Hurricane Laura, as expected, has strengthened today, as it travels over the very warm waters (90oF) of the Gulf of Mexico. With sustained surface winds over 145 mph, it is capable of causing catastrophic damage along the coastline between Texas and Louisiana and several hundred miles inland. Landfall is expected late evening today. Laura will likely strengthen a bit before the evening and hit the high end of the Cat 4 range of 130-156 mph.
Here is the projected path and timing of Hurricane Laura -
TS Laura forecast positions and max winds
INIT 26/2100Z 27.9N 92.8W 125 KT 145 MPH
12H 27/0600Z 29.7N 93.6W 130 KT 150 MPH
24H 27/1800Z 32.5N 93.5W 60 KT 70 MPH...INLAND
36H 28/0600Z 34.8N 92.7W 35 KT 40 MPH...INLAND
48H 28/1800Z 36.5N 90.1W 25 KT 30 MPH...INLAND
60H 29/0600Z 37.3N 85.6W 25 KT 30 MPH...INLAND
72H 29/1800Z 38.0N 79.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 30/1800Z 43.2N 64.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 31/1800Z 51.0N 49.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
Winds
Winds will stay strong even as the hurricane moves inland.
Storm Surge
15-20 feet of storm surge in some areas will be catastrophic.
Rain Forecast
Forecast Models
Forecasts about storm track and intensity are based on computer models which are fed current atmospheric conditions and which calculate weather and storm conditions several days into the future. There are many such models and most graphs like the ones above are based on the average results from several models. Here is an example of the results for Laura from several models at the NOAA National Hurricane and Weather Forecast System (HWRS).
The various models are in very close agreement at this point.
Laura’s track and intensity were predicted several days ago, as Laura scraped over Puerto Rico, the Dominican Republic and Cuba. The models have undergone small adjustments as the storm approached the Gulf and now the Gulf coast.
Some Analysis and Guidance
From the 11:00 am NHC bulletin -
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Laura has become a very powerful hurricane this morning.
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Laura is likely to continue strengthening today while it moves over warm waters of the northwestern Gulf of Mexico and the vertical wind shear remains low.
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After landfall, rapid weakening will occur, but Laura will bring a swath of damaging winds well inland over western Louisiana and eastern Texas.
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This motion will bring the center of Laura onshore in southwestern Louisiana or extreme eastern Texas tonight. By Thursday night, Laura is forecast to turn northeastward, and then east-northeastward on Friday as it becomes embedded in the mid-latitude westerlies.
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The UKMET and ECMWF models suggest that there is some chance that Laura re-intensifies as a tropical cyclone off the mid-Atlantic coast
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Unsurvivable storm surge with large and destructive waves will cause catastrophic damage from Sea Rim State Park, Texas, to Intracoastal City, Louisiana, including Calcasieu and Sabine Lakes. This surge could penetrate up to 30 miles inland from the immediate coastline. Only a few hours remain to protect life and property and all actions should be rushed to completion.
Latest reading by recon plane around 9:11 p.m. EDT, passing through Laura’s northern eyewall measured winds near surface at 138 knots = 159 mph, i.e., Category 5 intensity. There are no signs of slowing down, hours before landfall.
Satellite and radar imagery
Flying into the eye of the Hurricane
NOAA and the 53rd Weather Reconnaissance Squadron (53rd WRS) send aircraft with special instrumentation several times a day into the hurricane to make more precise and frequent measurements of parameters within hurricanes. The aircraft are equipped with radar and other instruments. Typically, they fly straight across the hurricane at altitudes between 1,000 feet to 10,000 feet. It sounds dangerous to fly into through the eye-wall of a hurricane swirling at 185 mph, but they have been doing so for decades with a near perfect record.
www.tropicaltidbits.com/… is an interesting site that plots the data from these recon flights in near real-time. Here is an example of the flight path across Laura today of the NOAA recon plane. The aircraft also drop dropsonde devices into the storm, which measure and relay vital signs of the hurricane as they fall down towards the ocean.
