High Ozone, SRM, and the Monsoon

Staff Writer, Nathaniel Diaz

Weather / Monsoon 
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The Sonoran Desert is alive with Health Watches for the high ozone as well as the high temperatures. Since we had such a cool May, June has made up for it in the first half of the month so far. The heat drives our monsoon flow. So the hotter the desert floor: the better our rain chances in the coming months.

Solar Radiation Management has been deployed since there are chances for a sprinkle this week with some monsoon action to our south. March 2016 was a horrible month for climate engineering. There was not a day empty of the toxins. April saw some action. May was devoid of most geoengineering. With rain chances back in the forecast, toxic lines in the sky have reemerged. 

Here is the Ozone and weather forecast from AirNOW:

Forecast Discussion: The Humboldt Mountain Monitor located northeast of the Valley recorded an exceedance of the federal health standard yesterday. Here in the Valley, several monitors reached Health Watch (HW) criteria. As for today and tomorrow, even more stable conditions than yesterday will likely result in more ozone accumulation. Therefore, we have an ozone High Pollution Advisory (HPA) in effect through tomorrow (Wednesday). Currently it looks like there will be some improvement on Thursday with ozone levels expected to stay slightly below HPA levels. However, we do anticipate a Health Watch will still need to be issued for Thursday. PM-2.5 has been hovering in the upper Good range the last several days and we don't expect that to change. There are several large wildfires throughout the state, but no significant impacts are expected here in the Valley. PM-10 has thrown a slight curveball today. Local activity near the West Chandler monitor this morning has resulted in elevated concentrations. As a result, PM-10 at that monitor will likely end up near the mid-Moderates for today. Given the localized nature of the elevated PM-10 levels, we will not make a last minute adjustment to today's forecast. As for Thursday, thunderstorms in southern Arizona could create outflows that cause gusty winds here in the Phoenix area, potentially kicking up dust. However, at the moment, our confidence in the strength of the outflows reaching the Valley is not very high. Therefore, for now we will keep PM-10 in the Good range and re-evaluate the situation tomorrow.

So be careful out there.


Source: AirNOW   

On Again, Off Again, the Monsoon is a Fickle Creature

Staff Writer, DL Mullan

Weather / Air Quality
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The monsoon will take a break in the western part of the state and bring with it hotter temperatures. Tuesday through Thursday will begin this on and off pattern. The coming weekend will see a return of storm chances and air quality concerns with dust storm formation.

Until then, keep your oven mittens in the car, July is not over and August is setting up to be as hot as ever.

Forecast Discussion: It has been an active few days now on the weather front! It started with the unusually large dust event that affected portions of Mexico on Thursday. This was likely caused by what is called a Mesoscale Convective System. This dust then moved northward into Arizona Thursday and Friday with a moisture surge. A pronounced haze was widespread. As a result PM-10 and PM-2.5 were already elevated before significant thunderstorm activity and multiple outlfows triggered a dust storm that impacted much of the Valley during the early evening on Friday. Ultimately, six Maricopa County monitors exceeded the PM-10 health standard. Then another round of strong winds, locally heavy rainfall, and blowing dust struck the Phoenix Metropolitan late last night into the early morning hours. This would account for the lingering haze seen today along with higher current PM readings. We remain in an unstable environment. Models are consistent in showing thunderstorms forming once again over the higher terrain. These then move westward under east-southeasterly steering winds into the Phoenix area during the early evening. Stronger outflows dropping out the higher terrain from the north and east versus the south will help limit the dust threat, but localized blowing dust is still possible. The steering flow is then expected to turn southwesterly by Monday, which is unfavorable for bringing convection into the Valley. Generally, ozone readings are running lower than this time yesterday, likely to due to this morning's cloud cover and the clearing winds from last night. We expect ozone to stay around the lower Moderate range through Tuesday.

North looking toward the Estrella Mountains

Source: AIRNow, Visibility Cameras,

Spring into Summer, Phoenix is Dry and Hot

Staff Writer, DB Holmes

Weather / Meteorology
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It is that time of the year again when temperatures rise as well as ozone concentrations. The rainless wind episodes have helped further dry out the deserts. Potential for blowing dust is still relevant as breezy conditions come into the Valley this weekend with windy conditions set up for the middle of next week.

Forecast Discussion: The official high in Phoenix on Wednesday was 95°F. As expected, we saw ozone concentrations go up around the forecast area under the light, west-to-east flow. The baseline for Thursday is higher, so it’s likely that levels will go higher as well under sunny skies and relatively light winds. An approaching upper-level system could boost levels further on Friday into the middle Moderate range before dropping off Saturday with increased surface breezes and atmospheric mixing. PM10 levels also bounced higher, into the lower Moderate range on Wednesday. The South Phoenix and West 43rd Avenue monitors registered 53 and 55 AQI, respectively. Buckeye was not far behind at 50 AQI. This is a testament to how dry the soil has become, and long-range models suggest there will be no rain expected over the next 2 weeks. We don’t anticipate any significant blowing dust this weekend, but it’s possible to see some pockets along the desert floor between Phoenix and southern California Saturday into early Sunday. Daytime temperatures are forecast to drop into the upper 80s, close to 90°F on Saturday and Sunday, warming slightly once again by Monday.

Source: AIRNow