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Oct
04
2017

Tropical Cyclone Activity Report – Atlantic Ocean / Caribbean Sea / Gulf of Mexico

Tropical Cyclone 16L is located about 70 miles west-northwest of San Andres Island

PDC Disaster Alert, displaying Global Clouds, Tropical Cyclone segments, positions, wind radii, and TAOS model…for TC 16L

Tropical Cyclone 16L will be nearing the coast of Nicaragua early Thursday, move across northeastern Nicaragua and eastern Honduras late Thursday…and emerge into the northwestern Caribbean Sea Friday.

The system will likely track close to the northeast coasts of Honduas and Nicaragua through Thursday, then near parts of Mexico’s Yucatan Peninsula Friday into early Saturday.

Rainfall totals may reach 30 inches in a few locations in Nicaragua, and 20 inches in Costa Rica…according to the National Hurricane Center.

The main impacts will include bands of locally heavy rain, rising high surf, and strong wind gusts.

It looks likely that the system will make landfall along the northern Gulf Coast, somewhere between Louisiana and Florida by Sunday.

Most guidance also suggests this landfall will most likely be as a low-end hurricane.

As Tropical Depression 16L strengthens…it will take on the name Tropical Storm Nate.

Here’s a satellite view, with the looping version…along with what the computer models are showing

Here’s an image that shows where TD 16L is, along with other current information / an image showing the current Watches and Warnings

Here’s a near real time wind profile of TD 16L

TD 16L has maximum sustained winds near 35 mph

According to the NHC:

Tropical Depression 16L Discussion Number 1
NWS National Hurricane Center Miami FL
1100 PM CDT Wed Oct 4 2017

There have been some structural changes to the depression during the past few hours. Inner-core convection began developing just after the issuance of the previous advisory, and Colombian radar images from San Andres are now showing a well-defined convective band to the east and southeast of the center. Despite these changes, Dvorak satellite estimates remain T2.0 from TAFB and SAB, so the initial intensity is held at 30 kt.

The depression probably only has another 12 hours or so before its center moves inland over northeastern Nicaragua, but it is still expected to reach tropical storm strength before that happens. Once the center re-emerges over the waters of the northwestern Caribbean Sea a little after 24 hours from now, high oceanic heat content and low shear should contribute to strengthening. Despite these favorable conditions, the amount of strengthening will be unclear until we know how well the inner core survives crossing over Nicaragua and Honduras. Strengthening is likely to continue through at least day 3 up until the time the cyclone reaches the central Gulf of Mexico. After day 3, there are some indications that higher shear and/or cooler shelf waters over the northern Gulf of Mexico could lead to some weakening, but that scenario is by no means a definite one at this time. Needless to say, there continues to be greater-than-normal uncertainty in the intensity forecast. The updated NHC intensity forecast has been adjusted downward just a bit through day 3 to follow an overall shift in the guidance, although it should be noted that the official forecast still lies above the normally skillful HCCA model.

If the intensity forecast is complex, the track forecast is not much easier. For the first 48 hours, the models appear split on how the depression will interact with a disturbance currently located near the Straits of Florida. For example, the ECMWF model shows some interaction with the disturbance’s low-level vorticity, which swings the depression more to the east on the right side of the guidance envelope. The GFS, on the other hand, shows no such interaction and has the cyclone on the western side of the guidance envelope. This setup has significant downstream effects after 48 hours because it keeps the ECMWF on an eastern route and the GFS on a western route as the cyclone heads toward the U.S. Gulf coast. The new NHC track forecast has been shifted slightly westward, although it is still not as far west as the consensus aids or the HCCA model. Interestingly, although the ECMWF ensemble mean is close to the operational run on the eastern side of the guidance envelope, there is a high density of members to the left close to the consensus aids, which lends additional support for the westward adjustment.

A G-IV mission and Florida special soundings will begin tomorrow to better determine the synoptic steering flow around the cyclone.

KEY MESSAGES:

1. The depression is forecast to strengthen and bring tropical storm conditions to portions of Nicaragua and Honduras through early Friday. Heavy rainfall could produce life-threatening flash flooding and mud slides in portions of Nicaragua, Honduras, Costa Rica, and Panama through Friday night.

2. The system could be near hurricane intensity when it approaches the Yucatan Peninsula late Friday or Saturday, bringing direct impacts from wind, storm surge, and heavy rainfall, and a hurricane watch has been issued for a portion of this area.

3. The system is forecast to continue strengthening over the Gulf of Mexico and could affect portions of the northern Gulf Coast as a hurricane this weekend, with direct impacts from wind, storm surge, and heavy rainfall. However, it is too early to specify the timing, location, or magnitude of these impacts. Residents along the Gulf Coast from Louisiana to Florida should monitor the progress of this system for the next several days and heed any advice given by local officials.

HAZARDS AFFECTING LAND

RAINFALL: The depression is expected to produce the following rain accumulations through Friday night: Nicaragua…15 to 20 inches, isolated 30 inches Costa Rica and Panama…5 to 10 inches, isolated 20 inches Honduras…2 to 5 inches, isolated 8 inches

Heavy rainfall will occur over a wide area, including locations well away from the center along the Pacific coast of Central America. This rainfall could cause life-threatening flash floods and mudslides.

WIND: Tropical storm conditions are expected to start in the warning area in Nicaragua early on Thursday, and spread into Honduras late Thursday. Tropical storm and hurricane conditions are possible within the watch area in Mexico beginning late Friday.

SURF: Swells generated by the cyclone are affecting portions of the coast of Nicaragua, and will begin to affect other land areas around the northwestern Caribbean later this week. These swells are likely to cause life-threatening surf and rip current conditions.

 

 

Atlantic Ocean

NOAA satellite image of the Atlantic

Caribbean Sea

Tropical cyclone 16L

NHC textual forecast advisory
NHC graphical track map
NOAA satellite image

1.) A sharp surface trough of low pressure interacting with an upper- level low is producing a broad area of disorganized showers and thunderstorms across southern Florida, the northwestern and central Bahamas, central Cuba, and the adjacent Atlantic waters. Strong upper-level winds are expected to inhibit significant tropical development of this system while it moves west-northwestward over the eastern Gulf of Mexico during the next day or two. However, locally heavy rainfall, some coastal flooding, and strong gusty winds, especially in squalls, are likely over portions of the Bahamas and Florida during the next couple of days.

* Formation chance through 48 hours…low…near 0 percent
* Formation chance through 5 days…low…near 0 percent

NOAA satellite image of the Caribbean Sea

Gulf of Mexico

Latest satellite image of the Gulf of Mexico

 

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