Matt Lanza

In brief: The National Hurricane Center released their post-storm report on Hurricane Beryl late last week, bumping its landfall intensity in Texas from 80 mph to 90 mph. The report also features a number of nuggets of information, statistics, and images. This post summarizes some of the highlights.

Hard to believe it’s been over 6 months now since Hurricane Beryl thrashed the Houston area. As is customary, the National Hurricane Center released their post-storm analysis on Beryl late last week, and there were some notable changes to the storm’s history. It is important to be clear that this is a common thing. When the storm is hitting, forecasters are consuming so much data and issuing constant updates that they don’t always have a chance to lock down all the finer details of the storm. In the postseason, there is the the luxury of being able to scrutinize all available data to make an objective determination of a storm’s data points. National Hurricane Center forecasters do this with every storm.

Beryl was a strong category 1 storm

While Hurricane Beryl was presumed to have a landfall intensity of 80 mph when it came ashore in Texas, the postseason review determined that this was too low. Beryl got an upgrade to a strong category 1 storm, with 90 mph maximum sustained winds at landfall. This is interesting, and it makes the comparisons to Ike somewhat more relevant in a data sense.

Ike came ashore as a weakening category 2 storm with 110 mph maximum sustained winds. Beryl came ashore as a strengthening category 1 storm, having rapidly intensified from a 60 mph tropical storm to a 90 mph hurricane in about 14 hours. While that’s still 20 mph of difference in maximum sustained wind, the fact that the two storms were trending in opposite directions, and all else the same, the weaker side of Ike wasn’t that much stronger than the “dirty” side of Beryl, which Houston experienced. This makes the similarities between the storms in terms of widespread tree damage and power outages more comprehensible in retrospect.

Also worth noting, Beryl peaked in the Caribbean as a category 5 storm with ~165 mph maximum sustained winds, confirming the intensity reported in the advisories. The report stated that “the maximum intensity of Beryl is somewhat uncertain due to temporal gaps in the aircraft data near the time of peak intensity, and issues with (microwave) surface wind estimates that prevented their use in this evaluation.” In other words, some of the data was unusable, and the timing of the reconnaissance flight into Beryl may have differed from the exact time of peak intensity. Whatever the case, 165 mph is dang strong.

Beryl didn’t weaken immediately at landfall

One reason Beryl came in stronger than the typical category 1 storm is that the storm likely continued to strengthen just beyond landfall. Where the storm came ashore is not exactly terra firma. Given the geography around Matagorda Bay, the technical landfall may have occurred before the storm truly got on land. The NHC determined this by noting that the minimum pressures recorded near the Texas coast occurred after landfall, indicating that the storm had passed but pressures were still lowering instead of rising as is typically the case. Basically, much like a large ship trying to make a 180° turn, Beryl needed a moment before it could tap the brakes.

No surprises with rain or storm surge

Generally speaking, Beryl produced a surge height of 5 to 7 feet above ground level between Matagorda and Freeport. Much of this is based on high water mark assessments by teams following the storm. Surge values decreased to about 4 to 6 feet above ground level between Freeport and Galveston. Maximum rainfall was around 15 inches in Thompsons in Fort Bend County. That was an exception, as most locations generally saw 8 to 12 inches of rain.

The forecast was excellent—except here

The NHC track forecast beat their average errors at almost all lead times on average through Beryl. A notable exception? When Beryl was in the western Caribbean and the majority of model guidance favored a Mexico landfall. From the report: “The largest track forecast errors occurred during the time that Beryl was moving through the western Caribbean when the forecasts for landfall on the western Gulf coast had a strong left or southward bias. Indeed, the Texas landfall position in the best track is at the right/northward edge of the official forecasts, and the forecast landfall points shifted significantly to the north as the storm approached the coast.” They go on to state that the TABM model (which basically just assumes a medium intensity storm) did best, whereas the ECMWF (Euro) and GFS (American) models failed. The reasons for the failure are not clear at this time.

A glaring caveat to all this? They do not include the ICON or European AI model in track errors, which in my subjective view did best capturing the risks to Houston. One major change we implemented at Space City Weather was to give those models much more weight after Beryl, and they continued to perform well last season. Google’s AI GraphCast also did a very good job identifying the northward risks early on.

Beryl remains a warning to Houston

We’ve said this countless times in the wake of Beryl and since: It was a warning to this region. Beryl had 14 hours of favorable conditions over water to strengthen and went from a tropical storm to nearly a category 2 hurricane. What if it had 24 hours, and started from a 70 mph tropical storm? 36 hours? We’ve seen this play out in Florida, Louisiana, and the Coastal Bend several times since 2017 with storms in the Gulf of Mexico. Harvey, Michael, Ida, Ian, Idalia, Helene, Milton to name some others. It really is a matter of when, not if. We need to continue to focus on ensuring we’re prepared every year with our hurricane kits, getting more people to adopt that practice, and continuing to invest in resiliency and infrastructure improvements, which is to say: Build the damn Ike Dike.

