News & Events

Wednesday, June 20 is an Air Quality Action Day (CODE ORANGE)

Tuesday, June 19, 2012

Ozone levels are expected to reach highs unhealthy for sensitive groups on Wednesday.

Current Conditions as of 2 PM on Tuesday: The cloud cover overhead from the morning hours is gradually diminishing, leading to increasing sunshine and temperatures climbing through the 70s. The clearing is setting the stage for a change in the weather pattern for the next few days.

A developing ridge of high pressure will bring temperatures in the 90s, high humidity to force dew point temperatures likely into the low 70s, and a short duration of possible Code Orange Ozone levels to the region before a frontal passage by the weekend.

Wednesday’s Forecast: Hazy, Hot, and Humid are the only words needed to describe the weather we are transitioning into for the second half of this week. Mostly sunny skies on Wednesday will lead to a quick rise in temperatures to likely the warmest levels we have seen so far in 2012. Highs are expected to reach the mid 90s. Increasing surface moisture will also drive up dew point temperatures into the low 70s. The combination of the high moisture and afternoon temperatures should drive the heat index quite close to the 100 degree mark! Winds will be light and mostly westerly throughout the day. This westerly transport with sunny skies will enhance Ozone formation to drive concentrations to high moderate and even some Code Orange level readings. There is a possibility that some cloud development could occur during peak heating hours, but skies should remain relatively clear enough to allow Ozone formation to reach these levels. Also rising with the high moisture and westerly transport will be PM 2.5 levels. PM 2.5 will climb into the moderate range, though Ozone will be the primary pollutant of concern.

Extended Forecast: Similar conditions will continue on Thursday with temperatures reaching the mid to upper 90s and the potential for Code Orange Ozone concentrations existing once again. PM 2.5 levels will remain in the moderate range with high moisture/humidity levels persisting. There might be a slightly increased chance for some afternoon cloud development that could hinder just how high Ozone levels climb. Currently, Code Orange levels for Ozone yet again remain a viable possibility. The arrival of a frontal passage on Friday currently yields the greatest uncertainty for the forecast period. The timing of this front and any associated showers/clouds will greatly impact the forecast for Friday. A slow arriving system could allow Ozone levels to again climb at least to the moderate range. Temperatures would also then potentially climb into the 90s once again. A faster arriving system could create improving air quality conditions with increasing clouds for the early portion of the day, then a cleaner air mass moving in behind the front late in the day. PM 2.5 levels could remain at least in the moderate range until late Friday under either scenario. A change in the weather pattern again for the weekend after the frontal system shifts off to our east will provide a return in closer to normal temperatures for the weekend. Cooler than normal weather with good air quality conditions could move in for next week, which could feel quite cold compared to the heat we are about to see for the next few days.

The Lehigh Valley/Berks County Air Quality Partnership encourages residents to consider using public transit or other forms of alternative transportation on all Air Quality Action Days.

Days when ozone levels are expected to be high:

* Conserve electricity and set your air conditioner at a higher temperature.
* Choose a cleaner commute—share a ride to work or use public transportation. Bicycle or walk to errands when possible.
* Refuel cars and trucks after dusk.
* Combine errands and reduce trips.
* Limit engine idling.
* Use household, workshop, and garden chemicals in ways that keep evaporation to a minimum, or try to delay using them when poor air quality is forecast.

Days when particle pollution levels are expected to be high:

* Reduce or eliminate fireplace and wood stove use.
* Avoid using gas-powered lawn and garden equipment.
* Avoid burning leaves, trash and other materials.

This forecast is brought to you by the Pennsylvania Department of Environmental Protection (PA DEP) and the Air Quality Partnership of the Lehigh Valley - Berks Area.

* For more information on the health effects of PM 2.5 and ozone, visit the EPA Airnow website.
* To see the current forecast and monitoring information for the Lehigh Valley / Berks Area, visit the PA DEP Forecast and Monitoring Site.
* To find out more information about the Air Quality Partnership of the Lehigh Valley - Berks Area, visit