NWS Update on Harvey’s impact

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Flash Flood Warning Until Thursday

From the Natchitoches Office of Homeland Security

Mary Jones, Director.

Tropical Storm Harvey is now moving southeast and expected to move back out into the Gulf of Mexico tonight. A very slight strengthening is forecast before Harvey makes another landfall as a tropical storm near Houston.

Timing and Overview:
The primary threat from Harvey will be heavy rain and associated flooding. The flooding threat is already ongoing across Deep East Texas and West Central Louisiana, and will spread northeast across the area late Tuesday through Thursday as Harvey moves northeast.

Secondary threats include isolated tornadoes (already ongoing) mainly south of Interstate 20. There is also a slight possibility that tropical storm force winds could affect portions of Deep East Texas and West Central Louisiana late Tuesday and into Wednesday.

Four State Impacts:

Expected Accumulations:

  • Additional rainfall amounts of three to six inches are expected south of Interstate 30 through 7am Sunday morning, with most of the rain falling between now and 7am Friday morning.
    • A swath of higher amounts between six and eight inches is expected from Deep East Texas northeast through Northwest Louisiana and into Southern Arkansas.
    • Isolated higher amounts near 10 to 12 inches will be possible across Deep East Texas.

Impacts:

  • Flash flooding will be possible.
    • A Flash Flood Watch is in effect until 7pm CDT Thursday for areas south of a line from Cherokee County, TX, to Winn Parish, LA.
  • Saturated soils will mean that trees can topple with lighter wind speeds.

Red River Impacts:

  • A reasonable worse case scenario with Harvey is that the Red River could see a three to six foot rise, starting this weekend, but the rainfall would have to fall north of Shreveport near or upstream of Fulton to have this kind of rise in Shreveport. This is NOT the current forecast, but a possibility given the uncertainty with Harvey’s track.