Otto small but will bring torrential rain and strong wind to portions of Central America

The biggest hazard from Otto will be the rain which is expected to be more than a foot in some locations.

The biggest hazard from Otto will be the rain which is expected to be more than a foot in some locations. Click to view full size.

It is late in the hurricane season but TS Otto has managed to find a small corner of the Caribbean Sea in which to flourish. Recent reports from the NHC indicate that Otto is nearing hurricane intensity and by looking at satellite images, it won’t be long until that status has been achieved.

Fortunately, Otto is small in size with tropical storm force winds extending only 35 miles out from the center. When it becomes a hurricane, those winds will also be confined to a relatively tiny area near the center thus wind is really not going to be the issue here.

Instead, rain is my big concern. Heavy rain is expected to fall across portions of Nicaragua, Costa Rica and Panama today and lasting through the remainder of the week. The extremely slow movement of Otto will only add to this hazard and for areas of Nicaragua especially, rainfall could be excessive and lead to substantial flooding with great risk to life and property. Obviously interests in the region should be paying close attention to the progress of Otto and be ready to head to safer locations should flooding commence. I am very worried about the amount of rain that could fall with this system and will continue to emphasize that fact throughout this event.

Otto is expected to move slowly westward over the next few days and eventually make landfall somewhere in southern Nicaragua and possibly straddle the border of Costa Rica. This is very far south for a hurricane to be making landfall no matter what time of the hurricane season it it. As such, people are not used to this which makes it even more important for folks to keep up to date with the latest information as Otto progresses.

There is no risk of the storm turning north in to the Gulf of Mexico and even the NW Caribbean Sea due to mid-level high pressure building in across the region, acting like a block and forcing Otto to remain south and move generally westward underneath the high pressure area. It is possible that the remnants survive the passage over Central America and emerge in to the southeast Pacific – if so, we’ll deal with that when the time comes.

I’ll have more in my video discussion which I will post later this afternoon.

M. Sudduth 8:50 AM ET Nov 22

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TD16 forms in SW Caribbean – forecast to become a hurricane

TD 16 track map from the NHC. Note the slow movement over the next five days and the forecast for the depression to become a hurricane as it approaches Central America.

TD 16 track map from the NHC. Note the slow movement over the next five days and the forecast for the depression to become a hurricane as it approaches Central America.

Hurricane season officially ends on November 30 but before we get to that date, we will have to deal with one more hurricane, or so it appears.

The NHC began issuing advisories on TD16 early this morning. The depression is located in the southwest Caribbean Sea, not far off the coasts of Panama and Costa Rica. Overall the environment is generally favorable with warm water temps and a small region of upper level winds that are conducive for additional strengthening. As such, the depression is forecast to become a tropical storm (name will be ‘Otto’) later today and eventually reach hurricane intensity as the week progresses.

Weak steering currents for the time being will result in a very slow motion of the depression as it meanders over the SW Caribbean. In the longer term, enough mid-level ridging should build in to gradually push the would-be hurricane towards the west and in to Central America. Precisely where landfall occurs remains to be seen but interests in Costa Rica, Panama and Nicaragua should be monitoring this system very closely.

The main hazard will be excessive rain and I cannot emphasize this enough. While the wind speed will gradually increase it is the rain that concerns me the most due to the slow movement. Right now there are no significant impacts being felt on land since the depression is far enough off the coast. However, once it begins to move westward later this week, bands of torrential rain will rotate onshore across southern Central America and the potential for flash floods will increase, especially in any mountainous areas. I will address this issue more once the NHC updates their “hazards impacting land” section of the Public Advisory. For now, residents and visitors to the region should be mindful of this system and be ready for the possibility of life-threatening flooding as the system approaches later this week.

Outside of TD16, the Atlantic Basin is quiet as we would expect for the last third of November. The season turned out to be fairly busy and with soon-to-be Otto on the horizon, the Atlantic will end up over-achieving for the year with activity running a little above the long term norm. I will have a more in-depth discussion of the 2016 season in a blog post scheduled for November 30. For now, we will focus on TD16 and its eventual impact to Central America.

I’ll have more in my video discussion which will be posted later this afternoon.

M. Sudduth 8:15 AM ET Nov 21

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