After a rainy Friday morning, we get a lovely weekend before storms possibly return on Monday

It’s been a busy morning with a line of heavy rain and thunderstorms moving through. We even had a tornado warning in Brazoria County earlier from this vigorous little storm. As of just about 7 AM, the heaviest rain is east of I-45, with Galveston and Chambers Counties in line for the worst over the next hour or so.

Very heavy rain and gusty winds will continue east across Galveston, Chambers, and eastern Harris Counties toward the Golden Triangle this morning. (RadarScope)

In addition to the rain, gusty winds of 40 to 45 mph are possible, especially in Galveston and Trinity Bays and near the coast. All of this will progress eastward toward Beaumont and Port Arthur through mid-morning with heavy rain and strong winds, as well as some embedded thunder. Most areas will finish with 1 to 1.5 inches of rain when all is said and done, with isolated higher and lower amounts.

Rest of today

Once this line of rain and storms exits to our east, we’ll be left with a few hours of showers or lighter rain and clouds this morning. By afternoon, we could see some clearing begin to push in from the west, so some sunshine may pop out, especially south and west of Houston before the end of today. Otherwise, look for highs in the 50s with a slight northwest breeze.

Weekend

This weekend looks splendid for the most part. There could be areas of fog overnight into Saturday morning, but I would expect those to clear out rather fast on Saturday morning. Otherwise, expect sunshine both Saturday and Sunday, with nothing more than the high clouds we’ve seen at times over the last month or so, especially south of Houston.

Sunday morning lows will probably be in the 30s in outlying areas, though a freeze seems unlikely (Pivotal Weather)

Both mornings should see lows near 40 or so in Houston proper and some upper-30s in the suburbs. Daytime highs will be near 60 on Saturday and probably the same on Sunday.

Monday

Next week is going to begin on an active note. From Sunday night into Monday, southerly winds will surge humidity in off the Gulf. At the same time, a storm system will kick start off the Rockies and move into the Plains, dragging arguably the strongest cold front of this winter across Texas. So what does it mean? A number of things.

First off, we’re likely to see winds pick up off the Gulf Monday, with gusts of 20 to 30 mph or even a bit stronger at times. We’ll all notice this.

It’s still too soon to really get into the finer details of things yet, but we are expecting scattered thunderstorms on Monday, and any of those storms could be on the stronger side. Right now it appears that gusty winds may be the biggest concern with any storms, but we’ll look at this closer through the weekend and report back with an update.

The Storm Prediction Center has the Houston area outlooked for Monday for a chance of severe weather. Not everyone will see severe storms, but a few places do have a chance for some rough weather Monday. (Pivotal Weather)

The Storm Prediction Center has us outlined for a slight (level 2 of 5) risk of severe storms right now. We’ll monitor this through the weekend.

Temperatures on Monday are also going to surge warmer, with highs likely in the 70s in the afternoon. Everyone should see a bit of rain but totals will vary widely depending on how storms setup. Again, we’ll fine tune this ahead of Monday.

For anyone heading to or visiting for the college football national championship, it’s entirely possible that you could head into NRG Stadium with temps in the 70s and leave with temps in the 40s or low-50s, so just be aware of that.

Rest of next week

On Monday evening, a cold front will sweep through the area, likely ushering in strong offshore winds and much colder weather. Wind gusts of 30 to 40 mph or even stronger will be possible Monday night and Tuesday behind the front. Much colder air will plunge in with lows in the 40s Tuesday morning and highs only in the low-50s. This might be the coldest air mass of the winter so far, and the coldest morning will be on Wednesday, with morning lows in the 30s everywhere and a light freeze possible in the suburbs.

A cold night is on tap Tuesday night into Wednesday morning with lows likely in the 30s just about everywhere and a freeze possible, if not likely in outlying areas. (Pivotal Weather)

After that, we warm back up again with temps near 60 on Wednesday and back to near 70 or so by Thursday.

Houston Marathon

Many of you are curious about the Houston Marathon. The good news is that right now the timing of systems looks good for a cooler run. The question becomes “how cool?” We should see another system bring a front into the area probably some time on Friday, leading to a cooler, breezier Saturday. As of now, I would expect race start temperatures on Sunday to be in the 40s with hopefully light winds. We would probably warm up into the upper-40s or low-50s by the end of the run. More to come!

What’s going on with the polar vortex, and is an Arctic outbreak on the way for Texas?

