Eric Berger

In brief: In today’s post we discuss this morning’s chilly start, and our warming trend through Saturday. We also provide some clarity on the weekend forecast. And finally, our Dwight Silverman explains what the heck happened to the cities in the Space City Weather App.

Encyclopedia Brown and the Case of the Missing Cities

We love a mystery, except when it involves weird problems with the Space City Weather app. We do, however, love a mystery when it’s solved.

Users of the app noticed that, over the past couple of weeks, the list of cities available to choose in the left-hand tray would be decimated to just a few, but by the end of the day the full list would be restored.

Initially, we thought this had to do with a new version of the National Weather Service’s Application Programming Interface, or API, which is how we get the data that populates the current conditions and forecasts on the app’s home page.

Then we found the problem, and it was ours, not the NWS’, fault (sorry, y’all!).

It turns out the strange case of the vanishing cities was caused by a bug in the app that was triggered when the temperature values coming from NWS drop below a certain point—something we couldn’t easily test for when it the new version of the app was under development because the weather was warm (which it seems to be in Houston until at least November).

The app calculates Heat Index and Wind Chill differently (they show up in the same box in the conditions portion of the home screen). When temperatures dropped and the app switched over from the Heat Index to Wind Chill, it generated a value that the app didn’t understand. It then quit showing the cities where it was cold.

But as the day warmed up and the current temps rose to the Heat Index threshold, the correct values were generated and the cities reappeared. Which is why, during the day, we’d have more and more cities return to the picker.

Our developer Hussain Abbasi has fixed the bug and a new version is now available in the Android and Apple app stores.

Thanks to everyone who sent reports via the Feedback selection in the app’s Settings page. Also, we’ve been tracking the progress of the issue in the App Feedback category in our Discourse forum. If you’re having an app issue, always check there for possible enlightenment.

Tuesday

Much of our region outside the urban core of Houston, and away from the coast, has fallen into the 30s this morning. It is quite chilly, although for virtually everyone it remains above freezing. Already light winds have already shifted to come from the east, and will soon shift from the south. Thus we will begin a warming trend that will persist into the weekend before another front arrives.

With sunny skies, temperatures today will rise into the mid-60s for much of Houston. Humidity levels will remain relatively low, and temperatures tonight will drop to around 50 degrees in the city, with slightly cooler conditions for outlying areas.

Wednesday and Thursday

A weak front on Wednesday will slow down a full-on warming trend. Accordingly, Wednesday and Thursday should be pleasant days with mostly sunny skies and highs in the low- to mid-70s. Humidity will be reasonably low, and nights should be in the 50s. With partly to mostly sunny skies, these should be mild, very pleasant days.

Friday and Saturday

With a more robust onshore flow setting up later in the week, these should be partly sunny and warmer days, with highs generally in the upper 70s. As dewpoints push upward to about 60 degrees, it will feel modestly humid. Nighttime lows will probably only fall to around 60 degrees. Rain chances, as they are all week, will remain near zero. By later on Saturday or Saturday night we’ll be on the lookout for the arrival of a stronger front.

Sunday and next week

In the big picture, a large slug of very cold Arctic air is going to surge into the midwestern United States by Friday and Saturday this week. We are talking about lows in the vicinity of -15 to -20 degrees in places like Illinois and Iowa by Sunday morning. The thing we have been watching down here in Texas is how far this very cold air will reach, or whether it will largely be shunted away from us to the east.

I don’t have 100 percent confidence, but at this point I think we are at least going to see a glancing blow. This won’t be a full-on Arctic front therefore, but even a glancing blow with this airmass should cool us down. Some of the more aggressive AI modeling brings us all the way down into the 30s by Monday morning, whereas some of our more conventional models are warmer.

Anyway, at this point I think the front will probably move in some time on Sunday, roughly. This will introduce some rain chances, but I’d bet Sunday is still at least partly sunny. Let’s go with highs in the 60s and then lows (roughly speaking) in the 40s on Sunday night. The early part of next week looks chilly, and we also might see some additional, mostly light rain showers as moisture overruns the lower levels of the atmosphere. Conditions likely warm up during the second half of the week.

