We topped off (officially) at 97° on Thursday, tying yesterday with June 9th for the hottest day of 2020 so far. Perhaps we could make a run today for….
No matter your age or favorite music, it’s almost always the 90s in Houston.
Maybe. If not, there is a valid chance we could do it Saturday or Sunday as well. Either way, expect a hot holiday weekend, and be sure to take it easy if you’re outdoors.
Today
Look for partly to mostly sunny conditions today. Saharan dust will again provide some haze. Air quality on Thursday did get to the “unhealthy for sensitive groups” level, and it may do so again today, so if you’ve been irritated by the recent dust events or have any respiratory ailments, today may bother you once again. High temperatures should aim for the mid- to upper-90s once more with plenty of humidity. Heat index values topped off around 105° yesterday. We should see similar to perhaps slightly lower peak heat index values today.
Heat index values should top off around 101° to 104° later this afternoon. (Weather Bell)
Rain chances aren’t zero, but they’re low for most of the area most of the day. We will watch some storms in Louisiana later this afternoon that will ride west into Texas this evening. If they can survive the trip, you may see a downpour or have a brief gusty thunderstorm east of I-45 after about 4 or 5 P.M. or so before the storms dissipate. This is a fairly low possibility.
Weekend
For the holiday weekend it will be hot. Both Saturday and Sunday should again see highs in the mid- to upper-90s and lows in the 70s. Humidity is going to creep upward this weekend, so look for peak heat index values around 105°, give or take a couple degrees on both days. Saharan dust may linger a bit, but it will slowly dissipate this weekend.
How about rain? Well, a trough and upper low look to setup shop over Mississippi and Alabama this weekend. Storms on the western periphery of that setup could graze eastern areas. This would be primarily a story for Liberty & Chambers Counties, if not mainly toward Beaumont. So a few heavy downpours are possible east of Houston. Areas to the north (Walker, Montgomery, and San Jacinto Counties) may also get grazed by some storms at times as well this weekend, particularly Sunday morning. For Houston and points south and west, your best shot at storms may be Sunday, and as it stands this morning, that’s a low probability. Either way, no significant issues are expected this weekend.
Next week
Look for scattered showers and thunderstorms on Monday and especially Tuesday. Not everyone will see rain, but it will be our area’s best shot at storms since last week, so hopefully we can participate. By Wednesday, high pressure begins to reload over Texas, building toward the weekend. We will likely be back to hot and mostly dry by the end of next week, with daytime highs back in the 95 to 97 degree range, if not hotter.
The 2020 Atlantic hurricane season got off to an early and fiercely active start back in May and early June, which had many people justifiably on edge wondering what was to come. Now, here we are on June 30th and we’ve had one additional storm since Cristobal made landfall in Louisiana at the beginning of June. Things have thankfully slowed down a bit. We’re going to aim to provide sort of a broad overview of the state of the tropics every Tuesday here at Space City Weather, just to keep you apprised of things we don’t make time or space for in the morning updates.
Tropical outlook in a sentence
While we will be watching the potential for some kind of hybrid system to develop off the Florida or Georgia coast early next week, we do not see any threats to the western Gulf for the foreseeable future.
Active start, sort of
Our most recent named storm was Dolly, which briefly threatened some fish in the north Atlantic back on June 23rd. Dolly just missed being the earliest “D” storm on record by 3 days. For those of you scoring at home, the earliest “E” storm was 2005’s Emily, which formed on July 11th.
We normally don’t get to the letter “D” storm until mid-August. (NOAA)
But interestingly, even though we’re running about 45 days ahead of schedule in terms of named storms, when you look at cumulative intensity, it’s less impressive. We like to sometimes look at what we call “accumulated cyclone energy,” or ACE to really hammer home how active a season has been to place it in better historical context. We can name more storms now because we have superior technology to even 10 or 20 years ago that allows the National Hurricane Center to name something borderline that might have slipped through the cracks in the past. Stronger storms likely would not have been missed in the past, so ACE provides a good way to almost compare apples to apples better than number of storms would.
So what is ACE? We said there would be no math, so I won’t go into the details of how it’s calculated. Read the Wikipedia article here for more (yes, it’s legitimate and accurate). Essentially, it’s just an equation that factors the length of time a storm had particular sustained winds. The stronger the winds, the longer it maintains strong intensity, the higher the ACE. Since it only factors in wind, by no means is it perfect. For instance, Hurricanes Harvey, Andrew, and Katrina won’t crack the top 25 list of storms that have generated the most ACE because they didn’t last long enough. So in that respect, the calculation is imperfect, but overall it’s a pretty good gauge of where a season stands historically. You can track seasonal ACE in real time here.
The accumulated cyclone energy for this season so far is running about 3-4 weeks ahead of schedule. (Colorado State)
So back to 2020: We have amassed 6.1 units of ACE this season so far. This is normal for about July 20th, so 3 or 4 weeks ahead of schedule instead of 45 days.
Regardless of how you want to slice it, we’re off to a fast start, so this pause is welcome.
Tropical outlook
Things won’t stay quiet forever, and it appears the next opportunity for a system will be sometime later this weekend or early next week, and in true 2020 fashion, it will occur in a peculiar manner. An upper level low over the Northeast looks to exit over the next couple days, but it seems like a weak little lobe off the south side either stays trapped over or drifts into the Southeast. Here’s the latest 500 mb GFS Ensemble mean view through next week, looking at what’s happening 20,000 feet up. Note the light blue color over the Southeast. This is showing an upper level disturbance of some type by the weekend.
The upper level pattern shown here by the GFS and also by the European model suggests shenanigans are possible off the Southeast coast early next week. (Tropical Tidbits)
From here, we start to see <waves hands> things happening. It appears this may gradually transition to a surface low as it drifts eastward, off the Georgia or Carolina coast and it’s plausible to think it could become tropical on its exit out to sea. While this will likely have limited impact to any land mass, we have a legitimate shot at having our earliest E/5th storm on record this year.
The European ensemble is particularly enthusiastic about a risk for a depression or weak tropical storm to from from the transitioning disturbance over the Southeast early next week. It likely will move steadily out to sea. (Weathernerds.org)
But that’s it; that’s the tropical update for the next 10 days or so. The overall background state of the Atlantic is one that has become more favorable in recent days. I won’t delve too much into the meteorology here, except to say that we’ve had some shifts in the atmosphere over the tropics that should, in theory, allow for a few more waves. But you’ve seen the Saharan dust here in Houston. It’s out there, and it’s widespread.
Yellow, orange, red, Saharan dust is all over. (University of Wisconsin CIMSS)
Anywhere you see yellow, orange, or red on that satellite image is an indication that dust is present. It’s all over the Atlantic basin right now, not necessarily abnormal for this time of year. But where you have dust, you have drier air and a less hospitable environment for tropical development. Suffice to say, with this all over, conditions right now are not ideal for tropical development in the Atlantic basin. In addition, you still have a good bit of shear as well. So the basin isn’t completely immune to storms, but it’s rather inhospitable.
Is there anything happening in fantasyland on the models? Nope. Things look quiet right now as we head through early or mid-July. Short of something rogue like this thing off the Southeast coast next week, we don’t expect much through mid-month. So breathe easy here in Houston for the time being. We’ll check back in on things in a week.
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.
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.
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!
