Matt Lanza

Summary: We are hoisting a Stage 1 flood alert for areas northwest of Houston that should see heavy rain later today. Street flooding is a good bet in those areas. Houston and points south and east will see substantially less rainfall. Things quiet down and cool down tomorrow.

Good morning! We covered the forecast mostly fine yesterday, but now that things are in focus, we can fine tune some details for you for today. First off, we are going to issue a Stage 1 flood alert on our Flood Scale for areas northwest of Houston. This means that we expect street flooding in spots, and it’s possible that we see some decent rises on some of the creeks or rivers in those areas. We could see enough rain to impact the Spring or Cypress Creek watersheds, among some others with rises or minor flooding. Also, the larger river systems north or northwest of Houston (Brazos, San Jacinto, Trinity) could see some decent rises.

Unique about this particular setup: Areas south and east of Houston may see minimal rainfall. Some places may even see no rain at all.

Here are a few more notes about this event.

Timing: There are already a few showers south of Victoria moving toward Matagorda, and through early afternoon a handful of isolated showers are possible. Most folks will be fine though. Between about 2 and 6 PM, we expect more isolated showers or storms anywhere in the area, eventually focusing northwest of Houston by evening in the areas of concern noted above. If you’re attending the Dynamo game this evening, I’m not too worried, but don’t be entirely shocked if it rains a bit or there is a brief lightning delay at some point. The worst rains north and west of Houston will be from about 6 PM through midnight, with everything eventually getting pushed east overnight and out of the area by morning. Some clouds or light rain will be possible Sunday morning.

Rain totals: You can see the forecast above, but there are risks. Houston and points south and east will see an inch or less, probably less than a half-inch in most spots. As you progress north and west from Downtown Houston, we should quickly see totals of 1 to 3 inches. In extreme northwest Harris County, Montgomery County, portions of Waller County, and north of there, expect 2 to 4 inches. A few locations in those areas will likely see 4 to 7 inches of rain, if not a bit more. This is where we are most concerned with flooding.

Again, there will likely be a sharp cutoff between 1 to 2 inch rains and minimal rain somewhere in the Houston area.

And Sunday? Cooler! Look for breezy conditions and temperatures stuck in the 60s for most of tomorrow. Some light rain or a few showers may linger in the morning, with gradual PM clearing. Overnight lows into Monday morning still look to be in the 40s and 50s.

Should anything serious change, we’ll update you later. Otherwise, just stay safe and make sure you stay weather aware, especially northwest of Houston later today.

Summary: Cooler weather is in sight as we head later into the weekend. Before that, it will be warm to hot and humid, and there will likely be heavy rain and strong storms north and northwest of Houston on Saturday evening. If you’re traveling north and west toward Austin, Waco, or Dallas Saturday afternoon or evening, use caution.

Today

We hit 88 degrees yesterday in what felt like an early summer preview. Expect more of the same today, though we could shave a couple degrees off yesterday’s temperatures with more clouds possible. An isolated shower or storm is possible, much like we saw yesterday across the area. This would be most likely in the afternoon hours.

Saturday into Sunday

The forecast gets more interesting here. As of now, Saturday morning looks warm, humid, but otherwise fine. An isolated shower or storm is possible from late morning into early afternoon. By mid to late afternoon, storm coverage should increase. Here’s how we expect it to go right now.

Storms could develop in the Houston area, along and north or west of US-59/I-69 after 2 to 3 PM. I suspect those storms will lift north and west a bit and eventually line up robustly between about College Station and Huntsville. There is some signal within the models of training storms up that way, so rain could continue to repetitively cycle over the same areas a bit. Eventually, as the front plows south and east, all of those storms will come with it. That should sweep back through the Greater Houston area between midnight and 5 AM or so. It will continue to progress east and out of our area on Sunday.

How much rain? I think we’re going to see a lot of variability, truthfully. From Houston south and east, probably a half-inch or less, unless the overnight storms pack more punch than we currently expect. Within Houston and the immediate suburbs north and west (Katy through Cypress and The Woodlands), we will probably see anywhere from a quarter-inch to an inch or more in an isolated spot or two. Farther north and west, along a line from about La Grange through College Station through Huntsville, rain totals will likely average 1 to 3 inches, and I would not be the least bit shocked to see someone end up with 5 inches or even a little more out of this. Flash flooding is a definite possibility up that way, and if you’re traveling between Houston and Dallas, Waco, or Austin tomorrow afternoon or evening, just be aware of this potential.

On Sunday afternoon, things should clear out, and the humidity will take a plunge.

Saturday’s highs will again be in the 80s, with morning lows in the 70s. Temperatures should drop into the 60s with the storms Sunday morning before recovering back to near 70 degrees in the afternoon. It will be noticeably cooler and breezy.

Next week

Monday looks absolutely spectacular for late April. Expect lows in the 50s (or even a handful of 40s!), highs in the low to mid-70s, and plentiful sunshine.

Tuesday should be similar humidity-wise but a touch warmer with lows near 60 and highs around 80 or a little hotter. The weather pattern may get a bit more unsettled for late week. Along with very warm highs well into the 80s to perhaps near 90 later next week, each day will have a slight chance of showers or thunderstorms. Details are still TBD. I don’t want to speculate a ton on next weekend yet, with plenty of big athletic events on tap. I don’t think the MS 150 riders will be enduring much of a headwind, but the rest of the forecast is up in the air. More to come.

Summary: Quiet weather continues through the weekend before we eye up some heat and rain chances again later next week. There’s about a 40 to 50 percent chance we hit our first 90 degree day of the year next week.

