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 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)

Severe thunderstorms in the Northeast US

July 1st, 2017 |

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

As noted in the Tweet above from NWS Gray/Portland ME, a record number of tornado warnings were issued by that office on 01 July 2017. According to their damage surveys, the tornadoes were rated EF-0 to EF-1, with some straight-line wind damage also seen. GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images with plots of SPC storm reports (below; also available as a 98-Mbyte animated GIF) displayed the overshooting tops and colder cloud-top infrared brightness temperatures associated with some of the thunderstorms. Note the significant offset between cloud-top features and storm reports — this is due to parallax from the large viewing angle of the GOES-16 satellite (which is positioned over the Equator at 105º West longitude).

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports in red on Visible, and in black on Infrared [click to play MP4 animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports in red on Visible, and in black on Infrared [click to play MP4 animation]

A comparison of Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1744 UTC (below) showed the early stages of convective development in far southwestern Maine, in addition to well-developed thunderstorms in eastern New York (which would later move northeastward to produce a swath of heavy rainfall that caused flooding at some locations).

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]

Thunderstorm development was fueled by high amounts of moisture that had moved into the Northeast US, as shown below by the Blended Total Precipitable Water product (values in the 40-50 mm or 1.6-2.0 inch range) and the Blended Total Precipitable Water Percent of Normal product (with values in excess of 200%).

Blended Total Precipitable Water product [click to enlarge]

Blended Total Precipitable Water product [click to enlarge]

Blended Total Precipitable Water Percent of Normal product [click to enlarge]

Blended Total Precipitable Water Percent of Normal product [click to enlarge]

The hourly evolution of moisture was depicted by the MIMIC Total Precipitable Water product (below).

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

Tropical Storm Bret

June 19th, 2017 |

GOES-16 “Veggie” Band (0.86 µm) animation of Tropical Storm Bret, 1545-2030 UTC on 19 June 2017 (Click to animate)

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

The fast-moving tropical system in the southern Caribbean Sea has developed a closed circulation and has been named Bret.  Tropical Storm Bret, shown above in an animation of GOES-16 Near-Infrared (0.86 µm) imagery that highlights land/water contrasts (the Orinoco River in Venezuela and Caribbean Islands — some with cloud streamers in their lee — north of Venezuela stand out clearly), is forecast to remain very close to the South American coastline.  Such proximity to land will likely hinder development. Further, wind shear in the atmosphere over the storm is predicted to increase.

Bret is embedded within a ribbon of very moist air (associated with the ITCZ) that stretches from Africa to the northwest Caribbean, as shown in the animation below (taken from this site) that shows morphed microwave observations of total precipitable water.

Microwave estimates of Total Precipitable Water for the 24 hours ending 1900 UTC on 19 June 2017 (Click to enlarge)

For more information on Bret, refer to the National Hurricane Center and the CIMSS Tropical Cyclones sites (where you can also follow the future of the system emerging into the Gulf of Mexico).