Eric Berger

We’ve been talking for several days about the collision of a cold air mass, in the form of a strong front, colliding with southerly moisture near Houston this weekend. The question for some time has been how far south the coldest air will get, and therefore where the line between rain, sleet, and snow will fall. As of late Sunday morning, we think that line will be further south than anticipated, possibly all the way down to Interstate 10. We will soon find out for sure—the best chances for a wintry mix will come this afternoon and evening.

As of 11am, precipitation is now moving into much of the Houston area. Already, rain has turned to snow in College Station, and a few locations in Montgomery County have reported sleet. As a quick reminder, the entire atmospheric column needs to remain at freezing temperatures to form snow, otherwise you can end up with sleet or even freezing rain.

As we get deeper into Sunday and Sunday evening with this storm, we wanted to share some key messages we think it’s important to share. For this, it’s important to know whether you live in an area with a “Winter Storm Warning,” a “Winter Weather Advisory,” or no warnings at all. Most all of Houston is not under a warning, but that doesn’t mean we won’t see any effects.

• Areas under a “Winter Storm Warning” face the greatest risk. And although there remain large amounts of uncertainty, it seems likely that much of the region shown in pink, above, will see 2 to 5 inches of snow. This is enough snow to cause significant problems in terms of driving, so travel to these areas later Sunday through Monday morning is not advised.
• Areas facing a “Winter Weather Advisory” likely will receive less than 2 inches of snow, and perhaps also some sleet. This is still enough of a wintry mix to cause problems on roadways, but because temperatures this afternoon should remain above freezing at the surface some travel today is OK. However, as temperatures fall to or near freezing tonight, travel may become problematic.
• For all other areas, surface temperatures should remain above freezing on Sunday and Sunday night as precipitation comes down. Therefore, while you may see some flakes in the air, or sleet, as far south as Interstate 10, it is unlikely to accumulate. The real question, of course, is, Is it going to snow at your house? For nearly all of Houston there’s a non-zero chance, but if you’re along or south of Interstate 10 the chance is still quite low. We will update later today if this changes.

This mess will come to an end tonight, as drier air filters into the region from the west. Generally, precipitation should taper off from west to east from about 10pm to 2am, or thereabouts. Monday will be a very cold day, with mostly cloudy skies and highs in the 40s for most of Houston.

After Wednesday evening’s line of storms, the Houston region will see several days of placid weather before another front arrives later on Sunday. This will bring with it a stronger shot of colder air and, for areas just north of Houston, the potential for snow. Cold weather will prevail throughout the period.

Thursday

Temperatures have dropped into the 40s across much of the area this morning, and in concert with northwesterly winds it feels brisk outside. Winds should slacken this afternoon, but even with mostly sunny skies our high temperatures are unlikely to climb above the mid- to upper-50s. Lows tonight will drop down to around 40 in the city of Houston with partly cloudy skies and light northerly winds.

Friday

This will be another mostly sunny and cold day, as northerly winds continue to bring dry air into the region. Expect highs generally in the mid-50s, and with clear skies overnight temperatures may be a few degrees cooler on Friday night than Thursday night.

Saturday

This will be our third chilly, sunny day in a row with highs again in the 50s. As winds shift to come from the east clouds may begin to build during the afternoon or overnight hours, but lows should still get down to around 40 in Houston overnight.

Sunday and Sunday night

An approaching front will combine with surface low pressure over the northwestern Gulf of Mexico to produce healthy rain chances on Sunday and Sunday night. We can be pretty confident this will be a cold and gray day, during which highs will struggle to climb above 50 degrees. Rain chances will increase as the day goes on. For now, it appears as though the greater rain accumulations will remain to the south of Houston, where totals could be on the order of 1-2 inches. However, north of a line from Wharton to Alvin to League City will probably see less, perhaps 0.5 to 1 inch of rain with this front. We’ll have to iron out those details in future forecasts.

We think things will be warm enough in Houston to keep this precipitation rain throughout the day and overnight hours, but there will be a dividing line—perhaps somewhere in Montgomery County?—where this precipitation turns into snow or sleet on Sunday evening. Matt will provide an update on the region’s snow chances with a post later today.

Next week

Our region will be cold and sunny next week in the wake of the front, with highs generally in the 50s and lows in the 30s. The urban core of Houston may remain above freezing, but there will almost certainly be freezing temperatures in the vicinity of the city, if not the entire metro area itself.

Virtual Houston Marathon

Due to the pandemic, the Houston Marathon is a virtual event this year. So instead of being run as a single event on January 17, participants can run their half and full marathons on any day between Friday, January 8 and Sunday, January 17. If you have some flexibility in your schedule, you will have options for weather. (My ideal conditions are temperatures in the 40s, clouds, and light winds, but we’re all different!) Both this Saturday and Sunday look chilly, and if you complete your run before noon on Sunday you should miss the rain. The absolute coldest temperatures in the week ahead should come on Tuesday morning, January 12, when I expect a freeze for most of Houston.

