Looky here, valid in only about 9 days, that is, just off the forecast confidence horizon, predicted rain for SE AZ! Valid for April Fool’s Day, at 5 PM AST. We hope its not another model cruel joke, since time is running out on the chances of cool season (Oct-Apr) rains.
SInce I know you love spaghetti, here’s some for about that same time, the evening before the map above, and it has a strong indication of a strong trough moving into the SW from the Pacific. Count on it. At the least, it will get real windy when this happens, count on it, and with a little more luck, there will be enough amplitude in the jet stream, that rain WILL occur.
The last batch of spaghetti was disappointing, that shown here about two weeks ago. Sure, there’s been a “trough bowl” in the SW as was predicted way back then; that’s what was producing the pretty clouds we’ve been seeing, the passages of weak troughs aloft over us, ones that have been also keeping the temperatures reasonable.
But, that predicted “trough bowl” so far back did not have the amplitude necessary to bring rain as was thought could happen back then. “Trough bowl” turned out to be more of a “plate”, than a “bowl.”
Here’s what I mean, below, from the first panel of spaghetti from last evening: see the little dent toward the south in the contour lines passing over Arizona? That represents a trough where clouds like to form, such as yesterday’s Cirrus clouds..
But we need the big polar jet stream over us to get rain in the cool season, not a wispy jet up at Cirrus levels as we have been having. You may have noticed how fast the Cirrus clouds were jetting along up there. Well, for the past couple of days, they were zooming along at over a hundred miles an hour.
What we need are deep, cold troughs where the red height contours (5700 meters in the above map) are way south of us. Here’s why rain is predicted in the first map, as an example. Below is the configuration of the jet stream for that day that rain is predicted, showing that the 5700 meter contour and the core of the jet stream is over central Baja California. Now THAT is a rain map for AZ!
Let us begin by breaking up the weather talk monotony with a photo of a bee evaluating a thistle1, this from a hike yesterday to some weather petros2, to resume the weather talk.
The cloud day pretty much ended with a brief appearance of Cirrocumulus overhead, enhanced by iridescence:
1Apparently bees think a lot more about stuff than we think.
2Below, an early weather forecasting icon petroglyph indicating that the forecaster was anticipating a sunny day except for some Cirrostratus clouds, ones expected to produce a halo. Pretty sophisticated I thought.