Winter began, meteorological speaking, yesterday with mid-afternoon temperatures in the upper 50s to low 60s with the wind driving the wind chill down to, I don’t know what, something really low . In other words, winter began here in Catalina about 18 h ago.
Enough already! Retired to AZ for warm air and low house prices. Pretty bad, too, out there this morning, with the temp at 44° F right now here in Sutherland Heights; colder yet in low spots of course. Only 36° F now in Black Horse Ranch.
More worse cold expected in about nine-ten days. Precip somewhat doubtful in that a more better cold slam that hits around the 20th1. Pretty strong support in the Lorenz plots (aka, “spaghetti plots”), too, for that cold slam, so get ready. Those crazy plots help us to discern whether a predicted pattern in the model output is an outlier or likely to occur.
In the meantime, going out of chronological order here, THIS coming week end’s lesser cold slam is DRY in Catalina in USA WRF-GFS model run from last evening’s run.
The Canadian GEM, however, based on the SAME global data as the US model, has rain a plenty here in Catalina and all of AZ, Sunday and Monday! The Canadians see a lot of tropical air feeding in from the sub-tropics over much of AZ ahead of the cold front that hits us later Monday, and that’s the reason for all the rain in that model. The US model doesn’t see the moist sub-tropical stream getting much out of Mexico.
Note the large separation between rain in Cal and rain in AZ in the panel below.
So, what’s a weather forecaster to do?
Lean on the Canadians! Their model was ahead of the game on our half-incher rains early in the month compared with the US mod, so they deserve that bit more credibility here, too, I think.
BTW, the two models were identical in not predicting rain in the passage of the cold front yesterday.
PS: Would post photos of yesterday’s gray, non-precipitating Stratocumulus, lacking ice in it2, of course, for you to review, but in transitioning to a new OS in the past two days, some things have gotten wrecked, don’t work anymore. SOS, as they say.
1Let’s see if any english teachers are reading this blog….
2Cloud lesson/pop quiz for cloud maven juniors: What cloud top temperature range would you guess for those non-preciping Stratocu. Recall it was a cold day, so you know they were at below freezing temperatures…..
Answer: Guess that tops must have been warmer than -10° C (14° F, in plain speak)!
In fact, the TUS afternoon sounding suggests they were about – 5 ° C (or only 23 ° F), way to warm for natural ice to form, hereabouts, anyway3.
3In really clean conditions, ice does form in clouds with tops as warm as -5° C4.
4These would really be a great factoids to pass along to your neighbors, ones that would enhance your weather esteem in their eyes. Memorization is recommended.