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.

Good evening. The Houston area has been mostly fortunate through this rain event so far. We’ve managed to avoid very high impact rains, though we all finally got doused this afternoon and evening. Still, rain totals, while impressive were mostly manageable, aside from pockets of street flooding.

You can see that the highest totals for the event so far are in northeast Harris County, where over 6 inches fell in about 3 hours today just east of Huffman. All told, we’re lucky. After 13″ of rain fell in extreme southwestern Wharton County yesterday, it was Jefferson County, Liberty County, and the Lake Charles area that were hammered today.

Areas east of Houston pummeled

18.03″. That’s how much rain fell today near Fannett in Jefferson County, just off exit 838 of I-10. This is at least the third, if not fourth time this area has had houses flood — since Harvey.

Over 17" recorded near Fannett, TX.
This area cannot catch a break. Some homes flooded for the 3rd time since 2017.

Fannett was not the only area to receive double digits today.  @mattlanza @Chad4caster @KBTXShel @MyRadarWX @MatthewCappucci @JohnnyParker012 @LeslieHudsonWx pic.twitter.com/0lDjgIhjqw

— Johnny Ray Lively® (@JRayLively) May 17, 2021

Went through this to rescue my wife. We were pushed around by the current. FM 365 in Fannett, Texas is completely submerged. Video taken a few hours ago. Please avoid this area. @TxStormChasers @NWSLakeCharles #txwx #flooding pic.twitter.com/mfEmF5l7HR

— Justin Aaron (@JustinAaronUH91) May 17, 2021

Southeast Texas is vulnerable to floods, but what has happened in the Beaumont-Port Arthur area in recent years is something different, and as someone who knows several folks in that area, completely exasperating.

And if that were not enough, the Lake Charles area, which has just barely had time to move on from Hurricanes Laura and Delta was battered today as well.

Lake Charles is completely flooded right now. Pics from Facebook. pic.twitter.com/RlrL5jABDM

— Couillon (@diabsoule) May 17, 2021

The combination of 15″ of rain and debris clogged waterways and drains in the wake of the aforementioned storms has led to water in homes and businesses in Lake Charles.

Repetitive disasters have become a hallmark of Southeast Texas and Louisiana, and it requires folks like us continuing to call attention to it without sugar coating it as “that’s just what happens here,” the linkages to climate change, and the reality that we need to continue to implement and expand mitigation measures. Or this will continue unabated.

Right now, we have just to get through this week.

Rest of tonight

Good news. The rain is tapering off from northwest to southeast as I type this, and we do not expect much, if any new development of storms overnight.

Tuesday

That said, we could see a cluster of storms find its way into the area by early morning Tuesday, as one model in particular (the HRRR) believes. I do think if we were to see that happen, it would be progressive, meaning a quick 1 or 2 inches of rain and then out. Granted, the ground is now saturated, so any rain of intense magnitude will be capable of producing flash flooding. But a quick moving system would be acceptable in this pattern. Additional storms will be possible later tomorrow afternoon or evening, though to be quite honest, the details are really fuzzy still. Tuesday will require a good bit of “nowcasting,” which means watching trends and making short-fused 12 to 18 hour forecasts at a time. Eric will update you in the morning.

Rest of the week

This week is a marathon, and we’re not sprinting to the finish. Wednesday and Thursday continue to look like active days with a combination of slower moving storms and saturated soils possibly combining to cause issues. We’ll remain in a Stage 2 flood alert unless something changes.

Just to underscore: As we’ve seen the last two days, these systems are relatively unpredictable with anything more than modest lead time. They are also capable of easily producing 2 to 4 inches of rain in an hour for more than one hour, and that will cause problems. So we know the potential for considerable heavy rain and flooding exists, particularly as soils saturate through the week. We still cannot tell you exactly where and when that will occur. We’ll continue to ask for your patience as we help you navigate the rest of this week. Stay safe.

Our next post will be Eric’s usual post on Tuesday morning.

The heaviest rainfall today has fallen east of Houston, from Chambers County to Lake Charles, Louisiana. Some locations have received more than 12 inches of rain and some serious flooding is underway.

Closer to Houston, a slow-moving band of showers has established itself just north of the Houston metro area. We expect this line of showers to slowly progress southward toward Interstate 10, and perhaps the coast, later this afternoon and evening. In the heaviest storms we’re seeing rainfall rates of 2 to 3 inches per hour, which is enough to quickly back up streets. Unfortunately, these storms will probably affect the central Houston area during the evening commute home. Plan accordingly.

These storms should begin to wind down as the sun sets, and we anticipate a reprieve overnight. Matt will have an update later today on the latest for what we can expect on Tuesday and Wednesday in terms of rainfall and flooding.

Good morning. We’re entering day two of a period that has the potential to bring significant rainfall and flooding across the metro area. The pattern is threatening because it may produce both short-term, intense rainfall as well as prolonged, widespread showers. Most of us should be fine in the end, but this kind of setup is worth monitoring very closely.

We are going to implement a Stage 2 alert on our Flood Scale for two reasons. While we do not think most of the area will see significant flooding, we do believe there is definitely the potential for localized flash flooding, especially on Wednesday and Wednesday night. Second, soils across the area are already wet, with reservoirs at full capacity.

Monday

Our overall confidence in the forecast today is low. While there is the potential for heavy rainfall, there is also some drier air in the atmosphere, and this may limit activity over the Houston region to scattered showers and thunderstorms. In any case, the best chance for heavy rainfall will lie just east of Houston, along Interstate 10 and heading into Louisiana. For the Houston area, most of us can probably expect accumulations of 0.25 to 1 inch of rain. Skies will otherwise be mostly cloudy, with highs in the low- to mid-80s. Rain chances back off tonight.

Tuesday

The disturbance in the upper atmosphere that is driving all of this unsettled weather will move closer to our region, and therefore the chance of heavy rainfall will increase somewhat on Tuesday, especially north of Interstate 10. (This could be a serious day for flooding in the Dallas-Fort Worth area). However, this does not mean the day will necessarily be a washout in Houston. I expect rainfall accumulations for most to average 0.5 to 1.5 inches, with the potential for more of course. Highs again will be in the 80s.

Wednesday

We still think Wednesday and Wednesday night will be the period that brings the best chance of heavy rainfall and flooding to the Houston metro area. This is when the upper-level low pressure system will pass more directly overhead. Basically, there should be enough moisture and lift to produce some very heavy rainfall. But whether the epicenter of this occurs along the coast somewhere from Matagorda Bay to Galveston, more inland over Houston, or north of The Woodlands, we just cannot say right now. I think most of the area will see 3 to 6 inches of rain from Tuesday night through Thursday morning, with the potential for some pockets of 10 inches or more. Where that occurs we just don’t yet know. This uncertainty is reflected in the large red area in the excessive rainfall forecast below.

Thursday and Friday

We think the potential for really heavy rain will start to dial back on Thursday morning as the upper-level low exits, but there should still be a healthy chance of showers and thunderstorms on Thursday and Friday. Both of these days should see mostly cloudy skies, with highs in the low 80s.

Saturday and Sunday

Some sunshine should return by the weekend, but I think we’ll still see at least some scattered to widely scattered showers on Saturday and Sunday. Highs will be in the low to mid-80s. Skies should turn mostly sunny by early next week.

Matt will have an update by around 7 pm CT on Monday.