Sunday, July 22, 2007

HGB Area


Maximum 1-hr Ozone (ppb)

Maximum 8-hr Ozone (ppb)


96 C570


Statistical Model

110 (121)


Human Forecast



Acutal (Observed)

76 C617




Today is the first day in a month that we may see ozone exceed the standard. The mostly north wind in the
morning and partly cloudy sky are favorable for ozone build-up. The statistical model does not give a number
more than 120 ppb (the old 1-hr standard) - we believe is due to the wind persistency in the forecast. If
wind continues to blow in the same direction, the ozone and precursors are unlikely to stay in a small area,
hence less likelyhood for high ozone. However, the seabreaze strength may be stronger than forecasted
therefore a higher ozone. The high ozone is likely to be in SE Houston, such as Seabrook or Friendswood.

The error for this forecast is about 20 ppb. The wind and cloud contribute to the uncertainties.

Yesterday's persistent SE wind blew pollutants toward NW - the high of 71 ppb is at Meyer Park at NW
Houston. Model and human forecast did very well.

7/22/2007 8:27:29 AM