22 Nov 2016

Late-Season Tropical Depression Forms in Southern Caribbean Sea

A late-season tropical depression formed in the southwestern Caribbean Sea on Nov. 21 and NOAA's GOES-East satellite provided a look at the storm. Tropical Depression 16 formed from System 90L, a tropical low pressure area that had been lingering in the Caribbean Sea for days. Tropical Depression 16 formed around 4 a.m. EST on Nov. 21.
Visible imagery from NOAA's GOES-East satellite at 10:45 a.m. EST (1445 UTC) on Monday, Nov. 21 showed that the depression's cloud pattern appeared better organized. Satellite imagery showed some banding of thunderstorms over the northern and western portions of the circulation and small bursts of deep convection near or over the estimated center.

NOAA manages the GOES series of satellites and NASA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Maryland uses the data to create images and animations. The image showed that the center of Tropical Depression 16 was about 300 miles from Nicaragua.
At 11 a.m. EST on Nov. 21 there were no coastal watches or warnings in effect. However, the National Hurricane Center (NHC) said that "Interests in Nicaragua, Costa Rica, and the islands of San Andres and Providencia should monitor the progress of this system, since a Tropical Storm Watch may be required later today or tonight."

At 10 a.m. EST (1500 UTC), the center of Tropical Depression Sixteen was located near 11.5 degrees north latitude and 79.3 degrees west longitude, about 175 miles (285 km) east-southeast of San Andres Island and about 305 miles (495 km) east of Bluefields, Nicaragua. The depression is nearly stationary and NHC expects a west-southwestward to westward drift over the next couple of days.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Some strengthening is forecast during the next 48 hours, and the depression is likely to become a tropical storm later today. The estimated minimum central pressure is 1002 millibars.

NHC noted that rainfall will affect parts of Panama and Costa Rica. "Outer rain bands from the depression are expected to produce rainfall accumulations of 3 to 6 inches across portions of central and western Panama and southeastern Costa Rica through Wednesday, with isolated totals upwards of 10 to 15 inches across the higher terrain. These rains could result in life-threatening flash floods and mud slides. Additional heavy rainfall may move into portions of Costa Rica Wednesday night into Thursday as the system approaches the coast."
National Hurricane Center forecaster Richard Pasch noted "There is moderate south-southeasterly [vertical wind] shear over the depression, and this should allow for only slow strengthening over the next day or two. In 72 hours or so, some relaxation of the shear is forecast with an upper-level anticyclone developing over the tropical cyclone, and the system is predicted to become a hurricane before landfall."

Image: Visible imagery from NOAA's GOES-East satellite at 10:45 a.m. EST (1445 UTC) on Monday, Nov. 21 showed that the depression's cloud pattern appeared better organized.