Heavy Rain, Flooding Possible For Southern Plains, Lower Mississippi Valley; Flood Watches Issued

Jon Erdman
Published: October 21,2015


 

A number of ingredients in the large-scale weather pattern are coming together the next several days to fuel a threat of heavy rain and flooding in the south-central United States. This potentially excessive rainfall could even cause flooding in areas where drought conditions have worsened in recent months.
Moisture and energy from Tropical Storm Patricia in the eastern Pacific may also add more fuel to this soaking scenario.
Below are the details on the heavy rain threat and how the tropics may be involved.
(MORE: Expert Analysis | Hurricane Central)

Heavy Rain, Flood Threat in the Southern Plains

Persistent southeasterly winds are pumping moisture from the Gulf of Mexico into the southern High Plains, where it will interact with an area of low pressure aloft over the Southwest. This will contribute to heavy rains as far west as eastern New Mexico, western Texas, western Oklahoma and southwest Kansas by Wednesday night and Thursday morning.
Flash flood watches have been issued by the National Weather Service for parts of west Texas, eastern New Mexico and western Oklahoma.

Flood Alerts

This rain will then spread across the rest of Texas, Oklahoma and possibly parts of northwest Louisiana and Arkansas by Thursday night or Friday. A separate weather disturbance moving through the southern tier of the U.S. will prolong the heavy rain threat into this weekend across those states.

Forecast Next 5 Days

In addition, moisture and energy from Tropical Storm Patricia in the eastern Pacific could be involved in this setup by this weekend. Computer forecast models are showing that after it makes landfall in Mexico, the mid-level remnants will get pulled northeastward into the south-central states by a southward dip in the jet stream over the western and central United States.
(MORE: Tropical Storm Patricia Forecast to Strengthen)
In all of the above mentioned areas, flash flooding is possible where heavy rain persists the longest. However, small-scale details will dictate exactly where this threat will be the greatest in the coming days. Our rainfall forecast map shows that a widespread area of the southern Plains has the potential to see 3 or more inches of rain through this weekend. Some areas may pick up 6 inches or more of total rainfall.

Rainfall Outlook

In addition, persistent onshore winds will bring some minor coastal flooding, high surf and dangerous rip currents this week to the Texas and Louisiana coasts.
Coastal flood advisories have been issued for portions of the Texas and Louisiana coasts.
(FORECASTS: S. Padre Island | Corpus Christi | Houston | Lake Charles, Louisiana)
This rain is needed to help a relatively rapidly-developing flash drought, which set in over the southern Plains and Lower Mississippi Valley from mid-summer on.
(MORE: Drought Has Returned Again)
The heavy rain threat, while squelching the recent wildfires, may be too much of a good thing in these areas, instead triggering flash flooding.

Timing the Flood Threat

Wednesday Night - Thursday:

• Main Threat Areas: eastern New Mexico, western Texas, western Oklahoma, and southwest Kansas. Rain advances east into central portions of Oklahoma and Texas later on Thursday and Thursday night.
• Cities: Amarillo | Lubbock | Midland | Dallas-Fort Worth | Oklahoma City

Thursday's Forecast

Friday:

• Main Threat Areas: southern Kansas, Oklahoma, northern Texas
• Cities: Abilene | Dallas-Fort Worth | Oklahoma City | Wichita

Friday's Forecast

Saturday:

• Main Threat Areas: central/eastern Texas, eastern Oklahoma, Arkansas and possibly western Louisiana
• Cities: Austin | Dallas-Fort Worth | Houston | Fort Smith, Arkansas

Saturday's Forecast

PHOTOS: May 2015 Southern Plains Flooding