Hurricane Otto strengthened quickly on Thursday morning as it neared the coast of Nicaragua and Costa Rica.  At 7:00 a.m. EDT on Thursday the center of Hurricane Otto was located at latitude 11.0°N and longitude 82.9°W which put it about 90 miles (150 km) southeast of Bluefields, Nicaragua.  Otto was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 976 mb.

A Hurricane Warning is in effect for the portion of the coast from Limon, Costa Rica to Bluefields, Nicaragua.  A Hurricane Watch has been issued for the portions of the coast from Bluefields to Sandy Bay Sirpi, Nicaragua and from the Panama/Costa Rica border to Limon, Costa Rica.  Tropical Storm Warnings are in effect for the portions of the coast from Bluefields to Sandy Bay Sirpi, Nicaragua and from Puntarenas, Costa Rica to Puerto Sandino, Nicaragua.

An Air Force Reserve Hurricane Hunter aircraft found that Hurricane Otto strengthened quickly during the overnight hours.  The reconnaissance plane found a circular eye with a diameter of 23 miles (37 km).  The eye is surrounded by a ring of strong thunderstorms.  Additional bands of thunderstorms are occurring north and west of the center of circulation.  Thunderstorms in the core of Hurricane Otto are generating upper level divergence which is pumping mass away from the center.

Hurricane Otto is a small hurricane.  Winds to hurricane force extend out about 20 miles (32 km) from the center of circulation.  Winds to tropical storm force extend out about 70 miles (110 km) from the center.  The Hurricane Intensity Index (HII) is 17.8.  The Hurricane Size Index (HSI) is 8.4 and the Hurricane Wind Intensity Size Index (HWISI) is 26.2.  These indices indicate that Hurricane Otto is capable of causing localized serious wind damage.

Hurricane Otto is moving through a favorable environment and it could strengthen further before it reaches the coast of Nicaragua and Costa Rica.  Otto is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.

A ridge of high pressure north of Otto is steering the hurricane toward the west and that general motion is expected to continue today.  On its anticipated track the center of Hurricane Otto will make landfall over southern Nicaragua or northern Costa Rica later today.

In addition to localized serious wind damage Hurricane Otto will produce a storm surge along the coast of Nicaragua and Costa Rica.  The surge will be highest north of where the center makes landfall because that is where the wind will push the water toward the coast.  Hurricane Otto will produce very heavy rain over parts of Nicaragua and Costa Rica.  The heavy could cause serious flooding and mudslides in some locations.  Outer rainbands could also produce heavy rain over portions of Honduras and El Salvador.