PinPoint Wx Blog: Stuck under the clouds again

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BRYAN, Tex (KBTX) - Well, it had to happen at some point.

On days like today, where I'm stuck in an office with no window, I like to have our LiveEye network routed to one of our giant television screens, so I can prop my feet up and pretend I'm looking out my window.

I wasn't kidding. It will be a glorious March afternoon, and you should get out and enjoy it, if you can! It's not all bad to end the week, but we will be looking at some changes.

Increase in cloud cover
We'll often make the distinction between general cloudiness and when "high clouds" move into the area. Mainly because high clouds can often give us some "filtered" sunshine. Thursday will be a day for that, then we're back to more quick moving, closer to the surface cloud cover for Friday and Saturday. Why is this, and how do we know?

Different layers at work
From our feet to cruising height for jet liners (and even higher) we need to consider what's going on in the atmosphere. High cloud cover comes from little patches of quicker movement (higher wind speed) in the atmosphere. As a more powerful patch of the jetstream moves overhead and drier air gets lofted upward, we often see cirrus clouds form.

Above is a model of upper level winds over the US Thursday midday. Notice the green color (corresponding to higher, not overly powerful, windspeeds) right on top of the Lone Star State. This is one of the ways we can assume high cloud cover will return to the area. One of the old adages in meteorology is that cirrus clouds usually point to a coming change in the weather. In this case, it's absolutely correct!

Move ahead to Friday and Saturday, and our cloud cover will come from a different source. High pressure will move eastward, helping wind turn to the southeast and gulf moisture to seep back into the area. We see similar forces at play just above our heads as the air from the most recent cold front washes out and warm air tries to make it's way back northward, continuing the constant tug-of-war between cold, dry, Arctic air and warm, humid, Tropical air.

What you see above is a map of temperature and wind speed/direction in the lower levels of the atmosphere. The warmer colors mean warmer temperatures. If you look closely, you can notice arrows pointing from warmer temps in South Texas to over our area. As warm air moves in, you often have rising air, which leads to condensation. For early Friday, that likely just means clouds, but could lead to some showers by the afternoon or by Saturday.

Long story short, you're looking at the difference between this:

And this:

This Weekend
Another weekend, another chance for rain, and another cold front! There's still some disagreement on when exactly this front will push through, but it will bring us cooler weather by the start of next week. Either way, Saturday looks to bring us the best chance for rain. Scattered showers look likely, with isolated thunderstorms definitely possible. Showers could linger into Sunday as we cool down in time for 40s by Monday morning.