Thursday, October 6, 2016

Menacing Matthew Threatens Bahamas, Much of Florida

This post is being written at 1 AM CDT on October 6th, and thus all information is valid at the stated time. Please do not use this blog post to make your decisions. Always refer to official sources (NWS, NHC, local emergency management, etc.) when making decisions.


This is Major Hurricane Matthew, currently tracking through the central Bahamas. It is a Category 3 hurricane with maximum sustained winds of 115 mph. After slamming into southwestern Haiti and eastern Cuba as a Category 4 hurricane, the mountainous terrain did disrupt the system a bit. But, with favorable conditions once again, Matthew has the opportunity (and is forecast) to strengthen. Here is the latest forecast track taken from the National Hurricane Center:


You can see that Matthew is forecast to reintensify into a Category 4 hurricane yet again and either move inland over Florida or parallel the coast just offshore. Anywhere within the cone is a possibility. But let's discuss a few points about the "cone of uncertainty":

  • The cone only describes where the center of the storm will go. It tells us nothing about the impacts. Impacts can be felt well outside of the cone.
  • The center of the storm is only expected to be inside the cone 67% of the time. The other 33% of the time, the storm may be outside of the cone.
  • The cone is built on historical averages, and does not represent the full certainty or uncertainty of the track.
On the above map, you see many watches and warnings out for the Bahamas and parts of the southeastern United States. Unfortunately, especially in the U.S., this map only shows the coastal portions that are under watches/warnings. So here's a map showing the counties under these watches or warnings:


So, using the same color scheme as above, you can see all the counties under the watches and warnings. But what do these mean?
  • TROPICAL STORM WATCH: tropical storm conditions (39+ mph winds) are possible within the next 48 hours.
  • TROPICAL STORM WARNING: tropical storm conditions are expected within the next 36 hours
  • HURRICANE WATCH: hurricane conditions (74+ mph winds) are possible within the next 48 hours
  • HURRICANE WARNING hurricane conditions are expected within the next 36 hours.
Now, these warnings only talk about the wind, not the storm surge or any other impacts. However, the National Hurricane Center has a prototype Storm Surge Watch/Warning product that will become operational in 2017. But, they have issued some Storm Surge Watches and Warnings ahead of Matthew:


  • STORM SURGE WATCH: life-threatening inundation from rising water moving inland from the shoreline somewhere within the watch area is possible within the next 48 hours
  • STORM SURGE WARNING: life-threatening inundation from rising water moving inland from the shoreline somewhere within the warning are is expected within the next 36 hours.
Note that these products are only available for the United States right now. However, the Bahamas could see a devastating storm surge of 10-15 feet above normal tide levels. In the United States, current forecasts call for:
  • 5-8 feet of storm surge between Sebastian Inlet, Florida, and the Savannah River in Georgia
  • 3-5 feet between Deerfield Beach, FL, and Sebastian Inlet, FL
  • 1-3 feet between Virginia Key, FL, and Deerfield Beach, FL
Now, there are numerous areas under evacuation orders right now. I will put it plain and simple. If you are under a mandatory evacuation,

DON'T WAIT. EVACUATE!

Right now is the time to rush your preparations to completion in southern and central Florida. If you are under a mandatory evacuation, you need to leave ASAP. Get cash out of the ATM, fill up your car with gas, charge your cell phone and laptop, collect important documents, have a 3-day supply of food and water for each person, and know where you're going if you plan to evacuate. There is some strong wording coming out of the local National Weather Service offices.

From NWS Jacksonville:
POTENTIAL IMPACTS IN
THIS AREA INCLUDE:
    - STRUCTURAL DAMAGE TO STURDY BUILDINGS, SOME WITH COMPLETE ROOF
      AND WALL FAILURES. COMPLETE DESTRUCTION OF MOBILE HOMES. DAMAGE
      GREATLY ACCENTUATED BY LARGE AIRBORNE PROJECTILES. LOCATIONS
      MAY BE UNINHABITABLE FOR WEEKS OR MONTHS.
    - NUMEROUS LARGE TREES SNAPPED OR UPROOTED ALONG WITH FENCES AND
      ROADWAY SIGNS BLOWN OVER.
    - MANY ROADS IMPASSABLE FROM LARGE DEBRIS, AND MORE WITHIN URBAN
      OR HEAVILY WOODED PLACES. MANY BRIDGES, CAUSEWAYS, AND ACCESS
      ROUTES IMPASSABLE.
    - WIDESPREAD POWER AND COMMUNICATIONS OUTAGES.
Similar wording has also been used by the NWS office in Melbourne. Again, this is a life-threatening situation, and you should not risk your life by staying if you are in a mandatory evacuation zone. If anything were to happen to you or your family and you live in a mandatory evacuation zone, emergency responders may not be able to get to you. Also, if you plan to leave closer to the storm's arrival, remember that, in Florida, there are many bridges. The Florida Highway Patrol tends to close bridges once sustained winds reach tropical storm strength. So, especially if you live closer to the beach, you need to leave sooner rather than later.

Right now, we are hoping for the best and preparing for the worst with regards to Matthew. Heed the advice of your local emergency management office or local law enforcement. If you are told to leave, then leave. Also, check your county's emergency management webpage to find local shelters or evacuation routes. Just keep in mind you may need to bring some supplies with you or that pets may not be allowed at some shelters. The time to activate your hurricane plan is now!

Be prepared, stay safe, and listen to your official sources.

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