Phoenix Ozone Health Watch with More Triple Digit Heat

Staff Writer, DB Holmes

Weather / Air Quality
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As of 9am the Ozone concentration was reported at 67. That is the number forecast for tomorrow and we have already hit that mark this morning.

Ozone is definitely the big story this week. Concentrations have pushed into the middle to upper part of the Moderate range over the past 48 hours. Models suggest we could see one or two monitors approach the health standard on Friday. Thus, we are issuing an Ozone Health Watch for Friday. History shows that the day after such an event usually sees lower concentrations. PM10 levels continue to be mostly in the Good range with one or two local monitors (West 43rd and South Phoenix) in the lower Moderate range. Daytime highs will hold steady between 106-111°F Friday through next week as high pressure maintains its position to the south. We're watching the long-range models for an indication of when the monsoon shift may occur. We are starting to see some signs of high pressure migrating north near the Four Corners around the 16th to the 21st of June. Thunderstorm activity may begin to pop up in Arizona's mountains around that time, but wide-spread moisture will likely hold off until the end of June.

For those individuals with respiratory issues, please limit outdoor exposure and stay in filtered air.

As the temperatures suggest, there is no end insight for triple digit heat, ozone production, or the monsoon. 

Source: AIRNow, Weather Channel

Excessive Heat, Summer Sun, No Dust

Staff Writer, DB Holmes

Weather / Air Quality
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It is going to be a scorcher for the first week in June. An Excessive Heat Warning is out especially for tomorrow's 112F. No high winds or dust storms likely. No break from the summer heat as temperatures stay above 105F.

Today's Air Quality

Forecast Discussion: The Phoenix-area air quality was again in the Good range for all pollutants on Saturday. The approach of a trough of low pressure from the northwest has helped to clear the air by providing some good mixing. High pressure to the southeast will hold its position this week, keeping that trough to the north of Arizona as it slowly advances east this week. Daytime highs across the Valley may reach 110°F on Monday, shaving a degree or two through the week, and eventually "cooling" to 105°F. Expect ozone levels to push back into the lower Moderate range by Monday and Tuesday under sunny skies. Particulates should hold in the upper part of the Good range. We do not anticipate any significant dust events this week.

Source: AIRNow, Weather, 

Triple Digit Yo-Yo Heat Ready for Action

Staff Writer, DB Holmes

Weather / Air Quality
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Hot and somewhat dry. Dew points have been in the 40's while humidity has been averaging in the 30-40% range. Desert heat comes and goes this week but only showing how this summer will be: hot. Just hot.

Memorial Day's Air Quality

Forecast Discussion: A salute to the veterans who gave their lives serving our county - Happy Memorial Day! Air quality conditions have fared pretty well in recent days. The modeled forecast of possible dust outflow from storms southwest of the Valley on Friday did verify with storm development, but did not result in dust. In fact local PM10 levels are in the middle Good range. With high pressure surging over Arizona Monday through Wednesday, winds should remain mostly light, keeping the threat of dust out of the picture. Ozone concentrations, however, may remain in the middle Moderate range much of the week under sunny skies. Daytime temperatures in Phoenix will range from 105-108°F Monday through Wednesday.

May 2014

24th-27th. Changeable skies: mixed cloud, sun, possible shower. Cool temperatures.
28th-31st. Possible showers again.

June 2014

1st-3rd. Changeable skies: mixed clouds, sun. Risk of a shower.
4th-7th. Varying amounts of clouds, sun. Dry.


Source: AIRNow, Weather Channel, Farmer's Almanac  

Do You Want a Dust Storm with Dinner?

Staff Writer, DB Holmes

Weather / Air Quality
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The start of the weekend looks good but there is the possibility of a dust storm from dry thunderstorms coming in from the west and southwest. Then Phoenix will be headed into the triple digits once again. A tropical storm is ramping up in the southwestern waters off Mexico. What will happen? Nothing so far in the forecast seems to indicate any problems from this tropical depression as it strengthens.

Still for those people with respiratory problems, stay inside with filtered air at any signs of dusty air.

