…and it will seem like one. Windy today, real windy tomorrow morning before the cold front goes by in the mid-morning. Clouds is already here, rain predicted to develop SE of us in Mexico during the day. A jet max at 500 mb is already to the south of us, and that means that the door is open for a moist flow from the Pacific ahead of the main storm today, before the main blast tomorrow. So, there’s a chance of sprinkles and light showers around our area even today from thick splotches of middle and high clouds and the virga that will fall out of them.
But tomorrow; that will fab. Bruising cold front, gusty puffs of wind to 40 mph or more here in Catalina, especially likely on the higher ground, before it hits, followed by our “usual” huge temperature drop of 15-20 degrees in 1-2 h around mid-day, lets say about 10 AM-noon tomorrow, Wednesday (U of AZ mod run from last night sez it passes between 8-9 am AST, FYI, sometimes its a little fast). There ought to be light to moderate rain, briefly even heavy rain as it passes, maybe with some ice in the bigger raindrops.
What exactly is moderate rain you ask?
0.10 to 0.30 inches per hour, water is running off stuff pretty good. Its pretty common in most of our frontal bands. Heavy rain, which I think we will see, is just more than 0.30 inches per hour; drops are bouncing off the pavement an inch or two in height, and there are a lot of them. Now, it may not LAST an hour, this is just what you would call it if that intensity is reached. As a respectable CMJ, you’ll want to keep these numbers in mind, in case your friends ask you about something like this, “You just said ‘moderate rain’, what izzat, anyway?”
What the chance of measurable rain in Catalina and environs between now and Thursday morning?
About 200-300 percent, maybe 1000 percent on top of Mt. Sara Lemmon or even on Samaniego Ridge with this Big Boy blaster tomorrow. (We’re breaking new forecast ground here….you won’t hear the NWS telling you that the chance of rain is 200 percent!) ((Tell your friends.))
Amounts of rain here in Catalinaland?
Mods have juiced things up a bit, but a friend reported that yesterday the WRF-GFS had “as much as 0.25 inches” here. Friends, I pooh-poohed that forecast yesterday because it was TOO DAMN LOW for what we have coming. Besides, we need more than that, and this storm will deliver.
From this weather bully pulpit, the minimum amount, surely to be exceeded here, is 0.20 inches, the top I think now is more like 0.70 inches, that is, its not likely to exceed that amount. The median amount, the one most likely, the average of these two extremes, is 0.45 inches, a really good, and very needed rain. Its great to be able to say things like this, make people happy, except maybe snowbirders. Look, too, for happy Catalina Mountains with a LOT of snow on them. Get cameras ready for extra nice shots Colorado-ee shots on Thursday!
Hah, just looked at the U of AZ mod for the first time, and it is predicting that Catalina is in the 0.25 to 0.50 amount category, and Mt Sara Lemmon gets 1.5 inches! Yay! This will be so great if it happens, for our water situation. You can see that output here.
Saturday’s violent clouds
Never seen anything like them, those strange, and to me, violent looking high clouds, seemingly with tiny rope vortices in them; I swear I could see rotation. Here are a couple of shots. They seemed to pop out of blue sky for a few minutes, then disappear, then pop out again downstream some (toward the east).
I didn’t remember to check PIREPS until long after the event. But, got help from NOAA’s David Bright who sent me a list of ones for Saturday morning throughout the West. Only one was intriguing in that list; “urgent, mod-sev turb….FL 310” (moderate to severe turbulence, flight level 31000 feet). But when I plotted the coordinates of that (9 AM AST PIREP, it was just about over San Diego, CA, and it was at 16 Z. There was nothing reported near us at the time of these photos, taken between noon and 1 PM (19-20 Z). But could that turbulent air, as represented by these clouds at Cirrus level, have gotten here from San DIego?
Below is the back trajectories starting at 9 km and 10 km ASL (30,000 to 33000 feet above sea level). Seems to lend credibility that our strange clouds MIGHT be the associated with the same region of turbulence reported by that pilot.
Adding more mystery is the truncated TUS sounding, also attached, and the wild wind shifts. Did they lose the balloon? Maybe the balloon couldn’t take it, gave up as it got close to the turbulent layer above 22 KFT. Note how wild the wind direction got above about 16 KFT, or about 550 millibars. Normally these plots extend to the top of the diagram, 100 mb, but not on the afternoon of the 16th. Hmmmmmm.
BTW, I have done a lot of work here for you on this strange case.
Yesterday’s beautiful uncinus, and another great sunset
Yes, mare’s tails on display yesterday. They make hygrometers out of of horse tail hair… Did you know that? Yep, its true. Horse tail hair responds to changes in humidity really well. You wonder who and how that was discovered? “Wow, look at how fat and short my horse’s tail is! Must be really humid today! I think I will grab a hair and make some kind of humidity sensor out of it, one that has linkages that trace the humidity on this little drum that goes around. I’ve always wanted to make something out of my horse’s tail.” (That venerable instrument? The horse hair hygrometer. Used for decades.)