Hurricane season 2020
Laura is the earliest named 12th Atlantic tropical cyclone on record.
The average number of named Atlantic storms per season is 11.3, so we have already blown past that average. And the hurricane season has barely started; mid-August through mid-October are the periods of the big hurricanes; earlier tropical storms tend to be few, weak and tend to stay offshore.
The 2020 Hurricane season so far is shown below (the chart also shows wind speeds for different storm categorizes).
North Atlantic tropical cyclones
Like most Atlantic tropical cyclones, Laura started as a tropical wave over western Africa.
The following map from NASA shows the tracks of all tropical cyclones during the 1985-2005 time period. The Pacific Ocean west of the International Date Line sees more tropical cyclones than any other basin, while there is almost no activity in the Atlantic Ocean south of the Equator. Tropical cyclones do not form around the equator.
Map of the cumulative tracks of all tropical cyclones during the 1985-2005 time period. Credit: NASA. www.nasa.gov/...
A large number of Atlantic hurricanes originate near the Cape Verde islands, off the west coast of Africa and are know as the “Cape Verde hurricanes.” These hurricanes form from a tropical wave that has passed over or near the Cape Verde islands after exiting the coast of West Africa. Hurricanes Dean (2007), Ivan (2004), Floyd (1999) Hugo (1989), Fran (1996), Isabelle (2003) are examples of Cape Verde hurricanes.
Atlantic Hurricane Season
According to weather.com/… , several factors contribute to the hurricane ramp-up that begins in August:
- African easterly waves are most developed, often serving as a seed for tropical storms and hurricanes to form.
- Saharan air layers, surges of dry air into the central and eastern Atlantic Basin that normally squelch tropical development in those areas, tend to give way by August as the parade of African easterly waves gradually add moisture. This effectively opens up more favorable real estate for tropical cyclone development.
- Vertical wind shear, the change in wind speed and/or direction with height, which can rip apart a tropical cyclone wannabe, tends to be low.
- Sea-surface temperatures rise toward a peak in early fall.
- Instability – the atmosphere's ability to generate convection (thunderstorms) to help initiate tropical cyclones – also rises toward an early fall peak.
Hurricanes and Climate Change
Yes, hurricanes are not uncommon, but there is a link between climate change and increased hurricane intensities. According to this paper from Yale, How climate change is making hurricanes more dangerous -
There’s now evidence that the unnatural effects of human-caused global warming are already making hurricanes stronger and more destructive. The latest research shows the trend is likely to continue as long as the climate continues to warm.
Generally speaking, the warmer the water temperatures, the more heat energy is available and the higher the potential for tropical cyclones to develop. So it’s reasonable to assume that as humans continue to release planet-warming greenhouse gases, the likelihood of tropical cyclone activity increases. The conventional wisdom is that storm intensity will increase but storm frequency will either decrease or remain unchanged.
Epilogue
For those in the path of the storm, please make preparations and stay safe. The best advise is to listen to forecasts and instructions from the NHC and local authorities, prepare for the worst and hope for the best. It is probably too late to evacuate from coastal regions; seek shelter.
Also, this will only make the COVID-19 situation worse, with limited testing and people possibly congregating in shelters.
We also wish some of this rainfall would head towards the west coast, but that never happens with Atlantic hurricanes anyways.
Further Reading
- National Hurricane center — www.nhc.noaa.gov
- weather.com/...
- Laura Rapidly Intensifying Into A Major Hurricane This Morning, Landfall Expected Tonight Near The TX/LA Border — blog.weather.us/...
- Aircraft Reconnaissance — www.tropicaltidbits.com/…
- Real-time GOES-16 satellite imagery — rammb-slider.cira.colostate.edu/...
- Atlantic Basin Storm Names and Pronunciations — www.weather.gov/…
- How To Tame a Hurricane — www.dailykos.com/…
- Hurricane Dorian Forecasts, Updates and Science - Part 2 (2019) — www.dailykos.com/…