In brief: Houston is emerging from the cold now with highs again in the 50s today and then 60s tomorrow and Sunday. Rain chances return Saturday night and Sunday. Locally heavy rain is likely on Sunday in parts of the area that could lead to some isolated street flooding. A much milder week is on tap next week, along with another chance of rain and storms later in the week.

After 4 straight mornings with lows in the 20s, Houston officially failed to drop below 30 this morning as we continue to thaw out. Still, keep an eye out for patchy black ice on area roads this morning. This weekend will feel and look more spring-like, however as rain returns to the forecast on Sunday, including some locally heavy rain.

Today

Yesterday was a chilly but nice day. Today will essentially be a carbon copy. Expect sunshine and highs well into the 50s.

Saturday

Onshore flow returns tomorrow, which means temperatures will get a boost into the 60s after morning lows in the mid to upper-30s. Look for sunshine to fade behind increasing clouds, a sign of things to come on Sunday.

Sunday & Monday

Scattered showers should begin to break out across the region around midnight or so Saturday night into Sunday morning. Look for coverage and intensity of showers to pick up after sunrise with the focus of the heavier downpours drifting from northwest to southeast. We wouldn’t be shocked to see a few places get multiple rounds of rain and thunderstorms on Sunday morning and afternoon.

With the amount of atmospheric moisture well above average (almost 200 percent of normal) on Sunday, there will almost certainly be enough heavy rain in spots to produce localized street flooding. If you have plans on Sunday, just keep that in mind. A cool front will nudge offshore Monday, likely ending the rain chances by mid to late morning.

Sunday morning lows will not drop below 50 degrees. Then, we’ll see a range of temperatures Sunday afternoon, with highs near 60 or so in Huntsville to near 70 in Lake Jackson. Mid to upper-60s should dominate in the city. Monday’s front has minimal “oomph” behind it, so look for temperatures to only be a few degrees cooler Monday.

Look for rain totals to average a half-inch to an inch on Sunday and Monday, but it’s likely that some more localized spots see 2 to 4 inches of rain. This seems especially possible from northern Harris into Montgomery, Liberty, and Polk Counties, but it can’t be entirely ruled out elsewhere.

Rest of next week

I am assuming next week is going to feature a lot of continued clouds, so soak up the sun while we have it around. Isolated showers are possible Tuesday and Wednesday. There is growing consensus in modeling that a somewhat stronger cold front is going to push through later next week. This seems likely to feature another round or two of rain and thunder. The details are TBD, but it’s possible we double down on some heavy rain risk later next week. Stay tuned. Temps look mild next week, with highs in the 60s and lows in the 50s.

In brief: Sunshine and slightly warmer temperatures in Houston this afternoon will allow for substantial melting of snow in the area, but very cold temperatures tonight will allow for a refreeze to take place, likely creating very hazardous driving conditions, possibly worse than today. But melting will resume after mid-morning Wednesday, and a top tier Houston snow event will fade into the history books.

Well, you did it Houston! You have witnessed one of the largest snowstorms in our history. We will await official numbers and do a rundown for you on that tomorrow. As of 10 AM, Hobby Airport had recorded 3″ of snow, making it the third largest snow on record there (fourth if you count the unrecorded 1895 storm). Officially at Bush Airport, it would probably be a top 10 storm, but exactly where it falls I’m not sure. Here on the border of Houston and West U, I can state we got 4 inches. Eric down near League City saw about 2 inches.

From the map, you can see that there was clearly a band from about Bellaire through Liberty County to just north of Beaumont and another from Bolivar into Sabine Pass. Those tended to be the champions of the storm. Vidor near Beaumont saw 6 inches, Baytown about 5.5 inches, and El Lago over 4 inches. Lake Charles ended up just shy of 5 inches, the third biggest snow on record there. The Atchafalaya in Louisiana was particularly hard hit with Lafayette’s 8 inches their biggest snow since the great 1895 storm. Rayne, which set the Louisiana state record in the 1895 storm with 24 inches saw 10.5 inches this time. New Orleans only saw 4 inches officially, but it makes it the largest modern snowstorm there on record.

We’ll have a full photo roundup coming soon. In the meantime, get your fix and follow us on our Instagram page.

Alright, so what now?

First, the sun’s out. Enjoy the snow while we have it. The Houston sun angle will go to work on this. Expect to see a good bit of melting today, especially on the roads and solid surfaces. Snow will melt less aggressively on the grass, so you’ll likely still get some time to play tomorrow morning. The big melt starting this afternoon will cause us problems tonight. All that muck on the roads is going to refreeze. And that may occur as early as 7 or 8 PM. It’s possible that road conditions may be worse tonight than they have been today due to ice. So use extreme caution if you have to go out tonight. Especially as temps drop into the 20s area-wide.

