9 September 2017 (Click to enlarge)

For further information on this dangerous storm, consult the National Hurricane Center, or the CIMSS Tropical Weather Website.

Hurricane Irma north of Hispaniola

September 7th, 2017 |

GOES-16 Low-Level Water Vapor Infrared (7.34 µm) Imagery, 0737 – 1232 UTC on 7 September 2017 (Click to animate)

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

GOES-16 Captured very strong Hurricane Irma, north of Hispaniola, early on the day on 7 September. The 7.34 µm channel shown is sensitive to water vapor, that is, water vapor in the atmosphere absorbs energy at 7.34 µm. The animation shows the storm moving steadily to the west-northwest. A far less-organized Hurricane Katia is over the southwestern Gulf of Mexico, with a strong jet extending from Katia northeastward along the east coast. A short animation of Visible Imagery with Geostationary Lightning Mapper data, below, from 1015-1230 UTC, shows considerable lightning activity continuing in the eye of the storm and in some of the convective bands that surround it.

GOES-16 Visible (0.64 µm) Imagery at 15-minute intervals underneath plots of GLM Group Activity in 3-minute intervals, 1015-1230 UTC 7 September 2017 (Click to animate)

Suomi NPP overflew Irma at about 1800 UTC on 7 September. Visible (0.64 µm) and Infrared (11.45 µm) imagery from the VIIRS Instrument on Suomi NPP is below.

Suomi NPP VIIRS Visible (0.64 µm) imagery, 1808 UTC on 7 September 2017 (Click to enlarge)

Suomi NPP VIIRS Infrared (11.45 µm) imagery, 1808 UTC on 7 September 2017 (Click to enlarge)

Hurricane Irma over the British Virgin Islands

September 6th, 2017 |

Suomi NPP VIIRS Visible Imagery (0.64 µm) at 1646 UTC on 6 September 2017, with and without annotation (Click to enlarge)

 

Suomi NPP overflew Irma as the storm moved through the British Virgin Islands. The toggle above shows the 0.64 µm Visible Image of the storm at that time, with and without annotations.  An infrared view from VIIRS, at 11.45 µm is shown below.

Suomi NPP VIIRS Infrared Imagery (11.45 µm) at 1646 UTC on 6 September 2017, with and without annotation (Click to enlarge)

(Imagery courtesy Will Straka, CIMSS)