Good Chance of Snow in Tucson Sunday Morning

The last few times before this, over the last few years, when the prospect of accumulating snow in Tucson has been played up, I have been skeptical. The most likely scenario always was for drier air to arrive with the coldest air. This time is different. Before the arctic air turns east and moves rapidly toward Tucson overnight Saturday, it will have had a long time to pick up moisture from the Pacific while hugging the California coast from San Francisco (overnight Friday) to Los Angeles (Saturday evening). The system will be moving east through Tucson rapidly on Sunday, and drier air should sweep in well before noon (per the consistent run-to-run GFS 700 mb RH progs for 18Z). And the heaviest precipitation should be all rain both in the foothills and in the valley until almost sunrise on Sunday. But there could well be a few hours of light, wet snow either side of sunrise when about a half-inch, maybe an inch average accumulates.

Bougainvillea and Ice

I took this picture at 10 AM today, February 3, 2011. By sunset a little over half of the ice had melted. The high at TUS airport was 38F, about the same as here.

The bougainvillea looked great at Christmas. But then near the beginning of the year there were two hard freeze events that took their tolls on the leaves and flowers. So I wasn't trying to protect these branches. Instead, I have a hodgepodge of covers and wraps and Christmas lights to try to protect the lower parts of the plants. I watered them last night, and will again tonight. I'm not sure what happened to the one irrigation line. It must have frozen during the night, and began spraying a fine mist straight up. The wind carried the mist onto these branches. In the top middle of the picture, against the brick background, you can see streaks of the airborne droplets.

It looks like the brunt of the next arctic outbreak will stay east of the Continental Divide. At least I hope so. But next week once again I'll have a wary eye on the weather stations along the I-80 corridor in Southern Wyoming for the first confirmation of sure trouble.