Tropical Storm Nate forms near Nicaragua

October 5th, 2017 |

GOES-16 ABI Band 2 Visible (0.64 µm) Imagery, 1127 – 1324 UTC on 5 October 2017 (Click to animate)

GOES-16 Visible Imagery, above, shows convection (imagery at 1-minute intervals) surrounding Tropical Storm Nate, just onshore in northeastern Nicaragua.

GOES-16 ABI “Clean Window” Infrared (10.3 µm) Imagery, 4 October 2017 at 2300 UTC through 1130 UTC on 5 October 2017 (Click to animate)

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

The Tropical Depression (#16) in the western Caribbean Sea has strengthened to become a minimal Tropical Storm, acquiring the name Nate. The animation from GOES-16, above, shows disorganized convection over the entire basin, stretching into the Pacific Ocean south of central America. (The sheared remains of Pacific Tropical Storm Ramon are also present south of Mexico). The animation below, from 0000-1300 UTC on 5 October 2017, shows the mid-level Water Vapor Infrared Imagery (6.95 µm) from GOES-16. Convection develops over the center of Nate, over Nicaragua, at the end of the animation.

GOES-16 ABI “Mid-Level Water Vapor” Infrared (6.95 µm) Imagery, 0000-1300 UTC on 5 October 2017 (Click to animate)

Microwave Imagery, below, from SSMI/S at around 1000 UTC on 5 October, (from this site) suggests that Nate is centered very near the coast of Nicaragua. Nate is forecast to move north into the Gulf of Mexico; its path through the northwest Caribbean suggests strengthening is possible if Nate remains far enough from land. Very warm water is present in the northwest Caribbean; that warmth extends to great depth as shown by this plot of Oceanic Heat Content; that warmth extends into the central Gulf of Mexico.

85 GHz Brightness Temperatures, 1000 UTC on 5 October 2017 (Click to enlarge)

Nate formed at a time when the Moon was Full. Thus, Suomi NPP Day Night Band Visible Imagery showed excellent illumination. The image below is from 0627 UTC on 5 October.

Suomi NPP Day Night Band Visible (0.7 µm) Imagery, 0627 UTC on 5 October 2017 (Click to enlarge)

Total Precipitable Water in advance of Nate is plentiful, as shown in the loop below (from this site). There is dry air over the continental United States, however, associated with a strong High Pressure System. Easterly winds south of that system are apparent in Scatterometer winds from early in the morning on 5 October.

MIMIC Morphed Total Precipitable Water, 1200 UTC 4 October – 1100 UTC 5 October 2017 (Click to enlarge)

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.

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.