Saturday afternoon's cold front will bring an end to the very un-January-like weather we've had the last several days. There's not a huge difference in temperatures behind this front because this air mass origniated in the Pacific. It's the Canadian or Arctic air masses (like the one we saw last week) that are responsible for the huge difference in temperatures. With the more frigid Arctic or Canadian air masses, we usually see a very large temperature gradient, or difference in temperatures between the air behind and ahead of the front. Temperatures can drop as much as 20 degrees in just a couple of hours. With the Pacific fronts we often see a slow decline of our temperatures. Sometimes, we may not even detect much of a difference in our temperatures. Often drier air will move in, with only a slight decrease in temperatures, but then that night with the drier air in place, overnight lows will be much cooler than the night before.
Another difference we usually see with Pacific fronts is a more westerly wind component. This would also help explain why there's not a huge difference in the temperatures. The drier air moving in from the desert Southwest and Mexico is not usually cooler air.
Pacific Cold Front
Today's front is a classic example of what to expect with Pacific fronts. Temperatures certainly did fall, but they were more gradual. Temperatures just before the front moved through around 2 pm in BCS were in the mid 70s. At 7pm, temperatures dropped to 60 degrees. While this does seem like a large drop in temperatures, much of that had to do with the loss of daytime heating once the sun set. Just imagine if an Arctic front had blown through how much colder temperatures would be in the evening! With the drier air moving in tonight we can expect temperatures to fall into the 40 across the Brazos Valley tonight. We can also expect some pretty breezy conditions tomorrow, with westerly winds at 10-15 mph, although expect some gusts closer to 20 mph.