Category 4 Hurricane Harvey’s Landfall Imminent; Catastrophic Rainfall Flood Threat; Strongest Texas Coastal Bend Landfall in at Least 47 Years

Weather.com

Hurricane Harvey has rapidly intensified and is now a Category 4 hurricane, with landfall just a couple hours away along the Texas Gulf Coast. However, the eyewall – the location of the strongest winds – is about to move onshore along the Texas Coastal Bend, and a wind gust of 101 mph has already been reported.

Harvey will be the nation’s first major (Category 3 or stronger) hurricane landfall in almost 12 years tonight, poised to clobber the Texas Gulf Coast with catastrophic rainfall flooding, dangerous storm-surge flooding and destructive winds this weekend that could leave parts of the area uninhabitable for an extended period of time.  

Right Now

After a slight pause Thursday night, Harvey has reintensified today with maximum sustained winds now 130 mph. Harvey is located about 35 miles east of Corpus Christi, Texas, moving northwest at around 8 mph.

(MORE: A Message from The Weather Channel’s Hurricane Expert)

Harvey’s central pressure has plummeted once again, another 25-plus millibars since early this morning, as another rapid intensification phase is ongoing.

Outer rainbands are currently spiraling ashore as far north as the upper Texas and Louisiana coasts, bringing periods of heavy rain and gusty winds.

Sustained hurricane-force winds (74-plus mph) have arrived along the Texas Coastal Bend. Hurricane-force winds extend outward up to 35 miles from the center, and tropical-storm-force winds extend outward up to 140 miles, according to the National Hurricane Center (NHC).

A Texas Coastal Ocean Observing Network station at Aransas Pass recently reported sustained winds of 79 mph and a wind gust of 101 mph.

Water levels are already 1 to 2 feet above average tide levels near Corpus Christi and Port Aransas, Texas, and levels are continuing to rise with the onset of high tide.

Current Warnings

A hurricane warning has been issued for a portion of the Texas coast, from Port Mansfield to Sargent, including the city of Corpus Christi. A hurricane warning means hurricane conditions are likely within the warning area. In this case, hurricane conditions are likely within 12 hours.

Importantly, sustained hurricane-force winds are about to move onshore within the hurricane warning area specified above.

Tropical storm warnings are in effect from north of Sargent to High Island, Texas, including the cities of Houston and Galveston.

(MORE: First Hurricane Landfall in Texas in Almost Nine Years)

The NHC also issued its first-ever public storm surge warning, which includes a swath of the Texas coast from Port Mansfield to High Island. This means a life-threatening storm surge is expected in the warned area in the next 36 hours. This warning does not include Galveston Bay, but does include Galveston Island and the Bolivar Peninsula.

Additionally, a tornado watch is in effect until 2 a.m. CDT Saturday for southeast Texas and far southwest Louisiana, as a couple tornadoes will be possible within Harvey’s outer rainbands. This watch area includes Houston, Galveston and Port Arthur, Texas.

A reported tornado damaged a McDonald’s sign in northeast Galveston late Friday afternoon.

Track/Intensity Timeline

With a favorable environment that includes deep, warm Gulf of Mexico water and low wind shear, Harvey may further strengthen and will likely be a Category 4 hurricane at landfall along the Texas coast tonight.

After making landfall, Harvey will be caught in a zone of light steering winds aloft that will stall the circulation for more than two days.

Once moving again, potentially by Monday, Harvey’s center may re-emerge over the Gulf of Mexico, opening up the possibility of some restrengthening before a final landfall in Louisiana. But that remains highly uncertain, as stalled or slow-moving tropical cyclones are notoriously difficult to forecast.

(MORE: Interactive Harvey Forecast Path)

This will likely be the nation’s first major hurricane (Category 3 or stronger) landfall since Hurricane Wilmastruck South Florida in October 2005, an almost 12-year run.

Harvey will also be the strongest landfall in this area, known as the Texas Coastal Bend, since the infamous Category 3 Hurricane Celia hammered the Corpus Christi area in August 1970 with wind gusts up to 161 mph, damaging almost 90 percent of the city’s businesses and 70 percent of its residences and destroying two hangars at the city’s airport.

The Texas Coastal Bend hasn’t seen a Category 4 landfall since Hurricane Carla, in September 1961, produced catastrophic damage from storm surge and high winds in Port O’Connor and Palacios, Texas, among other locations.

The only other Category 4 landfall of record near the Texas Coastal Bend was the infamous Indianola hurricane of August 1886, which devastated the town of Indianola just 11 years after another Category 3hurricane, eventually turning the former bustling port into a ghost town.

Harvey will bring a mess of coastal impacts, including storm-surge flooding, high surf with battering waves and damaging winds.