A message from Reliant

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Reliant is committed to giving back and making a positive impact in communities across Houston. We’re thankful to celebrate with you and help light up Houston during this festive season. May your holidays be bright, jolly, and full of cheer! #ReliantLightsYourHolidays

In brief: Following a brief warm-up this weekend, Houston’s temperatures are back on the cooler side this morning. We’re going to be cold for about 48 hours before the second half of this week is warmer and quite mild for December. By the weekend the forecast turns more uncertain.

December, one week in

It has certainly felt festive during the first week of winter in Houston. On Sunday, just as temperatures started to warm up a bit, another front blew into the region dropping the mercury precipitously. Through the first seven days of the month, the city’s average temperature of 50.8 degrees is nearly 7 degrees below normal for early December. We will now experience a couple of more chilly days before temperatures moderate in the middle of the week. And so it goes with roller coaster weather, which is often the norm in Houston during December as we are whipsawed between fronts and then the returning flow from a still warm Gulf.

Will this much colder pattern hold? Probably not. In he big picture, it does seem like the first week of December will end up being colder, on average, than the middle of the month.

Speaking of cold weather, I just wanted to send a shout out to the hometown football team. The Texans ventured into the unfriendly confines of Arrowhead Stadium on Sunday night and gutted out a win in a brutally hard-hitting game. Temperatures during the second half hovered around 20 degrees, with wind chills in the low teens. Is it time to start talking about playoffs?!

Monday

Today will be the coldest of the week. Highs will struggle to climb out of the upper 50s, and there will be a chilly northerly breeze throughout the day. Mostly cloudy skies this morning will give way to clearing skies later today, such that we will end up with a fair amount of sunshine. Winds will die down this evening, and with clear skies we’ll see ideal conditions for cooling. Much of the area surrounding Houston, and away from the coast, will drop into the upper 30s, with a light freeze possible in parts of Montgomery and Waller counties.

Tuesday

This will be a sunny day, with highs in the low 60s. Winds will shift to come from the south on Tuesday, beginning an onshore flow. But I still expect lows to drop into the upper 40s on Tuesday night.

Wednesday, Thursday, and Friday

These all look to be pleasant days, with highs generally in the 70s and lows in the 50s. Skies will be sunny to mostly sunny, and winds generally light.

Saturday and Sunday

Our weather this weekend will be determined by whether a front makes it into the region, and frankly it’s not at all clear what will happen. I think it is more likely than not some sort of front does make it in by Sunday, but I would really like to see some consistency before making a forecast. For now I’ll predict highs around 70 degrees on Saturday, and in the 60s on Sunday, but I don’t feel great about it. We’ll probably see a mix of sunshine and clouds, but again that is dependent on what happens with the front. Rain chances are low, but perhaps not zero.

Next week

Unfortunately the forecast for next week is similarly muddled. There are scenarios in which the early part of next week is in the 70s, and there are outcomes in which we get some rain and a significantly cooler front drives into Houston in the Monday or Tuesday time frame. For now I’m going to just say let’s wait and see.

In brief: Houston will be cold, gray, and intermittently rainy until Saturday, when we should see some sunnier skies for awhile. We may hit 70 degrees by Sunday, but after that we’ll have a few more cold days. It really is going to feel like winter in Houston.

Thursday

From Wednesday evening through the early hours this morning much of the Houston region has picked up 0.5 to 1.5 inches of rain due to a combination of increased atmospheric moisture and a front that has pushed in. For many locations (especially inland of Interstate 10) rain chances will be below 50 percent during the daytime today. For the most part, any developing showers should be light to moderate, rather than heavy.

In terms of temperatures, much of the region is in the low- to mid-50s this morning, and that is where we are likely to peak today. Lows tonight will drop into the low- to mid-40s across the region, with generally light winds.

