Harvey weakens to a minimal tropical storm with 40 mph at 11 AM EDT Sunday, but its impacts are far from over. As feared, and as models have suggested for days, it nearly stalls across south central Texas and will meander near the coast through at least mid work week. Tremendous rainfall and spin up tornadoes will continue Sunday, especially north and east of the center of circulation. Several more days of flooding rains are likely, including in the hard hit Houston Metro area. At this pace, Harvey is on track to be one of the wettest tropical cyclone events in U.S. history.

Training set up late Saturday into Sunday and rainfall rates of 3″+ per hour we felt in Southeast Texas. As of late morning Sunday another band eyes some areas already hit hard with life threatening flooding. The National Weather Service in Houston issued a Flash Flood Emergency with some serious wording. Catastrophic flooding in the Houston Metropolitan area is expected to worsen and could become historic. Interstates and major roadways are completely inundated with water. In some cases, water surpassed street signs and street lights. Officials urged people to go to their roofs instead of attics and call 911.

Rainfall totals may double through mid work week with the Gulf of Mexico fueling multiple waves of heavy rain. Record river and creek flooding is expected too. As of 9 AM CDT the National Weather Service in Houston estimates 25″ (over 2 feet of rain) has fallen in Dayton Texas and counting. Areas southeast of Houston were especially hit hard late Saturday and early Sunday. Over a foot of rain has been recorded at Houston Continental. These values are comparable to Tropical Storm Allison. It hit the Houston area hard with flooding in 2001.

Additional rainfall through at least mid-work week is highly dependent on where the center of Harvey lingers. The 0Z European model paints a realistic forecast of an additional 15-20″+ through midday Thursday. The official forecast from the National Hurricane Center is for an additional 15-25″ of rainfall. That would put Harvey rainfall totals at 40″+ (nearly 3 and half feet) in parts of Southeast Texas.

Elsewhere, Invest 92L emerges in the western Atlantic northeast of Florida. Areas of heavy rain will continue in central and southwest Florida through Monday. There is a small window for this low to become subtropical/tropical in nature before in merges with a frontal boundary by Tuesday. As of Sunday morning there is a 50% chance of subtropical/tropical depression development. Computer models bring this feature near the coastal Carolinas late Monday and Tuesday. Heavy rain is possible along with rough surf, depending on the exact track.

We’ll also have to watch the Main Development Region for at least the next week. Slow development is possible with a tropical wave over western Africa by work mid work week. This is worth watching as we approach the peak of hurricane season in early September. Below is the ECMWF model forecast for Thursday morning.

Harvey is one for the record books. It rapidly strengthened from a tropical depression to a category 4 hurricane in just two days over the warm Gulf of Mexico. It officially made landfall late Friday night as a category 4 hurricane with max winds of 130 mph and pressure down to 938 mb in Rockport Texas. This is northeast of Corpus Christi. A peak gust of 132 mph was recorded at Port Aransas. Harvey breaks the streak of no major hurricane landfalls in the U.S. It is the first major hurricane to strike the U.S. since Wilma in October 2005. It is the strongest hurricane to make landfall in the U.S. since Charley in August 2004. Harvey is also the strongest storm to hit Texas since Carla in 1961.

On Saturday morning Harvey weakens over land. While the winds will die down over the weekend the rain/coastal flood threat just gets started. There is nothing to guide Harvey out of Texas and it will linger through mid work week. Here is the 11 AM advisory from the National Hurricane Center. As of 11 AM Harvey is a minimal hurricane with 75 mph winds. It is nearly stationary and only crawls north at 2 mph. It will become a tropical storm Saturday afternoon. Heavy rain and coastal and inland flooding is likely through Thursday. This will be a catastrophic and life-threatening long-lived flooding event.

As of 11 AM Saturday over a foot of rain has fallen in parts of southeast Texas since Friday. The Weather Prediction Center constantly updates rainfall totals. So far Austwell, Texas has seen over 14″ of rainfall. Other hefty rainfall totals include Victoria, Texas at 9.37″ and the Houston Southwest airport at 6.40″. Models print out upwards of 20″ of rainfall by the end of the work week in spots. Below is the GFS forecast through Friday afternoon. 30″ in Victoria Texas is not unreasonable. The National Hurricane Center points out some isolated spots will see 30-40 inches of rain over the course of the next 5-6 days. Training bands will set up away from the center. Tornadoes may spin up in these bands, especially in the northeast quadrant. This includes the Houston area.

In addition to freshwater flooding coastal flooding will continue over the next few days. With a massive tropical system lingering near the Gulf a constant onshore wind will enhance coastal flooding/storm surge this weekend. Wave heights build up to 12 feet just offshore northeast of Corpus Christi Saturday morning. A storm surge of 4-7 feet is possible from Port Aransas to Sargent. Sargent to High Island, including Galveston Bay will see a 2 to 4 foot. High Island to Morgan City will see a storm surge of 1 to 3 feet.

The sensor at Port Lavaca is just one example of the extreme rising waters in coastal Texas. A surge of over 6 feet has continued since late Friday night. The graphic below is courtesy NOAA.

In addition to Harvey, an area of low pressure lingers over central Florida. It moves into the Atlantic late Sunday. Invest 92L may gain some tropical characteristics northeast of Florida (just offshore of the Carolinas) before it merges with a front early in the week. Those odds sit at 40% as of Saturday morning. This could enhance surf/rip currents in the coastal Carolinas early to mid work week.