Hi everyone. Just jumping in with a quick afternoon update on the forecast for severe weather in the Houston area. The bottom line is that the window for severe thunderstorms away from the immediate coast is closing quickly this afternoon.
What has happened is that rainfall near the coast and inland this morning has sapped the atmosphere of some of the instability needed to drive severe weather. (Such instability is necessary to promote the kinds of rising air that fuel strong thunderstorms). As a result the atmospheric environment is not really capable of supporting the kinds of supercells that produce tornadoes and other severe activity. We could still see a few isolated tornadoes this afternoon, but the threat is fading.
Severe thunderstorm threat shifts coastward. (NOAA)
In terms of precipitation, we’ve seen the heaviest rainfall so far along the coast today, near a warm front at the surface. A couple of inches have fallen and we’re likely to see additional accumulations over the next few hours with sporadic pulses of heavier rainfall. It is these coastal regions from Matagorda Bay to Galveston Bay and up toward Port Arthur that the greatest potential for strong thunderstorms lies. As this system continues to propagate to the east, the threat of heavy rainfall and storm activity, even along the coast, will diminish late this afternoon and evening.
Good morning. As we’ve been discussing this week, there is the likelihood of storms today, with the threat of severe weather during the daytime hours. There are two potential threats that I want to highlight before jumping in to the daily forecast.
Heavy Rainfall
We are already seeing light rainfall this morning across the southern portion of the region, and these showers are likely to intensify during the mid-morning hours. Much of the area is likely to pick up 1 to 3 inches of rainfall, but there is a risk of higher totals beneath the stronger storms. It is likely that areas along, and to the south and east of Highway 59/Interstate 69, will be most at risk for these totals.
To account for potential flooding we are instituting a Stage 1 flood alert, which means there will be a risk of nuisance street flooding later this morning and into the afternoon hours. The worst of the rains should shift eastward during the mid- the late-afternoon hours, and take the threat of flooding with it. Note that the Houston area’s primary radar is down for maintenance. Matt discussed some workarounds in yesterday’s update.
Severe storms
The other threat today will come from an unstable air mass that could produce strong storms. The risk of severe thunderstorms will come a little bit later, beginning during the late morning hours and persisting into late afternoon. It’s a tricky forecast because some of the morning rainfall could sap the atmosphere of energy to produce severe weather. In any case there is decent chance for damaging winds, a few tornadoes, and possibly even some hail to develop in the Houston metro area today shortly before noon, and persisting throughout the afternoon.
NOAA Severe Weather Outlook for Thursday. (NOAA)
Thursday
As outlined above, today will be something of a mess weatherwise. For parts of Houston I think effects will be minimal, but please do be weather aware today due to the potential for severe weather. In terms of temperatures, expect highs of around 70 degrees, with rising humidity. Winds, generally from the south, could gust up to 30 or 35 mph. The potential for rainfall and storms should really drop off by around sunset, and tonight should be fairly quiet with lows in the mid-60s.
Friday
A front will move into Houston from the northwest on Friday morning before stalling near or just offshore. Skies will be mostly cloudy, with highs in the low 70s. Some lingering showers and thunderstorms may redevelop near the coast during the daytime, due to the proximity of the front. Lows on Friday night will drop into the upper 50s for inland areas, while remaining a bit warmer closer to the coast.
NOAA rain accumulation forecast for now through Friday night. (Weather Bell)
Saturday
This will be another partly to mostly cloudy day, with highs of around 70 degrees. Some slight rain chances will linger near the coast. Sometime later on Saturday a reinforcing, drier air mass should move into Houston, ending any rain chances and bringing some cooler air. This will drop lows on Saturday night into the 50s for all but the the immediate coast.
Sunday
This should be a partly sunny day, with drier air, and highs in the mid-60s. Lows on Sunday night will drop into the 40s for inland areas, while staying in the 50s close to the coast.
Next week
Most of next week will bring partly to mostly sunny days, with highs in the 60s and lows in the 40s and 50s. Rain chances look minimal. This will be fairly typical weather for December. We likely will see a bit of a warming trend toward the weekend, with highs perhaps in the low 70s. We’ll see.
