Good Saturday morning to you. We’re giving you a bonus weekend post to just give you a head’s up about today’s storms possibly packing a little more punch than expected.
Houston set another record high yesterday at 82° at both IAH and Hobby (tied). The atmosphere over Southeast Texas has atmospheric moisture available that is more typical for August or September than December, particularly south of I-10. When you combine that with wintertime meteorological dynamics and a cold front, you can produce some heavy rain and strong storms.
As a result, the Storm Prediction Center has nudged up our storm risk today to “slight,” which is level 2 of 5 on their scale.
Much of the Houston area, especially south and east of the city is in a slight risk (2/5) for severe weather today. (NOAA)
As of 8 AM, the main line of storms associated with the cold front is just approaching the Bryan-College Station area. However, there are showers “front running” the main line. Some of those could strengthen as we warm up a couple degrees this morning.
Radar as of 8 AM shows the main line of storms west of Houston, but some new showers and storms developing out ahead of that line (RadarScope)
So, for today expect scattered showers and storms to develop in the Greater Houston area between now and 11 AM. Any storms that develop do have the ability to become strong to severe. The main threat from storms today will be strong, gusty winds. Hail is possible south of Houston as well, closer to Matagorda Bay. The tornado threat today appears fairly low, but you can never entirely rule one out in these scenarios. Expect the main rain event to move in around midday, pushing south and east through the afternoon. Conditions should improve after 1 to 3 PM as most of this pushes offshore or into Louisiana.
In addition to the chance of some severe weather, these storms will be capable of producing very heavy rain for a short time. We should see 1 to 2 inches on average, though that may vary a good bit from place to place, with some seeing a bit under an inch perhaps. Regardless, some localized street flooding and areas of ponding are likely today.
Rain totals of 1 to 2 inches are possible today as the showers and storms push through. (Pivotal Weather)
Bottom line: Have a way to receive weather warnings today, just to be safe. Storms could be strong to severe, particularly from 10 AM to 2 PM. Heavy rain is likely in spots, and some localized street flooding can’t be ruled out.
The rest of the forecast from Friday is mostly unchanged. We just wanted to re-emphasize the storm risk today. Stay safe, and try to enjoy the day.
Let’s start today’s post with some numbers as of yesterday, the 16th of December.
68.4°: The average temperature for December so far in Houston, a record for the warmest first 16 days of the month. 11: The number of 80° days recorded at Hobby Airport so far this December. (tying a record; it should be broken today) 9: The number of 80° days recorded at Bush Airport so far this December. (the record should be tied today) 5: The number of record warm low temperatures set or tied in Galveston this month.
Yes, it has been the warmest start to December on record in Houston. That doesn’t necessarily mean it will finish as the warmest December in our recorded history, but clearly this is an abnormal month. If you’ve had enough, you’ll get a chance to enjoy cooler weather beginning tomorrow. If you want more of this, there is a non-zero chance you’ll have an opportunity for that again in about a week.
Today
We have some dense fog across parts of the area this morning, particularly near the bays and Gulf and in the outskirts of the suburbs. Look for clearing this morning, and that will likely lead to one more day of low to mid-80s across the area with very high humidity.
Another day of 80s for inland locations today, as more records are likely to fall or be matched (Weather Bell)
Records today are 81° at Bush, 82° at Hobby, and 77° at Galveston. All three seem likely to be tied or fall.
Saturday
For those of you planning something outdoors on Saturday, the news is not great. Rain should develop in the morning, possibly heavy at times and accompanied by thunder. Rain will likely shut off from northwest to southeast through the early to mid-afternoon. We may manage a dry stretch after 3 PM. This will be especially true north and west of Houston. How much rain are we expecting?
Rain totals should average a half-inch to inch, though some areas could see well over 1 inch of rain when all is said and done Saturday night. (Pivotal Weather)
We should see on the order of a half-inch to an inch of rain across the area, welcome moisture for an area slowly trying to nudge into drought. Some areas will see more than that, however. An isolated strong to severe storm cannot be ruled out either, particularly from Houston south and east.
The front should get through the northwest suburbs of Houston by mid to late morning, the central part of the area by midday and the coast by early afternoon. Temperatures will drop from the 70s into the 60s, if not the 50s as the front passes, and they’ll stay there or slowly drop off a few more degrees through the day. In addition to cooler temperatures, a brisk north wind gusting to 20 mph or so will add some chill to the air.
Sunday
We’ll likely see a mix of clouds and sun on Sunday with temperatures warming from the 40s into the 50s, maybe upper 50s to near 60 with enough sunshine. It will remain at least a little breezy on Sunday.
Monday
A weak system will pass to our south Monday morning, perhaps passing close enough to deliver a few showers or even a rumble of thunder to the area before skies clear out late. The best chance for showers will be the closer you get to the coast. Look for morning lows again in the 40s with highs likely only at best in the mid-50s, possibly even a bit cooler.