Forecast Discussion: The lingering area of low pressure to the west finally opens up and and catches a ride on the main jet stream over the weekend. Before this happens, however, Arizona will see an influx of moisture into the eastern half of the state. Models also show possible dry thunderstorms developing in southwestern Arizona Friday afterno

Saturday's Air Quality Forecast

on near Yuma and Gila Bend. The outflow could generate some dust moving in all directions. The first PM10 monitor that would impacted in the Valley would be the Buckeye monitor. Models have the wind field (and possible dust) moving east across the Valley between 6 and 8 pm. This is the second consecutive day the models have had this solution. We have raised the PM10 forecast to reflect this possibility. Ozone levels may also increase on Saturday in response to Friday's outflow. The same model shows possible thunderstorm outflow moving south from Prescott into north Phoenix Saturday afternoon on the back side of the eastward-moving low pressure system. This would potentially affect the Surprise/Dysart/Sun City/north Peoria area the most. It's going to be a very active, interesting couple of days weather-wise which increase air quality uncertainty.

Source: AIRNow, Weather Channel 

Rain? You Don't Say

Staff Writer, DB Holmes

Weather / Air Quality
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Tomorrow the Valley of the Sun has a 30% chance of rain.

Forecast Discussion: Low pressure to the west will spin in place through much of the week. The southwest-to-northeast flow will keep the potential ozone and precursor train from southern California moving into Arizona. The good news is that smoke from southern California wildfires won't be much of an influence as crews have mostly subdued them. Local ozone levels continue to decrease steadily with highest levels in the lower Moderate range. With the churning trough of low pressure to the west, Arizona can expect gusty winds Tuesday and Wednesday. This could cause localized pockets of dust in the vicinity of recently disturbed soil. Overall maximum PM10 levels, however, should remain mostly in the Good range. Conditions improve Thursday as winds decrease.

Source: AIRNow, Weather Channel, 

Instant Summer, Just Add Heat and Ozone

Staff Writer, DB Holmes
Weather / Air Quality
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The heat gives us a break at the mid part of the week and then slowly builds back in as a cut off low spins away. For respiratory issues sufferers, the ozone has replaced dust and particulates in causing breathing difficulties. The ozone should return to a more normal range for this time of the year as clouds and cooler weather enter the picture this week.

May 19 Air Quality Forecast

Forecast Discussion: If the triple-digit heat came a little too early for you (104°F at Sky Harbor Friday and Saturday), take heart. Temperatures will "cool" to around 90°F by Wednesday as a trough of low pressure moves over Arizona. This trough will actually become cut off from the main flow, sitting over our area through next weekend as it eventually spins out and loses energy. This could eventually be good as far as wildfires go. Towards the end of the week, the low is expected to draw some moisture from the Gulf of Mexico into eastern Arizona. The mountains could see some showers next Saturday and Sunday. Regardless of the rain, the increased humidity should help reduce fire behavior. Ozone is the current topic of conversation. Yuma exceeded the 8-hour ozone health standard on Friday. Typically we'll see levels do the same in the Valley a day later. However, we were spared as the flow was more to the north-northeast rather than east-northeast. Unfortunately, Alamo Lake, Prescott, and Flagstaff all exceeded the standard on Saturday. Exceeding the ozone standard in those non-major-metropolitan areas is a classic case of ozone import from the west. Let's not forget that smoke from southern California may have played a role in enhancing the ozone development upstream. Looking forward, high clouds Sunday should keep ozone production down slightly. This may be just enough help to avoid exceeding the standard in Valley. Stronger winds develop Monday through Wednesday which should also help break up the invisible plume, decreasing the threat of elevated readings. Dust doesn't seem to be much of a concern for us this week, especially when moisture is drawn in later in the week.

Source: AIRNow, Weather Channel,

Ozone Concern and Triple Digit Heat for the Desert Valley

Staff Writer, DB Holmes

Weather / Air Quality
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Phoenix should have a quiet weather weekend as winds are subdued and temperatures remain hot. Ozone rose but now the westerly winds will pick up the smoke from the California wildfires. People with respiratory issues should take note.

Here is the rest of the forecast:

Forecast Discussion: Ozone levels soared into the upper Moderate range across the forecast area on Thursday, and that was without the help of southern California wildfire smoke. Now that the flow has switched out of the west, the likelihood of smoke-enhanced ozone affecting Arizona increases. In fact, locations north of the Valley (Prescott, Flagstaff) could see elevated concentrations the next several days. Locally, Valley concentrations will remain in the upper part of the Moderate range through Sunday. Winds will increase Sunday afternoon as another trough of low pressure approaches the region. This should break up the invisible daily plume of ozone, effectively lowering concentrations. PM10 levels should also remain in the Good range the next several days, increasing Sunday through early next week with stronger winds. Expect daytime temperatures to reach 102-104°F Friday through Sunday, decreasing Monday. Unfortunately, no rain is in the forecast for at least another 2 weeks.

