Hurricane Ophelia — the record-tying 10th consecutive Atlantic basin hurricane of the 2017 season — reached a satellite-estimated Category 3 intensity at 15 UTC on 14 October 2017. GOES-13 (GOES-East) Visible (0.63 µm) and Infrared Window (10.7 µm) images (above) showed a well-defined circular eye as the storm moved well south of the Azores. The tweet below underscores the unusual nature of the intensity and location of Ophelia (which also occurred over unusually-cold waters).

#Ophelia has shattered the record for northeastern-most forming Cat 3 in the Atlantic and is the easternmost overall. League of its own. pic.twitter.com/sZrHap5z1f

— Brenden Moses (@Cyclonebiskit) October 14, 2017

A DMSP-17 SSMIS Microwave (85 GHz) image (below) also revealed a circular eye structure.

One factor that might have aided this increase of intensity was the recent passage of Ophelia through an environment of higher Maximum Potential Intensity (reference), where maximum wind speed values of 100 knots resided (below).

* 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).

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.

* 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.

===== 17 September Update =====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 =====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.