Poor air quality today as Saharan dust takes hold

Saharan dust just began to infiltrate the Houston area yesterday, and it was not yet thick enough to obscure the sunset, which proved to be a real treat in spots.

Compare that to yesterday’s sunrise off the coast of Louisiana where dust was thicker.

Your sunrise and sunset mileage during dust events will certainly vary. Should the clouds clear, we expect thick dust today, but it may begin to disperse somewhat toward sunset, so there’s a chance we end up doing well. I think sunrise on Saturday may be fairly nice as well.

Aside from optical treats, there are practical issues with Saharan dust. The Texas Commission on Environmental Quality is forecasting today to be “unhealthy for sensitive groups” in the Houston area. Per the EPA air quality maps, we’re already one notch above that and “unhealthy” in much of the southeast half of the region.

Air quality is already considered “unhealthy” across the region today. It will improve gradually this weekend. (EPA)

If you have allergies, asthma, or other respiratory ailments, you will probably prefer to spend the better part of today indoors. Air quality should be improved a little bit tomorrow, though still probably considered poor. Sunday will be a little better than that.

As far as the rest of the weather goes….

Today

Radar is quiet for a change in the Houston area this morning, aside from a few light showers here and there. There are some storms north of Beaumont and some locally heavy rains in the Victoria area, with just nuisance showers in between.

Radar this morning shows heavier rains well off to our south and west. West of Katy has better odds of storms today than in or east of Houston. (College of DuPage)

Expect the heavier rains to our south and west to continue down there and lift northward today. This should keep those west of the Houston area and west of the hardest hit areas yesterday morning. While we could still see a few downpours or thunderstorms today, the focus will likely be between San Antonio and Columbus. If that should change, we’ll let you know. Yes, you might see some dust or “mud” residue on outside surfaces if it rains. Maybe. Rain would also help improve air quality.

With clouds, haze, or dust, don’t expect much in the way of true sunshine today. Highs will be in the 80s.

Weekend

Both Saturday and Sunday will feature a chance at a shower or thunderstorm. There may be a few small pockets where rain moves slowly and falls heavily for a time. So while many of us may not see much of anything this weekend, it’s not out of the question that a few neighborhoods end up with a couple inches of rain in a short time. I might give an edge to Sunday for having a higher rain chance, but both days will be setup for a few storms. Outside of that, expect a mix of clouds and sun with highs around 90, give or take a couple degrees and lows in the upper 70s.

See full post

Locally heavy rain possible tonight, mainly south or east of Houston

Today ended up being a mostly quiet one again for most of the region, with just a few showers here and there. Rainfall since about 7 AM today has been more than manageable with most areas seeing minor amounts. A couple areas, notably up toward Conroe and south toward Santa Fe and Galveston have seen close to or in excess of an inch of rain since 7 AM today.

Rain totals since 7 AM have been mostly minor, with a couple exceptions. (Harris County Flood Control)

So we’ve done alright so far. Heading into tonight, I will level with you: Eric and I are scratching our heads a bit. Yesterday, it appeared we had a pretty favorable setup for heavy rain leading into the nighttime, and yes it materialized, but not in the way we were anticipating until late in the game. Tonight we are presented with a set of data that is different than yesterday but does offer up some risk of heavier rainfall in spots.

Brace yourselves, some serious nerd-speak is coming in this paragraph: I just dug through a lot of the meteorology here, and what I’m coming up with does make me think some areas could see some locally heavy rainfall tonight. For one, we have a weak upper level low over Southeast Texas. Those are notoriously fickle systems, and they can become more active at night. Second, it appears there is some sort of weak boundary at the surface that’s roughly along US-59/I-69 from Victoria through Houston that then arcs to the east toward Beaumont. Boundaries like this can act as focusing points for thunderstorms. Third, model parameters suggest a good bit of instability in the atmosphere tonight. Higher instability means thunderstorms can develop and sustain themselves. Fourth, models suggest plenty of atmospheric moisture is available right now. Observations back this up, as the weather balloon launched at 7 PM from Lake Charles shows precipitable water values in the 90th percentile for this time of year, which means if storms can get going, they can rain heavily. Lastly, it appears that winds about 5,000 feet above the surface are going to increase off the Gulf from south to north tonight, aimed east of Houston. Winds at that level can act to provide additional ingredients and moisture needed for heavy rainfall.

This is a long winded way of saying that the meteorology that’s showing up right now backs up the idea that we could see some heavy rainfall tonight.

The question, as always, is can the ingredients actually come together in such a way to allow this to transpire. I really don’t know. These are fickle, tricky situations, so there’s always a chance a few things don’t happen and you end up with a couple isolated showers and storms and that’s that. But, if things do come together, we could be talking about repetitive showers and storms for some areas.

So, for most of the area tonight, let’s just call it a few showers or a storm possible. Some folks will see nothing. Others some heavy rain for a time. Totals of a quarter inch to an inch.

