Matt Lanza

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!

In brief: There have been few changes to the overall forecast today, with higher resolution modeling now coming into range on this storm and essentially validating most of what we’ve seen to this point. A legitimate, rare winter storm, with primarily snow and sleet is likely to impact most of the Houston area tomorrow night and Tuesday, causing significant travel disruption through at least Wednesday morning.

What’s new?

A few minor notes this afternoon, none of which are significant changes in thinking from this morning.

First off, the NWS has upgraded us to a Winter Storm Warning and increased their snow total forecasts for the Houston area.

They have also increased the “realistic worst case scenario” snow forecast.

Why has this happened? Well for one, modeling has continued to lock in colder with this storm, showing a sharp transition overnight Monday into Tuesday morning from plain rain, freezing rain, and a mix of sleet and snow to just sleet and probably mostly snow across the region. Secondly, high resolution weather models that only run about 48 to 60 hours out in time are now in range of the storm, confirming both that precipitation-type outcome and the potential for “banding” that will exacerbate local snowfall totals.

Again, we have to note: The snow will not fall perfectly uniformly across the region. Depending on where this “banding” sets up, that will determine places that are at risk for 6 inches or more of snow. Quite frankly, that could be anywhere in our area; we simply don’t know at this time. Recent model runs have favored the Houston through Liberty County areas, as well as Brazoria County through Beaumont areas, but that could easily change. I’d say we’ll know more tomorrow, but realistically, we may not know it until it starts.

Again, just to underscore: As long as the forecast stays on track, travel is going to be nearly impossible Monday after midnight and all day Tuesday. You will almost certainly be stuck where you are until at least later Wednesday morning. The exception to this may be the far north now (like north of Highway 105), where snow may end up lighter, no ice occurs, and roads may clear off a bit after the snow stops Tuesday afternoon. But even that may be optimistic. More to come on this.

Historical context

Realistically, this is the most significant snow threat to the region since Christmas Eve 2004. The 1895 storm stands alone as the greatest on record in Texas and Louisiana, and this storm will not dethrone that one. However, with that in mind, this has the potential to set a modern official snowfall record in Houston, which currently sits at a mere 3 inches back in February 1960. January 1940 also sits at 3 inches. While a few storms since then, including Christmas Eve 2004 have produced higher amounts in parts of the area, from a record-keeping perspective, we have a chance to make some noise.

Could it be a blizzard?

This morning I noted how wind gusts of 40 to 50 mph were possible on Galveston Island Tuesday morning with this storm. That obviously begs the question of whether or not this could end up meeting blizzard criteria. That will be hard. The technical requirements are:

1.) Sustained wind or frequent gusts to 35 mph or higher. (This will be close)
2.) Heavy snowfall or blowing snow that reduces visibility under a quarter mile. (This will be tough)
3.) Three consecutive hours of these conditions. (This will be very tough)

I’m not saying it can’t happen, but given how rigorous these requirements are, I have doubts that we’ll officially get there. But at least now you know what an official blizzard is. That said, we almost certainly will see blizzard-like conditions on the island if those winds come to fruition and a full changeover from sleet to snow occurs.

Whatever the case, we are into some seriously rare winter weather for Houston in what may end up being a generational winter storm. We will have the latest for you in the morning with revised model data at our fingertips.