We’re halfway through this May rainfall event, and still concerned about Wednesday

Good morning. We’re now approaching the half-way point of a multi-day heavy rainfall event that began Sunday and should wrap up on Thursday. We remain at a Stage 2 alert on our flood scale, which means the Houston region is likely to see flash flooding. The bottom line is that this air mass has produced explosive rainfall events the last two days (southwest, and then east of Houston) along the Texas coast, so it bears watching closely.

Tuesday

Although we should see showers and thunderstorms in Houston today, they may be less organized than on Monday. The primary threat for widespread, heavy rainfall is likely to lie north and east of the Houston metro area, where the atmosphere remains somewhat more unsettled. This area, north of Montgomery County and east of Harris County, is shown on the “excessive rainfall outlook” prediction below from NOAA for Tuesday and Tuesday night. Unfortunately, the area of “moderate” risk, denoted in red, could affect the Beaumont and Lake Charles areas that were hammered by heavy rainfall on Monday. Highs today will be in the mid-80s, with mostly cloudy skies.

Wednesday and Wednesday night

We continue to believe that the period from Wednesday morning through Thursday morning will bring the heaviest rainfall to most parts of Houston. This is because of vigorous atmospheric lift, and a setup that allows a regenerative flow of moisture from the Gulf of Mexico. During this time frame we think rainfall totals will average 2 to 6 inches across the region. Our main concern, of course, is higher bullseyes that drop in bursts and lead to flooding. This will will definitely be possible given the moist and unstable air mass overhead.

Where will these bullseyes occur? As you can see in the excessive rainfall outlook for Wednesday and Wednesday night, we just don’t have a great handle yet on where the heaviest bursts of rainfall will land along the Texas coast, and points inland. When we have more definitive information to share, we will share it.

Thursday and Friday

Whatever mess develops on Wednesday and Wednesday night will carry over into Thursday morning. Conditions should begin to improve during the afternoon hours, but if you’re looking for a guarantee of that, we can’t provide it. After the worst passes, we should still see on-and-off light to moderate showers to end the work week. However, these should for the most part not produce heavy, flooding rains. Highs will be around 80 degrees both days.

Saturday and Sunday

Saturday should be a lot like Friday, which is to say mostly cloudy with a healthy chance of light to moderate rain. We don’t expect a washout, by any means, but keep an umbrella handy. Some sunshine may break through on Saturday before the sun sets, and Sunday should see clearing skies. Rain chances on Sunday should fall back to around the 10 percent range, and remain low for several days. You’ll be ready for some sunshine, right?

Our next update will come by or before 7pm CT today.