They seem to go together every time we have Altocumulus clouds; aircraft flying through them create holes or canals! Have been photographing this phenomenon since the early 1980s, and I have not seen it so consistently occur every time there was a flake of Altocumulus around as has been the case here this winter! Its likely because our Altocumulus clouds have mostly been so cold, having temperatures lower than -15° C. Mid-level Altocumulus clouds can range in temperature from well-above freezing to below -30° C.
What was unusual about yesterday afternoon, if you caught it, was that you could make out the aircraft producing the “high temperature contrail” (aka, APIPs), a four engine prop aircraft flying just under the bottom of the Altocumulus layer. Even if you see a contrail in the Altocu, you can almost never make out the aircraft type for sure because its too high or in the clouds. But, because of our cool spell, those cold Altocumulus clouds were lower than usual, around 15,000 feet off the ground, or near the 500 millibar pressure level. The temperature at the bottom of this layer was -21° C. See annotated NWS sounding, courtesy of IPS Meteostar, below:
Here’s your aircraft shot, full size so’s you can really zoom in and see those engines:
The weather ahead, WAY ahead
Not a single model run since two days ago has produced a big trough in the SW US, in complete opposition to the interpretation of spaghetti ensemble output at that time. This would be, IMO, one the greatest busts of all time (not for me, of course), but for spaghetti ensembles (I was only foretelling what they told me), spaghetti considered to be one of the great forecasting advances of all time when computers became powerful enough to produce them in a timely manner.
If we believe these later model runs, it will be relatively hot and dry here, not cold and wet, as was suggested here.
But being of a stubborn nature, Cloud Maven Person is not yo-yo-ing on his forecast just yet. Surprises are almost certain in these model runs, since spaghetti still supports troughing beyond 10-12 days… Standing by for model yo-yo-ing….
A laugher (???) below from our very latest computer run (from IPS Meteostar again). This map in incredible in the lack of jet stream activity over most of the US!