Tuesday, August 25, 2020

Hurricane Laura: Updated 10pm CDT Tuesday

For more up-to-date coverage on Hurricane Laura, scroll up on the blog. 



-- Original Posting --

Quick 10pm update: Strengthening continues. Pressure has dropped to 978 mb with sustained winds up to 90 mph. More strengthening expected through the night. 

Quick 7pm update: The storm is strengthening. Pressure has dropped to 983mb, which is a considerable drop for three hours. Winds have increased to 85 mph. 

The Weather Channel produced this detailed map of the storm surge which will extend as far as 47 miles inland!
click to enlarge 
-- original posting --
Laura has 70 mph winds and a pressure of 990mb based on the latest Hurricane Hunter flights. However, since the last aircraft departed the storm, Laura is starting to show an eye (dark center in the photo below from 2:01pm). If that continues, the storm will intensify rapidly.

The official forecast of the center of the storm looks pretty solid as indicated below.
The amber is the area of 40-74mph winds as of 1pm. The brown is winds of 75 mph or higher. Red is the Hurricane Warning. Blue is a Tropical Storm Warning. M = major hurricane. H = hurricane. S = tropical storm. D = tropical depression. 

Below is a map of the time of earliest reasonable arrival of sustained winds of 40 mph or higher. All precautions should be completed by those times.

Here is a map of what I would call the "reasonable worst case winds." This is based on the storm being a mid- to upper Cat 3 storm. If the storm is stronger than the forecast, the wind gusts shown below would have to be increased. Hurricane Laura is expected to produce damage somewhat similar to Hurricane Rita except we forecast Laura to be a little farther west. 
click to enlarge
Wind gusts of more than 100 mph are sufficient to cause structural damage. Gusts to 75 mph are sufficient to cause power failures. In some areas, the power could be out for days. Please factor that into your planning.

From the NWS in Houston/Galveston.

Life-threatening storm surge is forecast with this storm. 
The surge will be locally higher immediately east of where the eye crosses the coast. Of course, the above does not include astronomical tides nor the high waves of a hurricane.

According to the National Hurricane Center (4pm Tues.),

There is the danger of life-threatening storm surge accompanied by large and dangerous waves from San Luis Pass, Texas, to the Mouth of the Mississippi River, including areas inside the Port Arthur Hurricane Flood Protection System. This surge could penetrate up to 30 miles inland from the immediate coastline in southwest Louisiana and far southeast Texas. Actions to protect life and property should be rushed to completion this evening as water levels will begin to rise Wednesday. 

Below is a map of the areas of possible inundation by the surge. 
If the storm intensifies more rapidly than expected, the eastern areas (pink) towards New Orleans could experience a significant storm surge. 

There will be inland flash flooding with this storm. Rainfalls may be ten inches near the coast. The map is rainfall for the 72-hours ending at 6pm Friday.

Tornadoes are likely along and east of the path of the eye. 

I'll have an update late this evening. 

Below are my suggested safety procedures. If you are in an evacuation area, please get it done as soon as reasonably possible. 
  • Make a hotel/motel reservation well inland. There is no point to getting on the road and finding everything already sold out. Be sure and cancel if you do not need the room.
  • Make provisions for infirm friends/relatives well in advance. 
  • Get prescriptions filled before you evacuate. 
  • Visit the ATM to make sure you have adequate cash for a week on the road. 
  • Put an app like AccuWeather's on your smartphone. It will keep track of your location and automatically provide the latest emergency warnings as you are on the go. 
  • Your "Go-Kit" should include at least two masks per person, soap, hand sanitizers, disinfectant wipes and, if available, disinfectant spray. Have clothes for at least a week. No one cares how stylish you are. If you are at a pharmacy, pick up some surgical gloves and, if you don't have them, work gloves. 
  • Fill your car with fuel. I still recommend a road atlas or map in addition to whatever navigation system you might have. 
  • Power failures are likely. If you have a generator, fill it with fuel. If you wish to purchase a portable generator, do not put it in the garage, indoors, or anywhere near an air intake. Carbon monoxide is a danger. 
  • Consider taking your passport or putting it in your safe deposit box. If the worst happens, you'll need it to prove identity for disaster documents. It will be difficult to recover in a ruined home.
  • Take at least two large bottles of water for each family member along with protein bars or other easy-to-carry food. 
  • If you decide to stay home, make sure you have a working fire extinguisher, non-electric can opener, and a first aid kit. 
  • Put your insurance documents in your safe deposit box or take them with you. This will facilitate filing a claim if you have serious property damage. 
You can get more information from me on Twitter @usweatherexpert.

I plan to update again late this evening. Thanks for reading. And, if the subject of how we create hurricane and other storm warnings is of interest to you, go here.

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