Increase in Gulf of Mexico water turbidity in the wake of Hurricane Irma

September 11th, 2017 |

Suomi NPP VIIRS true-color RGB images on 07 September and 11 September [click to enlarge]ep

A comparison of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images on 07 September (before Irma) and 11 September (after Irma) revealed a marked increase in turbidity of the shallow Continental Shelf waters off the coast of southern/southwestern Florida and the Florida Keys. Irma moved through that region on 10 September as a Category 3 hurricane — and even though the center of Irma moved northward off/along the west coast of Florida (with a wind gust to 75 mph at Key West) , the strongest winds were recorded along/near the east coast of Florida: wind gusts to 92 mph and 109 mph and 142 mph — stirring up particulates within the shallow Continental Shelf waters.

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

Large-scale (CONUS) VIIRS true-color before-Irma and after-Irma images are available here and here. Note that the cloud shield of Irma had expanded as far westward as Kansas, Texas and Oklahoma on 12 September ( GOES-16 true-color images) — in addition to large areas of dense smoke from wildfires in the Pacific Northwest (blog post) which was drifting eastward across the northern US.

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)