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, as the eye then approached 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.

GOES-16 views Thunderstorms in northern Minnesota

September 15th, 2017 |

GOES-16 (left) and GOES-13 (right) views of thunderstorms over northern Minnesota. Top: Visible (0.64 µm) ; bottom (10.3 µm , left; 10.7 µm , right), 2000 UTC – 2350 UTC on 14 September (Click to animate)

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

GOES-16 and GOES-13 animations of thunderstorms over northern Minnesota, above, courtesy Science and Operations Officer (SOO) Dan Miller from the Duluth National Weather Service Office, show how the superior spatial and temporal resolution of GOES-16 enhances the ability to monitor the evolution of storms. Not only are the individual cold overshooting tops much more apparent in the nominal 2-km resolution Infrared imagery of GOES-16 (lower left) (vs. 4-km for GOES-13 in the lower right), but their evolution is better captured by the 5-minute temporal cadence for GOES-16 (vs. 15-minute for GOES-13).

Visible (0.64 µm) imagery from GOES-16 (upper left) also has better spatial (nominally 0.5 km) resolution than GOES-13 (upper right, nominally 1 km). Note that the black points at the start of the animation in GOES-16 are regions of very high reflectivity that — for now — are incorrectly set to missing in AWIPS. Consider, for example, the visible signatures of the overshooting tops in GOES-13: are you certain you are tracking the same feature with the 15-minute time step? GOES-16 data show that overshoots can emerge and decay much more quickly than every 15 minutes!

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)