As expected, Houston saw periodic heavy rainfall this weekend from the outer bands of Hurricane Hanna, but totals were more than manageable. The heaviest rains came near the center of the storm, which moved inland near Port Mansfield and proceeded to drop as much as 15 inches of rainfall over South Texas, leading to widespread flooding. Hanna has now become a depression in northern Mexico and should dissipate today. Despite our region’s dynamic weather over the last week, we have more to come.
For the next couple of days our weather will be determined, to some extent, by “cutoff low” in the upper atmosphere. Presently this atmospheric disturbance is east of Houston, producing widespread showers over southwestern Louisiana and over the Gulf of Mexico. This upper low should slowly sag toward Texas, bringing a healthy—50 percent chance of rain—later today. Some of these storms could briefly produce heavy rainfall and lightning. The potential for showers and thunderstorms this afternoon should help limit high temperatures to about 90 degrees, with partly sunny skies. Winds will be light for most of the day and rain chances should slacken overnight—but not entirely go away.
This should be another day like Monday, with the atmospheric disturbance again influencing our weather. Storms likely will again develop over parts of the metro area during the late morning hours, and into the afternoon. These storms will have the potential to produce locally heavy rainfall but should be progressive enough to not lead to flooding. An unsettled atmosphere should again limit high temperatures to about 90 degrees.
By the middle of the week the upper-level low pressure system will likely have dragged itself away, to the southwest. However, the region will remain beneath a fairly moist atmosphere without enough high pressure to keep rain showers entirely away. A mix of clouds and showers should again help to limit highs to around 90 degrees.
Thursday and Friday
High pressure should begin to assert some control toward the end of the week, bringing a pair of sunnier days, and pushing high temperatures into the low- to mid-90s.
Saturday, Sunday, and beyond
It’s not entirely clear whether high pressure will hold sway over the region’s weather this weekend. At some point a front is likely to advance into Texas. Although it probably will stall out before reaching the Houston region—August begins this weekend after all—it could produce some storms on Sunday or Monday. The timing and details of this are all pretty fuzzy at this point so my best guess is partly to mostly sunny skies for this weekend, with fairly low rain chances.
After Hanna’s demise we’re turning our eyes to the next tropical system out in the open Atlantic, which likely will become Tropical Storm Isaias (pronounced ees-ah-EE-ahs per the National Hurricane Center). While the preponderance of the modeling has the storm moving toward Puerto Rico and then curving north before reaching Florida, we cannot rule out a more westerly track that brings the system through the northern Caribbean Sea and potentially into the Gulf of Mexico. We’ll watch the system, but we’re not worried at this point.