Major Hurricane Matthew

This has been quite an active season for the Atlantic basin, and the churning is not over yet. With the latest update from the National Hurricane Center, Hurricane Matthew is a Category 4 Major Hurricane with central pressure of 934 millibars and max sustained wind speeds of 145 mph. It is currently moving north at 7 mph and will be running into the western half of Haiti by daybreak. Below I've gone through the current setup and what it means for steering Matthew, a couple factors acting to weaken/strengthen Matthew, and what it means for Hispaniola/Caribbean and the Continental United States.

Meteorological Setup

There are a few atmospheric components working together right now aiding in the northward and further westward-tracking of Hurricane Matthew:

1. Bermuda High: The first component is the Bermuda high. This is a persisting high pressure system in atmosphere over the Western Atlantic Ocean. A high pressure system consists of a center acting as a hilltop of air with winds flowing clockwise around it.

2. Jet Stream: The Jet Stream is essentially acts as an imaginary wall between the tropical air mass and the polar air mass and works to transport various air masses around the globe.

3. Tropical Continental Low: This low pressure anomaly is partially created by the differing air masses between the Gulf of Mexico and the North American Continent, and partially due to the Bermuda High.

Now, how do all these work together to direct and strength the storm? With the current setup, the jet stream is currently flattened out rather than dipping deep into the continent and shooting northward again. Over the next few days, the Jet stream is going to dip in the belly of the continent and rise back toward the New England States. This shift of the jet stream will allow the Bermuda High to strengthen and a ridge to build up over the continent, ultimately resulting in stronger clockwise wind flow, but also causing a larger swath of that clockwise flow. As the ridge (or isolated high pressure) grows, the window of opportunity for Hurricane Matthew to move out to sea diminishes and a northnorthwesterly wind component is acting to steer Matthew toward the coast. In addition, there is clockwise flow from the High on the eastern side of the storm with counterclockwise flow from the Continental Low on the western side. This wind shear, or change in wind speed and direction with a change in distance, acts to "spin the top" and aids in the continued shaping of the storm rather than tearing it apart.

This is the storm surge forecast shared by Meteorologist Michael Lowry

Geologic/Hydrologic Factors

There are two opportunities geologically for Matthew to weaken prior to making any landfall in the Continental United States, both of which are higher levels of elevation. Both the Islands of Haiti and Cuba have mountains higher than 4,000 feet which will both act to slow some of the momentum of those 145 mph winds. This has other implications when forecasting for potential devastation,

There are also two factors hydrologically we need to be concerned with in the immediate future for Hispaniola and the Caribbean. The first of these is the rainfall in the mountains both in Haiti and Cuba. Increased rainfall in higher elevations increases the risk for devastating mudslides and flash flooding for those living there. These mudslides and floods can easily take trees, bridges, roads, and houses with them flowing downhill. The second of these is the warmth in the Caribbean Sea right now. Ocean temperatures of around 80 degrees Fahrenheit are normally a requirement for Tropical Cyclone formation and development, however the water temperature right now is around 85 degrees Fahrenheit with 80 degree water ; plenty warm enough for increasing the strength of Hurricane Matthew after losing momentum to the mountains.

Caribbean Concerns

The nations of Haiti, Cuba, and the Bahamas are all under Hurricane warnings right now. Coastal regions of western Haiti, eastern Cuba, and the eastern half of the Bahamas can expect 10-15' storm surge, heavy rains, and strong sustained winds for the next couple of days as Matthew crawls northward at 7 mph. Devastating flash flooding as well as wind damage to structures is expected in the Caribbean over the next 3-4 days.

*Para personas en esta region, es muy importante para oír a su líderes y toma acción para ahorrar sus familias si en una posición de gran pelígro.*

United States Concerns

This map depicts rainfall in the month of September different from the average.

There is still a fair amount of uncertainty as to whether there will be a landfalling location or not, however it is certain that the coastline from south Florida through the Carolinas will experience at least Tropical Storm force winds and decent rainfall at best. There is an increasing westward trend of model runs as we get closer to the potential impact of Hurricane Matthew, which means there is increasing danger for the coastline. We have already received way above average rainfall in Central and Eastern North Carolina, and one model is numerically representing over 11" of rainfall in areas along the South Carolina coast and over 8" in Wilmington. These are not official forecasts. These are only model representations. There is still plenty of time for these model representations to adjust before Matthew gets closer to the Continent. It is still imperative that we prepare for the worst, in case a landfall is experienced in the next week.

Hurricane Preparedness Plan

If you live along the coast, especially in the outer banks or other barrier islands, do NOT try to ride out this storm. Pay attention to Emergency Management and meteorologists to aid in making decisions to keep you and your family safe. If property is going to be destroyed by this storm, I hate to say it, but there is nothing you can do about it by staying there except putting your life on the line unnecessarily.

If Matthew continues to trend more westward, there is a good chance the Florida coast could lie in a hurricane warning, in which case FEMA and Emergenc
y Management would begin advising to board up housing and/or initiate evacuation plans.

For those along the Outer Banks and other barrier islands between Florida and the Carolinas, again, pay close attention to instruction from local Emergency Management, Meteorologists, and government officials to protect yourselves and your families.