One week to the Houston Marathon: Likely quite cold and dry

We are now just one week away from the Houston marathon. And as the event comes closer, the forecast continues to become clearer. At this time we can have relatively high confidence in a cold and probably dry day for the run, which we’ve been suggesting for some time would be most likely. But how cold?

Ensemble forecasting (looking at the various ensemble members of the global models) remains a better practice until about five days out, so it still makes sense to look at the range of possibilities rather than a specific, point forecast. And generally, the global models are in agreement that a cold front will move through the region next Friday, with some reinforcing colder air on Saturday at some point. Because the timing of this colder air remains uncertain, we still cannot have total confidence in the forecast. But I think it’s safe to say the temperature will fall within the following ranges:

Run start, 7am CT

European model forecast: 25 to 45 degrees

GFS model forecast: 27 to 42 degrees

Run finish, noon CT

European model forecast: 40 to 60 degrees

GFS model forecast: 40 to 55 degrees

GFS model forecast for highs and lows on Sunday. Green bar indicates most probably range. (Weather Bell)

As for precipitation, rain chances appear low if non-existent. Most likely we’ll have clear skies, which would lead to quite cold temperatures to start the day.

Back to your regularly scheduled Houston winter

After finding our way into the middle 50s yesterday afternoon, we’ve emerged from significant cold air for Houston to more standard cold air for Houston. And we’ll be warming up further this weekend. Let’s move into the details.

Today & Saturday

After our first four day streak of 30° or colder since 2011, we start today a bit milder. We’re starting Friday generally in the upper-30s or low-40s. We will warm up to the mid-50s this afternoon, or probably around to a couple degrees warmer than what we did on Thursday.

We’ve got clouds still moving across the area this morning.

This fun satellite setting lets you see clouds easier at night. You can just see the back edge of clearing (as of 6:20 AM) in the top left part of the image. Decreasing clouds today. (College of DuPage)

The clouds will be prevalent for a few hours this morning. There is some precipitation falling from them west of Houston, but it isn’t reaching the ground in most places. A stray sprinkle or ice pellet could fall this morning, but it won’t amount to anything. As the day goes on, we’ll see more sunshine, and it should end up a fairly nice afternoon.

We’ll continue with a theme of sunshine Saturday as well. Expect morning temperatures to start in the lower 40s and warm up to the low-60s tomorrow! If you’ve been waiting for a couple nice, fairly comfortable Houston winter days, Friday and Saturday will be acceptable.

Sunday

Onshore flow returns to the picture later Saturday into Sunday morning. Sunday will start with temperatures in the 50s and work on up to about 70 degrees or a little warmer. Water temperatures near the coast have dropped dramatically recently. The entrance to Galveston Bay is only around 50° this morning, and it has been in the mid to upper-40s at times this week.

Water temperatures near the Gulf Coast are quite chilly. (NOAA)

Although water temperatures aren’t quite that cold offshore, with the increasing air temperatures and humidity passing over cooler water, we’ll likely see some dense fog develop, especially around Galveston Bay on Sunday. There could be a shower or two Sunday, but for the most part it looks to be a dry, mostly cloudy day.

See full post

Houston Marathon forecast: Confidence in cool weather increasing

The normal high temperature for Houston, in mid-January, is 63 degrees, with a low of 43. Confidence is increasing that we’ll see conditions for the 2018 Houston Marathon that are cooler than this. Although not ideal for spectators, I find the colder the weather, the longer I can run. So I welcome the cold.

We’re still more than nine days away from the marathon on Jan. 14, but the broad outlines of weather for late next week are starting to come into slightly better focus. It now seems likely that daytime temperatures will warm during the middle of next week up to around 70 degrees. After that, on Thursday or Friday, it appears as though a cold front will slide through the area—perhaps bringing some rain, perhaps not bringing that much.

The GFS model is solidly on the chilly side for the Houston marathon in 2018. (Weather Bell)

If this holds, both Saturday and Sunday mornings would be chilly and dry, with lows in the upper 30s or 40s, rising up to daytime highs in the 50s. For now, this is the most likely scenario, probably a greater than 50 percent likelihood. Again, it’s difficult to have too much confidence in a forecast this far out, but the trendlines here are positive.

Houston emerges from a freeze, more typical winter-like weather ahead

The northern half of Houston is seeing freezing conditions again this morning, but temperatures will soon warm up today. For the first time in 2018, the region should see highs reach the 50 degree mark—still about 15 degrees below normal for this time of year. The warming trend will continue through the weekend before a moderately strong cool front arrives.

Thursday and Friday

Amazingly, the warming trend doesn’t mean we’re entirely out of the woods for some frozen precipitation. Thursday will see mostly sunny skies, and a cool but pleasant day. Overnight lows should fall into the mid- to upper-30s tonight, and a weak atmospheric disturbance could bring some clouds tonight and early Friday morning, and with this some very spotty sleet or cold rain is possible to the west and southwest of Houston.

Houston will see one more really cold night on Thursday night. (National Weather Service)

However, since the ground will remain above freezing we don’t anticipate any effects and, indeed, I don’t think most people will see anything. Friday itself should be a great day, with sunny skies and highs in the mid-50s.

See full post