A late-season tropical storm formed on November 21, 2016, and was named Otto. Otto formed from Tropical Depression 16 (System 90L), a tropical low pressure that had been lingering in the Caribbean Sea for days. Otto is currently a stationary system but is expected to start moving toward Costa Rica and Nicaragua and reach hurricane status over the next couple of days.
This is the 15th named storm of the 2016 Atlantic hurricane season. The season officially runs from June 1 to November 30, sharply peaking from late August through September.
According to meteorologist Philip Klotzbach, Otto marks the latest date of formation in the western Caribbean since Odette in 2003 and 4th latest on record (since 1851).
Otto officially became a tropical storm at 18:00 UTC today, NHC said.
At the time, it was located 285 km (175 miles) ESE of San Andrés island and 495 km (305 miles) E of Bluefields, Nicaragua. Its maximum sustained winds were 85 km/h (50 mph). Minimum central pressure is 1 000 hPa.
Otto is still nearly a stationary system and there are currently no coastal watches or warning in effect. However, interests in Nicaragua, Costa Rica, and the islands of San Andres and Providencia should monitor its progress, since a Tropical Storm Watch may be required later today or tonight.
A westward drift is expected over the next couple of days.
Additional strengthening is forecast during the next 48 hours, and Otto could become a hurricane during the next couple of days.
Tropical-storm-force winds extend outward up to 55 km (35 miles).
Outer rain bands from Otto are expected to produce rainfall accumulations of 76 to 152 mm (3 to 6 inches) across portions of central and western Panama and southeastern Costa Rica through Wednesday, November 23, with isolated totals upwards of 254 to 381 mm (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, November 24, as the system approaches the coast.
Tropical Storm "Otto" forecast track by NHC on November 21, 2016
Tropical Depression 16, soon to become Tropical Storm "Otto" - November 21, 2016. Credit: NASA Terra/MODIS
Tropical Depression 16 - Tropical Storm Otto at 17:45 UTC on November 21, 2016. Credit: NOAA/UW-CIMSS
72 hours of rainfall accumulation by 12:00 UTC on November 21, 2016. Credit: NASA/GPM
Featured image: Tropical Depression 16 - Tropical Storm Otto at 17:45 UTC on November 21, 2016. Credit: NOAA/UW-CIMSS