Thirty-five (six, seven, eight, nine…) and counting….

Nice rainshower starting right this second at 4:03 AM which will likely add to this total.  Just did add 0.01 inches.  I was hoping for an inch or more from this situation, and it can still happen before its over by late today.   But,  in the desert,  you always have to prepare to be disappointed when it comes to rain.  However, that 0.38 inches (now at 5:18 AM) is significant and will keep prospects for a great spring wildflower bloom going.   Local 24 h amounts can be found here, FYI.  BTW, when you see in this list that Mt. Sara Lemmon has a ludicrous “zero” precip, as in this list today,  its because its snow, not rain, and isn’t melting into the gage.

BTW, a great way to observe what’s going on around here is via the Wunderground maps here where you can animate the radar.  Also, if you pay them a very small fee, you can get these maps advertising-free.  These guys do a great job I think.

First, when you open this map, you will be surprised at the number of “personal” weather stations being displayed around SE AZ, especially if you drill down.  Almost certainly you will begin wondering whether YOU should have one as the herd instinct begins to activate.  That would be great if you got one!   It is pretty remarkable how folks get all wound up about weather and decide that the number of official reports aren’t good enough for them; they must have a station next to the BBQ grill in the backyard to REALLY know what happened, and what is happening while the grill is heating up.  I have one, if that helps in your decision process.  Its here.  You have to drill down on the Wunderground map, linked above, for it to show up, though.

Cold Dead Ahead

A second atmospheric “iceberg” is shooting down out of the north at us and winds up just to the northwest of us.  The USA NWS “WRF-GFS”  (I pronounce it, “WURF-GOOFUS”)  model (whose output is shown below) had that second low too far to the east for much of any precip here in prior runs.  But last night, that model has produced a forecast that raises our chance of precip from this second blast of cold air.  Eerily, these maps eventually resemble that horrible cold spell of last early February, though fortunately it will not nearly as cold this time.  Still, you get goose bumps looking at that historic pattern recurring again.

Here is a color-coded temperature forecast from the WRF-GFS at the 500 millibar level, around 18,000 feet.  Below, a couple of snapshots from that model run based on last night’s data.   The first map below is what this morning was supposed to look like over us.   This first map is just a 12 h prediction so its likely that there are few errors and it will look pretty much exactly like this.  (Remember though that the little errors that ARE there at the outset grow into mighty oaks in errors in a few to ten days out making those forecasts unreliable in details.)

Note on the first map, that “incoming”, namely, that purple blob of low temperatures approaching the USA border from Canada.  It will be extruding southward right to AZ while our present, overhead cold low spinner drifts off to the east, passing overhead of my house about 7 PM tonight.  I will be looking up then to see what it looks like.

The second map, valid for Saturday afternoon at 5 PM LST,  shows how that blob of purple approaching the US now, has spun off an “iceberg” that is shown sitting over Kingman, AZ, pretty much where the current cold low shown on the first map is sitting.  That means we have a very slight chance of more showers, some mixed with snow here as that one goes overhead on Monday.  The chances of precip are down because this blob of upper cold air has such a long overland trajectory.

Finally, its the last map that is eerily similar to the awful cold wave situation we had last February.  It brings shudders just looking at it, reminding one of all the damage that February cold snap caused.

You can see on this last map how the very lowest temperatures (purple areas) have extruded (I love that word!) all the way down into Colorado, while another vortex has formed in AZ.  Probably too dry for anything but a tiny chance of snow flurries here on Monday morning, maybe a couple of shallow glaciating Cumulus clouds in the afternoon is all we’ll see.

The following Tuesday morning will be awful cold.  Check NWS forecast for Catalina here.  You’ll see some temps below freezing are expected, and if you live in a gully, it will be much colder than those shown here on the clear nights ahead!  Check out the minimum temperatures some time as measured at the Catalina State Park (here, pluck the morning reports for Cat SP) in the CDO wash on clear nights.  Unbelievably low sometimes, as much as 10-15 deg colder than here at my site on a hill side.

Enjoy some more rain today!

The End