The National Weather Service released this map around 7 a.m. Houston time this morning. It shows Houston in the bullseye with another 4 to 6 inches of rain predicted in the next five days. Jeff Lindner, Harris County Meteorologist, warns that flash flood watches may be needed by Friday into the weekend.
Atmosphere Moisture Levels Support 1-3 Inches Per Hour Later Today
Yesterday’s active weather pushed down toward the coast overnight. The local air mass stabilized by Thursday morning. But afternoon heating and a rapid influx of Gulf moisture favor the development of numerous thunderstorms later today over the region.
Moisture levels in the atmosphere support heavy rainfall with hourly rainfall rates of 1-3 inches per hour possible under the strongest cells. Lindner notes that we saw this yesterday evening throughout the Lake Houston area.
Heaviest Rains Expected Friday
However, the main storm system will begin to move slowly into southwest and west TX on Friday. It will dominate local weather through the weekend, according to Lindner, as several disturbances rotate around around it and feed off the near-continuous stream of rich Gulf moisture over the area.
Upper level winds will support cell training over the area this weekend. Flash flooding will be a concern.
Rainfall Amounts, Impacts
Additional rainfall amounts of 4-6 inches will be possible over the next 5 days. Much of this will fall during periods of heavy rainfall. Isolated totals could be significantly higher under any areas of sustained training. Hourly rainfall rates of 1-3 inches will be possible, which could support rapid street flooding.
Ground Still Saturated
Grounds are still saturated from heavy rainfall in May. And some watersheds are still elevated from the rainfall yesterday evening. Rainfall over the next several days will likely generate run-off into local watersheds resulting in rises. Any areas of sustained heavy rainfall will increase the threat for channel flooding given the delicate groundwater situation currently in the area.
Posted by Bob Rehak on June 3, 2021, based on info from the NWS and HCFCD
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