Hurricane Maria downgraded to a Tropical Storm off the East Coast

September 26th, 2017 |
GOES-13 Infrared Window (10.7 µm) image, with Deep-Layer Wind Shear product [click to enlarge]

GOES-13 Infrared Window (10.7 µm) image, with Deep-Layer Wind Shear product [click to enlarge]

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

After its final 2 days of northward motion as a Category 1 storm well southeast of the Outer Banks of North Carolina, Hurricane Maria was downgraded to a Tropical Storm at 2100 UTC on 26 September 2017. A comparison of the 2345 UTC September GOES-13 (GOES-East) Infrared Window (10.7 µm) image and an overlay of the 00 UTC 27 September Deep-Layer Wind Shear product (above) showed that Maria had been moving northward into an environment of increasing northeasterly shear, aiding the decrease of storm organization and intensity. However, due to the large size of the strong wind field associated with Maria, surface wind gusts as high as 59 mph were reported along the Outer Banks.

The effect of increasing wind shear was obvious in the satellite presentation of GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) — the low-level circulation center (LLCC) was becoming more exposed with time, while deep convection remained southeast of the LLCC.

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to play MP4 animation]

The entrainment of dry air into the northern semicircle of Maria was evident as a warming/drying trend depicted on GOES-16 Lower-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below).

GOES-16 Lower-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images [click to play MP4 animation]

GOES-16 Lower-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images [click to play MP4 animation]

Maria: Tropical Storm Watch for the Outer Banks of North Carolina

September 24th, 2017 |
Track of Hurricane Maria [click to enlarge]

Track of Hurricane Maria [click to enlarge]

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

Hurricane Maria was downgraded to a Category 2 storm at 12 UTC on 24 September 2017 (above), when it was located about halfway between Miami and Bermuda.

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed a close-up view of the eye region of Maria during the daylight hours.

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Due to the large size of the radius of Tropical Storm force winds, a Tropical Storm Watch was issued late in the day for the Outer Banks and adjacent inland areas of North Carolina (below).

NHC advisory

UPDATE: 12 hours later, much of the Tropical Storm Watch was upgraded to a Tropical Storm Warning.

The Eye of Maria north of Hispaniola

September 21st, 2017 |

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

Hurricane Maria presented a very interesting eye structure during the course of the day on 21 September 2017, as shown in the mp4 animation above (also available as a YouTube video).  The animation shows 10.3 µm imagery every 2 minutes from 0849 UTC through 2122 UTC on 21 September 2017.

Pete Pokrandt, at the University of Wisconsin Atmospheric and Oceanic Sciences Department, created a similar animation using the 0.64 µm Visible channel on GOES-16.

30-second interval (using overlapping 1-minute interval Mesoscale Sector) GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images covering the 6-hour period from 1031-1631 UTC are shown below. During this time, Maria re-intensified to a Category 3 hurricane, with the eye centered just off the northeastern coast of the Dominican Republic.

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images at 30-second intervals (Click to animate)

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images at 30-second intervals (Click to animate)

For more information on Maria, visit the National Hurricane Center website.  The CIMSS Tropical Weather Website has information as well.

Hurricane Maria makes landfall in Puerto Rico

September 20th, 2017 |

GOES-16 Visible Imagery (0.64 µm), 1017-1117 UTC, at 30-second time steps, on 20 September 2017 (Click to animate)

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

Strong Category 4 Hurricane Maria has made landfall in Puerto Rico. According to the National Hurricane Center, landfall occurred around 1035 UTC near Yabacuo on Puerto Rico’s southeast coast. The GOES-16 30-second (using overlapping mesoscale sectors) Visible Animation, above, shows the storm as it made landfall. Maria had recently completed an Eyewall Replacement Cycle as it made landfall. The animation below, using morphed microwave imagery (from this site), shows the development of an outer eyewall and subsequent erosion of the inner eyewall during the 24 hours prior to landfall.

Morphed Microwave Imagery centered on Hurricane Maria for the 24 hours prior to landfall in Puerto Rico (Click to enlarge)

GOES-16 Clean Window Infrared (10.3 µm) Imagery shows a distinct eye as the storm makes landfall. Subsequently, however, the eye filled in as it moved over the mountainous interior of Puerto Rico.

GOES-16 Infrared (10.3 µm) Imagery, 0957-1136 UTC on 20 September 2017 (Click to animate)

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images (Click to play MP4 animation)

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images (Click to play MP4 animation)

A 2-panel comparison of GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) imagery during the 1020-1620 UTC time period is shown above. It can be seen that deep eyewall convection moved over much of the island as Maria made its journey across Puerto Rico.

Suomi NPP flew over Maria early in the morning on 20 September, when the storm was near St. Croix. The toggle below shows the 11.45 µm Infrared image from VIIRS and the Day Night Band Visible (0.7 µm) Imagery. The Moon on 20 September was a New Moon, so no lunar illumination was present for the Day Night Band. The eye of the storm was nevertheless apparent in the image.  A zoomed-in Infrared image over the eye is here.

Suomi NPP VIIRS 11.45 µm Infrared image from VIIRS and the Day Night Band Visible (0.7 µm) Imager, 0613 UTC on 20 September 2017 (Click to enlarge)

Suomi NPP overflew Maria again when the storm was moving offshore from Puerto Rico, and a toggle (Visible and Infrared) below shows the storm at 1724 UTC on 20 September. Click here for a zoomed-in image (Visible) over the eye.

Suomi NPP VIIRS 11.45 µm Infrared image from VIIRS and Visible (0.64 µm) Image, 1724 UTC on 20 September 2017 (Click to enlarge)

More information on Maria is available at the National Hurricane Center and at the CIMSS Tropical Weather Website.