Isolated Storms Yesterday

Skies remain a bit dingy this morning - some distant cloudiness north of the Catalinas.

There were isolated storm clusters in eastern Pima County yesterday. Here at the house there was thunder around 3:30 pm MST but just a light spit of rain.

The ALERT rain reports (below for 24-hours ending at 9:00 am this morning) show three areas with rainfall of 0.04" or greater - each of the three areas had one site with over 0.30". Not much of a show.

This morning's 500 mb plot and analysis (above, from Univ. of Wyoming) shows the large, but weak anticyclone centered somewhere in northwest New Mexico - upper-air data from Albuquerque have been missing since Saturday afternoon.

There continue to be two suspect observations with heights 20 to 30 m too low wrt nearby observations: Chihuahua, Mexico, and Phoenix, Arizona.

I called yesterday's sounding a mess, but this morning's is even worse (below). Dry air intruding from the west, below 700 mb, has destroyed the CAPE and left us with a dry, stable sounding.

Looks like we're in dire straits!

First Full Week Of August

Skies over much of Arizona have been hazy looking yesterday and this morning (above) due to elevated smoke from a wildfire burning in California east of Riverside - the Apple fire. Mike Luethold's post yesterday has a nice satellite image of the smoke plume from this fire. Image below is view of fire from Cabazon, California, on Saturday evening.

Things locally continue little changed, with most storm activity to our east and south. There were a several reports of amounts greater than half an inch yesterday: Sonoita 0.79"; Nogales 0.77"; Ramsay Canyon 0.66"; and Benson 0.51".

This morning's sounding from TWC (above) continues with considerable CAPE, but with mixing up to 600 mb required to reach the LFC - not likely to happen without a strong outflow. The wind profile is chopped up and light and variable up to 200 mb - what a mess.

Forecasts from the 12 UTC WRF-RR and WRF-NAM  below do indicate isolated storms into parts of eastern Pima County this afternoon. Both forecasts are valid at 5:00 pm this afternoon. Time will tell.

Dry Here Yesterday

Another morning view from Atmo similar to past several days. At bottom is view of Miami as TS Isaias passes by off shore.

Storms in southeast Arizona stayed far from Tucson, with heaviest activity over Cochise and Santa Cruz Counties - as per high density of detected CG flashes (above from Atmo and Vaisala) for 24-hours ending at 2:00 am MST early this morning.

Rain amounts below (from MesoWest for 24-hours ending at 7:30 am) show highest amounts around southern Huachuca Mountains - Art Douglas reported 1.40" at his place in Ash Canyon. 

Another TWC 12 UTC sounding (above) this morning that has large potential CAPE, but that will need a strong outflow to force storms, given the shallow afternoon BLs we've been experiencing. Note that there are several old, elevated layers that are well-mixed in temperature, but only one shallow layer near 700 mb well-mixed in moisture. Strange times. The intense, elevated inversion of the past several days has vanished, which is good.

The forecast 500 mb chart (above from 06 UTC GFS and valid at 5:00 pm this afternoon) indicates split centers in the 500 mb anticyclone, with a weak trough line separating the two and extending from southern Nevada to our area. The GEFS plumes (below) continue dry through the week at the airport - but again the operational GFS (blue) is a wet outlier - if anyone knows what's gone awry in the operational GFS, please let me know.

As for local storm chances - the nighttime and early am WRF forecasts mostly indicate storms again staying east to south of our area, but with one version forecasting some evening storms over eastern Pima County. Rain in my gauge tomorrow morning - not likely.

July Ends Here With A Sprinkle

Bit of pre-sunrise color this morning at 5:40 am MST.

Yesterday evening storms moved south-southeastward across the eastern Catalinas and into parts of the metro. Rain amounts in ALERT network (above) were light, and we had a sprinkle here a bit before 7:00 pm - Trace. The plots of detected CG flashes below (from Atmo and Vaisala) shows the storms came into the metro area and gradually dissipated. Most thunderstorm activity was, as per usual, in Santa Cruz and Cochise Counties. Nature detests straight lines, but look at that long line of CG flashes just south of the border.

This morning's sounding from TWC (above) has BL with considerable CAPE (much better than yesterday) and continued, fairly strong, north to north-northeast steering flow. Will be very interesting to watch what transpires this afternoon. Note that minor decreases in BL moisture could bring that nasty inversion below 400 mb into play.

Below is the August Outlook for precipitation from NWS-CPC. Looks like more of same our part of the country.

End Of July

Morning view from campus at 6:30 am MST this morning. Down at bottom is view of a wildfire burning near Mt. Wilson Observatory, in California, yesterday afternoon.