Source: AIRNow 

Windy, Dry Conditions May Create Another Dust Event

Staff Writer, DB Holmes
Weather / Air Quality
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When will this wind end? Not for the next 48 hours or so. Phoenix can expect windy conditions to persist with PM 10 and 2.5 particles being kicked up again.

Forecast Discussion: What an impressive dust event we saw Sunday morning. Contrary to some media reports out there, this was not a localized event. This was not a "dust storm". This was not isolated to Arizona. A large trough of low pressure moved through the western U.S. The leading edge of the cold front churned up an impressive amount of dust extending from the desert valleys of California and Nevada, through Baja, and finally northeast through Arizona and New Mexico. Looking at concentrations from monitors to the west, California was hit hard with dust first on Saturday morning. Around 10pm Saturday night, it was Las Vegas that got hit. Yuma saw concentrations spike around midnight. Then dust moved into the Phoenix area around 2 am on Sunday. The cold front continued east through the early morning hours, and by 11 am, levels and visibility improved significantly. About the same time our air cleared, Albuquerque, NM got slammed. This was a major dust event that could not be prevented on a local level no matter what control measures were in place. Nature vs. Man, and Nature won easily. As of 10am Monday morning, Phoenix-area PM10 levels are back in the Good range. Looking ahead, high pressure will move overhead this week, pushing daytime into the triple digits by Wednesday and Thursday. Unfortunately, we may see some more dust on Wednesday, this time from the east. Concentrations, however, should not result in an exceedance here in the Valley. Expect ozone levels to increase as well under sunny skies. The northeast and east winds could trap ozone and precursors in the Valley by mid-week, sending levels well into the Moderate range.

Anyone with respiratory issues may want to wear a mask or stay indoors with a good air filter. 

Source: AIRNow 

Dusty, Unhealthy Air Quality from the Baja to Four Corners Region

Staff Writer, DB Holmes

Weather / Air Quality 
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A windy day across the state of Arizona. Dusty, unhealthy, and opaque air led to exceeding the air quality standards. This morning as dawn rose the air looked like fog. Upon smelling the air, one knew something was not right with the air.

Today's Unheathly Air

Forecast Discussion: Another dry cold front is currently marching through Arizona. Stronger winds along and ahead of the cold front have kicked up an impressive plume of dust, stretching from the northern Gulf of California to the Four-Corners region! The dust is being carried west to east with the western extent now entering Maricopa County. Overall, the dust plume now seems to be dissipating. Visibility has improved compared to early morning readings, but additional dust is still possible today under gusty winds this afternoon. The large amount of long-range dust transport overnight from the lower deserts of southeastern California and Arizona have pushed PM-10 readings into the Unhealthy category. Very high hourly average PM-10 concentrations this morning will likely result in exceedances of the federal standard at multiple monitors today. People should consider limiting outdoor physical activity due to unhealthy air quality. For tomorrow and Tuesday, breezy conditions persist, especially on Tuesday, but the direction turns more northeasterly allowing PM concentrations to fall into the upper Good to lower Moderate category. As the disturbance clears the area, ozone will drop with levels remaining near or slightly above Moderate thresholds. Clear skies and high temps in the mid 80s to lower 90s are expected.

Weather Conditions for this week:

More wind on Tuesday and a chance of sprinkles at the start of next week. A gradual increase in temperatures until triple digits dominate the long range forecast until September.

Source: AIRNow, Weather Channel

Is it Summer Yet?

Staff Writer, DB Holmes

Weather / Air Quality

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The triple digits are not far away but have been postponed for another few days. Air quality will improve as the wind subsides.

Today's Air Quality Forecast

The cold front responsible for kicking up winds and dust yesterday has cleared the state. All monitors yesterday recorded PM readings in the Moderate category. Elevated readings and some haze are still noticeable this morning, but breezy winds by afternoon will help disperse dust. Also, enough moisture and instability exists for light showers to develop over the higher terrain north and east of Phoenix during the afternoon. A cooler air mass has moved in and high temperatures in the upper 70s today are about 10 to 15 degrees below normal for early May. Temps will be somewhat slow to recover as Arizona remains under the influence of a broad area of troughing. Air quality improves by tomorrow, but ozone will continue to range in the upper Good to lower Moderate categories.