Earlier this morning, over on our companion site The Eyewall, Matt wrote about a series of winter storms that are going to affect the United States. Part of the post dealt with a topic that a lot of readers have been asking about, the stability of the polar vortex, and whether that means an outbreak of arctic air is likely to reach Texas later this month. The short answer is that yes, the second half of January does look colder. But how cold? That’s a forecast that’s impossible to make as of yet. Here’s Matt with the details.

There has been a lot of speculation on social media about the polar vortex coming later this month. The reasoning is attributed to a sudden stratospheric warming event (SSW) that displaces the polar vortex from the Pole and dumps cold air into the mid-latitudes where most people live. It sounds pretty terrible, unless of course you love cold. So what’s the deal, really?

Every winter, the polar vortex strengthens over the North Pole. It basically houses the coldest air in the Northern Hemisphere. It’s never perfectly still, but it’s usually confined to the North Pole. Every so often, the polar vortex can be disrupted, allowing cold to leak out of the polar region and toward the mid-latitudes, where most people live.

An example of a stable polar vortex that is typically seen in winter (left) and a disrupted polar vortex (right), which happens from time to time during winter. (NOAA/UCAR)

The image above lays out, broadly how this happens. For example, this winter has been a mild one for most of the U.S. so far, and it’s not a shock that the polar vortex has been fairly strong.

One of the pathways to displace or split the polar vortex is by what we call a sudden stratospheric warming. What is that, and why does it matter? When we talk about the “polar vortex,” most meteorologists are actually referring to the stratospheric polar vortex. We’re looking about 10 miles and higher up in the atmosphere. That’s the actual polar vortex. When you think of the polar vortex, you’re likely thinking of blobs of intense cold that periodically drop into the U.S. during winter. So, they’re two fundamentally different things. Related, but different.

During some winters, there will be a disruption of the stability in the stratosphere that happens via a sudden warming event, where the strong westerly winds locking the polar vortex over the Pole can weaken or even reverse. When that happens it can release some of that cold from the polar region into the mid-latitudes, impacting the U.S. or Europe or Asia.

Stratospheric warming is ongoing, which may be enough to qualify as a lower-end sudden stratospheric warming event. (NOAA)

But that’s not a guarantee. No two SSWs are identical, and not every SSW will lead to a “release the hounds” cold air outbreak over the U.S. (or Europe or Asia). There’s a lot that we don’t completely understand about these events and what causes one to produce big cold or another to do little to nothing. But the bottom line here is that this year we are seeing a minor SSW event ongoing. This will do some work on the polar vortex, and it should allow for a relatively wavier jet stream heading into later January. That does not mean a repeat of the February 2021 or December 2022 cold events in Texas, but it could mean some pushes of stronger cold than we’ve seen so far this winter.

One hurdle right now is that snowfall across North America is running a good bit below normal.

Snowfall across North America is struggling mightily this year. (Rutgers University)

Snow cover is below average in the West, Canada, the Midwest, and Plains. Cold air modifies and moderates as it comes south, and when it travels over less snowy ground, it can moderate faster. This can change in the coming weeks, but will it happen in the Plains? That’s TBD.

The takeaway from all this is that a SSW event does *not* guarantee strong cold air. There are complicating factors involved that can prevent strong cold from materializing. However, an SSW event does tend to weaken the polar vortex and increase the odds that colder air could emerge from the polar regions at times in a few weeks. That does not necessarily mean a repeat of February 2021 (Uri). These types of situations occur several times a decade and most do not produce historic cold air like we saw in that event. But they can produce some of the coldest air of a given winter. So our advice: Sell the hype. But don’t be surprised if the forecast later this month turns a bit colder than we’ve seen so far this winter.

Friday looks soggy, but after that a glorious winter weekend awaits

Good morning. Temperatures have dropped into the upper 30s to lower 40s across most of the Houston metro area this morning, and this is the coldest we’re going to get until the middle of next week. We’re still looking at the likelihood of widespread showers on Friday before a mostly sunny and cool winter weekend.

Thursday

After the cool start, temperatures today should reach about 60 degrees under mostly sunny skies. Winds will continue from the east, and we may start to see some gusts this afternoon of 20 or even 25 mph. Clouds will start to build in this evening, but I think rain chances will hold off at least until midnight, and probably more likely until the hours just before sunset on Friday. Look for lows tonight to drop down to around 50 degrees in Houston.

NOAA rain accumulation forecast for now through Friday night. (Weather Bell)

Friday

A low pressure system will bring widespread rain chances on Friday, particularly during the morning hours. There’s no indication in the atmosphere or forecast models for anything extreme, both in terms of rain accumulations or severe thunderstorms. Most of the area probably will pick up between 0.5 and 1.5 inches, with the greater totals more likely south of Interstate 10, closer to the coast. In terms of timing, the showers should generally move in from the west and exit to the east of Houston by around noon, give or take a couple of hours. We should see some partially clearing skies by later Friday afternoon, with highs in the low- to mid-60s.