How cold will it get? Admittedly, models have tended to overforecast cold in recent cold snaps. In other words, they’ve gone too cold relative to what we actually saw. This may be different, however. With fresh snow on the ground in much of the area, that gives a “power-up” to cold conditions. Basically, if you have little snowpack left after today, expect lows in the 20s. If you have your ground mostly covered still, expect teens. The lows will vary widely across the area. An extreme cold warning is in effect for the region, underscoring that this won’t be anywhere near normal for us. Implement your maximum cold weather protection plans for pipes, plants, pets, and people tonight.

Temperatures rebound to the 40s tomorrow afternoon, and that should melt most of the rest of the snow except in shaded areas. Thursday morning’s commute may still feature patchy ice, but it will be navigable. Just use caution. Look for our photo roundup a little later today and our regular update in the morning.

In brief: Houston’s forecast appears mostly on track, with a definite trend toward the heaviest snow and sleet emerging south and east of Houston by Tuesday morning. Accumulations may be as high as several inches under the most persistent bands, with a general coating to few inches elsewhere. Winds will gust near the coast Tuesday morning as well, and a very cold night still looks on tap tomorrow night.

Happening now

Well, our much advertised winter storm is underway across the Houston area. We’ve seen reports of sleet, graupel, rain, and snow across the region. We seem to be settling down into a tiered setup now with snow and sleet north and west, sleet and graupel in the lighter precipitation, and sleet and rain near the coast.

That area of snow and some sleet occurring north and west of Houston is going to gradually fill in and drop south and east through the night. As it does so, we’ll pick up some accumulating snow. As it gets closer to the coast and the potential for banding gets underway, that’s when we may see locally heavy snow anywhere from I-10 southward to the coast.

Forecast for the night

So before 3 AM, look for this potpourri of precipitation types. Again, plain rain should be expected in spots near the coast especially. This is not a surprise and was anticipated ahead of time. After 3 AM, there will be a transition to all sleet and snow and eventually just snow. There is a good chance we will wake up to snow falling tomorrow, although how much on the ground is an open question with a few possibilities. Snow should end from northwest to southeast after 9 AM tomorrow.

Why have we been kind of cagey on snow accumulation numbers?

Those that read us closely can tell we’re throwing out various accumulation numbers based on model data and National Weather Service forecasts but we’re not exactly confident. Now, the event is underway so we should be highly confident, right? Not right. The SREF is a short-range ensemble model, meaning it’s run multiple times with varying snapshots at the beginning to produce a more realistic spread in outcomes. Basically, we want to see how bad or not bad it can get. As of the 3 PM run this afternoon, this model showed snow totals ranging from nada to as much as 7 inches at Hobby Airport.

Now, Hobby Airport almost certainly won’t get 7 inches of snow. It probably won’t get 0.0 inches either. The average on this particular model is around 2 inches, which is reasonable, but there is such a spread in options here that it doesn’t necessarily inspire much confidence. The trouble with this event is that we’re dealing with a wintry mix at the start, we don’t know where banding will establish, we’re in a place that rarely sees weather like this so it’s far outside of the bounds of the climatology (normal) these models use, and we have the Gulf of Mexico in our backyard. All that to say, this stuff is hard. If you want snow, hope for the best. If you do not want snow, hope for the best. May the odds be ever in our favor.

Sleet versus graupel

Here’s a true story. Back in my on-air broadcast days in Utica, NY, I once was describing a day where we had a bunch of graupel fall in Upstate New York and explained what it was. Immediately after the news, I received a call from an older gentleman who told me he had a dictionary in front of him, couldn’t find the word, and proceeded to lambaste me for making up words. I can assure you that it is a real word. So what is it, and how does it differ from sleet?

We’ve gotten reports of sleet and pictures of basically tiny “balls” of ice across the area. When you look at the pictures, however, they look more like Dippin’ Dots than ice pellets (sleet). That’s a tell-tale sign of graupel. The differences? Sleet is straightforward: A snowflake falls, hits a layer of milder air above freezing, melts, and then refreezes in colder air below that, falling as quite literally an ice pellet. Graupel happens when you get water droplets that are still liquid below 32°, (or what is called “supercooled”). The supercooled water droplets collide with and freeze on a snow crystal, a process called riming (which is a homonym of “rhyming”). They basically fall to the ground as snow pellets. They tend to be whiter (hence Dippin’ Dots-like!), whereas sleet is clearer. Sleet melts in your hand, whereas graupel may fall apart or crumble in your hand.

What many of you may have reported as sleet tonight was actually graupel. This is a weird storm because we have a pretty intense layer of dry air from the surface up to about 5,000 feet and from about 12,000 feet up to 30,000 feet. The region of the atmosphere where snowflakes will grow is up above 15,000 feet, so we’re seeing a bit of chaos ongoing above our heads. As the night goes on, this dry air will erode as the atmosphere cools, leading to more regular snow.

Eric will have the latest for you in the morning. Stay safe, stay off the roads tonight, and we’ll see where we are tomorrow!