Houston rainfall could strengthen to named storm

• Mexico and Texas are expected to get the brunt of the storm, forecasters say. Parts of the Houston metro area could get up to 8 inches of rain through Thursday.

Threat level: National Weather Service meteorologists give Houston and the rest of Harris County a moderate risk (3 out of 4) for excessive rainfall Tuesday and Wednesday.

• The main threats are the potential for flash floods, overflowing rivers and creeks, and coastal flooding.

Meanwhile, Harris County is the second least-prepared county in the country for climate disasters, per homeowners insurance resource ClaimGuide.org's risk assessment of more than 3,000 U.S. counties.

• Galveston County ranked 16th.

How it works: 50 of the assessed counties were ranked by expected annual loss, community resilience and social vulnerability.

• Harris County is anticipated to lose $2.2 billion annually and scored low on community resilience and high on social vulnerability.

• Galveston County is expected to lose $496 million annually. It scored high on community resilience and high on social vulnerability.

How it works: ClaimGuide.org's analysis is based on data from FEMA's National Risk Index, which determines an overall risk score for 18 natural hazards.

State of play: Texas leaders have already issued an extended disaster declaration this year for heavy rains, high winds, hail and storms that have hammered the area repeatedly since late April.