Wednesday, August 30, 2017

Tropical Depression Harvey Trekking Toward the Ohio Valley; Major Flooding Swamps East Texas; Heavy Rain Threat From Louisiana to Kentucky

August 30,2017
Harvey continues its trek inland, but its swath of torrential rain has triggered more massive flooding in east Texas and western Louisiana.
Despite weakening to a tropical depression, Harvey will continue to produce torrential rain the next few days from Louisiana to parts of the Ohio Valley, while record-breaking, catastrophic river flooding continues in southeast Texas.
(FULL COVERAGE ON HARVEY: Hurricane Central)
Harvey made its third and final landfall around 3:30 a.m. CDT Wednesday morning near Cameron, Louisiana, with maximum sustained winds of 45 mph.
Final landfall of Tropical Storm Harvey on Aug. 30, 2017.

Happening Now

Harvey's heavy rain has turned its sights on areas in northern Louisiana and will continue to move northward away from the Gulf Coast, including hard-hit Beaumont and Port Arthur, Texas.

Radar-Estimated Rainfall Past 24 Hours
Jack Brooks Regional Airport near Port Arthur, Texas, picked up a staggering 26.03 inches of rain Tuesday alone, more than doubling the previous calendar-day rainfall record in Beaumont-Port Arthur set over 94 years ago. Its four-day total from Saturday through Tuesday was an incredible 43.27 inches of rain, almost 25 inches greater than its previous record four-day rain record set in September 1980.
The resultant flooding swamped a storm shelter in Port Arthur, prompting evacuees to be moved to another shelter.
Heavy rain has also spread north and east into western Mississippi, southern Alabama and the Florida Panhandle.

Current Radar, Watches and Warnings

Houston Area's Record Storm Totals

The Cedar Bayou gauge near Highlands, Texas, reported a preliminary 51.88 inches of rain through 3 p.m. CDT Tuesday.
Two other Harris County Flood Warning System rain gauges, one along Clear Creek and another along Mary's Creek, reported totals of 49.40 inches and 49.20 inches, respectively.
In addition, a weather observer near Dayton, Texas, reported 49.23 inches of rain as of late Wednesday afternoon.
Pending final confirmation, these would be the heaviest storm totals from any tropical cyclone in the continental U.S. in records dating to 1950, topping the 48-inch storm total in Medina, Texas, from Tropical Storm Amelia in 1978, according to research by NOAA/WPC meteorologist David Roth.
Suffice to say, this is one of the worst flood disasters in U.S. history, with record-smashing river flooding lasting into next week, in some areas.
(FULL DETAILS: River Flooding May Last For Weeks In Some Areas)
The average rainfall within the Harris County Emergency Management network has exceeded that of Tropical Storm Allison (2001) in almost half of the time (2 to 3 days versus 5 days).
(MORE: How You Can Help Victims)
Houston's Bush Intercontinental Airport crushed its record-wettest calendar day Sunday by over 5 inches, picking up 16.07 inches of rain, just under the five-day total of 16.48 inches from Tropical Storm Allison in 2001. Houston's Hobby Airport also crushed a two-day rainfall record by almost 8 inches, picking up 23.06 inches of rain Aug. 26-27.

Rain to Continue, But There is Good News

After stalling out for several days, Harvey is on the move as high pressure over the western U.S. has finally weakened and high pressure centered near the Bahamas and Florida becomes Harvey's steering wheel.

Projected Path
A tropical cyclone's rainfall potential is a function of its forward speed, not its intensity. Therefore, torrential rain is expected in many of the already flood-ravaged areas, but Harvey is accelerating which is bringing an end to the rain from west to east in much of east Texas.
Harvey is finally moving from the hardest hit areas of Houston and Beaumont, but rain could still fall in far eastern Texas as Harvey pulls away. Here are the latest rainfall forecasts through Saturday from the National Hurricane Center and NOAA's Weather Prediction Center:
  • Extreme east Texas to southwest Louisiana, west/middle Tennessee and western Kentucky: 4 to 8 inches with isolated amounts up to 12 inches
  • Parts of Mississippi, Alabama, Florida Panhandle Gulf coasts: 3 to 6 inches
  • Parts of the Tennessee Valley, Ohio Valley and southern mid-Atlantic: 2 to 4 inches

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

Recap: A Truly Historic Hurricane

Harvey made landfall Friday night near Rockport, a town of less than 10,000 people and about 30 miles up the Texas coast from Corpus Christi.
Harvey is this nation's first major (Category 3 or stronger) hurricane landfall since Hurricane Wilma struck South Florida in October 2005, an almost 12-year run. A multi-day deluge of the Texas Gulf Coast with catastrophic and life-threatening flooding and destructive winds could leave areas uninhabitable for an extended period of time, the National Weather Service has warned.
Harvey went from a tropical depression to a major hurricane in 56 hours. It intensified rapidly to a Category 4 hurricane with winds up to 130 mph after moving over a pocket of hot water in the Gulf.
Harvey is also the strongest landfall in this area, known as the Texas Coastal Bend, 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 3 hurricane, eventually turning the former bustling port into a ghost town.
A storm surge of more than 6.6 feet was recorded at Port Lavaca, Texas, with destructive surge reported in other locations along the Texas Coastal Bend.