With rain in the forecast and at least the potential for some strong to severe storms tomorrow, Houston’s primary Doppler radar is offline for maintenance. You may say, “Why on earth would they do that?” Unfortunately, there’s no real time of year here that’s better or worse; it can storm all 12 months of the year. The maintenance necessary to replace the radar pedestal (extending the lifespan of the radar another 20+ years) is extensive and requires a lot of planning. So it’s not something they can just pause or shift. The good news is that Houston has two terminal Doppler radars (TDWRs) that cover most of the metro area, and adjacent radars to ours will provide imperfect but mostly adequate coverage through the outage.
Houston’s primary Doppler radar is down for critical maintenance and upgrades, but there are other options for viewing current weather data. (NWS Houston)
For those of you that use our app for radar coverage, there is a workaround. If you tap the radar in the app, you’ll notice two diamonds, one on the south side of Houston and one on the north side. Those are the aforementioned TDWR’s from Tomball and Pearland, and you should be able to pull data from those, covering essentially the entire metro area. If you live outside the city and suburbs, you can move the map around to a few other options. To the west, the radar north of Austin can cover most of the northwest fringe areas outside the Houston metro to about College Station and Brenham or so. Corpus Christi’s radar is useful for Matagorda Bay up through maybe Wharton. Lake Charles’s radar will cover the east side adequately to just east of Baytown. Coverage between about Huntsville and Lufkin will be a little trickier, but Shreveport and the Tomball TDWR will help there. Inconvenient for sure, but not a calamity, and this is great news for the long term health of our area’s extremely valuable Doppler radar.
Today
Wednesday will be a fairly calm day across the area. No trouble yet. We’ll see clouds roll in and thicken up from south to north through the day. They’re already starting to do so in fact. But some of the lower clouds could scour out by late morning before more clouds increase again later. Temperatures should peak in the mid to maybe upper-60s later today.
Tonight
Look for winds to kick up tonight, especially at the coast, where they could gust to 30 mph or so by morning. Scattered showers will spread north and east through the night, arriving in the Matagorda Bay area by midnight and across the rest of the metro area by morning on Thursday. Temperatures will only drop back a few degrees overnight, into the low-60s or so. They should even climb some toward morning.
Thursday
In a couple words: The worst of the weather tomorrow should occur from about 8 AM to 4 PM, with strong to locally severe thunderstorms, capable of producing strong winds, hail, and isolated tornadoes, as well as heavy rain.
Overview of tomorrow’s severe weather risk, showing the greatest risk along and north of I-10, where an enhanced risk (level 3/5) is in place. (NWS Houston)
We will have a couple things to watch for on Thursday. First and foremost, strong to severe thunderstorms may begin to break out across the area as early as the back half of the commute, after 8 AM or so. The atmosphere looks fairly primed to produce storms with strong winds, potentially some hail, and even a tornado or two around the region. This doesn’t look quite as foreboding as what we experienced almost a year ago back in January with the Pasadena tornado (which was an exceptional setup for severe weather here), but the parameters are definitely aligned for at least some severe weather.
More technically: There’s a pretty healthy amount of wind shear (wind changing direction with height) available tomorrow. You need wind shear for severe weather and tornado risk. But the window for that severe weather and tornado risk tomorrow looks conditional and narrow. In other words, we need the appropriate amount of instability to realize to generate thunderstorms. And on top of that, we need the storms to be able to tap into that shear and instability at low levels. This is not a slam dunk case for severe weather, but it’s enough to say that if storms can realize their full potential tomorrow there could be a couple tornadoes, especially north of I-10. We should have a better idea on this tomorrow and will have more for you before it gets messy out there.
In terms of rainfall, we are not expecting significant or widespread flooding. But street flooding is a decent possibility in a few spots tomorrow. Most areas will see a half inch to inch or so of rainfall, but a couple isolated spots will almost certainly see 2 to 3 inches of rain or even a bit more, much of which could fall quickly.
Total rainfall through Friday morning will probably average close to an inch in much of the metro area. Areas south and west may see less and north and east more, with isolated spots seeing 2 to 3 inches in a relatively short time. (Pivotal Weather)
All this should start to clear off to our east by late afternoon and evening, leaving us with clouds and a few showers. Temperatures and humidity will build up tomorrow, with highs near 70, and you’ll feel the dampness.