Tuesday through Thursday
Look for very nice weather for the middle of next week. Both Tuesday and Wednesday should be partly to mostly sunny. High temperatures should be in the 60s after morning lows in the 40s. Tuesday morning could even see some 30s in spots. Onshore flow should begin to kick back in on Thursday, but we’ll likely see a mix of sun and clouds and lower 70s with morning lows in the upper-40s and 50s. If you’re looking for some optimal holiday-ish weather for Galaxy Lights, Zoo Lights, Lightscape at the Houston Botanic Garden, or just walking around the neighborhood, you’ll have it here.
Christmas Eve & Christmas Day
Based on the best available modeling to us today, we have a cold front that will at least flirt with us on Christmas. There remains a very wide spread in possible outcomes. If you compare just the Euro and GFS operational models this morning, you get about a 15 degree spread in temperature outcomes for Christmas morning.
Click to enlarge this view of Christmas morning temperatures from the European model (left) and the GFS model (right), fairly wide goal posts. (Pivotal Weather)
Ensemble models don’t offer much clarity, with about 60% of the European ensemble members pushing a front through by Christmas and maybe 5% of GFS ensemble members. So, it will either be pleasantly cool (close to normal) or warm & muggy. One thing we can say with some confidence: It will probably not be truly cold this Christmas.
On December 3, 1933 Hobby Airport reached 85°, making it the warmest December day on record, a record that held for 88 years and finally fell yesterday when Hobby topped off at 87°. The City of Houston officially hit 84° on that December 1933 day, a record that stood until December 3, 1995, when Bush Airport hit 85°. Yesterday, for the first time since that 1995 day, Bush Airport hit 85° in December. Yesterday was most likely the warmest December afternoon on record in the Houston area. It’s not impossible to think today could be equally hot.
Today
After watching my Rutgers Scarlet Knights men’s basketball team upend #1 Purdue last night, it was tough to come down from that high. Then I opened the door this morning. We all have opinions about warm weather in winter ranging from “This is amazing” to “I hate everything.” I don’t personally care for it, but alas, here we are. Today will be another scorcher by December standards. We will have a mix of clouds & sun with highs likely in the mid-80s.
Back to the 80s again today! (NOAA)
Coastal fog has been mitigated some by a breeze overnight. We could see fog attempt to develop in Galveston and coastal locations at any point today though, particularly if winds lighten up some late. A stray shower or some drizzle is also possible today.
Tonight & Saturday
For those sick of the hotter weather, you may bask in the weekend. We will continue quite warm and humid tonight. Temperatures will not go very far, with steady readings in the 70s likely into the early morning hours. The cold front will arrive with authority after 4 A.M. on Saturday in central Houston, an hour or two sooner northwest of the city and an hour or two later southeast. By sunrise, the front will be offshore. Look for temperatures to plunge from the mid-70s into the 50s, where they likely will stay for most of Saturday.
Temperatures around 4 PM on Saturday will be far from the 80s! Look for 50s and a gusty breeze in most of the area. (Weather Bell)
In addition to a change of seasons, this front will come with some showers and storms. Look for a narrow but potentially noisy line of brief storms after 2 or 3 AM on Saturday, ending around sunrise. This will be followed by clouds, along with some light rain or a few showers perhaps. Wind gusts of 20 to 25 mph will accompany all this, just to add to the autumnal ambiance. I don’t expect us to see much sunshine on Saturday until perhaps late in the day.
Sunday
As skies clear out late Saturday evening and winds back down some, temperatures will fall as well. Look for Sunday morning to begin in the low to mid-40s in most places, with some 30s likely outside the city. Sunday itself looks gorgeous. Expect sunshine and highs a bit above 60 degrees.
Next week
The return to autumn or early winter weather will be brief. We warm up a little beginning Monday, with morning lows in the upper-40s and daytime highs in the low-70s under sunshine. Monday actually looks spectacular, although clouds may increase through the afternoon.
By Tuesday, onshore flow will begin to exert more influence. This will warm us and bump back up the humidity. Look for highs well into the 70s and lows in the 60s. More of this on Wednesday and Thursday is expected. Yes, we could hit 80 degrees again one or multiple times into late next week. In addition to all this, the usual suspects that typically accompany these December warm ups (clouds, scattered showers, and fog) will join us again as well.
When will we see another cold front? As of this morning, the Euro has one around Sunday next weekend, while the GFS is more like the Monday or Tuesday the week of Christmas. Keep the shorts handy a little longer.
Hobby Airport has started December with back to back 80 degree days, and there could be more to come. The last time we did back to back 80s in December was in 2019. We also accomplished the feat in 2016, 2015, 2013, and 2012, so it’s not super abnormal. Whatever the case, this is quite a departure from when I last wrote in this space a week ago and we had multiple European model ensemble members depicting 30s for lows in Houston this weekend. You can forget that. Let’s talk about what we can expect.