NOAA’s rainfall forecast through Thursday morning at 7 AM shows better odds of heavier rains east of Houston. Most places will just see some sporadic showers, but a few may see some more sustained, heavier rainfall. (Weather Bell)

Put a pin over downtown Houston and if you go south of there and east of there, you stand the chance of seeing perhaps some more sustained rainfall. In those places, I would say your odds of seeing a quarter inch to inch of rain are higher than northwest of Houston. There may also be a few isolated locations that see as much as 2 to 4 inches of rain or a bit more in a worst case scenario. The odds of that happening are not high, but as I laid out above, the ingredients are certainly in place. If I had to focus on an area tonight for the highest risk of this it would be from Baytown to Beaumont.

Anyway, we just wanted to provide some situational awareness for you this evening. Be safe!

Houston’s stretch of “comfortable for June” weather about to come to an end

Over the last couple weeks, I’ve turned into a statistics machine, focused on one value: Dewpoints. Not gonna lie, it’s been fun. Anyway, here’s another one for you today: As of yesterday evening, we had amassed 132 hours of dewpoint values at or below 65°F this month. Since 1990, the most hours in the month of June that comfortable was 197 hours in 2006. So, yeah, it’s been kind of great this month, as Junes go. Of course, as Eric alluded to yesterday, we really do need some rain. And we are going to get both the return of humidity and higher end rain chances as we go through the weekend and into next week.

Today

Yesterday was the 5th consecutive day with a high of 94° in Houston. Today could well be the 6th in a row. Expect a day much like yesterday with sunshine and some passing clouds. Rain chances aren’t zero, but they’re minimal for most of us. Areas south and west of Houston stand the best chance for some slow moving downpours this afternoon.

Saturday & Sunday

Whatever is left of our dry air will work its way off to the east by tomorrow, and we should be hot and humid. Rain chances will inch up with that change, as atmospheric moisture cranks back up closer to what is normal for this time of year.

The percent of normal precipitable water (basically, how much atmospheric moisture is available) from this afternoon through Sunday afternoon. Moisture returns to at or above normal by tomorrow or Sunday. (Weather Bell)

If Friday carries a 20 percent chance of a shower, Saturday and Sunday would probably carry about a 30 percent chance or even a bit higher. Any showers could be locally heavy this weekend. Look for morning lows in the 70s and afternoon highs in the low- to mid-90s on both days. With higher humidity, expect it to feel more like typical Houston summer, with heat index values back up at or above 100° each afternoon.

Monday through Wednesday

The atmosphere will pick up even more available moisture early next week, which should be enough to allow for numerous showers and thunderstorms each day. For any given location early next week, rain chances probably “only” reach 40 or 50 percent each day, but there will be a pretty good chance that most of us see at least some rain in that timeframe. Any rain could be heavy at times. It will be warm and humid with highs around 90°, give or take a couple degrees and lows in the mid- to upper-70s inland (80° or so at the coast).

See full post

Nothing but sunshine ahead for Houston

Since Wednesday’s cold front, Houston has had 50 consecutive hours of dewpoints below 60°, which continue as of 7 AM Friday. Recall, dewpoint is a much better gauge of “comfort” in summer than relative humidity, and for Houston anything below 65° generally feels really nice this time of year. Anything in the 50s is very comfortable. To put in context how rare an event this is in Houston in summer. We have only done 40 consecutive hours of dewpoints in the 50s in June, July, or August two other times since Bush Airport was established as the official reporting station for Houston in 1969:

  • June 8-9, 1996 (43 consecutive hours)
  • June 24-28, 1974 (110 (!) consecutive hours)

It appears that this one will place firmly 2nd on the list. This air mass would be a first ballot inductee to the Hall of Fame of Comfort for Houston summers. And it continues.

We do have a couple things to monitor. This dry weather is going to have an impact on soil moisture in much of Texas. We’ll discuss that more in-depth next week. In addition to that, this dry, offshore breeze is certainly aggravating for allergy sufferers (raises hand). But other than that, we have little to talk about.

So in lieu of much text today, our forecast will be shared primarily in gif form.

Today & weekend

It will be tough to let go of the current weather pattern. Thankfully, this weekend won’t be too bad!

It’s my birthday weekend, and the humidity will remain low. This is how I’m feeling.

Expect highs in the 90s and lows in the 60s or low 70s this weekend, with continued low humidity for June. Sunshine and nil rain chances.

Full sun, a week out from the solstice? Load up on sunscreen this weekend.

Next week

Onshore winds resume Monday, and that means our friendly neighborhood Houston humidity will be on the rise.

Humidity begins to return next week…

But it won’t be that bad of a week.

“Won’t be so bad” is a relative phrase.

Alright, yeah, it will end up being a pretty hot week. Look for mid-90s at least, with lows in the 70s.

By the middle of next week, it’s likely to feel like summer in all its glory here.

The next chance of any meaningful rain at all, outside of a localized downpour? Maybe next weekend?

The 90s and “No Rain:” A Blind Melon forecast.

We’ll check back in with you on Monday with more. Enjoy the weekend!