Eric Berger

Ok everyone, take a deep breath. The greater Houston region has experienced a nice reprieve from heavy rainfall today. That’s the good news. The bad news is that our atmosphere has recharged, and we are about to experience the worst of this potential flooding evening tonight and on Wednesday. The timing of all this remains in flux, but what follows is our best assessment for now.

Tuesday night

A pretty serious block of showers and thunderstorms are massing just to the west of Houston this afternoon, and we expect them to move toward our region this evening and during the overnight hours. These storms are being juiced by a slow-moving upper-level low pressure system, and they will have plenty of moisture to work with tonight.

We think most of Houston and the surrounding counties will see 2 to 5 inches of rainfall between now and sunrise on Wednesday, with higher isolated totals. These storms will be capable of producing intense rainfall rates above 2 inches per hour, which will quickly back up streets. Almost certainly some part of our region will see 10 inches of rainfall, or more, during the overnight hours. For now we are maintaining a Stage 2 flood alert, but this threat may need to be adjusted upward later this evening.

Although rainfall is the primary threat, some of these thunderstorms may bring severe weather as well. The National Weather Service has published a tornado warning that will remain in effect for the western half of our region until at least 9 pm CT tonight.

Wednesday

It looks like tonight’s storms may work over the atmosphere, and if this happens we would expect to see a break in storms on Wednesday morning, possibly lasting into the afternoon hours. After this point it’s really difficult to say what will happen with confidence, but I think it’s reasonable to expect another round of storms Wednesday evening or during the overnight hours. Where this sets up, and whether it’s as intense as Tuesday night, is something I just don’t really feel comfortable predicting.

Thursday and beyond

We think the focus of these storms will begin to swing eastward on Thursday. For the overall event, most areas will probably see an additional 4 to 8 inches of rainfall, on average, from now through Thursday. This means some areas will see more, and it is in those locations we are most concerned about flooding.

The map below shows NOAA’s best guess for rain accumulation totals from now through Thursday night, but this should not be taken as gospel.

Matt and I will be continuing to work this event, and will update again by around 10pm CT Tuesday night.

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.

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.