Extremely suppressed yesterday wrt thunderstorms. Plot above shows detected CG flashes for 24-hours ending at 1:00 am this morning (from Atmo and Vaisala). What can I say?

I have been noticing, for a number of weeks, that the operational GFS forecasts are wet outliers, in comparison to the GEFS forecast members. Don't know why this strange behavior is happening. Regardless, the GEFS forecasts indicate a very dry start to August.

From the NWS webpage, plot above shows rainfall since June 15th for a number of stations in southeast Arizona. Here at house we had much more rainfall in July than did the airport, thanks to the heavy storms on the 23rd in this part of town. July ended up with 1.97" here, which is about at the median for my 22 years of observations.

Mike Crimmins' running plot for the summer so far at airport is shown below. Links to Mike's plots for a large number of sites are available at:

https://cals.arizona.edu/climate/misc/monsoon/monsoon_summaries.html

Hot And Hot And Hot.........

There are a few clouds this morning far off to south of Kitt Peak in Mexico.

There were some thunderstorms around eastern Pima County yesterday afternoon, as per plot of detected CG flashes for 24-hours ending at 2:30 am MST last night (from Atmo and Vaisala). Nothing here at house; 15 ALERT sites had light showers and a site in north Oro Valley reported over half an inch. 

This morning skies are clear over all the Southwest, with only a bit of cloud cover in northern Sonora.

The morning forecast from the NWS is very grim for rest of week - above and below. Caution needed for outdoor activities, except around sunrise and sunset.

The 500 mb anticyclone builds strongly northward, reaching to the Arctic Circle by 5:00 pm on August 5th (as per the 00 UTC WRF-GFS forecast above). Forecast below from same run is for total rainfall during period ending at same time as above.

Back to having to water sensitive outdoor plants again.

Ending A Boring July

Alto cumulus drifting overhead about 8:00 am MST this morning. Seems we've been in the meteorological doldrums for much of July. One heavy rainfall event on the 23rd and little else.

Almost a donut hole in the CG flash plot (above, from Atmo and Vaisala) centered near or just west of downtown. Rainfall reports mostly in mountains and south to southeast of the city. There were, however, a number of sites that reported over half an inch.

Here at the house we had a brief spit of rain around 2:00 pm that wasn't enough to even wet the courtyard - so another Trace.

This morning's TWC sounding is very similar to yesterday's - see previous couple of discussions. Main difference today is that there are light westerly steering winds.

The 06 UTC GEFS plumes (below) for QPF at airport show some chance for light showers this early morning, which didn't happen, and then nothing for the coming week. Plumes for temperature (not shown) indicate gradual heating, and current NWS forecast high for Friday is 110 F - ugh.

Down at bottom is 12 UTC WRF-RR forecast for rainfall through midnight. That model forecasts isolated, light showers for eastern Pima County. Yet another day where chances for rain in the gauge here at house are very near zero.

August often makes up for a dismal July, and hopefully that will be the case this year. 

Last Five Days Of July

Large Cb to the distant east-northeast last evening as the sun set.

Was a suppressed day locally yesterday, with some thunderstorm activity to east and south in Cochise and Santa Cruz Counties. Composite radar chart above is from 5:00 pm MST yesterday, and  plot of detected CG flashes (below - from Atmo and Vaisala) is for 24-hours ending at 1:00 am this early morning.

Visible satellite image above is from about 7:30 am this morning. Hurricane Hanna has dissipated, but left heavy cloud cover across central Mexico. Also a bit of debris cloudiness drifting across Cochise County.

The 500 mb analysis this morning (below from University of Wyoming weather page) shows a large but weak trough along West Coast and a very large, and also weak, anticyclone covering the rest of the West. The high's main circulation center is between Amarillo and Midland, Texas. The observed 500 mb temperatures are very warm over southern Arizona and northern Mexico, i.e., -3 to -5 C which is a distinct negative for storms over lower elevations.

The morning sounding at TWC is also a very mixed bag: winds are very light below 300 mb; residual BL is shallow with drying 850 to 700 mb; however, PW is high, at just over an inch and a half. There are no clear steering level winds that would move storms far from higher elevations.

The 12 UTC WRF-NAM forecast below is for rain amounts through midnight tonight. Amounts are very light and also suggest a Tucson donut hole.

Between now and Wednesday morning, the main anticyclone center shifts westward, ending up to our west and northwest for much of coming week - not a good pattern for precipitation chances here. So, today may be last shot for July rain. Here at house, I'd be amazed if we get rain in the gauge, since the storm would have to develop nearly overhead, or build southwestward off the Catalinas.