Chance of storms and heavy rainfall on Wednesday ahead of a modest cool front

In brief: Today will be hot with scattered showers, but Wednesday should be more dynamic as a line of storms pushes into the area ahead of a weak cool front. Some heavy rainfall is possible with the front, but rain totals look highly variable. After this we’ll see sunny and somewhat less humid weather.

Tuesday

It is rather warm and muggy out there, with much of the region just barely falling below 80 degrees this morning. Atmospheric conditions are trending toward better rain chances, but Wednesday still looks like the better day at this point for widespread showers. The likelihood of rain today should be about 50 percent for areas south of Interstate 10, with lesser chances inland. With dewpoints in the mid-70s it will be a very muggy day, as highs push into the lower 90s this afternoon. Rain chances fall back tonight, with lows again perhaps only briefly dropping to 80 degrees or below.

Severe weather outlook for Wednesday. (NOAA)

Wednesday

This should be the last really humid day for awhile. Showers will again be possible on Wednesday during the late morning and early afternoon hours, primarily near the coast. Later in the day a line of (broken?) showers and thunderstorms will advance from the northwest. The timing is fuzzy, but I generally expect these showers to hit the area during the late afternoon or early evening hours as a weak front advances into the area. There is a ‘marginal’ risk of severe weather, with the primary threat being thunderstorms and heavy rainfall. Overall I expect much of the area to pick up between 0.5 and 3 inches of rainfall, but higher isolated totals are possible. Highs on Wednesday should reach the lower 90s ahead of the rain.

NOAA rain accumulation forecast for now through Thursday morning. (Weather Bell)

Thursday

Rain chances will linger into Thursday morning, especially closer to the coast, as the front slowly pushes offshore. Skies should be clearing during the afternoon hours, with high temperatures likely reaching the mid- to upper-80s. Winds will be from the north at 5 to 10 mph. As modestly drier air moves in, much of the region should drop into the 60s by early Friday morning.

Low temperature forecast for Friday morning. (Weather Bell)

Friday

This should be a sunny day with highs in the upper 80s and lower humidity. Lows on Friday night should again drop into the 60s for inland areas.

Saturday and Sunday

Our modestly drier air should hold on through the weekend. With sunny skies expect daytime temperatures of about 90 degrees. Lows will fall into the 60s for inland areas, with central Houston and the coast probably dropping to around 70 degrees. It won’t be fall-like, but nights and mornings should be pleasant enough.

Next week

The drier air holds on for a few days before, I think, temperatures are likely headed back into the lower 90s for a few days. After this Thursday our rain chances appear to be quite low for awhile.

Tropics

The Atlantic tropics are heating up, and Matt has full details over at The Eyewall. The short story is that there is nothing imminent in the Gulf of Mexico and zero threats to Texas at present. We’ll have more on this tomorrow or Thursday.

Finally, a hint of fall in the forecast for Houston. And maybe some rain, too.

In brief: Today’s post discusses an upcoming pattern change what will bring some rain midweek, and then some modestly cooler weather through the weekend. It won’t feel like fall, precisely, but it won’t be August-like either.

Fall, finally?

It is fitting that the Autumnal equinox comes on Tuesday, when precisely at 1:19 pm CT the Sun will move directly over the equator. Why? Because some semblance of almost fall-like weather is on the way for the Houston region. The last 10 days, or so, have felt very much like late summer in the region, with a string of daily high temperatures at Houston’s official monitoring station hovering between 92 and 95 degrees.

The last 11 days have been a little hotter than normal for September. (National Weather Service)

We have a couple of more warm-ish days before a weak front arrives mid-week. This won’t bring that much cooler air—although it will bring some—but it will knock some of the humidity out of the lower atmosphere. As a result temperatures will feel a little more comfortable. We are likely to see more 90-degree days in the weeks ahead, but I don’t think we are going to see any more prolonged stretches of highs in the low- to mid-90s.

Monday and Tuesday

These days should be similar, which is to say high temperatures generally in the vicinity of 90 degrees to the lower 90s, with plenty of humidity. Skies will be mostly sunny. Areas along and south of Interstate 10 have perhaps a 40 percent chance of seeing a passing shower or thunderstorm, while areas further inland probably have a somewhat less (but non-zero) chance). Winds will be modest, from the south-southeast, and nights warm, with lows in the upper 70s. All in all, it will be pretty sticky outside.

Wednesday

A cool front will approach the area on Wednesday, and this combined with surging moisture levels in the atmosphere should produce widespread showers and thunderstorms. Most of the area probably will pick up 0.5 to 1.5 inches through the period of Thursday morning, but the majority of this rain probably will come on Wednesday and Wednesday evening. This will be another warm and humid day before some slightly drier air begins moving in over night.

NOAA rain accumulation forecast for now through Wednesday night. (Weather Bell)

Thursday

I think we’ll see some lingering showers on Thursday morning, as it will take some time for the front to amble off the coast. By the afternoon we should see clearing skies and high in the upper 80s. Lows on Thursday night should drop into the 60s for all but areas near and along the coast.

Friday, Saturday, and Sunday

We still have some questions about the details for this weekend, because it’s just not clear how much oomph the front will have, but we can be confident in the big picture. Skies this weekend should be mostly sunny, with highs in the upper 80s to 90 degrees, and modest humidity. Nights will be a bit cooler, probably in the upper 60s. Some very slight rain chances likely return to the forecast on Sunday or Sunday evening. All in all, it looks like a warm, but fine weekend.

