News & Events

More Moderate Conditions Expected

Wednesday, August 26, 2009

Thursday's forecast: For the day Thursday, the cold front will stall out just south of the Mason-Dixon line. Most of the daywill be dry, with only a small chance for an afternoon thundershower. Cooler than Wednesday with highs in the lower 80s. Fine particulate may remain in the moderate range just owing to a lack of mixing, but ozone will fall back into the good range. *** Extended outlook: The weather forecast gets challenging in the Friday to Saturday time period. There will be two weather systems with the potential to affect us. One is tropical storm Danny just east of the Bahamas that will be moving northwestward and then eventually northward over the next several days. Further intensification of this storm is likely over the next two days. Some models take Danny very close to the Carolina coast by late Friday into Friday night, while others keep it out to sea further. The other system we have to watch is a cold front coming in from the Great Lakes. At this point, we will just say the weather will become unsettled with bouts of rain Friday into Saturday. Rain will obviously be heavier if Danny comes closer to us. Sunday, we could still have a good chance for showers as the Great Lakes cold front comes in. Cooler and drier air should then come in for the early part of next week. Overall air quality should be mainly good in the Friday to Sunday period, but if Danny stays further offshore and precipitation is lighter, we may remain in the moderate range for PM2.5, at least for Friday. All air quality should be good Saturday and Sunday as precipitation intensity increases along with increased mixing in the boundary layer.---McAuliffe

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.

Particle pollution (otherwise known as fine particulates or PM 2.5) is forecasted year round. Being of the photochemical nature, ozone is only forecasted during the summer months (generally from late April to mid September).

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