Flash floods in Texas have killed at least 107 people over the Fourth of July weekend, with more than 160 still missing.

The Flood Watch in effect for parts of the southern Plains, including much of Oklahoma and Texas, was expanded southeast this morning to encompass areas that were hit hard by catastrophic and deadly flash flooding last weekend, including Kerr, Travis and Burnet Counties.

Scholars and designers of early warning systems say that there are still huge gaps in our ability to predict flash floods and warn those at risk.

Steamy summer conditions for your Sunday with highs in the upper 80s but feeling like the 90s. Skies will be mostly cloudy with isolated storms this afternoon. Any storm could produce heavy rain and localized flooding. Monday is a NEXT Weather Alert Day for tropical downpours and an elevated flash flood risk.

Heads up if you're in the Hill Country or know someone who is. The threat for flash flooding in the areas devastated by last Friday's flooding have increased.

In the Midwest, quarter-sized hail and an isolated tornado cannot be ruled out, while in the South, flood alerts are in effect for areas that were devastated by flash floods last week.

Straighter, smoother streams flow more violently than those that meander due to a reduction in friction. Areas with steeper terrain can see water accelerate downhill at a much faster rate causing a more destructive flash flood than flatter, open areas.

Search crews continued the grueling task of recovering the missing as more potential flash flooding threatened Texas Hill Country.