Source: AIRNOW,  Weather Channel,

Giant Frogs, Giant Frogs, That's the Weather, Back to You

Staff Writer, DB Holmes

Weather / Air Quality

______________________________________

The heat is on right after a tiny three day vacation full of wind and potential dust. Is this the last gasp of spring weather making its way into the desert forecast? Or will the Valley of the Sun see more unsettled weather until Monsoon season begins? 

May 2014 Forecast for the Southwestern Region of the United States:

4th-7th. A few widely scattered showers.
8th-11th. Drier with some sunshine.
12th-15th. Clouds increase, turning warmer California, points east.
16th-19th. Fair, warmer.
20th-23rd. Scattered showers.
24th-27th. Changeable skies: mixed cloud, sun, possible shower. Cool temperatures.
28th-31st. Possible showers again.

The weather appears to be unstable with unseasonably low or high temperatures and storms that have moisture but leave Phoenix high and dry. Pretty soon, the forecast will call for giant frogs. Could the solar minimum be the cause of such erratic behavior in our weather patterns?

Forecast Discussion: Our hot and quiet weather this weekend will abruptly end early this week when the current ridge of high-pressure over the western U.S. flattens and is eventually replaced by a mid to upper-level trough of low-pressure. Generally, temps will go down, while southwesterly winds increase, peaking on Tuesday. Afternoon breezes up to 15 mph are expected to begin today and Monday. On Tuesday, widespread blowing dust across the Phoenix Metropolitan area is becoming more probable as models advertise sustained winds up to 25 mph with higher gusts. PM levels could reach the middle to upper Moderate range, but this may need to be adjusted higher depending on tomorrow’s model runs and how the storm is developing. An Air Pollution Health Watch for elevated PM-10 levels may be required for Tuesday (stay tuned). Ozone is also expected to reach the middle to upper Moderate range Monday and Tuesday as the storm imports precursors, but should fall back into the Good range in the wake of the storm’s passage. No precipitation is anticipated for the lower deserts, but high temps by Tuesday will be much cooler in the 80s. Enjoy the rest of the weekend and check back tomorrow for an updated forecast concerning the possible dust event on Tuesday!

The temperature forecast:

Last Year on this date:

High Temp:	94.1F
Low Temp:	66.6F
Average Temp:	80.1F
Dewpoint:	27.2F
Wind Speed:	6.8 Knots

Source: AIRNow, Weather Channel, Farmer's Almanac 

Triple Digits, Santa Ana, and Blowing Dust

Staff Writer, Nathaniel Diaz

Weather / Air Quality
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Triple digits will hit this weekend as a high pressure system comes over the Southwest, including Southern California which will bring Santa Ana conditions. Wind will lessen as the temperatures go higher but with another low pressure system on its way, windy conditions will return by the start of the week.

Forecast Discussion: After a windy past few days, much quieter weather is expected through the upcoming weekend due to a ridge of high pressure moving over the region. PM-10 levels across the Phoenix area were up into the Moderate category, but have since returned to the Good range as yesterday’s haze has cleared out and winds have calmed. Currently, most of the observation network is reporting Good pollutant levels. We are not expecting too much fluctuation in these readings besides an increase in ozone under increasingly west to southwest flow. The bigger story will be hot high temperatures nearing 100ºF for both Saturday and Sunday. Looking ahead, an early week storm system could cause blowing dust issues on Tuesday along with a 15 degree cool down in high temperatures. More on this potential dust event with the next forecast update.

Source: AIRNow, Weather Channel 

Hold onto Your Hats, It's Going to be a Windy Ride

Staff Writer, DB Holmes

Weather / Air Quality
____________________________________

Wind, wind, and more wind... is this Arizona? Triple digits this weekend could end that debate. So get out the pool supplies and water launchers, summer is here, even for just the weekend.

Forecast Discussion: Strong, gusty northerly winds will continue through midday Thursday as high pressure to the west is fighting to push the trough to the east of Arizona out of the way. That trough will pick up anchor on Thursday allowing the west coast ridge of high pressure to move over Arizona by Friday. Much lighter winds are expected Friday through the weekend under sunny skies. Daytime highs will also reach the middle to upper 90s on Saturday and Sunday. The air quality will also improve the next few days. Particulates have been held nicely in the Good range of the Air Quality Index (AQI) the past couple days due to northerly winds. Ozone, however, has pushed into the middle Moderate range at multiple Valley locations. Concentrations are starting lower this morning and we should see maximum ozone levels back in the Good range perhaps by today, but most likely by Thursday.

The weather forecast for the next week: 

Source: AIRNow, Weather Channel