What needs to change for more frequent cool fronts in Houston?

In brief: Houston will see more of the same through Monday or so, with temperatures running around 7 to 10 degrees warmer than normal and lots of sunshine. We turn up the humidity after Tuesday with increasing rain chances, though the best rain chances may end up to our north. Halloween evening will be warm with at least some chance of rain.

40 years ago today was Houston’s (official) 4th wettest day on record, with hundreds of flooded homes and 10 inches of rainfall. The culprit was a stalled out cold front and several prior days of rain that had primed and saturated the ground. The current forecast has nothing remotely resembling rain until next week.

Today through Sunday

The next few days should feature more of the same in Houston. Expect plentiful sunshine, generally pleasant mornings in the 60s, and afternoon highs in the upper-80s, about 7 to 10 degrees warmer than normal and not far from records. Each morning could see pockets of dense fog in the area, so just be mindful of that. A reinforcing shot of drier air may help shave off a few more degrees on morning lows tomorrow or Sunday, but that should be the only evidence of it that we notice.

Monday & Tuesday

We begin to slowly transition here to a more humid type pattern. Look for daytime highs to stay in the mid to upper-80s, with nighttime lows in the 60s to low-70s. More sunshine is expected, but I would not entirely rule out an isolated shower on Tuesday.

Rest of next week & Halloween

The forecast becomes pretty straightforward in a generic sense after Tuesday. We will have clouds, sun, high humidity, and a chance of showers developing. Look for much warmer nights and mornings and slightly less hot afternoons. The highest chance of rain will probably be Wednesday or Thursday. Yes, there is a chance of rain on Halloween, but it remains much too early to get specific. We are confident that it will be a warm evening though.

I am a little concerned that the best rain chances will elude us to the north after Wednesday, but we still have time to watch this. Rain totals through Thursday are shown above, as forecast by the NWS. Expect some variability here with some places seeing minimal rain and others seeing perhaps an inch or two.

Next cold front?

There continues to be model evidence of a cool front after next weekend. Exactly how strong and when exactly it arrives remains to be seen. I’d still keep my expectations low, but the signal has remained at least!

Why the struggle to cool off?

Yesterday, Eric noted how the 6 to 10 day outlook showed warm temperatures leading into November. Now, as noted we are hopeful for a cool front somewhere around day 10 or so, but it will be unlikely to deliver actual *cold* air. In order to get true cold here in Texas, it usually either has to come straight outta Canada and down the Plains, your typical ‘norther. Or it has to be manufactured more locally, usually by clouds, rain, and chilly but not necessarily truly cold temperatures. That latter scenario happens to us sometimes in later November through March most often. This time of year, for hints of something beyond just an autumn tease or a setup for more frequent cool fronts, we would probably need to see cold air building up in western Canada.

If we look at the Euro ensemble forecast of jet stream winds on the maps above, you’ll notice what is basically a straight shot of green, yellow, orange, and red from China and Japan to southwest Canada. This is the core of the jet stream, and when it is doing this (extending across almost the entirety of the Pacific into Canada), it basically limits how cold it can get up there. It keeps weather active, it ushers in storms, but it never allows any cold to settle. Without that, we kind of have an elevated floor for how cold it can realistically get down here in Texas, as any cold coming out of Canada would be weak to begin with and continue to modify milder as it came southward. This can all change quickly, but there’s absolutely no sign of it right now in any real modeling. Until that gives, expect milder than normal weather to continue more often than not. We’ll still have periodic fronts, but they’ll mostly just reinforce comfortable humidity levels more than anything. Certainly not a bad thing, but it would still be abnormally mild.