(MORE: Three Reasons Slow-Moving Tropical Storms and Hurricanes Are the Worst)

Devastating Rainfall Flooding

A tropical cyclone’s rainfall potential is a function of its forward speed, not its intensity.

(MORE: Water, Not Wind, the Deadliest Factor in U.S. Tropical Storms, Hurricanes)

With Harvey stalling for a few days, prolific rainfall, capable of catastrophic flash flooding, will result near the middle and upper Texas coast.

For now, areas near the Texas and southwest Louisiana Gulf coasts are in the biggest threat area for torrential rainfall and major flash flooding, potentially including Houston and Corpus Christi.

Local National Weather Service (NWS) offices have not minced words about the threat, warning of “some structures becoming uninhabitable or washed away” and “numerous road and bridge closures with some weakened or washed out,” with record river flooding expected in some areas.

Harvey’s heavy rain may not entirely exit the areas of Texas it soaks until sometime next Thursday, and may not exit the Mississippi Valley until next Friday.

(MAPS: 7-Day U.S. Daily Rainfall Forecasts)

Here are the latest rainfall forecasts from the NHC and NOAA’s Weather Prediction Center through next Wednesday. Keep in mind, locally higher amounts are possible where rainbands stall.

• Middle/upper Texas coast: 15 to 30 inches, with isolated totals up to 40 inches
• Deep South Texas and Texas Hill Country eastward to central and southwest Louisiana: 5 to 15 inches

To put this into perspective, these peak rain totals are roughly the average yearly precipitation in Austin (34.29 inches) and Corpus Christi, Texas (31.73 inches). So, a year’s worth of rain may fall in the span of a few days near the Texas Gulf Coast.

This forecast is subject to change depending on the exact path of Harvey, locations of rainbands and how long it stalls. Generally, areas along and east of Harvey’s path are in the greatest threat of flooding rainfall.

(MORE: Your Vehicle Can Be the Biggest Danger in a Flood)

Among the biggest uncertainties is the heavy rain potential in central Texas, including for the flood-prone cities of Austin and San Antonio. That all depends on how far inland and to the west Harvey tracks and how long it stalls in that area.

Flash flood watches have been issued for much of southeast, southern and parts of central Texas.

Storm Surge Threat

Here are the latest storm surge forecasts, according to the NHC. Peak surge will occur along along parts of the Texas coast tonight into early Saturday morning with Harvey’s landfall. Note that these inundations above ground level are worst-case scenarios along the immediate coast if the peak surge coincides with high tide.

• North entrance of Padre Island Nat’l Seashore to Sargent, Texas: 6 to 12 feet
• Sargent to Jamaica Beach, Texas: 5 to 8 feet
• Port Mansfield to north entrance of Padre Island Nat’l Seashore, Texas: 3 to 5 feet
• Jamaica Beach to High Island, Texas: 2 to 4 feet
• Mouth of the Rio Grande River to Port Mansfield, Texas: 1 to 3 feet
• High Island, Texas, to Morgan City, Louisiana: 1 to 3 feet

Here are the times of high tide tonight into Saturday night, all in local time.

According to the NWS, structural damage to buildings near the coast is expected, with “many washing away.” Battering waves riding atop the surge will lead to “extreme beach erosion,” “massive damage to marinas, docks, boardwalks and piers” in the areas of highest storm surge.

Importantly, rising water will cut off near-shore escape routes and secondary routes before peak surge arrives.

Given Harvey’s expected slow crawl near the coast, at least some coastal flooding, along with battering waves, could persist for several days over multiple tide cycles along the Texas and southwest Louisiana coasts into next week.

This coastal flooding and wave action could increase if Harvey’s center re-emerges over the Gulf and intensifies, potentially leading to a second storm surge along parts of the Louisiana or upper Texas coast next week. Again, this part of the forecast is highly uncertain at this time.

Furthermore, this water rise from the Gulf of Mexico won’t allow rain-swollen rivers and bayous to drain, compounding the inland flood threat.

Destructive Wind Threat

If that wasn’t enough, there’s the winds.

The NWS warns of “structural damage to sturdy buildings” and “complete destruction of mobile homes” where the eyewall of Harvey tracks.

Roads not already impassable by flooding may become blocked from downed trees or other debris. Power and communication outages will be widespread near and inland of the landfall in central and southeast Texas.

Furthermore, persistent winds, even if they are not particularly high-end when Harvey is over land, could down more trees than they otherwise would given the rain-soaked or flooded ground, possibly for several days as Harvey lingers.

The Federal Alliance for Safe Homes can help you plan for a hurricane. NOAA also has excellent resources to plan for flooding.

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