Next week

Most of next week looks sunny, with highs around 90 degrees and nights in the lower 70s. It’s not exactly going to be summerlike in Houston, with slightly lower humidity levels, but it won’t exactly feel like fall either. For me it always feels like we’re sitting in the cold front waiting room at this time of year.

After our latest dry spell, how did the greater Houston region do this summer with rainfall?

In brief: In today’s post we dive into the precipitation Houston recorded this summer. Most of the region got significantly less than normal, but we’re not in a drought. Why? We also dig into the forecast which indicates continued warm-to-hot temperatures and an increase in rain chances ahead.

Autumnal equinox looms

Alright, I’ll allow that it does not really feel like summer should be ending soon, especially with a 95-degree temperature reading at Bush Intercontinental Airport on Wednesday afternoon. And in reality, I am sorry to say, I don’t think we are done with heat just yet. Nevertheless, by next Monday we will come to the Autumnal equinox, which by some reckonings marks the beginning of fall in the Northern hemisphere. Note that we already passed into meteorological fall on September 1.

It’s been slim pickings on the rain front this month. Dark green lines indicate rain, red is records. (National Weather Service)

As I noted yesterday, we have had a fairly dry start to September. Since there is not a whole lot else to talk about today, and because the month so far has been dry-ish, I thought we might take a look at how the region did precipitation-wise over the course of the summer. As you can see in the map below, showing “percent of normal” rainfall over the last 90 days, the vast majority of the Houston region has received 50 to 90 percent of normal rainfall during the hottest part of the year.

Percent of normal rainfall over the last 90 days.

So why aren’t we in a drought? (Really, we are not). The answer is two-fold. We had some really nice rains in late spring that positioned our soils well for the summer months. And then, while conditions were drier than normal across Houston in July, August, and September, we did have periodic rains that brought a few inches at a time. So if you add that up, we’ve come through summer alright. Things have gotten fairly dry in parts of Houston in the last week, but I’m hopeful that we’ll see some decent rains next week to get us back on track.

Thursday

Yes, you can expect pretty much the same weather today that we’ve experienced for about the last 10 days: highs in the low-90s in central Houston, with slightly hotter temperatures further inland, and slightly cooler closer to the coast. Skies will be mostly sunny, with a slight chance of some showers and thunderstorms popping up this afternoon. Overnight lows will fall into the mid-70s.

Friday and Saturday

More of the same.

Sunday

By Sunday the pattern starts to become a little more unsettled, such that we might see rain chances of 20 to 40 percent by the afternoon. This may help to hold high temperatures down to about 90 degrees in Houston. If you have outdoor plans I don’t think these showers will prove to be too disruptive, as they should be scattered and brief.

NOAA rain accumulation forecast for now through next Wednesday. (Weather Bell)

Next week

Our pattern really should shift some next week, with better daily rain chances beginning by Monday. Overall accumulations next week will probably be on the order of 1 inch, but also there will likely be a great deal of variability in that. Modestly more clouds should keep highs on the order of 90 degrees, although rainier days may top out in the upper 80s. A weak front may back door its way into the region later next week, but that is far from certain.

Modest rain chances reenter the forecast, with a pattern change ahead

In brief: Houston will see plenty of sunshine through the weekend, but we will also start to see some slightly better rain chances. By later Sunday or more likely Monday, the pattern will change more noticeably, with increased clouds and the potential for widespread showers.

A slowly changing pattern

With one or two exceptions, most of the first half of September has seen sunny days with near zero rain chances. This pattern, especially over the last 10 days or so, has seen high pressure dominate our region’s weather. This is now slowly beginning to change, and by this weekend an upper-level system will shake things up. As a result we will see modest rain chances over the next couple of days before the potential for more widespread showers by Monday, which perhaps will persist for much of next week.

Today is probably the last day, for awhile, that much of the region pushes into the mid-90s. (Weather Bell)

Wednesday

Today will bring sunny skies into the region with our typical temperatures in the low 90s for much of the central metro area, with inland areas getting a little warmer than this and the coast remaining a little cooler. There is some support in high resolution models for the development of scattered showers, and perhaps a few isolated thunderstorms, between about 3 pm and 7 pm this afternoon and early evening, before the loss of daytime heating. Lows tonight will drop into the mid-70s for most locations.

Thursday and Friday

Both of these days should see sunny skies. I do think high temperatures may be 1 or 2 degrees cooler, but it will still be hot during the afternoon. Rain chances both days look a bit lower, perhaps on the order of 10 to 20 percent.

Saturday and Sunday

Most of the region should see highs of around 90 degrees this weekend, with mostly sunny skies. However, there will be a slight chance of some showers and thunderstorms as the atmosphere starts to become more unsettled. I think the more widespread rain chances will probably hold off until Monday, but I’m not sure of that. For now I’ll go with about a 20 percent chance of rain on Saturday, and maybe 40 percent on Sunday, but these are kind of fuzzy at this point.

We will see an increased likelihood of rain next week. (Pivotal Weather)

Next week

By Monday-ish we should see an atmosphere more broadly supportive of showers and potentially some thunderstorms. This should set the tone for next week, with something like a 40 to 60 percent chance of rain each day. This should also limit high temperatures to about 90 degrees, or less, on a daily basis. As of yet there’s no strong signal for the next cold front, but maybe something weaker may back door its way in later next week. We’ll have to wait and see.