Today
Look for more fog this morning that should again lift by mid-morning in most spots. Dense Fog Advisories are posted around the region, but the fog is a bit spotty. It appears Brazoria County has some dense, as may parts of Montgomery County. The Beaumont/Port Arthur area is also seeing dense fog. Everyone else seems to be fine or seeing lighter fog. But you may run into some patches of dense fog as you maneuver around the area this morning.
Most areas are seeing restricted visibility this morning, but dense fog is a bit spotty, mainly south or east of Houston. (NOAA)
Once the fog lifts, we will be left with a mix of clouds and sun this afternoon, as highs again make a run for 80 degrees. One of the differences between yesterday and today is that we could see a couple sprinkles or showers as a weak disturbance passes by. It may be enough to wet the ground in a few spots, but that’s about all.
Weekend
Saturday will see any morning fog lift once again, leading to a partly to mostly sunny day. A few showers can’t be ruled out Saturday afternoon, but those would be the exception, not the rule. Look for highs in the upper-70s to around 80 degrees after a warm morning in the mid-60s.
Look for mostly the same on Sunday, except it may be more like partly to mostly cloudy. Again, a slight chance of showers will exist, but nothing you need to change plans for I don’t think. Another morning in the mid-60s or warmer will transition to an afternoon in the upper-70s to 80 degrees or so.
Monday
Here’s where some intrigue begins. A cold front should actually press through the region early in the day. We will probably start the day well into the 60s in most spots, and then when the front passes through we will see temps hold or drop a bit. So 80 degrees probably isn’t in the cards for Monday.
Instead, expect a period of morning showers and storms, then cooler, breezy weather in the afternoon. Temperatures should drop into the 50s on Monday night.
Forecast lows for Monday night and Tuesday morning show something more autumn-like, at least for a day, with 50s and a few scattered 40s around. (Weather Bell)
Tuesday and beyond
Offshore winds are going to flip around and become onshore winds quickly late Monday night and Tuesday, leading to a substantial increase in moisture. Beyond that, we could be entering a bit of an active period of weather with showers, storms, and even some strong storms in the area ahead of another cold front. This would be most likely later Tuesday or Wednesday. Cooler air would settle in late next week but probably again for only a couple days. By next Saturday, the GFS Ensemble mean already has an over 90% chance that temperature anomalies will be at least 10 degrees warmer than normal.
If we look at multiple GFS Ensemble members, 90 percent of them, or more, say that temperatures will rebound back to at least 10 degrees warmer than usual next Saturday. (Weather Bell)
This means that of the 30+ GFS ensemble members, almost all of them see much above normal temperatures again next weekend.
The Arctic Oscillation
I’m going to take you more under the hood about things right now. Meteorologists use numerous tools to make forecasts. One of those tools is called “teleconnections.” We don’t often talk about those here in an effort not to bore you, but I think it’s instructive today and can explain some of why December looks to be so much different than how autumn has been for the last month or so.
Teleconnections are ways of explaining that because one thing happened in one place, there’s more predictability that something else could happen in another place. In other words, if you have a certain pattern over Alaska, that can often teleconnect to a certain pattern downstream over the continental United States. There are numerous teleconnections we can use, but one of the most useful ones is called the “Arctic Oscillation,” or AO. You can read more about the AO here if you’d like. The simplest explanation? As the AO trends more positive, this indicates a stronger polar vortex, one that’s more likely to stay near the North Pole where it belongs. We typically lean milder in those scenarios with most cold remaining in the high latitudes. If the AO flips significantly negative it can mean the polar vortex has weakened and is more likely to allow chunks of cold to travel south toward the mid-latitudes where more people live. For example, just ahead of the massive February freeze last winter, the AO got as low as -5, which was one of the most negative values of this index recorded since 1950. That did not cause us to get super cold here in Texas, but you bet it helped explain why.
So, why am I telling you about this? Well, if you look at a forecast of the AO Index for the next 2 weeks, what stands out?
The Arctic Oscillation is forecast to remain sustained positive the next 2 weeks, which should help skew the odds toward warmer than normal weather here most of the time. (Weather Bell)
It’s raging positive (green line). We are frequently forecast to be at or above +2, with some ensemble members getting as strong as +4 to +5 at times. While this doesn’t guarantee that we’re going to stay warm deep into December, it sure skews the odds that way. No single teleconnection is a magic bullet in meteorology, but they serve as pieces to a larger, complex puzzle we try to solve each day. Today, this one stands out as one that will have an outsized influence on our December weather, so I thought it would be a good time to explain this to you. Hopefully it’s insightful! Enjoy the weekend.
