How low can we go?

Last weekend, I mentioned during the newscasts that it appeared that some pretty cool weather was possible beyond the 7-Day. Well, it appears that it'll be coming to fruition. But how low will we go? Clouds and showers will have no problem keeping us on the chilly side on Monday, but what about Tuesday morning through Wednesday morning?

Tuesday morning depends on how quickly the rain/clouds get out of here. Let's see what the past couple of runs of the NAM computer model are showing. The NAM is a little slower than the GFS model in pushing this stuff out.

Here are two maps from the 12Z (7am CDT) run, showing the model forecast for 1am Tuesday morning. The first is of simulated reflectivity; that is, a forecast of what radar will look like. The second is 700 millibar relative humidity. 700mb is somewhere about 9500 feet up. We look at this to get a rough idea where clouds will be located. If there isn't green over a spot, then we have reason to believe that clouds won't be there. Of course, there are exceptions to this, but it gives a rough idea.

These two maps are of the same things at the same time, but are the 18Z (1pm CDT) run. There's some consistency between the two runs, which we like to see.

So, it looks like the showers should be getting out of here by 1am on Tuesday, with the clouds quickly departing after that. That would set us up for a fairly chilly night, especially with a high only in the lower or middle 60s. If winds stay light and we do clear out, I suspect we'll be dealing with fog... which may help keep us from dropping off too far.

Wednesday morning, I'm expecting clear skies and rather light winds. Even though the high pressure should be to our east by that time, the southerly winds won't do much to keep our temperatures up. Widespread lower 40s look to be in the cards.