Rain today, clouds yesterday

Yep, that’s right, rain IS imminent!  In case you forgot what they looked like, there’ll be a display of “hydrometeors” before 7 AM here in Catalina.  Should last the whole morning at least.  If you don’t believe me and think I just made this up, go here.

BTW, “hydrometeors”; what real meteorologists, well, maybe pretentious ones, call rain drops; remember, we’re METEORologists, we like to see things falling out of the sky.

Not raining now at 4:38 AM, but its on the radar here for the Catalina area from a great weather provider, Weather Underground.  Amounts here likely to be around an inch in the next 48 hours.  Still looking for a drop in temperature enough to bring our current (5: 1o AM) mid-fifties temperatures into the upper 30s in the rain as the cold front goes by, maybe tomorrow morning as well as a second little pulse of clouds and precip keeps things going for a second day.  That temperature drop should lead to a little snow in the heavier periods of rain.

Second pulse?

Racing from the north central Pacific is a little blob of clouds down the “backside” of our humongus trough.  Here, from the University of Washington Huskies, still playing basketball in the NIT tournament, is a 500 millibar map.  The blob of clouds that will extend our rainy spell is located, on this map, a few hundred miles west of San Francisco.  It is CRITICAL to us to get that second day of showers after the current front goes by with its strong rainband today.

The green lines on this map are contours along which the wind blows.   Here you can see a HUGE fetch from the north central Pacific to Oracle Road, Catalina.  To demonstrate this more clearly, click on the map below to get the full version, and place a finger on one of the green lines in the north central Pacific, say, just south of the Aleutians.  You might want to pick the one labeled, “5580”.   Then with your finger on that line, follow it southeastward (“down” toward the lower right), maintaining contact with the montior screen, until you exit the right hand side of the map.  I hope you haven’t had a peanut butter and jelly sandwich before doing this.

If this map pattern was stationary, that’s where the wind would go,  forever, “down” and then “up”.  Where your finger reached the point farthest to the south on this map, and where the wind makes a sharp turn around San Diego, is what we call a “trough”.  And, if you were to see a map at a LEVEL in the atmosphere, there would be a long extension of lower pressure from the Pacific Northwest to San Diego at the time of this map.  But no, we meteorologists complicate things by using constant pressure surfaces which go up and down in height all over the map instead of constant level surfaces instead of an easy to understand constant level map with highs and lows on it.  Oh, well.



This “second pulse” of clouds and precip is moving so fast, it will get to the “bottom” (south end where the wind curves to the north) of the trough before it has a chance to exit Arizona.  That will add a whole second day of showers and rain with a very low freezing level tomorrow. Its a bit rare to see something like that catch up so fast to the main trough and, in a sense, delay its passage.

 Yesterday’s clouds

Okay, you had yer flying saucer clouds here and there during the day, that is, in proper cloudspeak, Cirrocumulus (Cc) lenticularis (first photo), Altocumulus lenticularis (second photo, is lower, has shading, compared to Cc–that short flat cloud below the Altostratus layer), you had yer Altostratus band (3), followed by yer clear slot, beginning at 4 PM -hope you planned a picnic around it, or trip to the beach (4), then quickly followed by heavy, dense Altostratus layer, (see second shot with saucer cloud).

No sunset color due to the solid cloud banks to the west.  Should be enough breaks in “post frontal” low clouds for sunset color today, however.