News & Events

Code Orange: Air Quality Action Day Forecast for Today, Wednesday Dec 14

Wednesday, December 14, 2011

Read the forecast here. An excerpt:

For Wednesday, mostly clear skies and a decrease in winds overnight will allow a strong temperature inversion to develop by early morning. High clouds will begin to move in later in the morning associated with an approaching warm front from a developing low pressure system over the Midwest. Light winds and a continuation in rising dew point temperatures that we have seen so far this week will help PM 2.5 levels to rise into low Code Orange range for the day. As we move into the warm sector of the frontal system, winds will continue to remain light but become more south/southeasterly. This will recirculate some of the already modified air that we had over the region on Tuesday before the increase in northwesterly winds. A light breeze after the inversion breaks will help with mixing of the lower atmosphere but PM 2.5 levels will be high enough both in the morning and late tomorrow evening to forecast low Code Orange. Forecast highs will be several degrees above normal as well, in the upper 40s to near 50 late in the day. Some isolated showers may develop with the warm front but should remain the west of the forecast region.