There have been over a dozen tornadoes so far, with the total number of tornadoes still yet to be determined.
One apparent tornado crossed Interstate 10 and hit a storage facility in the western Houston metro suburb of Katy around 5:30-6 a.m. CDT Saturday morning.
At least one tornado was confirmed in northwestern Harris County, Texas.
In the southwest suburb of Missouri City, more than 50 homes were damaged in the Sienna Plantation neighborhood.
Following landfall, Hurricane Harvey slowed down and stalled over western Texas Hill Country, turning the Gulf of Mexico firehose on southeast Texas and southwest Louisiana for three days.
Harvey steadily weakened to a tropical storm as it sat and spun north of Victoria, Texas, from the early morning hours on Aug. 26 through late on Aug. 27.
Rainfall totals pushed more than a half-foot higher than totals seen in Houston's previous worst disaster, Tropical Storm Allison, and broke Lower 48 tropical cyclone rainfall records.
Numerous flash flood emergencies were issued for the Houston and Beaumont, Texas, metropolitan areas, and for Bastrop County and nearby communities.
Harvey, as a tropical storm, began to drift southeastward toward the Gulf of Mexico on Aug. 28, re-entering the Gulf of Mexico mid-afternoon near Matagorda, Texas.
Strong wind shear and Harvey-cooled waters in the Gulf of Mexico prohibited Harvey from significantly re-strengthening.
Still a named storm 117 hours after landfall, Harvey was the longest a Texas landfalling hurricane remained a named storm after landfall on record, according to Colorado State University tropical scientist Dr. Phil Klotzbach.
Harvey weakened to a tropical depression by 7 p.m. CDT on Aug. 30 when it was centered about 10 miles southwest of Alexandria, Louisiana.

Rainfall Totals

Here are the latest rainfall totals through 4 p.m. CDT Wednesday, all in Texas unless otherwise specified:
  • 51.88 inches on Cedar Bayou near Highlands, Texas (Preliminary Lower 48 tropical cyclone record)
  • 49.40 inches on Clear Creek at Interstate 45 near League City, Texas (Preliminary Lower 48 tropical cyclone record)
  • 49.32 inches on Mary's Creek near Friendswood (Preliminary Lower 48 tropical cyclone record)
  • 49.23 inches near Dayton (Preliminary Lower 48 tropical cyclone record)
  • 49.20 inches on Mary's Creek at Winding Road (Preliminary Lower 48 tropical cyclone record)
  • 47.35 inches in Port Arthur, Texas
  • 45.74 inches near Pasadena
  • 44.91 inches near South Houston
  • 43.38 inches at the NWS forecast office in Houston (League City)
  • 37.01 inches at Houston Hobby Airport
  • 31.26 inches at Houston Bush Intercontinental Airport
  • 22.84 inches in Galveston
  • 21.88 inches in Smithville
  • 19.64 inches in College Station
  • 15.60 inches near Victoria
  • 15.41 inches near Lake Charles, Louisiana
  • 12.33 inches near Hackberry, Louisiana
  • 10.07 inches at Austin's Robert Mueller Municipal Airport
  • 8.27 inches near Gautier, Mississippi
  • 7.14 inches in Lafayette, Louisiana
  • 6.23 inches near Corpus Christi
  • 5.33 inches at New Orleans/Lakefront
  • 7.91 inches in Bonsecour, Alabama
  • 7.45 inches in Gasque, Alabama

Strongest Wind Gusts

Here are the highest wind gusts we've seen from Harvey:
  • Port Aransas: 132 mph, sustained to 110 mph
  • Near Copano Village: 125 mph
  • Near Lamar: 110 mph
  • Rockport: 108 mph
  • Near Taft: 90 mph
  • Near Magnolia Beach: 79 mph
  • Palacios: 69 mph
  • Corpus Christi Int'l Airport: 63 mph
  • Austin Bergstrom Int'l Airport: 52 mph

Rainfall Perspective

Really, how much rain has fallen this week in southeast Texas?
In some spots of the West, it can take more than a decade to accumulate 50 inches of rainfall.
Check back with for updates on Harvey.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

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