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Nice contrast of sunshine and clouds at Kitt Peak this morning.
Plot of detected CG flashes from Atmo and Vaisala - above - shows that what little thunderstorm activity was stayed mostly out west in central Pima County. While some model forecasts yesterday indicated that storms from Catalinas could possibly drift into far north metro, the Catalinas were totally shut down yesterday, as were most of Cochise and Santa Cruz Counties.
Above shows 24-hour rainfall reports for the metro area (from MesoWest) - all goose eggs except for one site. The precipitation trace for that site is shown below. Trace is a stair-step of 0.01" amounts across a number of hours. Obviously bad data, but why? Perhaps a sprinkler or ???
This morning's 500 mb pattern over the Southwest is just frankly a mess. Light winds with main anticyclone center over northwestern Oklahoma and a weak center perhaps over northwestern Arizona. Little change in sight for next few days.
Forecasts for PW from the 06 UTC WRF-GFS (above valid at 11:00 am MST today and below valid at 11:00 am Tuesday the 21st) show a slow decrease over southern Arizona through the period. Not good.
I'll try to put this dismal month in perspective, using my local records, once we eventually get a decent rain.
Another morning with middle clouds drifting overhead. Heavier cloud to the northeast is debris from evening storms in Cochise county yesterday.
It has now been four months since there was 0.05" or more of rain in the gauge here!
Plot of detected CG flashes (above from Atmo and Vaisala) for 24-hours ending 2:00 am MST this early morning. Only minimal thunderstorm activity over Pima County yesterday. Just a few rainfall reports across the ALERT network, shown below for 24-hours ending at 8:00 am this morning - the 0.20" report northwest of Flowing Wells is erroneous (there's been no rainfall out there for at least three days).
Some changes have occurred during past 24-hours at 500 mb - morning chart above from SPC. The large anticyclone covering the southern 2/3rds of country has three centers of circulation this
morning: one over the Southeast; another over southwest corner of Oklahoma; and one near Yuma, Arizona. We are very near the trough line separating the western two centers, and have light north-northeast winds at this level.
This morning's TWC sounding (below) has a bit more CAPE and PW this morning, and is a bit more favorable for storms at lower elevations. Steering flow for storms remains light, but anvils will spread to the north.
At bottom is the 12 UTC WRF-RR forecast of radar echoes, valid at 4:00 pm this afternoon. Heavy anvil spreading overhead, but most of the nighttime runs try to inch storms from Catalinas into far north parts of metro area.
Middle and higher clouds overhead this morning at a bit after 9:00 am MST.
The 500 mb analysis this morning (above, from SPC) is more than a bit chaotic. The anticyclone center has shifted far to the east over Oklahoma and Arkansas. Winds at 500 are light and variable over Sonora and Arizona. The 12 UTC sounding from TWC (below) is also not very impressive - certainly not as good for storms as what I'd expected yesterday. There is only a sliver of CAPE and winds are light and variable up through 300 mb. Storms that do develop could have potential for local heavy rains.
Forecast from 06 UTC WRF-GFS (above) is for radar echoes at 6:00 pm this afternoon - Mostly debris cloud over city again, with some strong storms along north border of eastern Pima County - again, a forecast that is less than what I'd expected yesterday.
Forecast below is from the 12 UTC WRF-RR and is for precipitation through midnight tonight. That run forecasts little precipitation over eastern Pima County, and hints at another donut hole over the city.
So, it goes day-to-day in the summer thunderstorm season, which has been real dud so far.
Although there were heavy clouds and anvils during afternoon yesterday (view above a bit before 3:00 pm MST), there was minimal thunderstorm activity near the metro area. Plot of detected CG flashes below (from Atmo and Vaisala for 24-hours ending at midnight last night) shows thunderstorm activity north to east to south of the city - almost a donut hole pattern.
Across the ALERT network only 12 sites measured 0.04" or more (above and below for 24 hours ending at 6:00 am this morning). Three sites did have over half an inch - the site in the Catalinas may have been within the Bighorn fire burn scar, which would have made for nasty runoff.
Here at the house we had the slightest of sprinkles in the evening as decaying, thick anvil cloud from storms to the south moved by. All-in-all not much of a weather day for mid-July.
Nice view of Baboquivari from Kitt Peak this morning.
This morning's sounding from TWC (above) is the most favorable for deep convection and thunderstorms in quite a long time. Moisture and CAPE are good, and afternoon heating should produce a well-mixed and deep BL with cloud bases up around 600 mb. Winds however are light and variable through 300 mb, so storms that develop won't be moving very much, unless an organized, mesoscale outflow develops.
This time of year, when thunderstorms are occurring, it is not realistic to try to forecast beyond a couple of days, since the evolution of each day's storms affects what is likely to happen the next day. The NWS forecast for today through Friday night is shown below, and is basically the same each day. This outlook is essentially low-grade climatology for the airport, so it conveys little in the way of actual forecast information.
