A flood watch is in effect from now until 7:00 PM Wednesday, May 10, 2023.
Here are the headlines. According to Harris County Meteorologist Jeff Lindner expect:
- Heavy rainfall and flash flooding possible today-Wednesday.
- Street flooding along with significant rises on creeks, bayous, and rivers.
- Widespread rainfall 1-3 inches with isolated totals possibly reaching 5-7 inches or more.
- A pattern similar to May floods in 2015, 2016 and 2019.
Deep Tropical Moisture
A flood and flash-flood threat is materializing across SE TX and will last into Wednesday. Deep tropical moisture is in place with a nearly saturated air mass across the region. Continued onshore flow will pump a steady stream of low-level Gulf moisture into the region.
In the mid and upper levels, a stream of Pacific moisture is noted with total column water values near maximum levels for this time of year.
A mid- and upper-level low-pressure system currently over SW/S TX will slowly move ENE/NE into the Houston area today and tonight. Numerous showers and thunderstorms with excessive rainfall rates will be possible.
This pattern started yesterday afternoon. 2-4 inch-per-hour rates were recorded near Tomball. And the air mass now in place remains capable of such intense short-term rainfall.
Linder does not have much confidence in the details on how this will play out, but slow movement of cells suggests a flooding threat.
The National Weather Service’s Weather Prediction Center has placed much of the area in a moderate (3 of out 4) risk for excessive rainfall and flash flooding both today and Wednesday.
Rainfall Amounts and Ground Conditions
Widespread amounts of 1-3 inches are likely with higher totals of 5-7 inches. Lindner says he “would not be surprised to see an isolated location approach 10-12 inches.” The map below shows expected total rainfall accumulation through May 15.
Grounds are becoming increasingly wet from rainfall over the last 48 hours and there is certainly concern moving forward with the potential for excessive rainfall rates and significant amounts of run-off.
Rises on area creek, bayous, and rivers will be possible over the next 48 hours, especially where the heaviest rains occur. Some creek and bayou flooding will be possible.
A round of thunderstorms has been moving toward Houston all morning and has already dumped 2″ on Cinco Ranch.
Excessive Rainfall Outlook Tuesday/Wednesday
Excessive Rainfall Outlook Wednesday/Thursday
Monitor rainfall and channel conditions on a real time basis on the Harris County Flood Warning System.
This week is the fourth anniversary of the May 7, 2019 flood that damaged hundreds of homes in Kingwood’s Elm Grove and North Kingwood Forest villages. I asked Lindner if this pattern was similar.
He replied, “The upper level pattern this week is similar to previous heavy rainfall events in May of 2015, 2016, 2019. Given the moisture values in place along with the near continuous lift over the area…excessive rainfall rates will be possible in slow moving storms.”
The City of Houston has opened the floodgates at the Lake Houston Dam and is lowering water levels in anticipation of the approaching storms.
Posted by Bob Rehak on 5/9/2023
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