Matthew Continues Northwestward As Category 4
Hurricane Matthew
5:00 PM EDT on October 02, 2016
Location 14.6 N -74.8 W
Winds: 145 mph Gust: 175 mph
Pressure: 945 mb
Category: 4
Moving: NW at 5 mph
Matthew has maintained category 4 status throughout the day and now is heading to the northwest at 5 mph. This motion is forecast to become more northerly over the next day or two as it approaches the gap between Jamaica and Haiti. At this time the storm will be a category 4 or very strong category 3 hurricane. The models keep trying to have the center of the storm slip in between all the islands but I feel, unfortunately, someone is going to receive a direct hit. This is not to say the impacts will only be confined to the center but given the narrow width of hurricane force winds (145 mph) any distance from land it can make would make for a slightly better situation.
The major problem however, is the heavy rain forecast for these areas. Given the topography, Haiti could experience major problems with flooding rains. All interest in the area needs to keep monitoring the situation and be ready to act quickly. Jamaica will end up (if no major changes) on the left side of the center and be farther away from the center so that the effects are not as great as a direct hit. The storm has been “wobbling” some for the past couple of hours though its predominate motion is to the northwest. Strong hurricanes have been known to quickly stray from their forecast track. On example in particular is Hurricane Charley so if you are going to even be within the vicinity of the center, pay close attention.
The storm will then ride up into eastern Cuba where it will be a category 3 hurricane. Some weakening is expected due to the terrain it will have passed though at this wind speed it doesn’t really matter that much. This will still be a very dangerous storm and has overcome odds with regard to strength before and anything is still possible.
Where it hits in Cuba is difficult to say. The official forecast brings the storm to the eastern tip of Cuba. There have been models indicating that there could be a small chance it could hit west of the forecast track. This is to be expected since that area is also within the cone of uncertainty.
Once it reemerges off the coast of Cuba, it will begin to enter into the Bahamas. The strength of the system will be determined by how much it has weakened over Cuba and whether the upper anti-cyclone actually materializes over the storm at that time. This would allow strengthening once it is over warmer waters. The official forecast calls for a category 2 or 3 storm at this point and could very well be that strength but I wouldn’t rule out additional strengthening if the situation is favorable.
Matthew will be moving rather slowly at this point. Current forecast has it taking at least two days to clear the Bahamas which will obviously cause very rough conditions for the country at that time.
What happens after that still remains very complicated but I am beginning to narrow down the main players that will ultimately decide the future track of this storm.
I am going to use the 18Z GFS as an example of what I will be talking about. This is only for demonstration purposes and does not reflect an official forecast.
At this time the storm has just emerged off of Cuba and now heading into the Bahamas. Over the mid-Atlantic, you have a ridge of high pressure and the storm is located on the southwest edge rounding to the western side of that ridge. That combined with a trough over the Gulf of Mexico will guide the storm north-northwestward to this location and then close to the east coast. You can begin to see the effects of the upper-level low that has been hanging around the northeast for the past couple of days. This is indicated by the blue area to the east of Virginia.
The 500 mb vorticity map shows a stronger trough than originally forecast stretching from Virginia out in the North Atlantic.
This upper-level trough will begin to erode the ridge over the mid-Atlantic creating a weakness in the ridge to the northeast of the system. The weakening of the ridge to the east will allow the storm to start to feel this weakness and begin to slowly turn northward. The forward motion has also slowed the past couple of forecast runs which adds another variable into this equation. There is a trough forecast to traverse the CONUS and will begin to approach the eastern seaboard Friday. The storm will only be a few hundred miles away from the South Carolina coast by this time.
By then the storm will begin to feel the effects of the approaching trough. The trough, in tandem with the low pressure formed to the east, will move the storm northeastward then eastward away from the North Carolina coast.
In this example, even though the center may name make landfall, the storm will be large enough that its effects are felt along the coast.
I must caution you that what I explained is unique to this forecast example and may not be the long-term forecast thinking. It is very possible that the conditions may not play out as they were presented here but what I wanted to explain is the features to keep an eye out for:
-Mid-Atlantic ridge strength and placement
-Upper-level low and possible eroding of the ridge
-The trough approaching from the west
-Timing
-Speed of Storm
Where these things fall together will decide the future of the storm and right now there is no way to know how all of this will play out. We just need to wait until things become in better focus. Until then make sure you are prepared to take action if you live anywhere on the east coast. Have a plan. Make sure you have any supplies you may need in the event the storm makes landfall where you area. Pay close attention to the NHC, NWS, or local authorities regarding any decisions you should make.
The forecast above is an my opinion alone and may not reflect the forecast thinking from the NHC or other organization. Do not make any life or death decisions based on the information from this site.
I will try to provide another update tomorrow morning if possible. If not then, check back at noon or the late afternoon for more information.