In contrast, I show here three forecasts of afternoon/evening radar echo coverage from the 12 UTC WRF-RR run this morning. Forecast above is valid at 6:00 pm MST this afternoon. Forecast below is valid at 8:00 pm tomorrow afternoon; and forecast at bottom is valid at 6:00 pm on the 17th. Basically, the model forecasts each afternoon's thunderstorm activity to shift west and southward.
The model-based POPs for the metro area are quite low today and Friday, but significant tomorrow (appears like perhaps 50% or greater). The information content, in my opinion, is much greater in the model forecasts than that provided by the NWS forecast of climatology for the entire coming week.
Of course, only time will tell how accurate the WRF forecasts actually are.
View north from Kitt Peak at a bit after 10:00 am MST is looking right into center of the MCV (mentioned in previous post). Satellite view at 10:10 am below also shows the MCV - this feature is moving northward.
Could not find any decent 500 mb analyses this morning - so am showing the plot of the 12 UTC data above. It appears to me that the center of the anticyclone has shifted into southeastern New Mexico and may be located between El Paso and Midland, Texas. Morning analyses have been corrupted by two bad soundings: The Chihuahua height is about 30 m too low (as per continuing problems there); and the height at Norman, Oklahoma, is so bizarrely bad that their data should never have been transmitted.
Here are yesterday and today morning soundings for TWC. Levels above 500 mb are more moist today, but CAPE has decreased significantly. Steering winds have become light south to southwest today, compared to yesterday's nice layer of easterlies. Hard to forecast what our morning sounding might look like by evening - difficult feature is layer from 700 to 500 mb, which is fairly unstable. Perhaps interaction with higher elevations will lead to mountain storms.
It's a hard call, and the WRF runs since midnight are indicating that eastern Pima County will likely be totally suppressed this evening and tonight (at bottom is 12 UTC WRF-RR forecast of rainfall through 5:00 am tomorrow morning).
Storms north of the Catalinas at 6:00 pm MST yesterday. Storms continued through the night; however, coverage was much less than it was on Saturday evening. There was thunder here at house around 3:00 am this early morning, but not a bit of rain.
Plot of CGs (above from Atmo and Vaisala) is for 24-hours ending at 5;00 am this morning. Purple plots are CG flashes detected in preceding 3 hours, showing the early morning activity in parts of eastern Pima County.
Shown above is portion of the ALERT network centered over downtown - illustrates the hit/miss nature of the storms last night. Decaying convection did leave behind a distinct Mesoscale Convective Vortex (MCV), which is centered east of Sells in the 8:30 am composite radar chart below.
View north from Kitt Peak this morning shows a dusty horizon after yesterdays winds blew local dust out that way. Here at house we had wind gusts of 50 to 60 mph with considerable blowing dust, during about a half hour period as a decaying storm moved across the metro area. the storm had tracked along I-10 from east of Benson and then spread northward as it came into the metro area.
Trace below is from Angel Otarola's weather station about 5 or 6 miles east of here. Note the temperature plunge of almost 35 F as storm's gust front passed. Wind gusts were not as strong at his place, BUT he had about 0.45" of rain. Here at house we had only 0.01" of rain.
Plot of CG flashes (above from Atmo and Vaisala) is for 24 hours ending at midnight last night. Rainfall for the 24 hours ending at 6:00 am MST this morning is below. Looks like amounts were better than here in all directions - so a very local donut hole.
Will things try to come together for a repeat tonight?
Meant to do a "today" post earlier, but time got away. When Katie and I left here for a walk at 6:00 am MST this morning my thermometer read 86 F - certainly not the "cool of the morning."
View from Atmo at about 2:40 pm (above) shows large buildup to the northeast of the Catalinas. Visible satellite image below (from 2:30 pm) shows that buildup, and that most current activity is along the Rim.
The 12 UTC 500 mb analysis (above from SPC) shows that the large anticyclone was centered a bit north of Albuquerque with max heights nearly 6000 m. Note that Chihuahua heights have been 30 to 40 m too low for months, and that they are still goofing up the NOAA NWS analyses.
The 12 UTC TWC sounding (below) featured two old, elevated BLs and at most a small amont of CAPE. Very substantial lifting required to get the lower layer to its LFC. I'll be surprised if any storms make it into lower elevations this evening - time will tell.
Middle level clouds over the Catalinas this morning at sunrise.
A small MCS developed over northern Sonora last evening (IR image above from 10:00 pm MST on the 10th), with some storms to its north along the borderlands. Plot of CG flashes detected for 24-hours ending at 2:30 am this early morning is below. Some thunderstorms were still active in the early morning hours. The storms did produce an outflow that moved north into the metro area around midnight. But this was a very weak feature by the time it reached Tucson - time series (second below) for Tubac seems to show that two distinct outflows occurred down there.
Precipitation amounts were quite light (below shows 24-hour rainfall reports from MesoWest at 6:00 am). A couple of sites west of Sierra Vista had amounts approaching half an inch, but most reports were around 0.20" or less. Definitely a so-so "event."