Then we’ll see a slight warming trend through Friday, with mostly sunny skies throughout. Next weekend looks a bit warmer, but basically every morning during the virtual marathon period is likely to see lows in the 30s or 40s for Houston. If you prefer warmer weather, then the coming Friday, Saturday, or Sunday afternoons—January 15-17—may be your best bet as highs get into the upper 60s, perhaps. Rain chances seem fairly low throughout the running period, aside from the Sunday, January 10th mess described in the forecast above.

Houston will see a front bull through the area this afternoon and evening, and this could briefly bring strong showers and thunderstorms into the region. The front will move from west to east, clearing quickly. We’ll then see calm and cool weather until another front arrives Sunday. This second front will bring near freezing conditions to the metro area and a slight chance of snow north and west of the city.

Wednesday

Lows across much of Houston have only fallen to around 60 degrees, with a southeasterly wind providing a moderating flow of air. Skies are cloudy, and will remain so throughout the day due to elevated moisture levels in the atmosphere. Highs will get into the low 70s for most. We may see some scattered showers during the daytime hours, but the big event—the front—will come later. In terms of timing, I expect it to reach a line from Katy to Conroe between 3 and 6 pm today, central Houston an hour later, and to be off the coast between 6 and 9 pm tonight. The main threats are brief, heavy rainfall, and strong wind gusts. There is a very slight chance of an isolated tornado. Total rainfall amounts will likely average 1 to 1.5 inches north of interstate 10, and 0.5 to 1 inch closer to the coast.

Thursday and Friday

Thursday morning will see gusty winds, perhaps as high as 30 mph, as colder and drier air moves into the region. However, winds should subside somewhat during the afternoon hours. Expect mostly sunny skies and temperatures in the mid- to upper-50s on Thursday and Friday, with lows dropping to around 40 degrees in the city—colder north, and warmer near the coast.

Saturday

This should be another winter-like day for Houston, with highs in the 50s and a chilly night down around 40, with mostly sunny skies.

Sunday and beyond

The forecast for our second front this week remains uncertain. However, at this point we can probably pencil in cold, gray, and wet conditions for the second half of the weekend. This front could bring an additional 0.5 to 1 inch of rain to the Houston area on Sunday, but that is not set in stone. Nor can we entirely rule out the possibility of snow or sleet. However, right now it appears the track of air cold enough to allow for wintry precipitation will pass just north of Houston. Bottom line, we’re going to have to watch and see how the forecast evolves.

Anyway, Sunday will be chilly, with highs perhaps in the 50s, depending on the timing of the front. After it passes, much of next week looks cold and sunny, with highs in the 50s, and lows in the 30s and 40s.

Good morning. After several days of calm weather and sunshine, Houston’s forecast will soon turn a bit more dynamic for the rest of the week. We could see some storms with a frontal passage on Wednesday, and then more inclement weather with a front coming this weekend. With the latter front we think there is even a slight chance of wintry precipitation, including possibly snow, which we’ll discuss below.

Tuesday

This morning we have some fog issues for coastal areas, but this should clear up pretty quickly. Highs will reach about 70 degrees later today under mostly sunny skies. As winds come from the southeast later today, tonight will be the warmest one of the year so far, and probably for at least the next week. Lows probably will only drop into the mid-50s for much of the region.

Wednesday

We still have some questions about the timing and speed of the front, but the most likely time for its passage is around sunset in Houston, and a little bit later along the coast. Daytime temperatures therefore should reach about 70 degrees, with mostly cloudy skies and scattered showers. A line of storms is expected to move along with the front, and how fast the front moves will determine rainfall amounts. We probably will see accumulations of about 1 inch or so north of Interstate 10, and approximately 0.5 to 1 inch closer to the coast. Rains will end quickly with the front’s passage, as cooler and drier air moves in during the evening and overnight hours.

Thursday and Friday

The end of the week will be sunny and cool, with highs of around 60 degrees and lows near 40 in the city of Houston—cooler inland and warmer along the coast.

Saturday

The first half of the weekend should be similarly pleasant, with highs of around 60 degrees and partly to mostly sunny skies.

Sunday and beyond

The next front looks set to arrive on Sunday. The details are sketchy, but there is at least the potential for some wintry precipitation. As the front pushes into Houston there will be plenty of moisture along with a southerly storm track, and enough lift to generate precipitation. (Rain accumulations with the front probably will be on the order of 0.5 to 1 inch). The question is whether there will be enough really cold air in the atmosphere for freezing conditions almost all the way to the surface. That’s more likely the further north along Interstates 45 and 69 one goes. Right now I’d estimate that snow chances are decent for places like Huntsville and Livingston. However, we’re probably still at 20 percent, or less, for the city of Houston itself. But it will be something to watch.

Temperatures should be cold in the wake of Sunday’s front, with daytime highs generally in the 50s, and nighttime lows in the 30s and 40s to start next week.