Twofer

Rarely do passing lows get a two chances to produce rain, but the low passing overhead today and tomorrow, does. Ten days from now, its overhead again! How funny izzat? And precipful, too.

Measurable rain will fall today in Catalina CDP (“Census Designated Place”, i.e., its not a city), and in about 10 days when the SAME low returns after a boomerang trip down Texico way, thence to Baja, thence to so Cal, and back over Arizona on the 10th-11th after picking up some juice over the east Pac.

Thinking, as you are now, of a minimum of 0.05 inches and top of 0.50 inches, the latter larger amount if projected afternoon thunderstorms land on us.   Thus, best estimate, average of those two extremes, thinking Gaussian conceptual model modal value here, about 0.275 inches.

BTW, should be something in the way of an arcus cloud, or a batch of low scudding clouds underneath Cumulus and Cumulonimbus bases this afternoon as a windshift to the NW comes through in the afternoon or early evening hours, well in the next 18 h or so.  That could be a dramatic sight, and with that windshift, the temperature will drop 5-10° F.

When the low trudges over us the second time around in mid-October, the estimated extreme amounts are a trace minimum, and 1.00 inch max, in other words, pretty clueless here about how much could fall the second time around ten days from now.

If you don’t believe me about all this, here are is the WRF-GFS prediction for this afternoon, followed by the WRF-GFS model prediction 10 days from now, today being October 6th, in case you don’t know what the date is today, maybe you’re retired and lose track of the days and dates because you don’t have a lot to do everyday, just kind of sit there:

5 PM AST, today, October 6th.  Joe low goes by, heads toward Texas.
5 PM AST, today, October 6th. Joe low goes by, heads toward Texas.
5 AM AST, Friday, October 16th, the day before football day.
5 AM AST, Friday, October 16th, the day before football day.  Joe returns after visiting NM, TX, MEX,  Baja, east Pac, then  SC.  Full cycle here, from IPS MeteoStar.  Pretty humorous to watch this happen.

 Yesterday’s clouds, punctuated by a large worm

6:57 AM.  If you thought the clouds were fatter to the north most of the day yesterday, you were right.  Many modest Cumulus passed overhead of Catalina and then fattened up to the north because the lifting mechanism aloft was stronger to the north of us.  Quite a few  moiuntainstations registered over an inch to the north of us.
6:57 AM. If you thought the clouds were fatter to the north most of the day yesterday, you were right. Many modest Cumulus passed overhead of Catalina and then fattened up to the north because the lifting mechanism aloft was stronger to the north of us. Quite a few moiuntainstations registered over an inch to the north of us.

However for a moment, we did have a shower threat move toward us from the south, this:

11:52 AM.  Whilst on a hike up the Baby Jesus Trail, this appeared.  Looked promising!  But, vaporized into mere sprinkles.  If you saw this, you almost immediately were thinking of ice forms like needles and sheaths, since the cloud was relatively shallow, and its still warm aloft.  Needles and sheath (hollow columns) only form at temperatures above -10° C.  Such an occurrence is rare in Arizona, so, quite an interesting bit of hand-waving here.
11:52 AM. Whilst on a hike up the Baby Jesus Trail, this appeared. Looked promising! But, vaporized into mere sprinkles. If you saw this, you almost immediately were thinking of ice forms like needles and sheaths, since the cloud was relatively shallow, and its still warm aloft. Needles and sheath (hollow columns) only form at temperatures above -10° C. Such an occurrence is rare in Arizona, so, quite an interesting bit of hand-waving here.
10:57 AM.  Hike up the Baby Jesus Trail was punctuated by seeing a very colorful worm of some kind.  Not much else happened in weather or wildlife the rest of the way,  Morning glory coverage was a little disappointing.
10:57 AM. Hike up the Baby Jesus Trail was punctuated by seeing a very colorful worm of some kind. Not much else happened in weather or wildlife the rest of the way,  Morning glory coverage was a little disappointing.
4:17 PM.  I am sure when you saw this Cumulus congestus that you, as I was, thinking you'd see a little ice emit out the right, aging and descending side.  No ice was visible.  However, it was kind of neat to think how close we are now in our cloud assessments, right or wrong.
4:17 PM. I am sure when you saw this Cumulus congestus that you, as I was, thinking you’d see a little ice emit out the right, aging and descending side of this cloud.  In fact, no ice was visible. However, it was kind of neat to think how close we are now days in our cloud assessments, right or wrong.

The End

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.

4 comments

  1. Hi Art: That seems like an unusually long time for a low to exist, let alone come by again for a “second debut”. Reminds me of a cut-off low- the kind we sometimes get here in late spring or summer. Sincerely, Roland
    p.s. Hurricane Oho remnants forecasted to swing up here in a couple of days.

    1. Oho’s track reminds one of the track of Olga, the typhoon remnant that deepened explosively as it approached the Pac NW coast and became extratropical and was ultimately responsible for the infamous Columbus Day storm of 1962 that produced winds of over 130 mph. Billions of board feet or timber went down.
      And, the World Series in SFO was rained out for the third day in a row, a record at that time.

      Yes, tracks like “Joe” are pretty darn rare.

      art

Comments are closed.