Friday

I think we’ll probably see a lull in rain showers on Thursday night (not completely, but for the most part), however we could see the return of some additional light rain on Friday. These would be nuisance showers (i.e. one to two tenths of an inch, at most) rather than anything that will cause problems. However, with high temperatures likely peaking in the low 50s for much of Houston, this will add to the feeling of cold and dreary conditions. Rains should end completely by Friday evening, with lows dropping into the 40s area wide.

Saturday and Sunday

The onshore flow will return briefly on Saturday, setting the stage for some warmer conditions. I expect Saturday to be partly sunny, with highs in the mid- to upper-60s, and overnight lows dropping into the mid-50s. Sunday should see mostly sunny skies, with highs in the low 70s. A secondary push of colder air will arrive on Sunday (we may see some wind gusts up to 15 or 20 mph) but this should not preclude a fairly warm day, by recent standards. Lows on Sunday night will drop into the low- to mid-40s at least, however, with the influx of colder and drier air. Rain chances for the entire weekend are close to zero.

Next week

We will see a lot more sunshine next week than the region experienced this week. I expect most days to be partly to mostly sunny. The first half of the week will be chilly, with highs in the 60s and lows in the 40s (note that, at this point, Tuesday morning looks to be the coldest morning with lows possibly reaching the upper 30s in parts of Houston. We should warm into the 70s during the daytime by mid-week.

Another front likely arrives ahead of the weekend, but that is far enough in the future to be pretty fuzzy. As of today we are three weeks from the Christmas holiday which is simultaneously very soon (like wow, there’s a lot to be done) but also far enough off for any forecast to be meaningless. I’ll make a first stab at that next week.

In brief: After a very cold beginning of winter, temperatures will moderate today before another front arrives Thursday. In addition to falling temperatures we’ll see falling rain, with the period from Wednesday evening through Thursday bringing widespread showers. The weekend still looks nice.

Chilly start to December

So far the warmest temperature in the month of December has been 55 degrees, which was briefly reached shortly before 3 pm on Tuesday afternoon. We’re going to go a good 10 to 15 degrees warmer today, as a ‘warm’ front moves onshore and briefly brings a surge in temperatures and humidity. That moisture is important, because it will support widespread showers beginning this evening, and for much of Thursday across the area.

Wednesday

Temperatures this morning are running about 5 degrees warmer than on Tuesday, but it remains rather chilly across the metro area. We should still see a bit of sunshine this morning, but a more southeasterly flow is going to quickly build a cloud deck over the area. This warmer flow will push high temperatures into the 60s across the area this afternoon (upper 60s for coastal areas, lower 60s further inland). Rain chances remain low during the daytime hours today, but by this evening we should start to see some light showers to the southwest of Houston, and these will build into the area overnight. Lows will be in the 50s.

Thursday

Rain chances will be elevated throughout the daytime on Thursday, with accumulations adding up over time. I think much of the area will pick up 1 to 2 inches, but there will be the potential for isolated, higher totals. Overall I’m not particularly concerned about flooding, but this is something Matt and I will be closely monitoring. Temperatures will probably peak at around 60 degrees on Thursday morning, and then fall slowly throughout the day as a colder air mass sags into the area. My sense is that rain chances will fall off into 10 to 30 percent range overnight on Thursday, with lows dropping into the 40s.

Friday

We are going to see the potential for some additional, mostly light showers on Friday, especially near the coast as a disturbance passes. Look for daytime highs in the mid-50s, with lows likely in the upper 40s.

Saturday

Saturday is likely to start out cloudy, but we should see clearing skies, and this will probably help push daytime highs into the mid-60s. Lows on Saturday night, with mostly clear skies, should drop to around 50 degrees.

Sunday

This will be a pleasant day, with sunny skies and a high around 70 degrees. Throughout the day we should see a reinforcing front, but at this time conditions don’t look too windy on Sunday. With the drier air, I expect lows to drop into the 40s on Sunday night.

Next week

We probably will start next week with days in the 60s and lows in the 40s, warming to 70s and 50s for the second half of the week. Rainfall potential looks low. I’m not seeing much in the way of inclement weather, so all in all it looks like a rather nice week of December weather.