Eric Berger

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

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.

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.

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.

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.

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

With a little more than 10 days to go, we’re still in the realm of considerable uncertainty about the forecast for the 2018 Houston Marathon, but the good news is that the forecast remains fairly consistent from model run to model run. This can give us some small confidence that weather for the marathon will be a bit cooler than normal.

On Tuesday I discussed the use of ensembles, and for the sake of comparison I’ve looked at each individual member of the European ensemble (12z) run from today to determine what kind of temperature anomaly is forecast for the morning of Sunday, January 14th. Broken down by percentages, here’s what we have today:

Warm: 26 percent

Normal: 8 percent

Cold: 64 percent

Very cold: 4 percent

See full post