Saturday and Sunday

The weekend should see partly to mostly sunny skies, with dry air, and daytime highs generally in the low 60s. Friday and Saturday nights should be cool, but by Sunday evening we’ll see a resurgent onshore flow that will start to pump up atmospheric moisture levels and humidity. This will set the stage for another round of showers on Monday.

Monday and Tuesday

Monday could be a bit dynamic as a strong cold front approaches the area. This will bring showers, and potentially some strong thunderstorms during the daytime. We’ll try to have some better details on this for you in tomorrow’s update. The front will then bring some very strong northerly winds with it, with gusts up to 35 or 40 mph in Houston, and the potential for even stronger winds closer to the coast. These winds are likely to peak on Monday night and Tuesday morning, so that’s something to be aware of if you’re going to be out and about. This may be an issue for any tailgating associated with Monday evening’s College Football Playoff National Championship at NRG Stadium, depending on the timing of the front.

European model forecast for maximum wind gusts on Monday night and Tuesday morning. (Weather Bell)

Tuesday should be sharply colder, with highs only in the 50s to go along with the strong winds. Lows on Tuesday night will probably drop at least into the upper 30s for Houston, with a light freeze possible for areas further inland—we’ll see.

Rest of next week

We’ll likely warm back up by Wednesday or Thursday before another front brings things back down for the weekend. My sense is that startline temperatures for the Houston Marathon on Sunday morning will be in the vicinity of 40 degrees, but there’s still a lot of time to go before that forecast is set in stone.

Round one of the rain moves through, more coming later this week

We start this morning with a quick celestial note: Earth reached perihelion at 6:38 pm CT on Tuesday night, meaning it reached the closest point to the Sun in its (slightly) elliptical orbit about our star. Ironically for northern hemisphere residents, though we are closer to the Sun during the winter by a few million miles, it is coldest time of the year. This is due, of course, to the tilt of the planet’s axis rather than proximity to the Sun. We’ll reach our furthest point from the Sun, aphelion, just after midnight on July 5 of this year.

Earth’s orbit is slightly elliptical. (NASA)

Speaking of weather, rain showers on Tuesday evening and this morning overperformed a little, dropping 1 to 2 inches across most areas south of Interstate 10, with lesser amounts inland. We’ll now see a couple of drier days before rain showers return on Thursday night and Friday. All of this is working toward a gorgeous, winter-like weekend.

Wednesday

Skies will be mostly cloudy today, with highs pushing perhaps into the mid-50s. After some gusty conditions overnight as a coastal low pressure system passed by, winds will be lighter today, generally from the north, at 5 to 10 mph. Lows tonight will be fairly chilly, dropping into the low 40s in Houston, with cooler conditions further inland.

Thursday

This will be a mostly sunny day, probably, with highs in the upper 50s. Winds will be light, generally from the northeast. Another coastal low will be building offshore, but I think its associated rain showers will remain away from the Houston area during the daytime and evening hours. Lows on Thursday night will drop to around 50 degrees, with some light rain possible after midnight.

NOAA rain accumulation forecast for Friday. (Weather Bell)

Friday

This looks to be a wet day, with most of the area picking up between 0.5 and 2.0 inches of rain between early Friday morning and the evening hours. Rain accumulations should be greatest closer to the coast, and the low pressure system. I think the worst of the weather, including stronger thunderstorms, will remain offshore. So I expect this to be a mostly mellow rain event, but it will definitely put a damper on any outdoor plans you have. Look for highs in the upper 50s, and lows Friday night dropping into the low to mid-40s.

Saturday and Sunday

The weekend looks fine and mostly sunny. Highs on Saturday will be around 60 degrees, with overnight lows in the mid-40s, and then a bit warmer on Sunday, in the low 60s. It should be a great winter weekend for outdoor activities. Enjoy!

Next week

A chance of rain showers returns on Monday before a stronger front moves through. This will set the stage for colder mid-week weather, with the temperature likely bottoming out on Wednesday morning. A light freeze looks possible for inland areas, but we’ll have to see as we get closer. Temperatures then warm up again before another front likely cools us down for next weekend. If you’re weather watching for the Houston marathon on January 14, the forecast still looks chilly and dry, but the details remain fuzzy. Nevertheless I’m cautiously optimistic about running conditions!