Today through Sunday

After a wild Wednesday morning, things calmed down dramatically as expected yesterday. After another cool morning, we should warm back up into the 70s or near 80 degrees this afternoon. Humidity will remain low, and winds will be lighter than Thursday.

For Saturday, look for more sunshine with clouds, morning lows in the 50s, and highs sneaking back above 80 in most spots away from the coast. We should notice a lot more humidity and more clouds around on Sunday. The morning will start out noticeably milder, with low temperatures only in the mid-60s. Expect to see highs in the low to mid-80s under partly sunny skies.

Monday

Things start to change a bit Monday. One thing we will notice is more wind. Breezy conditions set in probably by Sunday but on Monday, they’ll nudge up a little with gusts over 30 mph at times and stronger at the coast and southwest of Houston.

Morning lows will be well into the 60s and highs in the 80s. Rain chances remain low. I do expect to see some additional clouds on Monday, and as is often the case with an influx of humidity in springtime, some showers or sprinkles can’t be entirely ruled out.

Tuesday through Thursday

The chance of rain remains pretty low in the Houston area for most of next week because we expect to see a pretty robust capping inversion in place over the region. This implies that in a layer in the atmosphere, temperatures will actually warm as you go up. This creates what is basically a block in the atmosphere to limit cloud growth and thus reduce rain chances. This is common in spring in Houston and is why we see far less really severe weather than our neighbors to the north and west in the Plains. While things could change, for now expect isolated showers, a slight chance of a thunderstorm, and otherwise partly to mostly cloudy skies into Thursday morning, with increasing rain chances thereafter.

Otherwise, it’s going to get warm with an early summer preview. Right now, we have about a 40 to 50 percent chance to top out at 90 degrees in Houston officially on Wednesday or Thursday. Parts of the Rio Grande Valley should push 100 degrees as well. For Houston, the average date of our first 90 degree day has occurred on April 29th since 1995. We’re getting close.

Last summer we started using more charts of “wet bulb globe temperature” (WBGT) instead of heat index. The WBGT looks at numerous factors besides just temperature and humidity and tends to offer a more realistic view of how serious the heat will be for our bodies. Last summer saw numerous days in the high and extreme category. While it will get hot and humid later next week, as of now we’re sitting mostly in the elevated to moderate level for heat. So this will serve as a reminder that summer is coming, rather than feel a ton like summer. I’m mostly showing this today to start getting you comfortable with how these categories work; instead of a number, we see a category. And lots of people continue moving to this area. You’ll be seeing a lot more of this during summer.

It does look like storm chances and front chances will increase late next week or weekend, but we’ll look into that more on Monday.

We’ll begin today with the tropics. Colorado State University released their annual April hurricane season forecast yesterday. It was pretty impressive. They call for 23 named storms, 11 hurricanes, and 5 major hurricanes. This is the most active April forecast that they’ve released. This is another signal ahead of the upcoming season that suggests a very busy summer awaits us. I wrote all about the forecast and what you should take from it over at The Eyewall. Busy forecast don’t always translate into busy forecasts for Houston. However, we encourage you to prepare this season, as you should each season.

Today

We’ve got one more spectacular day with low humidity. We’ll warm from the 50s and low-60s this morning well into the 80s this afternoon. It’ll be warm for sure!

But the humidity will be tolerable. Lots of sun means ozone production, so, yes air quality will be an issue this morning and late this afternoon.

Weekend

We will trade off a couple degrees tomorrow for higher humidity. We’ll also begin to add back some more clouds. Look for highs in the lower half of the 80s after morning lows in the 60s. Expect similar temperatures on Sunday but with more humidity and a slightly warmer morning.

On Sunday, the cold front that will play a role in the eclipse forecast will approach from the west. It should push through the Brazos Valley, and it may even get as far south and east as Brookshire, Cypress, or The Woodlands. From there, it slams on the brakes and throws things into reverse, moving back to our north and west, reaching back to I-35 by Monday morning. Besides clouds, there will probably be at least a few showers in the area Sunday as this front maneuvers.

Monday & solar eclipse outlook

As far as Monday’s eclipse goes, we don’t have any real positive news to share today unfortunately. Here in Houston, we have maybe a 10 to 15 percent chance that skies will be clear enough for good viewing. Those odds may be even lower for Austin and San Antonio.

If you absolutely want to chase this thing in Texas, your best bets may be Texarkana or Dallas, where there’s currently about a 30 to 40 percent chance that skies will be favorable. Still not great, but better than much of the rest of the state. Do keep in mind that North Texas is highlighted for potential severe thunderstorms on Monday, however. If you are able to road trip, southeast Missouri or southern Illinois look favorable on Monday. If time, money, and logistics are no object, northern New England or New Brunswick and Quebec in Canada are your best bets.

Weather-wise, locally expect plentiful clouds and isolated to scattered showers Monday. A thunderstorm or two will be possible in the afternoon, especially north of Houston. Highs should be in the low-80s with high humidity.

Rest of next week

The pattern is setting up such that Tuesday looks stormy to our north. Expect a few showers or thunderstorms locally, but I don’t think we’re going to see a whole lot around here Monday night and much of Tuesday.

That could change Wednesday. Somewhere in Texas, we’re likely to see a robust area of thunderstorms (what we call an MCS in meteorology, mesoscale convective system). This would probably develop somewhere in the I-35 corridor on Tuesday night and ride southeast across the eastern half of the state and into Louisiana on Wednesday.

We are highlighted under Tuesday’s severe weather risk for this reason (it would most likely be toward Wednesday morning), as well as Wednesday’s risk. It’s a bit too early to pinpoint details or how much rain we might see, but if you have plans Tuesday night or Wednesday morning, keep an eye on this forecast. Things should calm down a good bit and turn much less humid to close out next week.