68 F dewpoint at TUS, too. With this kind of dampness, it should be an exciting day with clouds topping the Catalinas, and you know when that happens, its another sign of really heavy rain in the area. In fact, we have a little strip of Stratus fractus along the base of the Catalina’s now (5:29 AM).
Let’s go to the National Weather Service’s web page and see if they are excited about today… Yes! They are pumped, with “green” shading designating those areas of southeast Arizona in a NWS flash flood watch!
Here’s the 4 AM map below, courtesy of our University of AZ Wildcats National NCAA Baseball Champions Weather Department. What a great final game that was! (You can get their latest map here.)
After a mostly disappointing day, an unusual summer day in which there were no clouds being launched off the top of Mt. Sara Lemmon, and temperatures were unusually “cool”, there was finally a strong, whitish brightening of the sky to the east, with darkening to the northeast beyond Charoleau Gap, as the sun slid below the horizon.
And if you were looking at the Weather Underground (now having been absorbed by The Weather Channel in some kind of capitalistic power grab) web page for the Catalina area, you saw that the brightening beyond the Catalina Mountains yesterday evening was due to the anvils of an approaching complex of Cumulonimbus clouds. But as we know, they don’t always make it after dark coming from the east, only on some days. They often fade away, or only produce sprinkles.
It began to rain pretty hard right at 9:30 PM, but there had been no lightning preceding it. I was surprised at how hard it was initially raining, thinking earlier that the rain was going to be old stratiform rain from dead Cumulonimbus remains, very steady and light, maybe adding up to just few hundredths. Then “BLAM” this brilliant bolt nearby and two huge booms of thunder setting off a car alarm near us. How great that was! Rain continued to fall until about 2:30 AM. That lack of lightning suggests the rain producing cell was building right over us, finally climbing to heights and with updrafts strong enough to produce the first lightning. Sprinkling again now (for a couple of minutes) from Altocumulus opacus clouds… Very unusual to have morning rain here as you know.
You can get the regional values of rain here from the Pima County Alert gage network and also here from the U of A’s rain measuring network. Three Alert locations had over an inch, and many more in the U of A network! What a great start to the summer rain season!
Below, “the brightening” as Stephen King might put it, showing that deep clouds were around, and they were approaching from the east. The anvils, well above 30,000 feet, are still in full sunlight, and the sun is shining through the thin, probably haze-free air up there. Its undiminished light remains white when striking those cloud tops, not having had the shorter wavelengths scattered away by aerosols (until the sun subsides farther below the horizon).
