Remnant circulation of Tropical Storm Erika

September 3rd, 2015 |

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 (GOES-East) Visible (0.63 µm) images (above; click to play animation) revealed the low-level circulation of the remnants of Tropical Storm Erika moving off the coast of Georgia early in the day on 03 September 2015 (15 UTC surface analysis). Although there was one brief convective burst over the low-level circulation center (LLCC), it is unclear whether this was initiated by an outflow boundary from the ongoing thunderstorm activity farther offshore or was aided by enhanced boundary layer convergence in the vicinity of the LLCC.

During the preceding nighttime hours, the remnant LLCC could be seen on a Suomi NPP VIIRS Day/Night Band image at 0631 UTC or 2:31 AM local time (below), still inland over southeastern Georgia.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared (11.45 µm) images [click to enlarge]

The LLCC was also seen on the morning Terra MODIS Visible (0.64 µm) image (below); the coldest MODIS Infrared (11.0 µm) cloud-top IR brightness temperatures associated with the deep convection east of the LLCC were -82º C (violet color enhancement).

Terra MODIS Visible (0.64 µm) and Infrared (11.0 µm) images [click to enlarge]

Terra MODIS Visible (0.64 µm) and Infrared (11.0 µm) images [click to enlarge]

The 10-day motion of the vorticity field associated with Tropical Storm Erika (and its remnants) can be followed using the atmospheric motion vector (AMV) 850 hPa Relative Vorticity product from the CIMSS Tropical Cyclones site (below; click to play animation).

Atmospheric motion vector 850 hPa Relative Vorticity product [click to play animation]

Atmospheric motion vector 850 hPa Relative Vorticity product [click to play animation]

Hourly GOES Animations from August 2015

September 1st, 2015 |


The YouTube video embedded above shows GOES-13 Water Vapor (6.5 µm) images each hour for all of August 2015. The 10.7 µm Infrared window channel animation is shown below. Both show a remarkable lack of thunderstorm activity in the Caribbean Sea.


In addition, hourly Water Vapor (6.5 µm) and Infrared window channel (10.7 µm) imagery from GOES-15 is shown below.



The GOES-15 imagery includes the northern fringe of the Intertropical Convergence Zone, and the active Eastern Pacific hurricane season is apparent, including several storms that have threatened the state of Hawai’i. The atypically strong August storm that hit the Pacific Northwest is also seen at the end of the animations.