Good morning. Today I want to look back at this weekend’s oddball cold front, and ahead at what will be a very winter-like week.
PAST WEEKEND
Remember all the uncertainty last week about the will-it or wont-it make it cold front? It did make it through Houston late Friday and early Saturday — but only barely. Even this morning, two days later, if we look at temperatures we can see the front stalled about 50 miles or so to southeast of Houston. We only narrowly missed high humidity and 80-degree temperatures this weekend.
Also, why was it so gray? Shouldn’t a cold front push all this mess out and bring us clear skies? Often such fronts do, but in this case we had a surface front, in which cold air pushes in at the surface, but it is overrun at higher levels of the atmosphere by warmer air. In fact, if you were to go up just a few thousand feet up in the atmosphere you’d find temperatures in the 60s.
The following is a Skew-T plot for Bush Intercontinental Airport, which is kind of messy, but it shows you this temperature inversion. The blue (dew point) and red (temperature) lines are co-mingled at the surface, but nevertheless it’s easy to see the surface temperature is about 10 degrees Celsius (~50 degrees F), and the lines move to the left as they go up. This means the temperature is falling for the first 1,000 feet of the atmosphere, as it rises. However, by 1,000 feet the temperature starts climbing back up, reaching 16 degrees Celsius from the 2,000 to 4,000 foot level.
Basically what we had this weekend was cold air at the surface coming down from the northwest, but you still had moist air moving in, above this thin layer, from the Gulf of Mexico. This mositure caused the gray skies and scattered showers.
TODAY-TUESDAY
This weekend’s gray pattern will continue through Tuesday, with highs in the low 60s, lows around 50 degrees, and scattered rain. We’ll continue to see cool conditions due to just a thin later of cold air at the surface, with warmer, moist air overrunning higher up.
WEDNESDAY-FRIDAY
A stronger front should arrive late on Tuesday or Wednesday morning, bringing with it one final shot of rain. I don’t expect most areas to see more than a tenth of an inch or two, however. This front will finally begin clearing skies sometime on Wednesday or Wednesday night, and allow overnight lows to fall to around 40 degrees for the rest of the work week.
Sun!
NEXT WEEKEND
There’s still some uncertainty, but right now I’d be on next weekend being really nice, with partly to mostly sunny skies, highs in the low- to mid-60s, and cool nights in the 40s.
This was my first skew-t plot. I have understood concept of inversion for years, but this graphic helps a lot in illustrating the inversion. Thanks.
You’re quite welcome!
Growing up in Ohio and Michigan, we never – or at least rarely – saw the sun in winter so this weekend was old hat to me. If we did have a clear day, it was because an Alberta Clipper (which sometimes was more like a Manitoba Mauler) pushed through. But that meant highs in the teens or single digits with below zero dew points (that’s some awfully dry air).
We took the clouds and we LIKED IT (pardon the early morning Monty Python reference).
Isn’t that SNL?
A bit of both. Remember “we lived in a lake”?
Ahh, yes.
I’m partial to the clouds myself. Since it doesn’t ever snow, the clouds + cold signals winter to me.
I’d like to add a question: Why are there still mosquitoes flitting about in my front yard. I killed one of them – a big black and white striped thing – but yet another has gotten in to my house…
I believe it is because we have had such a wet fall, and November has been comparatively warm.
I am a 3 minute drive from the Louisiana border. I keep thinking the front is through and then, I don’t. The wind keeps shifting….North to South….then North again….