Friday
The forecast gets a bit trickier on Friday. The storms of Thursday will be well off to our east as a cold front slips into the region. However, it looks as if this front may stall near the coast or just offshore. This would keep us generally a bit cloudy and unsettled with shower chances, depending on exactly where it stalls. Temperatures will be mainly in the 60s, with 70s will be possible near the coast on Friday. The exact placement of the front will determine how warm it is on Friday.
Weekend into next week
That front may backpedal onshore Saturday, bringing more clouds and showers. Morning lows will range from the 50s inland to 60s near or south of the front. By Sunday, the stalled front should be escorted out into the Gulf by a second cold front which will usher in cooler, drier air and hopefully some sunshine for early next week. Admittedly, I’m skeptical about much clearing right now but we’re still several days out.
Texans tailgating looks okay right now, with temperatures probably in the 50s to low-60s most of the morning, warming into the mid-60s or so for the afternoon. I’m not going to completely rule out a shower, but I would lean toward drier weather at the moment.
Temperatures will drop off some next week, especially in the morning before we warm back up again toward next weekend. (Weather Bell)
Temperatures will drop to the 60s for highs, 40s for lows early next week, and another warming trend may impact us next weekend.
On a chilly morning like this, it is not difficult to imagine that winter will begin soon. But could spend this entire post discussing when winter begins. Is it Dec. 1? Is it the winter solstice, Dec. 21 this year? Is it the region’s first freeze? For the sake of simplicity, since this is a weather website, we’re going to use “meteorological winter,” which encompasses the months of December, January, and February. That works well for Houston because that is, invariably, when the region’s coldest weather visits us.
The big driver for our weather this winter will be a robust El Niño in the equatorial Pacific Ocean. This warming of the equatorial Pacific Ocean will almost certainly persist throughout winter. When El Niño is present during the winter months, it generally has a pronounced effect on the Pacific jet stream. Instead of being variable in its track, often entering North America near the state of Washington and southern British Columbia, it more consistently tracks into California and Mexico’s Baja peninsula. This brings a more southerly storm track, including over Texas.
This should make for a fairly straightforward forecast for Texas, including the Houston area, during the winter time months. There is, however, one risk that I’ll discuss below. But first, the outlook. According to NOAA (and historical trends during El Niño), we can expect near-normal temperatures this winter in Texas.
Winter outlook for temperatures. (NOAA)
Additionally, given the more southerly storm track, we can expect more precipitation this winter. Note I said precipitation, as during the winter months we can see rain as well as the potential for sleet, snow, and even freezing rain. In any case, since the atmosphere overhead is likely to be more disturbed, this should make for a fairly wet winter. That should help take care of our lingering drought, especially along the Sabine River area.
Winter outlook for precipitation. (NOAA)
So that’s what we can expect during a typical El Niño winter. But there is a wild card at play, and that is the lingering effect of very warm temperatures this year (driven largely, but not exclusively, by climate change). As long-time readers will know, the interaction between land and sea temperatures is a crucial part of weather forecasting, and the sea surface temperatures are out of whack right now.
A non-nominal El Niño
Here’s what I mean by that. The map below shows the sea surface temperature anomaly this fall. Clearly we can see the warmth in the equatorial Pacific Ocean due to El Niño. But much of the northern Pacific and Atlantic Oceans are also very warm, which is not normal leading into an El Niño winter.
Sea surface temperature anomaly map for fall, 2023. (NOAA)
Now let’s compare that to what sea surface temperature anomalies were like during the last four strong El Niño events, 1982-83, 1997-98, 2009-10, 2015-16, during the period of November to March. This is what sea surface temperatures have looked like during the last four winters, so it is basically what we should expect to happen this winter if all else were equal.
Sea surface temperature anomaly during the last four strong El Niño winters. (NOAA)
But all else is not equal. I realize we’re doing a bit of comparing apples to oranges here, but the basic takeaway should be clear: Northern Hemisphere sea surface temperatures heading into this winter look almost nothing like they would during a typical El Niño winter—they’re much warmer. Therefore I would rate this winter forecast as low-confidence, with a high amount of risk.
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