High pressure over the Central Appalachians in combination with a low-pressure system that extended from the Northern Plains down into West Texas provided the focus for strong southerly winds that pumped abundant amounts of moisture up from the Gulf of Mexico and across southeastern Texas. The copious moisture triggered and sustained thunderstorm complexes over the coastal areas of Texas over the Memorial Day weekend. Up to 16 inches of rain was reported in just 24 hours in Chambers County, Texas just east of Galveston Bay. Nearly 12 inches of rain was reported in Harris County just outside of Houston.

The Tropical Rainfall Measuring Mission satellite (known as TRMM) was placed into service in November of 1997. From its low-earth orbit, TRMM has been measuring rainfall over the global Tropics using a combination of passive microwave and active radar sensors. The TRMM-based, near-real time Multi- satellite Precipitation Analysis (MPA) at the NASA Goddard Space Flight Center monitors rainfall over the global Tropics. MPA rainfall totals are shown here for the period 28-31 May 2006 for southeast Texas and the surrounding region. The highest totals (shown in red) occur just inland from the coast near Matagorda Bay along the central part of the Texas Gulf coast where MPA rainfall totals exceed 10 inches (darkest red area). Another area of heavy rain is visible near the border with Louisiana just north of Beaumont, TX where amounts are on the order of 7 inches (lighter red area). The totals reported near Galveston Bay and Houston may have been too small in scale or occurred over too a brief period to be captured by the MPA as evidenced by the relatively low totals there.